The role of prior familiarisation and meaningfulness of verbal and visual stimuli on directed forgetting.

ABSTRACTIntentional forgetting of unwanted information is a crucial cognitive function that is often studied with directed forgetting (DF) procedure, whereby cuing some study materials with Forget (F) instruction impairs their memory compared to cuing with Remember (R) instruction. This study investigates how the nature of information (verbal or pictorial), its semantic significance (meaningful or meaningless), and the degree of prior episodic familiarity influence DF. Before the DF phase, stimuli were familiarised by pre-exposing them 0, 2, or 6 times in a prior preview phase. Finally, memory for all items was assessed with old/new recognition test. Experiment 1 employed words, Experiment 2 utilised fractal images, Experiment 3 featured both meaningful and meaningless object images, and Experiment 4 used words and nonwords. Our results indicate that materials that produced better memory performance are not always harder to intentionally forget. Previewed items showed reduced DF compared to non-previewed items regardless of the nature of information, and meaningless stimuli are challenging to intentionally forget regardless of their degrees of familiarisation unless they are meaningless verbal materials. Collectively, the results highlight the importance of joint consideration of the stimulus format, its meaningfulness, and its episodic familiarity in understanding conditions that interact with intentional forgetting.

Eye movement analyses of strong and weak memories and goal-driven forgetting.

Research indicates that eye movements can reveal expressions of memory for previously studied relationships. Specifically, eye movements are disproportionately drawn to test items that were originally studied with the test scene, compared to other equally familiar items in the test display - an effect known as preferential viewing (e.g., Hannula, Ryan, Tranel, & Cohen, 2007). Across four studies we assessed how strength-based differences in memory are reflected in preferential viewing. Participants studied objects superimposed on background scenes and were tested with three-object displays superimposed on the scenes viewed previously. Eye movements were monitored at test. In Experiment 1 we employed an item-method directed forgetting (DF) procedure to manipulate memory strength. In Experiment 2, viewing patterns were examined across differences in memory strength assessed through subjective confidence ratings. In Experiment 3, we used spaced repetitions to objectively strengthen items, and Experiment 4 involved a list-method DF manipulation. Across all experiments, eye movements consistently differentiated the effect of DF from other strength-based differences in memory, producing different viewing patterns. They also differentiated between incidental and successful intentional forgetting. Finally, despite a null effect in recognition accuracy in list-method DF, viewing patterns revealed both common as well as critical differences between list-method DF and item-method DF. We discuss the eye movement findings from the perspective of theoretical accounts of DF and other strength-based differences in memory.

Examination of relational memory in multidimensional schizotypy.

We report the first study to examine the association of positive, negative, and disorganized schizotypy with relational memory. Relational memory refers to memory for relations among multiple elements of an experience, and this form of episodic memory is different from memory for individual elements themselves. Using a cornerstone task from the neurocognitive literature that is designed specifically to assess relational memory, we found that negative schizotypy, but not positive or disorganized schizotypy, is associated with impaired relational memory performance. The deficit was observed both in poorer accuracy and slower response time. The results demonstrate the importance of examining schizotypy as a multidimensional construct, and indicate that using a total schizotypy score both obscures the nature of the association with various dimensions of schizotypy and also explains only half of the variance accounted for by taking into consideration the multidimensionality of schizotypy. These results add to previous findings that negative schizotypy is associated with a wide array of episodic memory deficits linked to impairment in retrieval and processing of contextual information.