Explicit and Implicit Memory Loss in Aging

Richard E Hicks,Victoria E Alexander,Mark Bahr

doi:10.5539/ijps.v10n3p40

Richard E Hicks, Victoria E Alexander + Show 1 more

Open Access

https://doi.org/10.5539/ijps.v10n3p40

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Abstract

How our memory is affected as we age has been given considerable attention over recent decades as we strive to understand the cognitive processes involved. Memory types have been identified as either explicit (declarative - related to episodes or semantics) or implicit (non-declarative – related to procedures, habits, or earlier priming). Studies have identified likely age-related decline in explicit but not implicit memory though there are opposing results suggested from other studies. It is thought cognitive reserve capacities might explain any non-decline as aging individuals use alternative or additional pathways to ‘remember’. This theory might be supported indirectly if older members remember material accurately but take longer to supply answers. In our current study we re-examined whether age-related differences in accuracy and speed of access in memory are present in both implicit and explicit memory processes and we increased the number of experimental age groups (from 2 to 3) - most previous studies have compared just two groups (young, and old). With three groups (young, middle-old, and older aged groups) we can identify trends across the age range towards deterioration or preservation of memory. We examined sixty-six participants (49 females; 17 males) aged 18 to 86 years (M = 50.27, SD = 21.06) from South-Eastern Queensland and divided these into younger (18 to 46 years of age), middle old (50 to 64) and older aged (65+) cohorts. Participants were administered tasks assessing implicit and explicit memory using computer presentations. Consistent with most prior research, no age differences were identified on accuracy in the implicit memory tasks (verbal and non-verbal, including priming), suggesting that memory for implicit material remains preserved. However, on the explicit memory tasks, older adults performed less accurately than the younger adults, indicative of decline in explicit memory as we age. The finding of a decline in explicit memory but no significant decline in implicit memory confirms most earlier research and is consistent with a view of modular decline rather than overall decline in memory with increasing age. In addition, differences found in speed of response in otherwise accurate implicit memory with older respondents significantly slower, suggests possible support for the cognitive reserve hypothesis.

Highlights

How our memory is affected as we age has been given considerable attention over recent decades as we strive to understand the cognitive processes involved
Memory types have been identified as either explicit memory (‘declarative’ - related to episodes or memory for events involving explicitly for example what we had for breakfast or items from lists of learned words, numbers or faces) or implicit memory (‘non-declarative’ – related to procedures, habits, or priming) (Sigelman & Rider, 2018)
The current study investigated whether a decline occurs in accuracy and time taken to process implicit memory materials; and examined similar decline in explicit memory

Summary

Introduction

How our memory is affected as we age has been given considerable attention over recent decades as we strive to understand the cognitive processes involved. Memory types have been identified as either explicit memory (‘declarative’ - related to episodes or memory for events involving explicitly for example what we had for breakfast or items from lists of learned words, numbers or faces) or implicit memory (‘non-declarative’ – related to procedures, habits, or priming) (Sigelman & Rider, 2018). As part of the study of memory (and its decline with age) different cognitive and biological areas have been examined, not just the explicit and implicit memory processes which are the focus of this article. Some of these broader areas have included the numerous physiological and biological studies that include those addressing theories on memory loss (e.g., see Park & Festini, 2016); the importance of nutrition in aging (Vauzour et al, 2017); neuronal effects as we age including effects in dementia (e.g., Kennedy et al, 2012; Nyberg et al, 1996; Wang et al, 2011); working memory loss (Wang et al, 2011); cognitive reserve in dealing with memory loss in ageing and dementia

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