Perceiving persistence under change and over structure

We explored the hypothesis that to perceive an event is to detect an invariant specific to the style of change and an invariant specific to the object undergoing the style of change - the reciprocal invariants of transformation and structure, respectively. Events were defined by seven geometric transformations that produced a variety of styles of change over different objects. In Experiment 1, we examined the generative and abstract aspects of transformational invariants. An event was presented as a sequence of static samples and examined in interpolation and extrapolation tasks. The transformational invariant proved sufficiently generative and abstract to specify a unique style of change. In Experiment 2, we found that types of change and types of objects interacted, which implies that certain styles of change are more compatible with certain object structures. In Experiment 3, we found that the structural invariant was reliably detectable but that the degree to which structural properties were preserved depended on the kind and amount of transformation applied. Taken together, the experiments provide support for the hypothesis that perceiving an event is detecting the two reciprocal invariants of transformation and structure that together specify the event.