Age-Related Changes in Associative Memory

Older adults suffer from many cognitive impairments relative to young adults and one of the most established types of age-related cognitive decline is a reduction in memory performance. Memory for single units of information (item memory) have been shown to be less susceptible to cognitive ageing than memory for associations among units of information (associative memory). An associative deficit hypothesis has been used to describe these observations as an age-related impairment in forming links between single units of information. The thesis elucidated specific differences between item and associative memory and evaluated how such differences correspond to their differential susceptibility to the effects of cognitive ageing. This indicated links between the associative deficit hypothesis and other theories of age-related memory decline, in particular, to the notion of age deficits in memory resulting from age deficits in self-initiated processing (in the absence of environmental support). Experiments 1-3 considered associative memory where the processing of associations was encouraged by distinctiveness of memory stimuli. Environmental support provided by distinctiveness was shown to improve associative memory in older adults. Experiments 4-7 considered how item and associative memory differ in their support from preexisting knowledge. Experimentally equating preexisting knowledge for item and associative memory tests eliminated the age-related associative deficit. Furthermore, it was found that preexisting knowledge could be used to enhance associative memory performance in older adults by providing support to encoding and/or retrieval processes. Experiment 8 established that item and associative memory processes were equally disrupted by a concurrent task, which indicated that both memory types are similarly affected by levels of available cognitive resources. In general, age-related associative deficits were considered to result from differing levels of environmental support for item and associative memory as opposed to a differential decline of item and associative memory processes.