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Shedding light on the functionality of the looking at nothing-phenomenon for memory retrieval

People fixate on blank locations if task irrelevant visual stimuli previously occupied that region of space. This so-called ‘looking at nothing’ phenomenon has been associated to information retrieval from an integrated memory representation. Although, it has been found that looking at nothing increases accuracy of memory retrieval for visual information (Ferreira, Apel, & Henderson, 2008), it is unclear whether it also affects the retrieval of auditory information from memory (Richardson, Altmann, Spivey, & Hoover, 2009). To test the relation between gaze behaviour and memory retrieval of auditory information, two experiments were conducted. In Experiment 1, participants listened to four sentences, each associated to one of four areas on the screen. Subsequently, they had to verify an auditorily presented statement about one of the sentences, by retrieving the related information from memory. During the retrieval phase, they could gaze freely. Eye fixations were recorded throughout the experiment with a remote eye tracker sampling gaze data of the right eye at a rate of 50Hz. As predicted, participants fixated proportionally more often towards the spatial area that was associated to the auditory information then to one of the irrelevant locations. When participants answered correctly, they showed looking at nothing behaviour. However, when they gave a wrong answer, looking at nothing behaviour could not be observed. These findings suggest that eye movement towards emptied spatial areas are part of information retrieval from memory for auditory information.

In Experiment 2 we went one step further and investigated whether there is a causal link between gaze behaviour and retrieval performance. Therefore, eye-movements were manipulated as the independent variable. Participants followed the same procedure as in Experiment 1 with the one difference that during retrieval, participants could either gaze freely, or had to look at a fixation cross that appeared in the area associated to the tested sentence or in one of the other three areas. This manipulation of eye movements significantly affected retrieval performance: When participants gaze was guided away from the relevant location, retrieval performance decreased in comparison to when they were allowed to gaze freely. When gaze behaviour was guided towards the relevant location, retrieval performance did not increase in comparison to the free gaze condition.

Our results suggest that looking at nothing behaviour does affect memory retrieval of auditory information and therefore support the assumption of looking at nothing as a consequence of an internally stored memory representation. However, indexing towards the emptied location does not serve as an additional retrieval cue for auditory information.

Litterature:

Ferreira, F., Apel, J., & Henderson, J.M. (2008). Taking a new look at looking at nothing. Trends in Cognitive Science, 12(11), 405-410.

Richardson, D.C., Altmann, G.T.M., Spivey, M.J., & Hoover, M.A. (2009). Much ado about eye movements to nothing: a response to Ferreira et al.: Taking a new look at looking at nothing. Trends in Cognitive Science, 13(6), 235-236.