The human mind rapidly parses high-dimensional dynamic input into useful representations. Identifying the source of relevant sensory information in time is critical to the formation of informative perceptions. One source of information to aid perceptual processing is the temporal regularity of sensory input. Knowledge of what regularities are utilized and how they are utilized is critical to understanding how perception functions in a dynamic world. The objective of this dissertation is to explore the adaptations of perception to temporal regularities in the environment. Chapters 1 and 2 use short term priming paradigms to examine the temporal segregation of perceptual information. Chapter 1 shows that inverted versus upright faces have different time courses of priming, suggesting that familiarity plays a role in temporal segregation. Furthermore, for faces, there are individual differences in priming dynamics related to perceptual identification ability. Chapter 2 examines the influence of occurrence and co-occurrence statistics in the same task. Several incremental reductions of stimulus frequency at different levels of representation all slow priming compared to higher occurring word stimuli. Word associations as a measure of co-occurrence, produce waxing and waning priming effects, with a small effect of the order of the associative relationship. Priming based on direct measures of linguistic co-occurrence produces priming dynamics that are similar to associative priming. Words which are expected to repeat provide a small increase in priming compared to priming by repeating a word. These priming effects are interpreted as the result of habituation. The findings in Chapters 1 and 2 generalize the habituation account of priming effects to faces, demonstrate its dependence on the occurrence rates of stimuli, and show that temporal co-occurrence regularities for particular items only result in small changes to the basic dynamics. Chapter 3 uses a spatial cueing paradigm to test if we adapt to diagnostic spatial-temporal relationships. Participants implicitly learn and generalize diagnostic cue-target relationships with long delays between cues and target. Diagnostic relationships are also learned for short cue-target delays when no shift of expectation is required. As a whole, these experiments find that temporal regularities pertaining to familiarity and general occurrence relationships are strongly reflected in the dynamics of perception, and that directional associations or expectations between individual stimuli deviate only slightly from general dynamics

Previous functional magnetic resonance imaging (fMRI) research on action observation has emphasized the role of putative mirror neuron areas such as Broca's area, ventral premotor cortex, and the inferior parietal lobule. However, recent evidence suggests action observation involves many distributed cortical regions, including dorsal premotor and superior parietal cortex. How these different regions relate to traditional mirror neuron areas, and whether traditional mirror neuron areas play a special role in action representation, is unclear. Here we use multi-voxel pattern analysis (MVPA) to show that action representations, including observation, imagery, and execution of reaching movements: (1) are distributed across both dorsal (superior) and ventral (inferior) premotor and parietal areas; (2) can be decoded from areas that are jointly activated by observation, execution, and imagery of reaching movements, even in cases of equal-amplitude blood oxygen level-dependent (BOLD) responses; and (3) can be equally accurately classified from either posterior parietal or frontal (premotor and inferior frontal) regions. These results challenge the presumed dominance of traditional mirror neuron areas such as Broca's area in action observation and action representation more generally. Unlike traditional univariate fMRI analyses, MVPA was able to discriminate between imagined and observed movements from previously indistinguishable BOLD activations in commonly activated regions, suggesting finer-grained distributed patterns of activation.

The processing of Navon figures (Navon, 1977), i.e., hierarchical letter stimuli, has been studied in experimental settings for many years. In particular, they have been studied in the context of visual hemifield studies and yielded an interaction between hemifield and whether a target is at the local or global level, with a right hemisphere advantage for the global level, and a left hemisphere advantage for the targets at the local level (Sergent, 1982). This is a ventral stream process, however, and we were interested in whether there might be a similar interaction for hierarchical motion stimuli, presumably a dorsal stream process. Hence we developed a series of dynamic geometric Navon figures in order to study global/local rotation processing. These figures consist of a global figure (a triangle or a square) made up of local figures (also triangles or squares). Both global and local figures can rotate in either clockwise or counterclockwise directions independently. We found that there is no right or left visual field perceptual advantage for either the global or local levels of these figures. However, curiously enough, we found that there is a significant processing advantage for clockwise motion compared to counterclockwise motion. We also found a highly significant interaction between the detection of a particular rotational motion and the presence or absence of that motion in the figure being examined. Finally, our data strongly support the Global Precedence Hypothesis which says that people generally tend to focus on the global properties of an object before local properties and that processing proceeds in a global-to-local direction.