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Selected publications (15-12-2009)

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Memory in Pigeons and baboons

  • Fagot, J. & Thompson, RKR. & Parron, C. (2010). How to read a picture : Lessons from nonhuman primates. Proceedings of the National Academy of Sciences of the USA (PNAS), 107, 519-520 (PDF) 
  • Fagot, J. & Cook, R. (2006). Evidence for large long-term memory capacities in baboons and pigeons and its implications for learning and the evolution of cognition. Proceedings of the National Academy of Sciences of the USA (PNAS), 103, 17564-17567. ABSTRACT. Previous research has shown that birds and primates have a rich repertoire of behavioral and cognitive skills, but the mechanisms underlying these abilities are not well understood. A common hypothesis is that these adaptations are mediated by an efficient long-term memory, allowing animals to remember specific external events and associate appropriate behaviors to these events. Because earlier studies have not sufficiently challenged memory capacity in animals, our comparative research examined with equivalent procedures the size and mechanisms of long-term memory in baboons and pigeons. Findings revealed very large, but different, capacities in both species to learn and remember picture–response associations. Pigeons could maximally memorize between 800 and 1,200 picture–response associations before reaching the limit of their performance. In contrast, baboons minimally memorized 3,500–5,000 items and had not reached their limit after more than 3 years of testing. No differences were detected in how these associations were retained or otherwise processed by these species. These results demonstrate that pigeons and monkeys have sufficient memory resources to develop memory-based exemplar or feature learning strategies in many test situations. They further suggest that the evolution of cognition and behavior importantly may have involved the gradual enlargement of the long-term memory capacities of the brain. (PDF)
  • Cook, R. & Fagot, J.(2009). First trial rewards promote 1-trial learning and prolonged memory in pigeon and baboon. Proceedings of the National Academy of Sciences of the USA (PNAS), published online before print May 26, 2009, doi:10.1073/pnas.0903378106. ABSTRACT. There is a long-standing debate in educational settings on the influence of positive and negative consequences on learning. Although positive rewards seem desirable from an ethical perspective, 1-trial learning has been best demonstrated in the animal literature with tasks using highly salient negative consequences, such as shock or illness, and so far only in tasks requiring the acquisition of a singular stimulus-response association. Here we show that pigeons and baboons can concurrently learn, in a cognitively challenging memorization task, hundreds of pictureresponse associations after a single exposure and that this rapid learning is better promoted by a positive outcome after the first picture presentation. Further, the early positive outcomes had beneficial effects on the memory of learned acquisitions that was detectable up to 6–8 months after initial training. Beyond their significance for educational policies, these findings suggest that the psychological and brain mechanisms controlling rapid, often 1-trial, learning have a long evolutionary history. They may represent the phylogenetic precursor for the disproportionate impact of first impressions in humans and the phenomenon of fast word learning in children (PDF). 

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Comparative cognition

  • Vauclair, J. & Fagot, J. (1996). Categorization of Alphanumeric Characters by baboons (Papio papio) : Within and between class stimulus discrimination. Current Psychology of Cognition, 15, 449-462. ABSTRACT : Using a video-task requiring the manipulation of a joystick, we explored how baboons categorize alphanumeric characters displayed in various typefaces. Two baboons were trained in a symbolic matching-to-sample task with 21 different fonts of the characters "B" and "3" as sample forms, and colour squares as comparison forms. After training, there was a positive transfer of performance to novel fonts (Experiment 1). This transfer relied on the use of categorical procedures, because an identity maching-to-sample task showed accurate discrimination between exemplars belonging to the same category (Experiment 2) PDF
  • Fagot, J., Kruschke, J.K., Dépy, D. & Vauclair, J. (1998). Associative learning in baboons (Papio papio) and humans (Homo sapiens) : Species differences in learned attention to visual features. Animal Cognition, 1, 123-133. ABSTRACT. We examined attention shifting in baboons and humans during the learning of visual categories. Within a conditional matching-to-sample task, participants of the two species sequentially learned two two-feature categories which shared a common feature. Results showed that humans encoded both features of the initially learned category, but predominantly only the distinctive feature of the subsequently learned category. Although baboons initially encoded both features of the first category, they ultimately retained only the distinctive features of each category. Empirical data from the two species were analyzed with the ADIT connectionist model (Kruschke, 1996a). ADIT fits the baboon data when it has an attentional shift rate of zero, and fits the human data with a non-zero attentional shift rate. These empirical and modeling results suggest species differences in learned attention to visual features. PDF
  • Vauclair, J., Fagot, J., & Hopkins, W.D. (1993). Rotation of Mental Images in Baboons when the Visual Input is Directed to the Left Cerebral Hemisphere. Psychological Science, 4, 2, 99-103. ABSTRACT : The mental rotation phenomenon was examined in baboons and humans using a video formatted matching-to-sample task. Sample stimuli were presented either centrally, or in the right or left visual half-field. Immediately afterwards, subjects had to identify the previously presented sample stimulus from its mirror-image after both had been rotated to the same angular deviation. A mental rotation phenomenon was found in baboons and humans but in baboons this effect was limited to conditions where visual input was directed to the right visual half-field. These data represent the first evidence of mental rotation in a nonhuman species. PDF
  • Hopkins, W.D., Fagot, J. & Vauclair, J. Mirror-Image Matching and Mental Rotation Problem Solving by Baboons (Papio papio) : Unilateral Input Enhances Performance (1993). Journal of Experimental Psychology : General, 112, 1, 61-72. ABSTRACT : Three experiments, using a matching-to-sample procedure, were conducted examining mirror-image matching and mental rotation in three baboons (Papio papio). In Experiments 1 and 2, target stimuli were presented for 100 msec. in duration to either the left (LVF) or right visual half-field (RVF). The results of Experiment 1 indicated no significant difference in performance between asymmetric patterns and mirror-image stimuli. Experiment 2 examined the affect of stimulus orientation on matching. For asymmetric patterns, RVF accuracy increased with repeated testing. In contrast, RVF accuracy decreased for mirror-image stimuli with repeated testing. Despite high accuracy for both stimulus sets, no significant linear trend was found between response time and increased angular disparity (0 to 180 ). Experiment 3 assessed the affect of bilateral visual input on accuracy and response time. Results indicated lower accuracy and longer response times under conditions of bilateral input contrasted with unilateral. Overall, these data (a) indicate that baboons can solve mirror-image matching and mental rotation problems and (b) emphasis the importance of unilateral stimulus presentation in solving these types of problems. PDF
  • Dépy, D. , Fagot, J. & Vauclair, J. (1997). Categorisation of Three-Dimensional Stimuli by Humans and Baboons : Search for Prototype Effects. Behavioral Processes, 39, 299-306. ABSTRACT : A symbolic matching-to-sample procedure was adopted to investigate whether humans (n=2) and baboons (n=2) discriminate more accurately the prototypes of polymorphous categories than less typical exemplars. Subjects were initially trained to discriminate between two categories of stimuli defined by the possession of any two out of three possible binary features. In transfer, prototypes, which contained all the three feature values of their categories, and novel two-out-of-three feature exemplars were presented for discrimination. Humans solved the task in a propositional way, and showed no evidence for a better performance with the prototypes than with other exemplars. By contrast, monkeys classified the prototypes more accurately than the other examplars. The analysis of training performance showed, however, that their discriminations did not involve prototypical representations of the categories, but rather depended upon feature-response associations. It is argued that monkeys’better performance with the prototypes rested on peak shift and/or novelty effects.
  • Fagot, J., Deruelle, C. (1997) Processing of Global and Local Visual Information and Hemispheric Specialization in Humans (Homo sapiens) and Baboons (Papio papio). Journal of Experimental Psychology : Human Perception and Performance , 23, 429-442. ABSTRACT : Global precedence and hemispheric specialization were examined in baboons (n=8) and humans (n=14) using a video-formatted matching-to-sample task. Compound sample stimuli, such as a large square made of smaller circles, were displayed in the left (LVF) or right (RVF) visual half-field. Thereafter, two forms were presented, one matching the sample at the global or local level, the other being neutral. By manipulating a joystick, subjects had then to select the form matching the sample. Experiments 1-2 showed in humans a global advantage in scores and response times, and a global-to-local interference. In baboons, a local advantage was observed, and the global-to-local interference did not occur. For the two species, a LVF (right hemisphere) advantage was found for global matching, and a reversed but not significant RVF (left hemisphere) advantage occurred for local matching (Experiment 2). Global processing in monkeys was not facilitated when local elements were connected by lines (Experiment 3) or were adjacent (Experiment 4). Moreover, global precedence persisted in humans with unfamiliar forms (Experiment 5), showing that the familiarity factor did not account for the findings. Overall, species differences suggest that (1) global precedence is not a universal trait, and (2) that this effect in humans does not have purely perceptual or sensory bases. PDF 
     
  • Deruelle, C. & Fagot, J. (1998). Visual search for global/local stimulus features in humans and baboons. Psychonomic Bulletin & Review, 5, 476-481. ABSTRACT : Fagot and Deruelle (1997) demonstrated that, when tested with identical visual stimuli, baboons exhibit an advantage in processing local features, whereas humans show the "global precedence" effect initially reported by Navon (1977). The present experiments investigated the cause of this species difference. Humans and baboons performed a visual search task, in which the target differed from the distractors at either the global or the local level. Humans responded more quickly to global than to local targets, whereas baboons did the opposite (Experiment 1). Human response times (RTs) were independent of display size, both for local and global processing. Baboon RTs increased linearly with display size, more so for global than for local processing. The search slope for baboons disappeared for continuous targets (Experiment 2). That effect was not due to variations in stimulus luminance (Experiment 3). Finally, variations in stimulus density affected global search slopes in baboons but not in humans (Experiment 4). Overall, results suggest that perceptual grouping operations involved during the processing of hierarchical stimuli are attention demanding for baboons, but not for humans. PDF
  • Fagot, J. & M. Tomonaga (1998). Global-Local Processing in Humans (Homo sapiens) and Chimpanzees (Pan troglodytes) : Use of a Visual Search Task with Compound Stimuli. Journal of Comparative Psychology, 113, 3-12. ABSTRACT : When tested with identical compound stimuli, baboons primarily process the local aspects of the forms while humans process primarily their global shape (Fagot & Deruelle, 1997). Four experiments were conducted to assess the processing of such forms in the chimpanzee, a closer human-related species. In Experiment 1, humans and chimpanzees were tested with compound stimuli presented in a visual search task. Results demonstrated a speed advantage to process the global-stimulus level in humans, and no advantage for either level in chimpanzees. Experiment 2 manipulated the global size and the density of the local elements. Humans showed an overall advantage to process the global shape. Chimpanzees showed a speed advantage to process the local shape in the low density condition, but no advantage in the dense conditions. In Experiment 3, local elements were either disconnected or connected by line segments. Chimpanzees showed a global advantage with connected stimuli, and a local advantage with the disconnected ones. Species differences in perceptual grouping may account for the results. Moreover, data from baboons, chimpanzees and humans suggest a phylogenetic trend in the way compound stimuli are processed. 
     
  • Dépy, D., Fagot, J. & Vauclair, J. (1999). Catégorisation d’objets visuels : Données comparatives et processus cognitifs chez le singe et l’homme. In Gervet J & Pratte M (Ed.s). Elements d’éthologie cognitive : Du déterminisme biologique au fonctionnement cognitif. (pp 325-341). Paris : Hermes Science Publications. 
     
  • Dépy, D., Fagot, J. & Vauclair, J. (1999). Processing of above-below categorical relation by baboons (Papio papio). Behavioural Processes, 48, 1-9. ABSTRACT Three video-formatted experiments investigated the categorization of "above" and "below" spatial relations in baboons (Papio papio). Using an identity matching-to-sample task, six baboons correctly matched line-dot stimuli based on the "above" or "below" location of the dot relative to the line (Experiment 1). Positive transfer of performance was then observed when the line-dot distance depicted in the sample stimulus differed from that of the two comparison stimuli (Experiment 2). Using a go/nogo procedure, two baboons were further trained to discriminate whether a "B" character was displayed "above" or "below" a "3" character (Experiment 3). After training, a positive transfer of performance was observed with the same type of stimuli depicted in different type fonts. Altogether, these results suggest that baboons may form conceptual representations of "above" and "below" spatial relations, and categorize visual forms on that basis. PDF
  • Fagot, J., Martin-Malivel, J. & Dépy, D. (1999). What is the evidence for equivalence between objects and pictures in birds and nonhuman primates ? Current Psychology of Cognition, 5-6, 923-950. ABSTRACT This paper questions the way birds and nonhuman primates, some species often studied in animal psychology laboratories, process pictures of objects. After having defined three main modes of picture perception that might occur in animals (i.e., the independence, confusion and equivalence modes), we review the literature providing direct evidence in favor of these three possible modes of processing. This review reveals that experimental evidence for object/picture equivalence are weak and often inconsistent in birds, and even in non-human primates. It also underlines the role of several experimental factors on picture processing modes.
  • Fagot, J, Deruelle, C & Tomonaga, M (1999). Perception des dimensions globales et locales de stimuli visuels chez le primate. Primatologie, 2, 61-77. Cet article présente les résultats de trois expériences comparatives sur la perception des dimensions globales et locales de formes visuelles chez trois espèces de primate. En recourant aux mêmes formes visuelles présentées dans une tâche d’appariement à un modèle, la première expérience révèle que les babouins traitent de manière prioritaire les dimensions locales des formes, alors que les hommes traitent en priorité les dimensions globales. Une tâche de recherche visuelle a été proposée dans la seconde expérience, afin de mieux comprendre ces différences entre l’homme et le babouin. Les résultats montrent que l’analyse des aspects globaux des formes visuelles requiert un traitement attentionnel chez le babouin, alors qu’il semble se faire de manière automatique chez l’homme. Enfin, la troisième expérience a posé la question d’une éventuelle évolution phylogénétique des effets de précédence, en testant des chimpanzés dans des conditions similaires à celles de l’expérience 2. Les résultats sur le chimpanzé indiquent que le traitement des aspects locaux des formes nécessite une charge attentionnelle plus importante que celui des aspects globaux, mais ne révèlent aucun avantage significatif pour percevoir la dimension « globale » ou « locale » des formes. Cette série d’expérience suggère que les mécanismes à l’origine des effets de précédence ont évolué au sein de l’ordre des primates.
  • Wasserman, E. A., Fagot, J. & Young, M. (2001). Same-different conceptualization by baboons (Papio papio) : The role of entropy. Journal of Comparative Psychology, 115, 42-52. ABSTRACT. We trained six baboons to make one of two report responses to 16-icon same arrays versus 16-icon different arrays. In the same arrays the icons were all the same as one another, whereas in the different arrays the icons were all different from one another. In Experiment 1, the baboons discriminated the same arrays from the different arrays and they transferred their discriminative responding to arrays of novel icons. In Experiments 2 and 3, the baboons exhibited strong sensitivity to the degree of display variability when they were shown mixed arrays that comprised some same and some different items. The information theoretic measure “entropy” systematically described these results and outperformed several rival metrics. Finally, in Experiments 4 and 5, the baboons’ response to displays that contained jittered and blurred icons suggested that their same-different conceptual behavior was not based on the spatial orderliness of the visual arrays. PDF
  • Martin-Malivel, J. & Fagot, J. (2001). Perception of pictorial humans faces by baboons (Papio papio) : effects of stimulus orientation on discrimination performance. Animal Learning and Behaviour, 29, 10-20. ABSTRACT. The effect of stimulus rotation was assessed in four Guinea baboons (Papio papio), using pictures of familiar human faces presented in a computerized go/no-go task. In Experiment 1, 2 baboons were initially trained to discriminate upright faces, and 2 others were trained to discriminate upside-down faces. For the two groups, postlearning discrimination was impaired when the training faces were rotated 180°. In Experiment 2, upright and upside-down priming faces appeared prior to the display of target faces. For the two groups, response times were faster when the prime and the target faces had the same orientations than when they were depicted under different orientations. Finally, Experiments 3 and 4 identified variations in facial contours as the most salient discriminative cue controlling performance in 2 baboons. Altogether, our results provide no evidence that the baboons processed the pictures as representations of faces. It is suggested that the effect of rotation derived from the encoding of the pictorial faces as meaningless mono-oriented shapes, rather than as natural human faces.
  • Fagot, J. & Tomonaga, M. (2001). Effects of element separation on perceptual grouping by humans (Homo sapiens) and chimpanzees (Pan troglodytes) : Perception of kanizsa illusory figures. Animal Cognition, 4, 171-177. ABSTRACT : The processing of Kanizsa-square illusory figures was studied in two experiments with four humans and two chimpanzees. Subjects of the two species were initially trained to select a Kanizsa-square illusory figure presented in a computerized two-alternative forced choice task. After training, adding narrow closing segments fo the pacman inducers that composed the Kanisza illusory figures lowered performance in both chimpanzees and humans, suggesting that the discrimination could be controlled by the perception of illusory forms. A second experiment assessed transfer of performance with five sets of figures in which the size of the inducers and their separation were manipulated. Only for chimpanzees was performance directly controlled by separation, suggesting that chimpanzees are more sensitive than humans to the separation between visual elements. PDF
  • Wasserman, E., Young, M.E. & Fagot, J. (2001). Effects of number items on the baboon’s discrimination of same from different visual display. Animal Cognition, 163-173. ABSTRACT. Three experiments explored the baboon’s discrimination of visual displays that comprised 2 to 24 black-and-white computer icons ; the displayed icons were either the same as (same) or different from one another (different). The baboons’ discrimination of same from different displays was a positive function of the number of icons. When the number of icons was decreased to 2 or 4, the baboons responded indiscriminately to the same and different displays, exhibiting strong position preferences. These results are both similar to and different from those of pigeons that were trained and tested under comparable conditions. PDF
  • Malivel, M. & Fagot, J. (2001). Cross-modal interference and conceptual categorization in baboons. Behavioural Brain Research, 122, 209-213. ABSTRACT. This study investigates concept formation and cross-modal integration in baboons. Response times were recorded in a categorical task involving discrimination between human and baboon vocalizations. We show that a brief presentation of human or baboon prime pictures conceptually related to the target sound shortened response speed of one baboon. Cross-modal priming effects were replicated with degraded pictures, and were also found in a sample of humans. Cross-modal priming demonstrates that this baboon had formed amodal abstract concepts of the human and baboon categories. PDF
  • Fagot, J., Wasserman, E. & Young, M. (2001).Discriminating the relation between relations : The role of entropy in abstract conceptualization by baboons and humans. Journal of Experimental Psychology : Animal Behavior Processes, 27, 4, 316-328. ABSTRACT. Two baboons (Papio papio) successfully learned relational matching-to-sample : They picked the choice display that involved the same relation among 16 pictures (same or different) as the sample display, although the sample display shared no pictures with the choice displays. The baboons generalized relational matching behavior to sample displays created from novel pictures. Further experiments varying the number of sample pictures and the mixture of same and different sample pictures suggested that entropy plays a key role in the baboons’ conceptual behavior. Two humans (Homo sapiens) were similarly trained and tested ; their behavior was both similar to and different from the baboons’ behavior. The results suggest that animals other than humans and chimpanzees can discriminate the relation between relations. They further suggest that entropy detection may underlie same-different conceptualization, but that additional processes may participate in human conceptualization. PDF
  • Barbet, I. & Fagot, J. (2002). Perception of the corridor illusion by baboons. Behavioural Brain Research, 132, 111-115. ABSTRACT. The corridor illusion was assessed in four baboons (Papio papio) by way of judgmental task implying a comparison between the size of two figures presented on various backgrounds. Findings demonstrate that the baboons are sensitive to the corridor illusion. PDF
  • Fagot, J. & Deruelle, C. (2002). Perception of pictorial eye-gaze by baboons (Papio papio). Journal of Experimental Psychology : Animal Behavior Processes, 28, 298-309. ABSTRACT. Pictorial faces looking left or right were presented to baboons (Papio papio) before the display of a target letter in the left or right hemifield of a monitor screen. Baboons had to provide go or no-go responses taking into account the identity of the target letter. The 1st 6 experiments showed no reliable effect of eye gaze on discrimination speed, using either schematic gazes or pictures of real gazes. Experiment 7 showed that eye gazes facilitated target processing when eye cues were perfect predictors of target location. Findings suggest that baboons do not spontaneously process eye-gaze direction but can learn to do so if the gaze has a predictive value. Implications of these findings on baboons’ perspective-taking abilities are discussed. PDF
  • Fagot, J., Barbet, I., Parron, C. & Deruelle, C. (2006). Amodal completion by baboons (Papio papio) : Contribution of background depth cues. Primates, 47, 145-160. ABSTRACT. Four baboons (Papio papio) were tested in a computerized two-alternative forced choice task in which partially occluded graphic stimuli were shown either on linear perspective backgrounds depicting a corridor or on uniformly black backgrounds. The results indicated that baboons complete partly occluded stimuli and that amodal completion is facilitated by the display of pictorial background depth cues. Inter-individual differences emerged in the ability to extrapolate three-dimensional information from two-dimensional visual information.
  • Fagot, J., Goldstein, J, Davidoff, J. & Pickering, A. (2006). Cross species differences in colour categorisation. Psychonomic Bulletin and Review, 13, 275-280. ABSTRACT. Berlin and Kay (1969) found systematic restrictions in the color terms of the world’s languages and were inclined to look to the primate visual system for their origin. Because the visual system does not provide adequate neurophysiological discontinuities to supply natural color category boundaries, and because recent evidence points to a linguistic origin (Davidoff, Davies, & Roberson, 1999), a new approach was used to investigate the controversial issue of the origin of color categories. Baboons and humans were given the same task of matching-to-sample colors that crossed the blue/green boundary. The data and consequent modeling were remarkably clear-cut. All human subjects matched our generalization probe stimuli as if to a sharp boundary close to the midpoint between their training items. Despite good color discrimination, none of the baboons showed any inclination to match to a single boundary but rather responded with two boundaries close to the training stimuli. The data give no support to the claim that color categories are explicitly instantiated in the primate color vision system. PDF
  • Martin-Malivel, J. Mangini, M., Fagot, J. & Biederman, I (2006). Do humans and baboons use the same information when categorizing human and baboon faces ? Psychological Science, 17, 599-607. ABSTRACT. What information is used for sorting pictures of complex stimuli into categories ? We applied a reverse correlation method to reveal the visual features mediating categorization in humans and baboons. Two baboons and 6 humans were trained to sort, by species, pictures of human and baboon faces on which random visual noise was superimposed. On ambiguous probe trials, a human-baboon morph was presented, eliciting "human" responses on some trials and "baboon" responses on others. The difference between the noise patterns that induced the two responses made explicit the information mediating the classification. Unlike the humans, the baboons based their categorization on information that closely matched that used by a theoretical observer responding solely on the basis of the pixel similarities between the probe and training images. We show that the classification-image technique and principal components analysis provide a method to make explicit the differences in the information mediating categorization in humans and animals. PDF
  • Barbet, I. & Fagot, J. (2007). Control of the corridor illusion in baboons (Papio papio) by gradient and linear perspective depth cues. Perception, 36, 391-402. The corridor illusion was recently demonstrated in baboons with background pictures containing rich depth information (Barbet and Fagot 2002, Behavioural Brain Research 132 111-115). In the current research we determined the contribution of gradient texture and perspective lines to that illusion. In experiment 1, the corridor illusion was tested in two baboons, with pictures of a hallway as backgrounds, or the same image of the hallway represented by perspective lines. Findings confirmed that the baboons experience the corridor illusion with the picture of the hallway, and showed that this illusion remained with the perspective-line backgrounds. The same procedure was adopted in experiment 2, but with a hallway drawn from gradient textures. The two baboons experienced the illusion in this experiment too. Thus both gradient and perspective line cues convey sufficient information to control the corridor illusion in baboons. In baboons, the processing of these two kinds of depth cues interacts with the perception of object size, suggesting homologous processes of pictorial depth perception in humans and non-human primates. PDF
  • Parron, C. & Fagot, J. (2007). Comparison of Grouping Abilities in Humans (Homo sapiens) and Baboons (Papio papio) with the Ebbinghaus Illusion. Journal of Comparative Psychology, 4, 405-411. ABSTRACT. This research comparatively assessed grouping mechanisms of humans (n = 8) and baboons (n = 8) in an illusory task that employs configurations of target and surrounding circles arranged to induce the Ebbinghaus (Titchener) illusion. Analyses of response behaviors and points of subjective equality demonstrated that only humans misjudged the central target size under the influence of the Ebbinghaus illusion, whereas baboons expressed a more veridical perception of target sizes. It is argued that humans adopted a global mode of stimulus processing of the illusory figure in our task that has favored the illusion. By contrast, a strong local mode of stimulus processing with attention restricted to the target must have prevented illusory effects in baboons. These findings suggest that monkeys and humans have evolved modes of object recognition that do not similarly rely on the same gestalt principles. PDF
  • Parron, C. & Fagot, J. (2007). Processing of biological motion point-light displays by baboons (Papio papio). Journal of Experimental Psychology : Animal Behaviour Processes, 4, 381-391. ABSTRACT. Humans apply complex conceptual judgments to point-light displays (PLDs) representing biological motion (BM), but how animals process this kind of display remains uncertain. Four baboons (Papio papio) were trained to discriminate BM from nonbiological motion PLDs using an operant computerized test system. Transfer tests were given after training with novel BM stimuli representing humans or baboons (Experiment 1), with inverted PLDs (Experiment 2), and with BM stimuli in which body parts had been spatially disorganized (Experiment 3). Very limited transfer was obtained with the novel and inverted displays in Experiments 1 and 2, but transfer was much higher after spatial disorganization in Experiment 3. It is suggested that the baboons did not retrieve and interpret the articulated shape of the human or monkey body from the BM PLD stimuli, but rather focused their attention on the configural properties of subparts of the stimuli. Limits in perceptual grouping and restricted abilities in picture-object equivalence might explain why the baboons did not map BM PLD displays onto what they represent. PDF
  • Parron, C., Call, J. & Fagot, J. (2008). Processing of two-dimensional pictures by pictorially-naive baboons (Papio-papio), gorillas (Gorilla gorilla) and chimpanzees (Pan troglogytes). Behavioural processes, 78, 351-357. ABSTRACT. This study assessed how pictorially naïve nonhuman primates understand pictures. Fifty-five baboons with no prior exposure to pictures were trained to grasp a slice of banana presented against a pebble in a two alternative forced choice task. Post-training testing involved three stimulus pairs : (1) real banana slice vs. its picture, (2) the banana picture vs. a real pebble and (3) banana picture vs. a pebble picture which were presented twice. Preliminary data were also collected on naïve gorillas (n=4) and chimpanzees (n=7) using the same procedure. Baboons revealed a preference for the food picture in (2) and (3) and often ate this stimulus, but the food item and its picture were accurately discriminated in (1). These results suggest that baboons mistook the pictorial stimulus and its referent, but processed the banana pictures as poor exemplars of the real banana category. Among apes, only gorillas ate the banana pictures, suggesting that picture-object confusion may also occur in this species. Findings are discussed as pertaining to the general issue of representational abilities in nonhuman primates, and its evolution. PDF
  • Parron, C. & Fagot, J. (2008). Baboons (Papio papio) spontaneously process first- but not second-order configural relationships in faces. American Journal of Primatology, 70, 415-422. A two-alternative forced-choice discrimination task was used to assess whether baboons (N=7) spontaneously process qualitative (i.e., first-order) or quantitative (i.e., second-order) variations in the configural arrangement of facial features. Experiment 1 used as test stimuli second-order pictorial faces of humans or baboons in which the mouth and the eyes were rotated upside down relative to the normal face. Baboons readily discriminated two different normal faces but did not discriminate a normal face from its second-order modified version. Experiment 2 used human or baboon faces for which the first-order configural properties had been distorted by reversing the location of the eyes and mouth within the face. Discrimination was prompt with these stimuli. Experiment 3 replicated some of the conditions and the results of experiment 1, thus ruling out possible effects of learning. It is concluded that baboons are more adept at spontaneously processing first- than second-order configural facial properties, similar to what is known in the human developmental literature. PDF
  • Fagot, J., Bonté, E. & Parron, C. (2009). Concept of uprightness in baboons : Assessment with pictures of realistic scenes. Animal Cognition ;12,369-79. How nonhuman primates process pictures of natural scenes or objects remains a matter of debates. This issue was addressed in the current research by questioning the processing of the canonical orientation of pictures in baboons. Two adult guinea baboons were trained to use an interactive key (IK) on a touch-screen to change the orientation of target pictures showing humans or quadruped mammals until upright. In experiment 1, both baboons successfully learned to use the IK when that key induced a 90 degrees rightward rotation of the picture, but post-training transfer of performance did not occur to novel pictures of natural scenes due to potential motor biases. In Experiment 2, a touch on IK randomly displayed the pictures in any of the four cardinal orientations. Baboons successfully learned the task, but transfer to novel pictures could only be demonstrated after they had been exposed to 360-480 pictures in that condition. Experiment 3 confirmed positive transfers to novel pictures, and showed that both the figure and background information controlled the behavior. Our research on baboons therefore demonstrates the development and use of an "upright" concept, and indicates that picture processing modes strongly depend on the subject’s past experience with naturalistic pictorial stimuli.PDF
  • Truppa, V., Spinozzi, G., Stegano, T. & Fagot, J. (2009). Picture processing in Tufted Capuchin Monkeys (Cebus apella). Behavioural Processes, 82, 140-152. Although pictures are frequently used in place of real objects to investigate various aspects of cognition in different non-human species, there is little evidence that animals treat pictorial stimuli as representations of the real objects. In the present study, we carried out four experiments designed to assess picture processing in tufted capuchin monkeys (Cebus apella), using a simultaneous Matching-to-Sample (MTS) task. The results of the first three experiments indicate that capuchins are able to match objects with their colour photographs and vice versa, and that object-picture matching in this NewWorld monkey species is not due to picture-object confusion. The results of the fourth experiment show that capuchins are able to recognize objects in their pictures with a high level of accuracy even when less realistic images, such as black-and-white photographs, silhouettes and line drawings, are employed as bi-dimensional stimuli. Overall, these findings indicate that capuchin monkeys are able to establish a correspondence between the real objects and their pictorial representations. PDF
  • Fagot, J. & Parron, J. (2010). Relational Matching in Baboons (Papio papio) with Reduced Grouping Requirements. Journal of Experimental Psychology : Animal Behaviour Processes, 36, 184-193 (PDF). Analogical reasoning is a corner stone of human cognition, but the phylogenetic origins of this skill are still unknown. Recent animal studies have suggested that only apes can solve the 2- by 2-item relational matching (RMTS) analogy problem, with potential benefits of language- (Premack, 1983) or token training procedures (Thompson, Oden, & Boysen, 1997). In this study, 6 baboons were initially trained in an RMTS task in which the same and different relations were exemplified by compound stimuli made of 2 adjacent patches of colors. Learning occurred in this task with a first set of colors and transferred to probe trials with new colors (Experiment 1). Manipulation of the size of the sample or comparison stimuli (Experiment 2) showed that the performance was not merely controlled by the surface of the color patches, suggesting cognitive flexibility. Performance collapsed to chance level when a gap was introduced between the 2 elemental features composing the same or different displays (Experiment 3). Nevertheless, this effect of gap size was abolished by training (Experiment 4). It is suggested that monkeys share the ability to judge relations between relations with humans and apes, even in the absence of language or token training. However, this ability has been previously masked by a local mode of processing that hinders the processing of the stimuli as pairs rather than as independent objects.
  • Fagot, J. & Parron, C. (2010, in press). Picture perception in birds, perspective from primatologists. Comparative Cognition & Behavior Reviews. In their target article Weisman and Spetch (in press). question the validity of pictures to present real things to birds, mostly because pictures are primarily made for the human eyes, and not for the eye of birds with different functional properties. Here we argue that this issue of picture validity is similarly critical for primatologists, even when they study the “higher” nonhuman primates with a more similar visual system, and emphasize cognitive limitations in referential abilities that may be an important source of differences in picture processing modes between human and animals.
  • Davidoff, J. & Fagot, J. (2010, in press). Cross-species Assessment of the Linguistic Origins of Color Categories. Comparative Cogniton & Behavior Reviews.This article considers the relation between language and categorical perception (CP) of color. Two opposite theories are reviewed, the universalist position arguing that categories are universal with an essentially biological origin, and the relativist position that holds that color categories are essentially arbitrary and derive from color terms of the speaker’s language. A review of the human literature presents developmental, neuropsychological, cross-cultural, neuro-imaging and computer simulation evidence that CP of colors has at least partly linguistic origins. As animal studies also contribute to this debate, we then review evidence of CP in the visual and auditory domains, and pinpoint the inconsistencies of the literature. To make a direct comparison between humans and monkeys, experimental studies compared humans and baboons for their color thresholds and in a recognition memory task designed to assess CP of colors. Only humans showed better between-category than within-category discrimination performance, suggesting species differences in the processing of a color continuum. That study along with some of our previous researchessupport the theory of a linguistic origin for color categories in humans.
  • Bonté, E., Flemming, T. & Fagot, J. (2011). Executive control of perceptual features and abstract relations by baboons (Papio papio). Behavioural Brain Research, 222, 176-182 (Word file) Studies of executive control often reveal significant limitations in nonhuman primate performance relative to that of humans. In the present study, 24 socially-housed baboons were tested on a computerized version of the Wisconsin Card Sorting Task (WCST) to assess individual differences in executive control. In a second experiment, the same baboons completed a version of the WCST with paired-relational stimuli rather than those that varied on a single dimension to evaluate their set-shifting abilities with abstract relations (same/different). All baboons completed the required shifts on the traditional WCST, but only 12 baboons succeeded in making relational shifts. Age was found to be a significant factor in the level of success on both tasks with younger baboons (mean age 4 years) outperforming older, albeit not aged, baboons (mean age 11.5 years). These results implicate an earlier decline in executive control processes for nonhuman primates with more pronounced effects for cognitive flexibility of abstract relations.

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Lateralization for visual processing in primates

  • Vauclair, J. Fagot, J. & Hopkins, WD. (1993). Rotation of mental images in baboons when the visual input is directed to the left cerebral hemisphere. Psychological Science, 4, 99-103. ABSTRACT. The mental rotation phenomenon was examined in baboons and humans using a video-formatted matching-to-sample task. Sample stimuli were presented either centrally or in the right or left visual half-field. Immediately afterward, subjects had to distinguish the previously presented sample Stimulus from its mirror image after both had been rotated to the same angular deviation. A mental rotation phenomenon was found in baboons and humans, but in baboons this effect wax limited to conditions in which visual input was directed to the right visual half-field. These data represent the first evidence of mental rotation in a nonhuman species. PDF
  • Fagot, J. & Vauclair, J. (1994). Video-task assessment of stimulus novelty effects on hemispheric lateralization in baboons (Papio papio). Journal of Comparative Psychology, 108, 156-163. ABSTRACT : Using a video formatted matching-to-sample task, we examined effects of stimulus novelty on hemispheric specialization in 6 baboons (Papio papio). After familiarization with a set of 8 composite stimuli, baboons were tested with either (a) familiar stimuli paired in a novel way, (b) novel stimuli composed of familiar elements, or (c) novel stimuli differing in structure from the previously used stimuli. Analyses have focused on visual field differences between initial and later trials in each condition. For response times, the visual half-field (left, right) by type of trials (first, last) interaction was significant. This finding reflects shorter left compared to right visual half-field response times for initial, but not for terminal trials. Regarding accuracy, scores were smaller for the initial trials than for the later ones, but there was no significant difference between LVF and RVF. Overall, this study suggests that hemispheric lateralization changes with practice, and that the right hemisphere of the baboon plays a critical role in the processing of novelty. PDF
  • Deruelle, C. & Fagot, J. (1997). Hemispheric Lateralisation and Global Precedence Effects in the Processing of Visual Stimuli by Humans and Baboons (Papio papio). Laterality, 2, 233-246. ABSTRACT : This paper examines the effect of global precedence (GPE : Navon, 1977) and its lateralisation from a comparative perspective. Using a divided field matching-to-sample task with compound stimuli, Experiment 1 demonstrated consistent patterns of lateralisation in humans and baboons, corresponding to a right-hemisphere advantage for global processing and a left- but non significant advantage for local processing. Species differences emerged in terms of GPE ; humans showed a global precedence effect, and baboons were better for local than for global matching. In Experiment 2, a visual search task was used to assess the origin of species differences in term of GPE. Humans processed the global structure of the forms pre-attentively, whereas baboons used an attentional search strategy. From this finding, it is argued that lateralisation in Experiment 1 was rooted in early perceptual mechanisms. So far, consistent patterns of lateralisation for global/local processing have been found in baboons, chimpanzees and humans, suggesting that this phenomenon has a long evolutionary history.
     
  • Hopkins, W.D., Fagot, J. & Vauclair, J. Mirror-Image Matching and Mental Rotation Problem Solving by Baboons (Papio papio) : Unilateral Input Enhances Performance (1993). Journal of Experimental Psychology : General, 112, 1, 61-72. ABSTRACT : Three experiments, using a matching-to-sample procedure, were conducted examining mirror-image matching and mental rotation in three baboons (Papio papio). In Experiments 1 and 2, target stimuli were presented for 100 msec. in duration to either the left (LVF) or right visual half-field (RVF). The results of Experiment 1 indicated no significant difference in performance between asymmetric patterns and mirror-image stimuli. Experiment 2 examined the affect of stimulus orientation on matching. For asymmetric patterns, RVF accuracy increased with repeated testing. In contrast, RVF accuracy decreased for mirror-image stimuli with repeated testing. Despite high accuracy for both stimulus sets, no significant linear trend was found between response time and increased angular disparity (0 to 180 ). Experiment 3 assessed the affect of bilateral visual input on accuracy and response time. Results indicated lower accuracy and longer response times under conditions of bilateral input contrasted with unilateral. Overall, these data (a) indicate that baboons can solve mirror-image matching and mental rotation problems and (b) emphasis the importance of unilateral stimulus presentation in solving these types of problems. PDF 
  • Vauclair, J. & Fagot, J., (1994). Video-task assessment of stimulus novelty effects on hemispheric lateralization in baboons (Papio papio). Journal of Comparative Psychology, 108, 2, 156-163. This comparative study explored the ability to process distance and its lateralization in humans and baboons. Using a conditional matching-to-sample procedure in a divided-field format, subjects had to decide whether or not the distance between a line and a dot belonged to a short- or a long-distance category. Experiments 1, 2, and 4 demonstrated the ability of baboons to process and categorize distances. Moreover, humans showed better distance processing for right visual field/left hemisphere presentations than for left visual field/right hemisphere (LVF-RH) displays (Experiments 1-2). The same bias was found in baboons (Experiment 1), but in a weaker way. In Experiment 3, naive human individuals were tested and the difficulty of the discrimination was enhanced. There was a LVF-RH advantage which vanished with practice. Results are discussed by referring to theories (i.e., Kosslyn, 1987) of visuospatial processing for coordinate and categorical judgments. PDF
  • Dépy, D., Fagot, J. & Vauclair, J. (1998). Comparative Assessment of Distance Processing and Hemispheric Specialization in Humans and Baboons (Papio papio). Brain and Cognition, 38, 165-182. ABSTRACT : This comparative study explored the ability to process distance and its lateralization in humans and baboons. Using a symbolic matching-to-sample procedure in a divided-field format, subjects had to decide whether or not the distance between a line and a dot belonged to a "short" or a "long" distance category. Experiments 1, 2 and 4 demonstrated the ability of baboons to process and categorize distances. Moreover, humans showed better distance processing for right visual field/left hemisphere presentations than for left visual field/right hemisphere (LVF-RH) displays (Experiments 1-2). The same bias was found in baboons (Experiment 1), but in a weaker way. In Experiment 3, naive human individuals were tested and the difficulty of the discrimination was enhanced. There was a LVF-RH advantage which vanished with practice. Results are discussed by referring to recent theories (i.e., Kosslyn, 1987) of visuo-spatial processing for coordinate and categorical judgements. PDF
  • Vauclair, J., Fagot, J. & Dépy, D. (1999). Nonhuman primates as models of hemispheric specialization. In Haug M. & Whalen R.E. (Eds.). Animal Models and Human Emotion and Cognition (pp. 247-259). New York : APA Books

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Handedness in primates

  • Fagot, J. & Vauclair, J. (1988). Handedness and manual specialization in the baboons. Neuropsychologia, 6, 795-804. Manual preferences of six baboons were tested with three kinds of experimental tasks : (1) a simple reaching on a board or in a hole ; (2) a box opening ; (3) two visuo-spatial tasks requiring precise alignments of apertures. The distribution of right and left hand preferences was found to be symmetrical for the simple reachings (3 right- and 3 left-handers) and was consistent with the preferences in the box opening task. However, manual tasks with strong visuo-spatial components gave a unimodal distribution with a left hand preference for the group for aligning and adjusting the apertures. These results suggest the coexistence within an individual of two types of preferences according to the distinction between handedness and manual specialization.PDF
  • Fagot, J. & Vauclair, J. (1988). Hand preference and bimanual coordination in the lowland gorilla. Brain Behavior and Evolution, 32, 89-95. One could hypothesize from previous studies that gorillas, as a group, might show a right-hand preference, making this species an exception among nonhuman primates. A study of 10 captive gorillas observed while reaching for food and tested on unimanual and bimanual tasks does not support this conclusion. Instead, the present study found (a) a symmetrical distribution of subjects with right-hand (n = 3), left-hand (n = 3), and no hand preference (n = 4) when simply reaching for food and (b) a left-hand preference by 7 of 8 gorillas tested on a spatial task requiring precise alignment of two openings. These results stress the importance of considering the kind of task employed in the assessment of lateral preferences. Furthermore, it is suggested that it might be useful to distinguish between the handedness of a gorilla when simply reaching and its manual specialization for novel and complex tasks.
  • Fagot, J., & Vauclair, J. (1991). Manual laterality in nonhuman primates : A distinction between handedness and manual specialization. Psychological Bulletin , 109, 1, 76-89. ABSTRACT : This article examines individual and group manual lateralization in nonhuman primates as a function of task’s demand. It is suggested to distinguish low- from high-level manual activities with respect to the novelty variable and to the spatiotemporal scale of the movements. This review shows that low level tasks lead to (a) symmetrical distributions of hand preferences for the group and (b) manual preferences that are not indicative of the specialization of the contralateral hemisphere . In contrast, behaviors expressed in high-level tasks (a) show asymmetrical distributions of hand biases for the group, and (b) seem to be related to a specialization of the contralateral hemisphere. Two types of lateralization, handedness and manual specialization, correspond to the two levels of the tasks that are distinguished. PDF
  • Fagot, J., Dréa, C. & Wallen, K. (1991). Asymmetrical hand usage in rhesus monkeys in tactually and visually regulated tasks. Journal of Comparative Psychology, 105, 260-268. ABSTRACT : Asymmetrical hand use by socially-housed rhesus monkeys was investigated using a series of tactually- and visually-guided tasks. The first experiment recorded manual preferences of 29 rhesus monkeys in solving a haptic discrimination task requiring a hanging posture. There was a significant left-hand population bias with 21 monkeys having a significant left-hand bias, 4 a significant right-hand bias, and 4 no significant hand bias. A second experiment, consisting of four tasks, investigated the critical components of the first experiment by varying the posture (hanging, sitting, or tripedal) and the sensory requirements (tactile or visual). Posture influenced hand bias, with a population level left-hand bias in hanging and sitting postures, but an almost symmetrical distribution of hand use in the tripedal posture. A significant left-hand bias was found for both sensory modalities, but the bias was stronger in the tactually-controlled tasks. Results suggest a possible specialization of the right hemisphere in the rhesus monkey for tactile, visual, or spatial processing. PDF
  • Vauclair J, Fagot J. (1993). Manual and hemispheric specialization in the manipulation of a joystick by baboons (Papio papio). Behav Neurosci, 107, 210-4. Manual performance asymmetries were examined in 8 baboons (Papio papio). Using a joystick, monkeys had to track and hit with a cursor a randomly moving target on a monitor. The left or right hand was tested first, depending on group assignment, followed by a transfer to the other hand. A transfer effect is reported for the total number of trials to criterion and total number of successful trials. No effect was found for response time. However, for both test and transfer, the group initially tested with the left hand exhibited more controlled movements as demonstrated by shorter cursor’s paths. Overall, it appears that the spatial components of the task are more sensitive to laterality effects than response times or learning scores. PDF
  • Fabre-Thorpe, M., Fagot, J., Lorincz, E., Levesque, F. & Vauclair, J. (1993). Laterality in cats : Paw preferences and performance in a visuomotor activity, Cortex , 29, 15-24. ABSTRACT : Laterality in paw usage was investigated over a period of 6 years in 44 domestic cats trained to perform a reaching movement towards a moving spot of light. Both paw preferences and paw performances were recorded. With respect to paw preferences, 23 subjects used one paw for more than 90 percent of the trials. Among these lateralized animals, there was more left- (n=17) than right-pawed (n=6) cats. The analysis of visuo-motor performances included, among other measures, reaction time, movement time, and reaching accuracy. The more-used paw had a shorter reaction time and was also more accurate than the less-used paw. The greater accuracy of the more-used paw appeared within the subgroups of lateralized and of left preferent subjets, but not in nonlateralized or in right preferent ones. No difference was found regarding movement time. The findings thus demonstrate a functional advantage of being lateralized. Moreover, the results confirm the existence of an asymmetry of paw preference in cats and show a consistent relation between paw preference and paw performance.
  • Fabre-Thorpe M, Fagot J, Vauclair J. (1991). Comptes Rendus de L’Académie des Sciences, III, 313, 427-433. In a group of 44 cats overtrained on a task where they had to reach for a moving target, paw performance and paw preference were investigated. More than half of the cats (n = 23) were strongly lateralized in that they used one of their paws to perform more than 90% of the reaching attempts. Among these lateralized cats, left-pawed ones (n = 17) significantly exceeded right pawed-animals (n = 6). Investigating both the accuracy and speed scores, the comparison between lateralized and non-lateralized cats (using a criterion of 90% lateralization) showed that although the accuracy scores did not differ, lateralized cats were significantly quicker to trigger their movement. No difference was found concerning the movement time. For the whole group of 44 cats the comparison between the performance levels obtained with their two forepaws showed that the more frequently used paw was significantly more accurate and faster to trigger and to execute the movement than the less used paw. This study shows that, in pointing towards a moving target, cats display an asymmetry in paw preference that is associated with a performance asymmetry.
  • Fagot, J. & Vauclair, J., (1993). La latéralisation chez les singes. La Recherche, 252, 298-304.
  • Fagot, J. & Bard, K. (1995). Asymmetric Grasping Response in Neonate Chimpanzees (Pan troglodytes) Infant Behavior and Development, 18, 253-255. ABSTRACT : The strength of grasping responses was stronger for the right than for left hand in 13 chimpanzees of mean age 14.8 days. This finding demonstrates that lateralization is present in neonate chimpanzees and suggests some evolutionary links between lateralization in apes and humans.
  • Anderson, J.R., Degiorgio, C., Lamarque, C. & Fagot, J. (1996). A multi-task assessment of hand lateralization in Capuchin Monkeys (Cebus apella). Primates , 97-103. 

 

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Lateralization for haptic perception in humans

  • Fagot, J., Lacreuse, A., & Vauclair, J. (1994). Hand movement profiles in a tactual-tactual matching task : Effects of spatial factors and laterality. Perception and Psychophysics, 56, 347-355. ABSTRACT. We examined the effect of spatial factors and hemispheric lateralization upon hand-scanning strategies in 14 right-handed men tested in a tactual-tactual matching task. The experiment involved comparisons (judgments of same or different) between two objects sequentially touched by the fingertips of the left or right hand. Stimuli were made of smoothly joined cubes whose junctions were not haptically discernible. Exploratory strategies were inferred from the durations and locations of hand contacts with any of the cubes composing the stimuli. Accuracy was greater when the same stimulus was touched twice by the same hand than when different hands were used to feel it. With regard to strategies, both hands touched the upper parts of the object longer than the lower parts. Subjects also inspected more portions of the objects ipsilateral to the hand used. Overall differences in time spent touching cubes were greater for the right hand than for the left hand, showing that touch times were less evenly distributed on object parts for the former than for the latter. In this study, the process of information gathering by touch appears to be determined by the intertwining integration of contextual factors (e.g., stimulus position in space), biomechanical constraints on hand movements, and such cognitive factors as hemispheric differences on the ability to encode spatial pattern information. PDF
  • Fagot, J., Hopkins, W.D. & Vauclair, J. (1993). Hand movements and hemispheric specialization in dichhaptic explorations. Perception, 22, 847-853. ABSTRACT. Dichhaptic testing has been widely used to assess lateralization in tactile processing. The rationale of dichhaptic testing is that simultaneous exploration of two objects enhances competition between relevant cortical areas in the right and left hemispheres. The synchronization of hand movements in a dichhaptic situation was investigated to determine whether both hands explore the two shapes simultaneously. Fourteen men were tested with the aid of a dichhaptic intermodal task. Tactile stimuli were composite shapes and the activity of each hand was assessed through analysis of hand contacts on each part of the shape. Only 20% of the total exploration time was devoted to simultaneous investigation of the two shapes. In addition, it was found that (i) the recognition accuracy was greater when the target shape was explored by the left hand compared with the right, and (ii) the left hand touched a greater number of parts of the stimuli than the right. Overall, comparison of the present data with those from a previous, monohaptic, task with the same stimuli suggests an advantage of dichhaptic over monohaptic testing to demonstrate laterality differences in accuracy of recognition. However, it is suggested that this advantage is due to cognitive factors rather than to competition between homologous cortical areas.
  • Fagot, J., Lacreuse, A. & Vauclair, J. (1993). Haptic discrimination of nonsense shapes : Hand exploratory strategies but not accuracy reveal laterality effects. Brain and Cognition, 21, 212-225. ABSTRACT. Studies on haptic processing show inconsistent results concerning sex and hand differences. We present a novel approach in which manual exploratory strategies were examined. Twenty-four right-handed adults of both sexes had to monohaptically explore unseen meaningless stimuli and then to recognize their visually presented outline drawings among drawings of different stimuli. Tactual stimuli were composed of eight smoothly joined cubes whose junctions were not haptically discernible. The computer recorded number and duration of hand contacts on each cube. Analyses included the accuracy of the recognition phase, the number and duration of exhaustive explorations of the stimulus, and the number of cubes simultaneously touched. Neither hand nor sex differences were found for the accuracy measurement. The number and duration of exhaustive explorations also provide no evidence of hand differences. However, the left hand touched simultaneously more cubes than the right and this asymmetry was more pronounced in males than in females. Such an asymmetry was apparent in the very first contact of the hand with the shape. It is suggested that exploratory strategies may be more sensitive measures in revealing hand lateralization than the accuracy measurement . PDF
  • Lacreuse, A., Vauclair, J. & Fagot, J. (1996). Latéralisation hemisphérique et strategies d’exploration manuelle chez l’homme. L’année Psychologique, 96, 131-145.
  • Lacreuse, A., Fagot, J., Vauclair, J. (1996). Left versus right hand differences in exploratory strategies : Facts and relevance to the development of haptic devices. Proceedings of the Fith Annual Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 567-573. ABSTRACT : The literature provides conflicting results with regards to hand/hemisphere lateralization in haptic perception ; while some papers report a left hand advantage for recognizing haptic forms, other studies indicate either a right hand advantage or no hand difference at all. Four experiments with right handed subjects will be presented, in which scanning strategies and performance were investigated when subjects touched nonsense forms by either the left or right hand. The research involved a novel apparatus and composite stimuli made of cubes whose junctions were not haptically discernible. During the inspection of the shape, the location and duration of any hand contact with the cubes comprising the stimulus were recorded, allowing thus an analysis of exploratory strategies. The first experiment implied the inspection of a target stimulus with either the left or right hand. Thereafter, subjects were requested to identify the drawing of the target stimulus displayed among different drawings. No hand differences were obtained in terms of scores. It was found, however, that in men the left hand touched the stimuli more globally than the right. In the second experiment, subjects were requested to inspect in simultaneity two forms with two hands (i.e., dichhaptic task), before recognizing the forms on the visual array. Here, the left hand outperformed the right hand. Moreover, as in the previous experiment, the left hand touched the shape more globally than the right. Results also demonstrated that only 20% of the total exploration time was devoted to a simultaneous inspection of the two forms. The two additional experiments focused on hand performance and exploratory strategies for recognizing the stimuli, instead of learning them. No hand differences were observed in strategy, whatever the mode of exploration (either dichhaptic or monohaptic). By contrast, recognition achieved by the left hand was better than that of the right hand, but this effect was restricted to dichhaptic recognition only. Overall, we conclude that this series of experiments demonstrates the reality of hand/hemispheric differences in the processing of haptic information by men. We argue, moreover, that these findings are of particular relevance for the development and use of haptic devices that are designed to display haptic information on body segments (e.g., tactile or force feedback devices). Firstly, they suggest a serious consideration of the laterality factor for stimulating subjects, in order to enhance pattern recognition. Secondly, they suggest that information presented to the left hand would be more easily processed if it was displayed globally, whereas information presented to the right hand would be more easily and efficiently processed when made available in a sequential manner. Finally, the results show a limited capacity to process two distinct sources of haptic information at the same time.
  • Fagot, J., Lacreuse, A. & Vauclair, J. (1997). Role of sensory and post-sensory factors on hemispheric asymmetries in tactual perception. In Christman, S. (Ed.) Cerebral Asymmetries in sensory and perceptual processing (pp. 469-494). New York : Elsevier. 

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Methods and procedures

  • Fagot, J. & Bonté, E. (2010). Automated testing of cognitive performance in monkeys : Use of a battery of computerized test systems by a troop of semi-free ranging baboons (Papio papio). Behav Research Methods, 42, 507-516. Fagot & Paleressompoulle (2009) published an automated learning device (ALDM) to test the cognitive functions of nonhuman primates within their social groups, but the efficiency of the ALDM procedure with large groups remains unknown. Ten ALDM systems were provided ad libitum to a troop of 26 semi-free ranging baboons initially naïve with computerized testing. The test program taught baboons to solve two-alternative forced choice (2AFC) and matching-to-sample (MTS) tasks. 1000 000 trials were recorded for the group during a period of 85 days (Experiment 1). Their analysis shows that 75% of baboons participated at high frequencies and quickly learned the 2AFC and MTS tasks. Experiment 2 compared the baboons’ behavior when the ADLM systems were either accessible or closed. ALDM reduced frequencies of object-directed behaviors, but had no overt consequence on social conflicts. Experiment 3 tested the process the global or local attributes of visual stimuli in MTS-trained baboons, in order to illustrate the efficiency of ALDM for behavioral studies requiring complex experimental designs. Altogether, this study validates the use of ALDM to efficiently test monkeys in large social groups. ALDM has a strong potential for a variety of scientific disciplines, including for biomedical research. PDF 
  • Fagot, J & Paleressompoulle D. (2009). Automatic testing of cognitive performance in baboons maintained in social groups. Behav Res Methods, 41,396-404. ABSTRACT. Laboratory procedures used to study the cognitive functions of primates traditionally have involved removal of the subjects from their living quarters to be tested singly in a remote experimental room. This article presents an alternative research strategy favoring testing primates while they are maintained in their social group. The automatic learning device for monkeys (ALDM) is a computerized test system controlled by an automatic radio frequency identification of subjects. It is provided ad lib inside the social group of monkeys, for voluntary self-testing on a 24-h schedule. Nine baboons were tested with ALDM during a 7-month period. Experiments were performed to assess learning in motor control and abstract reasoning tasks. The results revealed high trial frequencies and excellent learning performance, even in tasks involving the highest cognitive complexities. A different study using ALDM with a group of 3 rhesus monkeys revealed social influences on learning. Beyond its interest for cognitive psychologists, ALDM is of interest for pharmacologists and cognitive neuroscientists working with nonhuman primates. ALDM also can serve as an enrichment tool for captive animals and may be used to study a variety of species other than primates. PDF
  • Vauclair, J. & Fagot, J. (1995). Une méthode non verbale pour étudier les asymétries hémisphériques visuo-spatiales chez l’homme et l’animal. Revue de Neuropsychologie, 5, 1-31.
  • Wilde, J., Vauclair, J., & Fagot, J., (1994). Eye movements in baboons performing a matching-to-sample task presented in a divided-field format. Behavioural Brain Research, 63, 61-70. ABSTRACT : We examined eye saccades in a baboon solving a video-formatted matching-to-sample (MTS) task. In that task, the animal had to place a cursor by way of joystick manipulation within the boundaries of a fixation point (FP) displayed on a monitor. A sample stimulus was then flashed in either the left or right of FP. Immediately thereafter, two comparison forms were displayed and the animal had to select the comparison form matching the sample. A new video technique requiring no specific head or body constraints was employed to monitor eye movements. Expt. 1 indicated that the gaze was centered on FP during the fixation procedure. However, some goal-directed express saccades, with mean latencies of 100 ms, were observed during sample presentation. Expt. 2 used an overlap procedure in which FP remained visible during sample presentation. Latencies of express saccades increased by approximatively 20 ms. Expt. 3 showed in four baboons that the overlap procedure did not affect scores. It is concluded that the computerized MTS task ia a valuable tool for the assessment of hemispheric lateralization in visual processing in intact primates, as long as the sample is not displayed longer than 120 ms.
  • Fagot, J., Arnaud, B., Chiambretto, M. & Fayolle, R. (1992). Lateralization in haptic processing : An apparatus for analyzing manual exploratory strategies. Behavior Research Methods, Instruments, & Computers, 24, 1, 54-59. ABSTRACT. We describe an apparatus for testing laterality in haptic processing in the discrimination of nonsense shapes in humans or monkeys. The system, which permits either mono- or dichhaptic discrimination, automatically provides data on the measurement of accuracy along with information on hand exploratory strategies.

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Edited books

  • Fagot, J., Rogers, L., Ward, J., Bullman-Fleming, B. & Hopkins, W.D. (Eds.) (1997). Hemispheric specialisation in animals and humans . Hove : Psychology Press. W.D. SYNOPSIS. Hopkins, D.M. Rabinowitz, Manual Specialization and Tool-Use in Captive Chimpanzees (Pan troglodytes) : The Effect of Unimanual and Bimanual Strategies on Hand Preference). C. Deruelle, J. Fagot, Hemispheric Lateralization and Global Precedence Effects in the Processing of Visual Stimuli by Humans and Baboons (Papio papio). A. Lacreuse, D.M. Fragaszy, Manual Exploratory Procedures and Asymmetries for a Haptic Search Task : A Comparison between Capuchins (Cebus apella) and Humans. R.J. Andrew, Left and Right Hemisphere Memory Traces : Their Formation and Fate. Evidence from Events during Memory Formation in the Chick. M. P. Bryden, E.A. Roy, I.C. McManus, M.B. Bulman-Fleming, On the Genetics and Measurement of Human Handedness. C. Porac, Eye Preference Patterns among Left-handed Adults. P.E. Cowell, N.S. Waters, V.H. Denenberg, The Effects of Early Environment on the Development of Functional Laterality in Morris Maze Performance. J.P. Ward, C. Cantalupo, Origins and Functions of Laterality : Interactions of Motoric Systems. L. Rogers, Early Experiential Effects on Laterality.
  • Fagot, J. (Ed) (1999). Picture perception in animals. Special issue of Current Psychology of Cognition, 18, 5-6, 1999.
  • Fagot, J. (Ed) (2000). Pictures perception in animals (reedition of CPC, 18, 5-6, 1999 special issue). Hove, UK : Psychology Press. Book Description. Given its biological importance, object recognition is a topic central to the field of comparative psychology and neuroscience. Picture Perception in Animals aims to contribute to this important domain in a unique way, by questioning the realistic nature of pictures to animals and the validity of pictorial representations for inferring the processing of objects or scenes that exist in the real world. This book will be of primary interest to comparative psychologists and developmental psychologists but will also be of value to psychologists, neuroscientists and anthropologists who study the processing of real objects through the convenient use of pictures.

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Others  (Cross cultural studies, research on human development, autism)

  • Davidoff, J., Fonteneau, E. & Fagot, J. (2008). Local and global processing : observations from a remote culture. Cognition, 108(3), 702-709. ABSTRACT. In Experiment 1, a normal adult population drawn from a remote culture (Himba) in northern Namibia made similarity matches to [Navon, D. (1977). Forest before trees : The precedence of global features in visual perception. Cognitive Psychology, 9, 353–383] hierarchical figures. The Himba showed a local bias stronger than that has been previously observed in any other non-clinical human population. However, in Experiment 2, their recognition of normal or distorted (“Thatcherized”) faces did not appear to have been affected by their attention to detail as has been suggested for autistic populations. The data are consistent with a cultural/experiential origin for population differences in local processing and suggest that attention to the local and global properties of stimuli may differ for hierarchical figures and faces. PDF
  • De Fockert, J., Davidoff, J., Fagot, J., Parron, C. & Goldstein, J. (2007). More accurate size contrast judgments in the Ebbinghaus illusion by a remote culture. Journal of Experiment Psychology : Human Perception and Performance, 33, 738-742. ABSTRACT. The Ebbinghaus (Titchener) illusion was examined in a remote culture (Himba) with no words for geometric shapes. The illusion was experienced less strongly by Himba compared with English participants, leading to more accurate size contrast judgments in the Himba. The study included two conditions of inducing stimuli. The illusion was weaker when the inducing stimuli were dissimilar (diamonds) to the target (circle) compared with when they were similar (circles). However, the illusion was weakened to the same extent in both cultures. It is argued that the more accurate size judgments of the Himba derive from their tendency to prioritize the analysis of local details in visual processing of multiple objects, and not from their impoverished naming. PDF
     
  • Deruelle, C., Rondan, C., Gepner, B., B. and Fagot, J. (2006). Processing of compound visual stimuli by children with autism and asperger syndrome. International Journal of Psychology, 41, 97-106. ABSTRACT. A typical modes of visual processing are common in individuals with autism. In particular, and unlike typically developing children, children with autism tend to process the parts of a complex object as a priority, rather than attending to the object as a whole. This bias for local processing is likely to be due to difficulties in assembling subparts into a coherent whole, as proposed by Frith (1989) using the term “weak central coherence” or WCC. This study was aimed to better characterize the processing of complex visual stimuli by children with autism. Thirteen children with autistic spectrum disorders were individually paired with children of two control groups, one matched on verbal mental age (VMA) and one matched on chronological age (CA). Participants from the three groups were tested in two tasks. The first task involved hierarchical global/local stimuli, inspired by Navon (1977). The second task employed compound face-like or geometrical stimuli. This task emphasized the processing of configural properties of the stimuli (i.e., spatial relationships). Children from the three groups showed a perceptual bias favouring the global dimension of the stimuli in the first task. By contrast, children with autism were deficient compared to normal children for the processing of the configural dimensions of the stimuli in the second task. These results suggest that visual cognition of children with autism is characterized by a dissociation between global and configural processing, with global processing being preserved and configural processing being altered in these children, therefore delineating the extents and limits of the WCC theory (Frith, 1989). PDF
  • Deruelle, C. & Fagot, J. (2005) Categorizing Facial Identities, Emotions and Genders : Attention to High- and Low- Spatial Frequencies by Children and adults. Journal of experimental child psycholology, 172-184. ABSTRACT. Three age groups of participants (5-6 years, 7-8 years, adults) matched faces on the basis of facial identity. The procedure involved either low- or high-pass filtered faces or hybrid faces composed from two faces associated with different spatial bandwidths. The comparison stimuli were unfiltered faces. In the three age groups, the data indicated a significant bias for processing of low-pass information in priority. In a second task, participants were asked to identify the emotion (smiling or grimacing) or gender (male or female) of hybrid high-pass/low-pass faces. Opposite results emerged in the two tasks irrespective of the age group ; the gender discrimination task indicated a bias for low-pass information, and the emotion task indicated a bias for high-pass information. These differences suggest independent processing routes for functionally different types of information such as emotion, gender, and identity. These routes are already established by 5 years of age. PDF

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