Studies of directed forgetting in older adults.

Abstract

Younger and older adults were compared in 4 directed forgetting experiments. These varied in the use of categorized versus unrelated word lists and in the use of item by item versus blocked remember-forget cueing procedures. Consistent with L. Hasher and R. T. Zacks's (1988) hypothesis of impaired inhibitory mechanisms in older adults, a variety of findings indicated that this age group is less able than yoimger adults to suppress the processing and retrieval of items designated as to be forgotten (TBF). Specifically, in comparison with younger adults, older adults produced more TBF word intrusions on an immediate recall test (Experiments 1A and 1B), took longer to reject TBF items (relative to a neutral baseline) on an immediate recognition test (Experiment 3), and recalled (Experiments 1A, 1B, and 2) and recognized (Experiments 1B and 2) relatively more TBF items on delayed retention tests in which all studied items were designated as targets.In this article, we present four experiments comparing the performance of younger and older adults on directed forgetting tasks. In this type of task (e.g., see Bjork, 1989), participants are presented items to study, some of which they are told to remember and others of which they are told to forget. Because the cueing as to which items are to be remembered (TBR items) and which are to be forgotten (TBF items) occurs after the items have been presented for study, participants must pay some attention to each item as it is presented. Thus, the directed forgetting paradigm investigates the ability to forget some inputs that one has recently attended to while at the same time remembering others presented in the same context and near the same time. To the degree that one is successful at this task, as younger adults generally are, the following trends are seen: The presence of TBF items on a list does not reduce recall or recognition of TBR items; there are few intrusions of TBF items when participants are asked to report only TBR items; and performance on TBF items is relatively poor when, on a later retention test, participants are asked to report TBF as well as TBR items.

Specificity of inhibitory deficits in normal aging and Alzheimer's disease

“…Motor inhibition deficits were also observed on the stop-signal task [66,74], the go/no-go task [80] and the antisaccade task [18]. Finally, decreased directed forgetting abilities in working and episodic memory have also been reported [9,106]. However, a negative effect of aging on suppression abilities has not been systematically observed (see [63] for the Stroop task, [27,66,67,96,102] for negative priming and [48] for inhibition of return), or is sometimes explained by more basic cognitive variables, such as a decrease in processing speed [88,89,101], fluid intelligence abilities [93] or circadian preferences [59; see 105].…”

Brain imaging of the central executive component of working memory

“…In other words, they require "controlled attention" capacity, which is a domain-free attentional capacity to maintain or suppress actively working memory representations [45]. The other interpretation is that the three executive functions involve an inhibitory capacity, which is considered by certain authors as a basic unit of working memory or executive functioning [e.g., 37,130]. Taken as a whole, the results of this study suggest that executive functioning is characterized both by the unity and diversity of processes.…”

“…A third problem is that each executive function can be assessed by several cognitive tasks. For example, inhibition function has been evaluated by the Stroop test [117], the Hayling task [23], the stop-signal paradigm [73], the antisaccade task [100], the negative priming [119] and the directed forgetting paradigm [130]. Finally, as Duncan [43; see also 19 and 99] has pointed out, tasks cease to be effective tests of executive function as soon as they are performed more than once and thus become automatic.…”

Alexithymia impairs the cognitive control of negative material while facilitating the recall of neutral material in both younger and older adults

“…First, we wanted to examine whether alexithymia scores influence the ability of adults to accurately recall negative TBR and inhibit negative TBF items. Second, we wanted to examine whether age influences the ability of individuals to inhibit unwanted, negative memories (i.e., the TBF items), as the literature is unclear about what to expect with negative material; on the one hand, decreased cognitive control in advanced age might lead to an inability to inhibit negative TBF items and a decreased ability to actively recall negative TBR items (e.g., Dywan & Murphy, 1996;Hasher, Zacks, & May, 1999;Jacoby, Bishara, Hessels, & Toth, 2005;Zacks, Hasher, & Radvansky, 1996, but see Zellner & Bäuml, 2006). On the other hand, the literature examining the "positivity effect" suggests older adults should exhibit an increased ability to inhibit the recall of negative TBF intrusions and a decreased ability to actively recall negative TBR items (Charles et al, 2003;Mather & Carstensen, 2005;Mather & Knight, 2005).…”