Special interests in language include, speech errors, derivational and inflectional morphology, stuttering, delayed auditory feedback, ambiguity and connotative meaning in language comprehension, and effects of prosody on the perception of computer compressed speech. Other special interests include relations between language perception and production, and the neural bases of language, memory, and normal cognitive aging, as discussed next. Dr. MacKay's lab is currently engaged in two lines of research directed at understanding the neural bases of language, memory, and normal cognitive aging. Our main neuroscience-linked research line concerns brain correlates of normal cognitive aging in healthy 65-90 year olds. This research has examined age-linked differences between the process of forming new connections versus the process of activating already formed connections in various contexts, including language production (especially the tip-of-the tongue phenomenon; see Burke, MacKay, Worthley & Wade, 1991), explicit versus implicit tests of memory (see MacKay & Abrams, 1996), speech perception and language comprehension (e.g., the verbal transformation effect; see MacKay, Wulf, Yin & Abrams, 1993), and very short-term memory for language, especially the effects of aging on the formation of single, theoretically-specified connections in the repetition blindness and deafness paradigms (see MacKay, Miller & Schuster, 1994). This line of research has shown that normal aging greatly impairs the formation of new connections but has relatively little impact on the process of activating already formed connections, and refines previous research on this topic where hundreds of unspecified new and old connections have been uncontrolled or free to vary. Dr. MacKay has been the PI for a major project funded by the National Institute on Aging, on the organization of cognitive processes in old age. The project addresses mechanisms underlying age-related changes in cognition, especially comprehension, memory, and the production of language and other cognitive skills, and focuses on tasks and phenomena where older adults are predicted to exhibit superior performance to young adults, unlike previous work where declines in abilities of older adults have been the main focus. The project also carries practical implications for many areas of cognitive psychology, from the everyday difficulties of older adults in learning and using new information, to teaching techniques for adult education programs.
