Abstract
In the cued visual search paradigm, processing in working memory is known to produce a greater effect on search RT than the mere presentation of an initial cue. An item in WM which validly or invalidly cues a search target respectively decreases or increases RT. Soto and Humphreys (2008) report that increases in the task load reduce the validity effect, perhaps by reducing top-down activation from WM. It has also been suggested that effects on search occur particularly when items are being consolidated in WM. Here we examined how WM load interacts with the effect of altering the time lag between the memory cue and search displays, separating out effects from different serial positions in WM. With a 2-item WM load, the first item influenced subsequent search but this effect did not vary across the time lags. The second item had a large effect on search, the effect was independent of the WM load and it increased at the short time lag (but remained significant even with a long time lag between the memory and search displays). Decreasing effects of WM influence on search, as the WM load increases, reflect the reduced activation of early items in a WM list relative to late items. The final items in a list take time to consolidate but influence performance irrespective of the load. The results suggest that there is differential activation in WM as a function of the serial position of stimuli, that search is most strongly modulated when WM is being consolidated but that substantial WM effects remain even after consolidation has taken place.
Meeting abstract presented at VSS 2012