Julie L. Earles

Mediators of Long-Term Memory Performance Across the Life Span

An individual-differences approach was used to examine the component processes that predict episodic long-term memory performance. A total of 301 participants ages 20-90 received a 7-hr cognitive battery across 3 days. Key constructs hypothesized to affect long-term memory function were assessed, including multiple measures of working memory and perceptual speed. Latent-construct, structural equation modeling was used to examine the relationship of these measures and age to different types of long-term memory tasks. Speed was a key construct for all 3 types of memory tasks, mediating substantial age-related variance; working memory was a fundamental construct for free and cued recall but not spatial memory. The data suggest that both speed and working memory are fundamental to explaining age-related changes in cognitive aging but that the relative contributions of these constructs vary as a function of the type of memory task.

Age Differences in Context Integration in Memory

This research examined the role of contextual integration in memories of younger and older adults. In 2 experiments, recall of a target picture to a context picture cue was better when sentences were generated that integrated the picture pair and when the picture pairs were already related to each other. Age differences were smallest when sentences were generated for semantically related pairs. Older adults generated the same type sentences as younger adults, although they generated fewer integrations for unrelated pairs. In a 3rd experiment, younger adults could not differentiate between younger- and older-generated sentences from Experiment 1, and the sentences did not differentially affect recall performance. The results are discussed in terms of age differences in self-initiated processing when using context.

Age differences in inhibition: Possible causes and consequences

Abstract The relations among age, inhibition, perceptual speed, susceptibility to interference, and working memory were examined in a sample of 301 adults age 20 to 90. Younger adults were found to have more efficient inhibitory mechanisms than were older adults. Significant inhibition, however, was found in all age groups, including the older age group. Older adults were also found to be more susceptible to interference from irrelevant information. There was a small negative relation between interference and inhibition, suggesting that participants with the most efficient inhibitory functioning may be the least susceptible to interference. Perceptual speed, an index of processing efficiency, was found to mediate nearly all of the age-related variance in inhibition and interference. Interference, but not inhibition, was found to mediate some of the age-related variance in working memory.

Directed forgetting of actions by younger and older adults

Memory for actions that are performed is substantially better than memory for descriptions of actions (e.g., Earles, 1996). In fact, people may form memories for actions even if they do not intend to or want to remember them. The directed forgetting paradigm was used to test the ability of younger and older adults to intentionally forget simple actions (also known as subject-performed tasks, or SPTs). Participants were asked to perform the action described by a verb—noun pair (e.g., break toothpick) or to read the pair, but not to perform the action. Following each pair, the participants were told either to remember or to forget the pair. Younger adults intentionally forgot verbally encoded pairs significantly better than did older adults. Actions that were performed, however, were difficult for both younger and older adults to intentionally forget. The performance of an action thus seems to result in strong item-specific processing that makes the action difficult to intentionally forget even for younger adults who can successfully intentionally forget verbally encoded items.

Semantic context influences memory for verbs more than memory for nouns

Three experiments revealed that memory for verbs is more dependent on semantic context than is memory for nouns. The participants in Experiment 1 were asked to remember either nouns or verbs from intransitive sentences. A recognition test included verbatim sentences, sentences with an old noun and a new verb, sentences with an old verb and a new noun, and entirely new sentences. Memory for verbs was significantly better when the verb was presented with the same noun at encoding and at retrieval. This contextual effect was much smaller for nouns. Experiments 2 and 3 replicated this effect and provided evidence that context effects reflect facilitation from bringing to mind the same meaning of a verb at encoding and at retrieval. Memory for verbs may be more dependent on semantic context because the meanings of verbs are more variable across semantic contexts than are the meanings of nouns.

Interrelations of Age, Self-Reported Health, Speed, and Memory

Contributions of self-reported health to adult age differences in perceptual speed and memory were assessed for 301 adults ages 20-90. Participants were asked 4 health status questions, given 3 perceptual speed tests, 2 working memory tests, and 2 memory tests. Self-reported health was found to predict speed better than it predicted memory. Covariance structural equation modeling was used to assess the relations among age, self-reported health, perceptual speed, working memory, and memory. The results support the hypothesis that any effects of self-reported health on age differences in memory are mediated by perceptual speed.

Adult age differences in recall of performed and nonperformed items.

Memory for performed cognitive activities (e.g., psychometric tests of intelligence), for performed brief actions (e.g., hand wave), and for nonperformed items (e.g., written words) was assessed for 102 older and 101 younger adults. Although enactment improved recall, the beneficial effects of enactment were the same for both age groups. In fact, more than 80% of the age-related variance in memory for performed items was shared with memory for nonperformed items. Working memory and perceptual speed were important to the age differences in memory for both types of items. Performed and nonperformed items showed different serial position effects. However, the correlation between memory for the 2 types of items was high, especially for older adults, suggesting that the 2 types of memory share many common processes.

Equine-assisted therapy for anxiety and posttraumatic stress symptoms

We tested the efficacy of the Equine Partnering Naturally(©) approach to equine-assisted therapy for treating anxiety and posttraumatic stress disorder (PTSD) symptoms. Participants were 16 volunteers who had experienced a Criterion A traumatic event, such as a rape or serious accident, and had current PTSD symptoms above 31 on the PTSD Checklist (PCL-S; Weathers, Litz, Herman, Huska, & Keane, ). Participants engaged in tasks with horses for 6 weekly 2-hour sessions. Immediately following the final session, participants reported significantly reduced posttraumatic stress symptoms, d = 1.21, less severe emotional responses to trauma, d = 0.60, less generalized anxiety, d = 1.01, and fewer symptoms of depression, d = 0.54. As well, participants significantly increased mindfulness strategies, d = 1.28, and decreased alcohol use, d = 0.58. There was no significant effect of the treatment on physical health, proactive coping, self-efficacy, social support, or life satisfaction. Thus, we found evidence that the Equine Partnering Naturally(©) approach to equine-assisted therapy may be an effective treatment for anxiety and posttraumatic stress symptoms. Future research should include larger groups, random assignment, and longer term follow-up.

Effects of aging, distraction, and response pressure on the binding of actors and actions.

Two experiments provide evidence for an age-related deficit in the binding of actors with actions that is distinct from binding deficits associated with distraction or response pressure. Young and older adults viewed a series of actors performing different actions. Participants returned 1 week later for a recognition test. Older adults were more likely than young adults to falsely recognize novel conjunctions of familiar actors and actions. This age-related binding deficit occurred even when older adults could discriminate old items from new items just as well as could young adults. Young adults who experienced distraction or time pressure also had difficulty discriminating old items from conjunction items, but this deficit was accompanied by a deficit at discriminating old and new items. These results suggest that distraction and response pressure lead to deficits in memory for stimulus components, with any deficits in binding ability commensurate with these deficits in component memory. Aging, in turn, may lead to binding difficulties that are independent of attention-demanding executive processes involved in maintaining individual stimulus components in working memory, likely reflecting declines in hippocampally mediated associative processes.

Adult age differences in binding actors and actions in memory for events

Three experiments provide evidence for an age-related deficit in the binding of actors with their actions. Young and older adults were tested on their memory for a series of events, each involving an actor performing a simple action. Older adults had greater difficulty than did young adults at discriminating old events from novel conjunctions of familiar actors and actions, even when the two groups were equated on memory for each of those features in isolation by using a longer retention interval for young adults. These results are consistent with an age-related associative deficit linked to declines in hippocampal and prefrontal cortical functioning. They further provide evidence that age differences in source monitoring are not limited to speech acts but, rather, generalize to more complex actions. Finally, they provide evidence for age differences in susceptibility to conjunction memory errors, stemming from decreased reliance on recollection and increased reliance on familiarity with increased age. Example videos may be downloaded from www.psychonomic.org/archive.