Recent accounts of visual object affordance suggest that evoked representations for action serve to potentiate motor response components (such as a specific hand) to respond to the most afforded action (Tucker & Ellis, 1998). The present thesis aims to investigate further this hypothesis, and to examine the underlying nature of affordance-generated effects.
Using the stimulus-response compatibility (SRC) paradigm, a set of eleven experiments investigate; a) the conditions under which the effect of affordance may be generated, b) the nature of affordance in terms of response specificity, c) the time course of affordance-based effects.
Initial findings (Ch pter 4) show that affordance, operating as a constituent component of corresponding stimulus-response (S-R) mappings, results in facilitation of performance, over non-corresponding mappings, even when the affording object is unrelated to an imperative task. Findings show that an object's affordance does indeed influence action. In addition, effects are shown to build over time. Chapter 5 investigates response specificity and concludes that affordance is
probably due to generation of a more abstract spatial code rather than affordance for a specific limb. Chapters 6 and 7 provide evidence relating to attentional, spatial coding, and frame of reference effects that constrain
the investigation of affordance. Finally, experiments in Chapter 8 employ a different method for testing for the effect of affordance on behaviour. Using novel objects as primes, and involving a series of training and
testing, the results in Chapter 8 lend support for the idea that attention is a major contributor in achieving correspondence effects through affordance. In addition, results show that the end goal of an action sequence is better afforded, than the means of arriving there.
The findings in this thesis consolidate previous evidence on the role of affordance on action and provide new evidence in relation to the nature of affordance and the conditions in which it can be measured independently of potentially confounding factors.