Abstract
There is renewed interest in the idea that expectation contributes to the inhibition of return (IOR) effect in spatial orienting. Spalek (2007) asked participants to report where they thought a target was programmed to appear (although a target never actually appeared) following presentation of an abrupt-onset peripheral cue. Participants reported "expecting" a target to appear opposite the cue with greater-than-chance likelihood, and to appear at the cued location with lower-than-chance likelihood. However, using a different task in which participants guessed in which of four locations a target was hidden, Danziger and Rafal (2009) reported the opposite result: greater-than-chance selection of the cued location. The present study aimed to determine why opposite patterns of results occurred in these two studies. In Experiment 1, a procedure similar to Spalek (2007) was used, and similar results were observed. In Experiment 2, participants shifted their eyes to the location where they expected the target to appear following an abrupt-onset cue, triggering the appearance of the target. In contrast, to Experiment 1, participants made "expectation" eye movements to the cued location with greater-than-chance likelihood. A potential key difference between Experiments 1 and 2 is that expectations could be confirmed or disconfirmed by target presentation in Experiment 2 but not in Experiment 1. The procedure in Experiment 3 replicated Experiment 1 but with targets presented following each response. Indeed, the results of Experiment 3 resembled those of Experiment 2. The results of these experiments demonstrate that there is unlikely to be one foolproof way to measure "expectation", and that behaviours that appear to measure expectation are sensitive to task-specific factors that can lead to either of two conclusions; that a pattern of measured expectation is consistent with the behavioural IOR effect, or that a pattern of measured expectation is completely counter the behavioural IOR effect.
Meeting abstract presented at VSS 2014