Curent Projects

Working Memory and Attention. In recent years, it has become clear that working memory is closely related to attentional control and is related to performance in various attention-related tasks. Specifically, interfering with working memory appears to interfere with the control of attention, and individuals with less working memory capacity are less able to control attention compared to individuals with greater working memory capacity.

HAL. has studied the relationship between working memory and attention using experimental manipulations of working memory (single-task vs. dual-task situations), and has found that increasing working memory load increases distractibility. HAL has also used individual differences approaches to study the relationship between working memory capacity and selective, Interestingly, HAL finds no relationship between working memory capacity and contingent involuntary orienting; but individuals with weaker working memory had a more difficult time withholding attention from an irrelevant cue.

Intertrial Effects in Visual Search. Attending to a visual stimulus facilitate or interferes with attending to visual stimuli at a later point in time. For example, selecting a red target from among green non-targets on Trial N is facilitated when the target on Trial N-1 was also red. Thus, search is facilitated if the target on Trial N is the same as the target on Trial N-1; a phenomenon called priming of popout (PoP).  HAL has demonstrated that PoP reflects both target activation effects and distractor inhibition effects. Recently, HAL has examined a “dual-stage” account of intertrial repetition which suggests that intertrial effects are due to both priming processes that affects selection and a memory-retrieval process.

Selective Inhibition to Locations.

Lateralization in Endogenous and Exogenous Attention. Some cognitive operation occur more fluently in the left or right cerebral hemisphere. For example, language is lateralized to the left hemisphere and spatial processing is lateralized to the right hemisphere. Using the spatial blink task, HAL found that spatial blink effects (reduced accuracy on centrally-presented targets following peripheral distractors) varied between the left and right visual hemifields. Specifically, the spatial blink effect for same color distractors was larger when the distractor appeared in the left hemifield than the right hemifield, which may suggest a lateralization in exogenous and endogenous attention.