The present study manipulates first and second order transitional probabilities during the statistical learning of short sequences. Participants were exposed to four sequences of three stimuli (ABC) repeated during the task, with each stimulus corresponding to the position of a red dot on a touchscreen. Participants were required to touch the dots as quickly as possible and response times were recorded between the first two stimuli (Transition Time 1 or TT1) and between the last two stimuli (TT2). In the first experiment the transition AB of a triplet ABC was fully predictable (p(B|A) = 1) while the second transition BC was unpredictable (p(C|B) = .5). The second experiment was a serial version of the exclusive-or (XOR), all first order transitional probabilities were equally unpredictable (p(B|A) = .5, p(C|B) = .5), while the combination of the first two stimuli fully predicted the last stimulus (p(C|AB) = 1). Results showed that participants were able to learn both type of transitional probabilities. The different evolution patterns of TT1 and TT2 and their implications in term of statistical learning mechanisms are discussed.