Human contingency learning is strongly related to operant conditioning, that is, the observation that people (and animals in general) tend to learn whichever response has the greatest probability of realizing a particular desired outcome. Human contingency learning refers to the acquisition of implicit or explicit knowledge of statistical correlations between stimuli and/or responses. Among other things, exposure to stimulus pairings can influence speed of responding, accuracy of responding, causal attributions, and affective evaluations.