Abstract
In an orientation judgement task Liu and Becker (2013) demonstrated that working memory load affected participants' guesses, but not response precision. As attention has previously been shown to affect the precision of orientation judgements (Anderson & Druker, 2013), we were interested in investigating the effect of attention and visual short-term memory together in the same task, and with varying memory demands and cue reliabilities. Experimentally, two gabors at different orientations briefly appeared. Participants rotated a centrally presented response gabor to match one of the indicated target gabors. Attention was manipulated by a brief luminance cue and memory by presenting the two possible targets simultaneously or sequentially. Increased memory load increased the proportion of trials on which participants guessed. When attentional cues were informative, the precision of responses improved. When the cue was not informative, participants made fewer guesses on valid trials compared to invalid trials. Precision was unaffected by a non-informative spatial cue. Our results provide evidence that under conditions of reduced target uncertainty, attention improves precision because resources do not need to be divided across two stimuli, whereas when two gabors are equally probable targets, attention improves the likelihood that the stimuli will be encoded into memory. For both informative and non-informative cues, the cueing effect was larger on simultaneous compared to sequential trials, providing evidence that attention also serves to reduce competition from irrelevant stimuli.
Meeting abstract presented at VSS 2014