Learning bundles of stimuli renders stimulus order as a cue, not a confound

The order in which stimuli are presented in an experiment has long been recognized to influence behavior. Previous accounts have often attributed the effect of stimulus order to the mechanisms with which people process information. We propose that stimulus order influences cognition because it is an important cue for learning the underlying structure of a task environment. In particular, stimulus order can be used to infer a "stimulus bundle"--a sequence of consecutive stimuli that share the same underlying latent cluster. We describe a clustering model that successfully explains the perception of streak shooting in basketball games, along with two other cognitive phenomena, as the outcome of finding the statistically optimal bundle representation. We argue that the perspective of viewing stimulus order as a cue may hold the key to explaining behaviors that seemingly deviate from normative theories of cognition and that in task domains where the assumption of stimulus bundles is intuitively appropriate, it can improve the explanatory power of existing models.