Exploring the Relationship between Long-Term Memory and Attention through Attentional Templates
It is assumed that the contents of visual working memory (VWM) guide attention. This notion has been challenged by work which has demonstrated that multiple searches for the same target changes contralateral delay activity (CDA), an event-related potential that is the putative marker of the amount of information maintained in VWM. It has been suggested that the disappearance of the CDA with an invariable target marks the transfer of the attentional template from VWM storage to long-term memory (LTM) storage. Therefore, LTM may guide attention in many situations where it has previously been assumed that VWM guides attention. However, while the transfer of attentional template from VWM to LTM is demonstrated through a decrease in the amplitude of the CDA, this shift has not been accompanied by a corresponding behavioral change in response times. The purpose of the present study was to test the hypothesis that a LTM template leads to faster performance than a VWM template (the LTM template hypothesis). Two experiments were conducted to explore this hypothesis. In Experiment 1, the LTM template hypothesis was examined by comparing performance between two different groups of subjects: the first group searched for a target that changed on every trial (variable) while the second group searched for a target that was invariable across trials. In Experiment 2, one group of subjects searched for both the variable and invariable targets. The results showed that a LTM template (invariable target search) leads to faster performance than a VWM template (variable target search). Roughly six times as many trials were required for an effect on performance compared to the number of trials required for an effect in CDA amplitude. Eye tracking results suggest the change in performance is due to more efficient search initiation and target verification.
visual search, eye tracking, long-term memory, attentional templates, visual attention
Networked Digital Library of Theses and Dissertations