The role of top-down suppression in mitigating the disruptive effects of task-irrelevant feature changes in visual working memory

Abstract

Studies of change detection have shown that changing the task-irrelevant features of remembered objects impairs change detection for task-relevant features, a phenomenon known as the irrelevant change effect. Although this effect is pronounced at short study-test intervals, it is eliminated at longer delays. This has prompted the proposal that although all features of attended objects are initially stored together in visual working memory (VWM), top-down control can be used to suppress task-irrelevant features over time. The present study reports the results of three experiments aimed at testing the top-down suppression hypothesis. Experiments 1 and 2 tested whether the magnitude or time course of the irrelevant change effect was affected by the concurrent performance of a demanding executive load task (counting backwards by threes). Contrary to the top-down suppression view, the decreased availability of executive resources did not prolong the duration of the irrelevant change effect in either experiment, as would be expected if these resources were necessary to actively suppress task-irrelevant features. Experiment 3 showed that a visual pattern mask eliminates the irrelevant change effect and suggests that the source of the effect may lie in the use a high-resolution, sensory memory representation to match the memory and test displays when no task-irrelevant feature changes are present. These results suggest that the dissipation of the irrelevant change effect over time likely does not depend on the use of top-down control and raises questions about what can be inferred about the nature of storage in VWM from studies of this effect.

Event-based encoding of biological motion and location in visual working memory

“…It is of note that compared with the lifetime of the irrelevant dimension in Treisman and Zhang (2006, 3.0 s), Logie et al (2011, 1.5 s), and Bocincova et al (2017, 1.25 s), the lifetime of the irrelevant dimension in the current study, which is or is not related to biological motion, was much longer. However, caution should be taken in reaching this conclusion as the current study used different materials and indices from the aforementioned two studies.…”

“…Logie et al (2011) later conducted a more thorough investigation by manipulating the duration of the delay (0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 s) as well as the type of irrelevant dimension (location, colour, and shape). They found that all the three irrelevant dimension types could be encoded into VWM involuntarily (see Bocincova et al, 2017, for a similar study). Critically, in line with Treisman and Zhang (2006), the distracting effect vanished after a delay period, although the irrelevant location was maintained for a longer time than the irrelevant colour or shape.…”

“…One possible reason for the absence of a distracting effect on accuracy in the current study was that the representations of the current memorised stimuli were fairly stable in VWM, and the signal of irrelevant change was too weak to impair the stored representations. Indeed, Treisman and Zhang (2006), Logie et al (2011), and Bocincova et al (2017) used a whole-report display (the same number of objects was used between memory and test arrays). When the irrelevant dimension changed, all the related irrelevant values in the test array changed.…”

“…Finally, Bocincova et al (2017) recently suggested that the irrelevant dimension was not stored in VWM, but relied on a high-capacity iconic or fragile WM trace (Vandenbroucke et al, 2011), which would be erased by pattern masks that were similar to the memory stimuli. However, a key difference between the Bocincova et al (2017) study and the current study was that the target stimuli in Bocincova et al were two-featured bindings, whereas they were single features in the current study. It is possible that extra irrelevant features were difficult to be extracted into VWM when VWM retains bound representations, whereas it could be relatively easy when VWM retains single features.…”

New perspectives on binding in visual working memory

“…This is long enough to rule out short‐lived iconic (sensory) memory as a basis for recall performance in these tasks. However, there is evidence that the effects of task‐irrelevant location changes on change detection performance for feature bindings decline significantly over longer delay durations (Bocincova, van Lamsweerde, & Johnson, ; Logie, Brockmole, & Jaswal, ; Treisman & Zhang, ). It is therefore possible that location is important for feature binding only at short to intermediate delays, and a different storage format supports memory at longer delays.…”