Semantic Priming from Uncued Distractors in Alzheimer's Disease.

Research Question: Are semantic impairments in Alzheimer's disease (AD) partially due to deficits in spatial attention?

Methods And Results: In a target detection task, both older adults (OAs) and AD individuals were facilitated by valid spatial cues, but only OAs were impaired by invalid cues compared to neutral. In a reading task, spatial cues validly or invalidly cued the location of pictures, which were related or unrelated to subsequent, centrally presented, words. OAs showed semantic priming only after valid cues, whereas AD individuals showed priming after valid and invalid cues.

Age-related delay in reduced accessibility of refreshed items.

Previously, we demonstrated that in young adults, briefly thinking of (i.e., refreshing) a just-seen word impairs immediate (100-ms delay) perceptual processing of the word, relative to words seen but not refreshed.

Foraging for thought: an inhibition-of-return-like effect resulting from directing attention within working memory.

Perceptual processing of a target stimulus may be inhibited if its location has just been cued, a phenomenon of spatial attention known as inhibition of return (IOR). In the research reported here, we demonstrated a striking effect, wherein items that have just been the focus of reflective attention (internal attention to an active representation) also are inhibited. Participants saw two items, followed by a cue to think back to (i.

Lost thoughts: implicit semantic interference impairs reflective access to currently active information.

Why do we lose, or have trouble accessing, an idea that was in the focus of attention only a moment ago, especially in the absence of any apparent distraction? We tested the hypothesis that accessing a single item that is already active is affected by implicit interference (interference of which we have little or no awareness). We presented masked words that were semantically related or unrelated to a single visible target word that participants were cued to think of (refresh) a half second after its offset. Masked related but not unrelated words increased time to refresh the target but did not influence time required to read a target that was physically present.

Age differences in brain activity during perceptual versus reflective attention.

This functional magnetic resonance imaging study presented participants with a face and scene simultaneously on each trial, and assessed the impact of perceptual versus reflective selective attention on activity in parahippocampal place area. Young and older adults showed equivalent activation in parahippocampal place area when cued to attend to the scene when the stimuli were perceptually present and when cued to refresh (briefly think about) the scene after the stimuli were no longer present. The groups also showed equivalent deactivation when cued to attend to the face when the stimuli were perceptually present.

The consequence of refreshing for access to nonselected items in young and older adults.

We examined the effect of competition on briefly thinking of just-seen items. In Experiment 1, participants saw a set of either three related or three unrelated words and then read one of the words again (repeat) or thought briefly of one of the words (refresh). Participants read the set a second time, after which they either refreshed a second word from the set or read a new word.

Preserved spatial memory over brief intervals in older adults.

Two studies compared young and older adults' memory for location information after brief intervals. Experiment 1 found that accuracy of intentional spatial memory for individual locations was similar in young and older participants for set sizes of 3 and 6. Both groups also encoded individual locations in relation to the larger configuration of locations.