Cognitive influences on the crossed-hands deficit: An investigation of the dynamic nature of tactile processing

Abstract

Theories of tactile localization ability are based largely on the study of crossing effects, in which crossing the hands leads to a significant impairment in performance. This work has resulted in a rich literature that establishes tactile localization as inherently multisensory in nature. However, new work suggests that the studies used to date have made incorrect assumptions about the processes underlying performance (Maij et al., 2020) and the perceptual information that is considered (Badde et al., 2019). This thesis proposes the addition of a new parameter to existing theory that allows for these new results to be incorporated into the existing literature—specifically, the influence of cognitive factors on performance. The Introduction provides an overview of the current state of the literature, as well as the novel findings that seem to contradict it. I then propose a framework that highlights the malleability of tactile localization. The empirical work focuses on previously unexplored cognitive influences on tactile localization performance. In Chapter 2 I demonstrate that visual imagery influences performance, and importantly, that individual differences in visual imagery ability influence imagery’s effect on performance. In Chapter 3 I demonstrate that an individual’s attentional set influences performance, and that results previously thought to be due to changes in perceptual signal are likely due to changes in attentional focus. In Chapter 4 I highlight the biases in theory and measurement practice that have limited our understanding of tactile localization more broadly. The General Discussion then provides a detailed discussion about how to incorporate the findings of this thesis with existing literature, which requires a paradigm shift to how we view tactile localization.