THE COGNITIVE CONSEQUENCES OF FORGETTING: AN INVESTIGATION OF IOR IN ITEM-METHOD DIRECTED FORGETTING

Abstract

This dissertation investigated the occurrence of an increased magnitude of inhibition of return (IOR) after Forget (F) compared to Remember (R) memory instructions using a directed forgetting cueing paradigm. In such a paradigm, participants are presented with a word in a peripheral location, which is followed by an R or F instruction. A target then appears either at the same location as the previous word, or at a different peripheral location. Participants are required to respond to this target as quickly as possible. Typical results in this task show that participants are slower to respond to targets that appear in the same location as a previously presented word compared to targets appearing in a new location, this is known as IOR. Interestingly, there is an interaction between memory instruction and IOR such that the magnitude of IOR is greater after F compared to R instructions. Previous investigations of this F>R IOR difference suggested that it results from a bias against responding toward the location of F-items, and thus that memory instruction interacts selectively with the motoric form of IOR (Taylor & Fawcett, 2011). The experiments in Chapter 2 tested three alternative hypotheses but found no support for those alternative hypotheses. The experiments in Chapter 3 used eye tracking technology to control whether the oculomotor system was active or suppressed. This allowed an explicit test of whether memory instruction interacts with motoric IOR (which occurs when the oculomotor system is active) and with visual IOR (which occurs when the oculomotor system is suppressed). Contrary to Taylor and Fawcett’s (2011) conclusion, memory instruction interacted with both the motoric and visual forms of IOR. I conclude that instantiating an instruction to forget involves a stage of processing that is shared between the motoric and visual forms of IOR. I discuss the possibility of this process being the differential withdrawal of attention from F compared to R items, or differential modification of the mental salience of information related to F compared to R items.