Uncovering evidence for the inhibition of return effect in the non-spatial domain

Abstract

Our attentional system has the remarkable ability to allow familiar contexts to guide attentional orienting, while still retaining the ability to orient rapidly to novelty in our environment. Many cognitive paradigms have been used to investigate the particular process that is responsible for orienting attention to novel events, but each paradigm has produced a unique set of boundary conditions. One such paradigm has studied an effect labelled Inhibition of Return (IOR), which has been argued to tap into an attentional mechanism that rapidly orients attention to novelty, but only in the spatial domain. The IOR effect was initially taken as evidence of a fundamental difference between spatial attentional orienting and non-spatial attentional orienting. However, there were a small number of early studies that questioned the view that the IOR effect can only be observed in the spatial domain. In this dissertation, I built upon the evidence for non-spatial IOR by uncovering the effect using a Target-Target (TT) procedure. Although a number of prior studies had failed to observe non-spatial IOR using a TT procedure, I was able to uncover non-spatial IOR effects using a TT procedure by introducing an intervening event. The IOR-like effect that was uncovered using this procedure was labelled the intervening event effect. I introduced a dual process framework to explain the intervening event effect. According to the dual process framework, intervening events between consecutive targets can disrupt an episodic integration process, allowing the influence of a separate opposing process to be measured more directly. Using the dual process framework, I studied the level of processing of the intervening event that was necessary to disrupt episodic integration, as well as the context-sensitivity of the episodic integration process. Lastly, I investigated the role of subjective expectancy in the studies used to measure non-spatial IOR in this thesis.