The effects of the duration of remember and forget cues were examined to test the differential rehearsal account of item-based directed forgetting. In Experiments 1 and 2, cues were shown for 300, 600, or 900 ms, and a directed forgetting effect (better recognition of remember than forget items) was found at each duration. In addition, recognition of both remember and forget items increased with cue duration. These 2 effects did not interact. The results of Experiment 2 further showed that memory for the cue associated with the study items increased with cue duration as well. The results of Experiment 1 were replicated in Experiment 3 for cue durations of 1, 2, and 3 s. Finally, a similar pattern of results was found for cue durations of 2, 4, and 6 s for associative recognition of random word pairs. If subjects cannot immediately terminate the processing of forget items, the lingering processing of these items is as beneficial as the continued processing of remember items. Alternatively, subjects may use inefficient or counterproductive strategies that ironically improve memory for the information they wish to forget.

We use a vibrotactile-delayed match-to-sample paradigm to evaluate the effects of interference on working memory. One of the suggested mechanisms through which interference affects performance in working memory is feature overwriting: Short-term representations are maintained in a finite set of feature units (such as prefrontal neurons), and distractor stimuli co-opt some or all of those units, degrading the stored representation of an earlier stimulus. Subjects were presented with two vibrotactile stimuli and were instructed to determine whether they were of the same or different frequencies. A distractor stimulus was presented between the target and probe stimuli, the frequency of which was a function of the target stimulus. Performance on the task was affected by the frequency of the distractor, with subjects making more erroneous same judgments on different trials when the distractor frequency was closer to the probe than to the target, than when the distractor was further from the probe than the target. The results suggest that the frequency of the distractor partially overwrites the stored frequency information of the probe stimulus, providing support for the feature-overwriting explanation of working memory interference.

Previous research has shown that the picture superiority effect (PSE) is seen in tests of associative recognition for random pairs of line drawings compared to pairs of concrete words (Hockley, 2008). In the present study we demonstrated that the PSE for associative recognition is still observed when subjects have correctly identified the individual items of each pair as old (Experiment 1), and that this effect is not due to rehearsal borrowing (Experiment 2). The PSE for associative recognition also is shown to be present but attenuated for mixed picture-word pairs (Experiment 3), and similar in magnitude for pairs of simple black and white line drawings and coloured photographs of detailed objects (Experiment 4). The results are consistent with the view that the semantic meaning of nameable pictures is activated faster than that of words thereby affording subjects more time to generate and elaborate meaningful associations between items depicted in picture form.

Previous research has shown that hit and false alarm rates and claims of remembering are greater when test items are shown in the same context that was present at study. In the present article, the effects of environmental context (photographs of scenes shown in the background) were evaluated in a yes-no recognition task when context was manipulated on the computer screen compared with when subjects were wearing virtual reality glasses (Experiment 1), in a forced-choice recognition task to address the question of criterion changes (Experiment 2), and in a free-recall task (Experiment 3) to address the issue of generality. The results show that both specific item-context associations and the familiarity of an old context influence memory performance. We suggest that the effects of environmental context are like other instances of reconstructive memory and can both support and distort recognition memory.

Traditionally, working and short-term memory (WM/STM) have been believed to rely on storage systems located in prefrontal cortex (PFC). However, recent experimental and theoretical efforts have suggested that, in many cases, sensory or other task-relevant cortex is the actual storage substrate for WM/STM. What factors determine whether a given WM/STM task relies on PFC or sensory cortex? In the present article, we outline recent experimental findings and suggest that the dimensionality or complexity of the to-be-remembered property or properties of a stimulus can be a determining factor.