Research Interests

Age-related Changes in Top-Down Attentional Control

Currently, I am investigating age differences in top-down attentional processing during visual search. Previous research by Wolfe and colleagues has shown that when observers have knowledge of specific characteristics of a target (e.g., the target’s color), they can find that target among different colored distractors in a display much more quickly. We are finding that older adults can also benefit from the use of this top-down (i.e., knowledge-driven) processing during visual search to the same extent as younger adults. This is an exciting area of research because it demonstrates that not all aspects of attention or cognition are sensitive to the aging process.

We are continuing with this research looking at whether older adults can still use top-down information when they are required to inhibit/ignore an irrelevant, but attention grabbing, item in the display. Additionally, I have been further examining which physical characteristics (e.g., color or orientation) of the target are most beneficial for guiding older adults’ search of the target. There also appears to be evidence that providing more than one feature of the target (e.g., the target’s color and orientation) may not aid in the search of that target any more than providing only one feature

Memory, Attentional Resources & Aging

My research program has also focused on using divided attention paradigms to assess how limited attentional capacity, or resources, explain declines in memory ability in older adults (aged 60 +). These divided attention paradigms require older adults to perform a distractor task during either the encoding or the retrieval stage of memory. Specifically, I have been interested in whether the aging process affects encoding and retrieval processes differently.

Previous research has shown that distractor task performance drops disproportionally for older adults (relative to younger adults) while recalling information (Whiting & Smith, 1997; Whiting, 2003). This would suggest that older adults may be deficient in the attentional resources required to recall information. Some of my recent research has shown that performing a distractor task while encoding (studying) information also affects recall for both age groups. What appears most intriguing is that some encoding strategies, such as the self-generation of words to-be-remembered, may actually be less resource intensive than standard memory instructions (i.e., no memory strategy provided) for older adults while still increasing memory recall above baseline levels (Whiting, 2003). This later finding suggests that older adults might benefit the most from memory strategies that do not require a great deal of executive processing. I am also interested in different means of measuring divided attention ability such as attention operating characteristics and time sharing paradigms.

Using fMRI to Measure Age-related changes in Cognition

In cooperation with the Madden Lab at Duke University, we have been using neuroimaging techniques to examine age-related changes in cognition. In a recent paper Whiting et al. (2003) we showed that younger and older adults exhibited different patterns of activation during a semantic memory task even though there were no age differences in behavioral measures (lexical decision). We theorized that during the task younger and older adults may have used different strategies which may have lead to the different patterns of activation. That is, younger adults seemed to rely more on perceptual features to complete the lexical decision task (deciding whether a string of letters is a word or not) whereas older adults appeared to rely more on semantic information. In another study we are examining executive function in younger and older adults using fMRI. The preliminary results suggest that age differences in executive processing tasks may be best explained in terms of output response conflicts rather than more central processing mechanisms. The technological advances in fMRI have opened a new door into understanding age-related changes in cognition, and new theories of aging will clearly be dependent on this area of research.