Search PubMed⌕ Search

Biomedical subjects

L Hasher

Publications and source records attributed to L Hasher.

At least 19 recordsLinked to original sources
PubMed2001

Wisdom and aging: irrational preferences in college students but not older adults.

A decision-maker is "irregular" if she would choose B from [A, B, C] but not from [A, B] (for example, preferring vanilla ice cream in a choice between vanilla and chocolate, but chocolate in a choice among vanilla, chocolate and strawberry). Similarly to previous studies we observed irregular choices by college students faced with hypothetical discount cards for supermarkets. However, older adults showed no such tendency. The same pattern was observed in three separate studies. We interpret the results in terms of a choice strategy by older adults that protects them from excessive spending.

Adolescent↗
PubMed2001

Working memory span and the role of proactive interference.

The authors investigated the possibility that working memory span tasks are influenced by interference and that interference contributes to the correlation between span and other measures. Younger and older adults received the span task either in the standard format or one designed to reduce the impact of interference with no impact on capacity demands. Participants then read and recalled a short prose passage. Reducing the amount of interference in the span task raised span scores, replicating previous results (C. P. May, L. Hasher, & M. J. Kane, 1999). The same interference-reducing manipulations that raised span substantially altered the relation between span and prose recall. These results suggest that span is influenced by interference, that age differences in span may be due to differences in the ability to overcome interference rather than to differences in capacity, and that interference plays an important role in the relation between span and other tasks.

Adolescent↗
PubMed2001

Instructional manipulations and age differences in memory: now you see them, now you don't.

The instructions for most explicit memory tests use language that emphasizes the memorial component of the task. This language may put older adults at a disadvantage relative to younger adults because older adults believe that their memories have deteriorated. Consequently, typical explicit memory tests may overestimate age-related decline in cognitive performance. In 2 experiments, older and younger adults performed a memory test on newly learned trivia. In both experiments, age differences were obtained when the instructions emphasized the memory component of the task (memory emphasis) but not when the instructions did not emphasize memory (memory neutral). These findings suggest that aspects of the testing situation. such as experimental instructions, may exaggerate age differences in memory performance and need to be considered when designing studies investigating age differences in memory.

Adolescent↗
PubMed2001

Implicit memory is not immune to interference.

Does interference, a primary source of forgetting in explicit memory, also affect implicit memory? Several early and highly influential studies have suggested that implicit memory is immune to interference. In contrast, a number of subsequent investigations have reported evidence for interference. As well, amnesic patients, whose performance relies primarily on implicit memory, often show interference effects. A review of methods, materials, and findings suggests that interference occurs on implicit tests when targets and nontargets are similar and so compete as potential responses to the memory cue. Further, there is some evidence that the degree of interference on implicit tasks is affected by the number of competing items and their strength relative to the target. Interference effects in implicit memory seem to parallel those in explicit memory, and the authors consider the implications of this conclusion for theoretical concepts of memory and the brain.

Attention↗
PubMed2001

Implicit memory is vulnerable to proactive interference.

We investigated the possibility that implicit memory, like explicit memory, can be disrupted by proactive interference. Participants first viewed a list of words, with nontargets in the first half of the list and targets in the second. Nontargets were either similar in structure (e.g., "ANALOGY") or unrelated (e.g., "URGENCY") to the targets (e.g., "ALLERGY"). After several filler tasks, participants completed an implicit fragment-completion test (e.g., "A_L_ _ GY") for the target items. Participants who viewed similar nontargets completed fewer fragments with target items and made more intrusions than did participants who viewed unrelated nontargets. Together with previous findings, these results suggest that similar nontargets can compete with target items to produce interference in implicit memory.

Adult↗
PubMed2000

Cross-cultural differences in memory: the role of culture-based stereotypes about aging.

The extent to which cultural stereotypes about aging contribute to age differences in memory performance is investigated by comparing younger and older Anglophone Canadians to demographically matched Chinese Canadians, who tend to hold more positive views of aging. Four memory tests were administered. In contrast to B. Levy and E. Langer's (1994) findings, younger adults in both cultural groups outperformed their older comparison group on all memory tests. For 2 tests, which made use of visual stimuli resembling ideographic characters in written Chinese, the older Chinese Canadians approached, but did not reach, the performance achieved by their younger counterparts, as well as outperformed the older Anglophone Canadians. However, on the other two tests, which assess memory for complex figures and abstract designs, no differences were observed between the older Chinese and Anglophone Canadians. Path analysis results suggest that this pattern of findings is not easily attributed to a wholly culturally based account of age differences in memory performance.

Adult↗
PubMed2000

Working memory, inhibitory control, and reading disability.

The relationships among working memory, inhibitory control, and reading skills were studied in 966 individuals, 6-49 years old. In addition to a standardized measure of word recognition, they received a working memory (listening span) task in the standard, blocked format (three sets containing two-, three-, or four-item trials) or in a mixed format (three sets each containing two-, three-, and four-item trials) to determine whether scores derived from the standard format are influenced by proactive interference. Intrusion errors were investigated in order to determine whether deficits in working memory were associated with the access, deletion, or restraint functions of inhibitory control. The results indicated that deficits in working memory were characteristic of individuals with reading disabilities at all ages. These deficits may be associated with the access and restraint functions of inhibition. Working memory skills increased until the age of 19. The blocked format showed a gradual decline in adulthood whereas the mixed format did not. The different patterns suggest that the decline in working memory skills associated with aging may result from growing inefficiencies in inhibitory control, and not diminished capacity.

Adolescent↗
PubMed1999

Aging and time-of-day effects on cognition in rats.

This study used an animal model to investigate the importance of the time at which testing occurs for age differences in learning and memory. Groups of old and young rats were entrained to a 12-hr light-dark schedule and administered tests of delayed alternation and inhibitory avoidance conditioning at the beginning or end of their high-activity cycle. Apart from normal age differences in test performance, the behavioral results demonstrated that old but not young rats were affected by the time of testing. In both tasks, old rats tested late in the activity cycle performed significantly worse than did old rats tested early in the cycle, under conditions that challenged memory processes that are known to involve the hippocampus. The results indicate that circadian disruption in old age can adversely affect memory and related cognitive function, with important implications for inhibitory control.

Age Factors↗
PubMed1999

Inhibition in the processing of garden-path sentences.

The Hartman and Hasher (1991) garden-path sentence completion task has been used in several studies to assess the efficiency of the deletion function of inhibition (e.g., L. Hasher, R. Zacks, & C. P. May, 1999 ), with results suggesting that younger adults are efficient at suppressing once relevant but no longer appropriate information, whereas older adults generally are not (e.g., M. Hartman & L. Hasher, 1991: L. Hasher. M. B. Quig, & C. P. May, 1997; C. P. May & L. Hasher, 1998). An alternative interpretation of patterns of access to relevant and no-longer-relevant sentence endings focuses on the difficulty of selecting final words for sentence frames and on integration effects in implicit memory (M. Hartman, 1995). This alternative is considered and found wanting on the basis of both new and old empirical data. On the basis of present data and related findings, it is concluded that the task does measure inhibitory efficiency.

Adolescent↗
PubMed1999

The role of interference in memory span.

In two experiments, we investigated the possibility that susceptibility to proactive interference (PI) affects performance on memory span measures. We tested both younger and older adults (older adults were tested because of the suggestion that they are differentially susceptible to PI). We used two different span measures and manipulated testing procedures to reduce PI for these tasks. For older adults, span estimates increased with each PI-reducing manipulation; for younger adults, scores increased when multiple PI manipulations were combined or when PI-reducing manipulations were used in paradigms in which within-task PI was especially high. The findings suggest that PI critically influences span performance. We consider the possibility that interference-proneness may influence cognitive behaviors previously thought to be governed by capacity.

Adult↗
PubMed1998

Synchrony effects in inhibitory control over thought and action.

Two experiments explore whether synchrony between peak circadian arousal periods and time of testing influences inhibitory efficiency for younger and older adults. Experiment 1 assesses inhibitory control over no-longer-relevant thoughts, and Experiment 2 assesses control over unwanted but strong responses, as well as performance on neuropsychological tasks that index frontal function. Inhibitory control is greatest at optimal times for both age groups and is generally greater for younger than for older adults. Performance on 2 neuropsychological measures (Stroop and Trails) also changes over the day, at least for older adults, and is correlated with inhibitory indexes, suggesting that for older adults changes in inhibition may be mediated by circadian variations in frontal functioning. By contrast, access to well-learned responses is not vulnerable to synchrony or age effects.

Adolescent↗
PubMed1998

Distractibility, circadian arousal, and aging: a boundary condition?

Two studies assessed the presence of a synchrony effect between peak circadian arousal and time of testing for both older and younger adults. Participants performed a reading aloud task that included distracting words that were either present or absent and, if present, were either thematically related or unrelated to the target text. As well, the distracting material was presented in either spatially predictable or unpredictable locations. In each experiment, older and younger adults were tested at optimal versus nonoptimal times. Both experiments showed age differences in susceptibility to distraction, replicating earlier findings (e.g., M. C. Carlson, L. Hasher, R. T. Zacks, & S. L. Connelly, 1995). Neither showed differences due to time of testing, suggesting a boundary condition for cognitive disruptions associated with circadian arousal patterns.

Adolescent↗
PubMed1997

Dual mechanisms of negative priming.

Three experiments examined whether negative priming is a dually determined effect produced by inhibitory mechanisms and by a memorial process. Younger adults (Experiment 1) and older adults (Experiments 1-3) were tested in procedures that varied the likelihood of inducing retrieval of the prior trial. This was done by making test-trial target decoding difficult (Experiments 1 & 2) or by making prior information useful on some nonnegative priming trials (Experiment 3). Younger adults demonstrated negative priming under retrieval and nonretrieval conditions, with patterns of performance indicating different sources of negative priming effects. Older adults showed negative priming only under retrieval-inducing conditions, consistent with the view of deficient inhibitory mechanisms for older adults. The data suggest that contextual variables critically determine whether negative priming is largely due to inhibition or to episodic retrieval.

Adolescent↗
PubMed1997

Cognitive gerontology and attentional inhibition: a reply to Burke and McDowd.

Our response to the Burke and McDowd critiques (in this issue) begins with a history of the origins of the inhibitory deficit view and of its development since 1988 as well as with an account of some particularly useful findings and of our preferred mode of theory building, which is nonformal and empirically driven. Against this background, we find many points of agreement with Burke and McDowd but also many points of disagreement. For example, we agree with Burke that many aspects of language comprehension and production are age invariant, but we disagree that all such findings count against our viewpoint. Likewise, we readily acknowledge the problems in measuring inhibition that McDowd so clearly documents, but do not feel that this is a fatal problem as long as the inhibitory deficit view continues to be viable within the basic attentional literature, continues to permit the integration of a large body of existing data, and continues to generate new predictions.

Aged↗
PubMed1997

Inhibitory control over no-longer-relevant information: adult age differences.

Hartmann and Hasher (1991) used a garden-path task in which younger and older adults generated the final word for each of a series of high-cloze sentences. Under instructions to remember the final word, the experiment included critical sentences for which the generated word was replaced by a new, to-be-remembered target. Using an implicit priming task, the first experiment replicated a basic finding: Younger adults showed priming only for the target words, whereas older adults showed priming for both the generated and target words. Two experiments explored the boundary conditions. One showed that an additional sentence that interpreted the new target word enabled older adults to narrow access to only the target word. The provision of additional time following the introduction of the new target word did not. Specific information, not more time, is required for inefficient inhibitory mechanisms to clear the recent past from memory.

Adolescent↗
PubMed1996

Studies of directed forgetting in older adults.

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 younger 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 (Experiment 1B and 2) relatively more TBF items on delayed retention tests in which all studied items were designated as targets.

Adolescent↗
PubMed1995

Aging, distraction, and the benefits of predictable location.

Three experiments examined the impact on reading time for younger and older adults in the absence vs. presence of distraction (marked by font type) in either fixed predictable locations (Experiments 1 and 2) or unpredictable locations (Experiment 3). Consistent with earlier work (S. L. Connelly, L. Hasher, & R. T. Zacks, 1991), older adults were markedly disrupted, relative to young adults, when distraction was present in unpredictable locations. When the location of distraction was fixed, however, the very large disadvantage that older adults otherwise experienced (slowed by as much as 46 s) diminished substantially (to as little as 2 s). Fixed location also eliminated the relatedness effect, by which older adults are especially susceptible to distraction from meaningfully related material.

Adolescent↗