Previous studies have reported several factors, including prior knowledge, past experience, immediately preceding events, and rate of event repetitions that influence humans’ ability to predict and perceive sequentially occurring probabilistic events. However, many of these factors are correlated and most earlier studies made little effort to disentangle their confounding effects. I will present a series of human behavioral experiments, in which we systematically inspected the separate and joint effects of these factors within a simple visual perceptual paradigm. We found that, rather than simply balancing past and present statistics, the best model describing human performance is probabilistic and it assumes a parallel working of several factors: a) reliance on prior statistical knowledge of the sequence as a function of stimulus uncertainty, b) a “regression to the mean” kind of effect that could reflect a general strategy of non-commitment, and c) an independent short-term repetition effect which influences performance asymmetrically.