Age-Related Changes In Memory Abilities In Older Adults

Abstract

The aim of this thesis was to investigate the relationship between ageing and two important everyday memory abilities, prospective remembering and autobiographical recall. In Study 1, 30 young adults (19 - 29 years), 30 middle-aged adults (30 - 59 years), and 29 older adults (60 - 86 years), completed a naturalistic prospective memory task called the Virtual Street; and an autobiographical memory interview for the recall of recent and remote life episodes. Task performance was referenced against a more traditional laboratory-based memory test, one which allows the computation of parameters of memory performance in a process dissociation procedure (PDP) paradigm. The findings suggested that prospective memory abilities were poorer for middle aged and older participants; however, all participants performed well on the errand completion aspect of the task. On the autobiographical remembering task, older adults reported more extraneous detail in both recent and remote episodic recall compared to young adults, yet tended to have a coherent storytelling approach to explaining their memories. There were no discernible age differences in recognition on the laboratory measure; however older adults did show a negative bias in their responses. In Study 2 the autobiographical memory recall abilities of older adults were further investigated. A sample of 80 adults aged between 55 and 90 years completed several neuropsychological tests. Participants’ recall of semantic self knowledge, and remote and recent vivid episodic memories was assessed in a modified verbal autobiographical fluencies (VAF) task. Participants also completed a picture source memory task, similar to the task in study 1, and measures of executive functioning, including the Controlled Oral Word Association Test-FAS version, Digit Span, and the Trail Making Test (TMT). It was hypothesised that there would be age differences in performance on these measures, especially in recollection and vivid episodic recall. Furthermore, it was hypothesised that performance on the picture memory task should be a significant predictor of the detail of vivid episodic recall regardless of memory age, and secondly that executive functions should be more related to the recall of semantic information. In theory, this would suggest hippocampal involvement for vivid episodic recollection and provide a novel test of the multiple trace theory (MTT) of memory consolidation. The findings showed that the oldest group of participants produced fewer responses in both remote and recent fluency tasks. Only remote vivid details were significantly predicted by the picture memory task; however, semantic information was predicted by executive functions. Based on the results of these two comprehensive studies it is apparent that age-related changes in everyday memory do not indicate a clear cut decline in specific functions but rather result from a complex interplay of factors.