The effects of saliency and task difficulty on visual search performance in ageing and Alzheimer's disease.
We asked whether the poor performance on visual search tasks typical of patients with Alzheimer's disease (AD) is the result of a selective deficit in the ability to shift attention from item to item, or the consequence of an inefficient processing of each item within the search set. We attempted to manipulate the ease of attention shifting and item processing in a visual search task by manipulating target salience and task difficulty, respectively. Significant effects of both target saliency and task difficulty for both AD patients and age-matched controls were obtained, with the AD group displaying greater effects of both of these manipulations than the controls. This interaction remained even when the reaction time data were log-transformed to account for the overall slower reaction times of the AD group. We conclude that inefficiency in visual search tasks in AD probably represents the product of both attention shifting and target processing factors.
Tales
Andrea
A
School of Psychology, Cardiff University, Cardiff CF11 3YG, Wales, UK.
Muir
Janice
J
Jones
Roy
R
Bayer
Anthony
A
Snowden
Robert J
RJ
D000368:Aged; D000375:Aging / Q000502:physiology*; D000544:Alzheimer Disease / Q000503:physiopathology*; D001288:Attention / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D008606:Mental Processes / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D012016:Reference Values; D014796:Visual Perception / Q000502:physiology*