Biomedical subjects

Elizabeth A Maylor

Publications and source records attributed to Elizabeth A Maylor.

At least 19 recordsLinked to original sources

PubMed2007

Similarity and attraction effects in episodic memory judgments.

In the decision-making literature, it is known that preferences between two options can be influenced in different ways by the introduction of a third option. We investigated whether such influences could be demonstrated when making decisions about qualitative aspects of episodic memories. In a baseline condition, participants were asked which of two dissimilar events they remembered more vividly: (A) a well-known Olympic victory, or (B) the death of a well-known public figure. In two further conditions, a third event was added: (C) an Olympic victory similar and competitive to A, or (D) an Olympic victory similar but inferior to A. With the addition of C, participants were less likely to choose A than B (similarity effect), whereas with the addition of D, they were more likely to choose A than B (attraction effect), suggesting that effects known in decision-making can be generalised to relative judgments about episodic memories.

Adolescent↗

PubMed2006

No difference between conscious and nonconscious visuomotor control: evidence from perceptual learning in the masked prime task.

Negative compatibility effects (NCEs) in the masked-prime paradigm are usually obtained when primes are masked effectively. With ineffective masks-and primes above the perceptual threshold-positive compatibility effects (PCEs) occur. We investigated whether this pattern reflects a causal relationship between conscious awareness and low-level motor control, or whether it reflects the fact that both are affected in the same way by changes in physical stimulus attributes. In a 5-session perceptual learning task, participants learned to consciously identify masked primes. However, they showed unaltered NCEs that were not different from those produced by participants in a control group without equivalent perceptual learning. A control experiment demonstrated that no NCEs occur when prime identification is made possible by ineffective masking. The results suggest that perceptual awareness and low-level motor control are affected by the same factors, but are fundamentally independent of each other.

Adolescent↗

PubMed2006

A new conceptualization of alexithymia in the general adult population: implications for research involving older adults.

OBJECTIVE: The purpose of this study is to test the validity of existing conceptualizations of the alexithymia concept, with particular reference to aging. METHODS: Two hundred and forty-eight healthy adults completed measures of alexithymia and psychosocial functioning; younger and older adults (n=121) also completed a measure of emotional responsiveness. RESULTS: Older adults engaged in less introspective thought traditionally thought to denote increased alexithymia. However, reduced introspection was associated with improved mental wellbeing, and, thus, could not be construed as a deficit. Difficulty identifying and describing emotions did not differentiate older and younger adults, but were both associated with heightened depression, anxiety, and poor perceived quality of life. CONCLUSIONS: In clinical practice and research, the Toronto Alexithymia Scale (TAS) is almost exclusively used, with "total" score typically used to index alexithymia. As one of the subscales of the TAS measures reduced introspection, calculating total scores may not be appropriate and may particularly overestimate levels of alexithymia in older adulthood.

Adolescent↗

PubMed2006

Effects of color heterogeneity on subitization.

Small numbers of items can be enumerated rapidly and accurately via a process termed subitizing. In two experiments, we examined the effect of target color heterogeneity on subitizing efficiency. In contrast to the findings of Puts and de Weert (1997), we found that observers were no less efficient at subitizing displays containing red and green items than they were at subitizing displays of a single color. We propose that these findings are consistent with subitization operating on items represented within a location master map that codes where objects are but not what they are. The data are discussed in relation to recent findings concerning the detection of single-feature targets and the functional architecture of early visual processing.

Adolescent↗

PubMed2006

Effects of zinc supplementation on cognitive function in healthy middle-aged and older adults: the ZENITH study.

A randomised double-blind placebo-controlled design was employed to investigate the effects of Zn supplementation on cognitive function in 387 healthy adults aged 55-87 years. Several measures of visual memory, working memory, attention and reaction time were obtained using the Cambridge Automated Neuropsychological Test Battery at baseline and then after 3 and 6 months of 0 (placebo), 15 or 30 mg Zn/d. Younger adults (< 70 years) performed significantly better on all tests than older adults (> 70 years), and performance improved with practice on some measures. For two out of eight dependent variables, there were significant interactions indicating a beneficial effect (at 3 months only) of both 15 and 30 mg/d on one measure of spatial working memory and a detrimental effect of 15 mg/d on one measure of attention. Further work is required to establish whether these findings generalise to older adults in poorer mental and physical health and with less adequate Zn intake and status than the present sample.

Aged↗

PubMed2005

Task switching across the life span: effects of age on general and specific switch costs.

The authors investigated age-related changes in executive control using an Internet-based task-switching experiment with 5,271 participants between the ages of 10 and 66 years. Speeded face categorization was required on the basis of gender (G) or emotion (E) in single task blocks (GGG... and EEE...) or switching blocks (GGEEGGEE...). General switch costs, the difference between switching block and single task block performance, decreased during development and then increased approximately linearly from age 18. In contrast, specific switch costs, the difference between switch trial and nonswitch trial performance in the switching block, were more stable across the same age range. These results demonstrate differential age effects in task-switching performance and provide a fine-grained analysis of switch costs from puberty to retirement.

Adolescent↗

PubMed2005

The efficiency of feature-based subitization and counting.

The enumeration of small numbers of objects (approximately 4) proceeds rapidly, accurately, and with little effort via a process termed subitization. Four experiments examined whether it was possible to subitize the number of features rather than objects present in a display. Overall, the findings showed that when features are presented randomly and are uncorrelated with object numerosity, efficient enumeration is not possible. This suggests that the visual system does not have parallel access to multiple feature maps and that subitization processes operate exclusively on representations coding the locations of objects. The data are discussed with respect to theories of visual enumeration and search.

Adult↗

PubMed2005

Search, enumeration, and aging: eye movement requirements cause age-equivalent performance in enumeration but not in search tasks.

Response time (RT) and fixation frequency were measured for young and older adults in search and enumeration tasks under high- and low-attentional competition conditions. There was an age-related decrement in search rates for single targets both for RT and fixation frequency, but there was no deficit in enumeration rates either with or without distractors even though serial enumeration rates were much slower than single target search rates. Fixation frequency per item in serial enumeration was much greater than in serial visual search for a single target. Enumerating targets with distractors produced an overall increase in RT and fixation frequency that was greater for older adults. The data are contrary to a generalized slowing account, and an alternative is proposed on the basis of the need to make eye movements in enumeration but not in search tasks.

Adolescent↗

PubMed2005

Age-related deficits in free recall: the role of rehearsal.

Age-related deficits have been consistently observed in free recall. Recent accounts of episodic memory suggest that these deficits could result from differential patterns of rehearsal. In the present study, 20 young and 20 older adults (mean ages 21 and 72 years, respectively) were presented with lists of 20 words for immediate free recall using the overt rehearsal methodology. The young outperformed the older adults at all serial positions. There were significant age-related differences in the patterns of overt rehearsals: Young adults rehearsed a greater number of different words than did older adults, they rehearsed words to more recent serial positions, and their rehearsals were more widely distributed throughout the list. Consistent with a recency-based account of episodic memory, age deficits in free recall are largely attributable to age differences in the recency, frequency, and distribution of rehearsals.

Adult↗

PubMed2005

Effects of age on searching for and enumerating targets that cannot be detected efficiently.

We investigated the effects of old age on search, subitizing, and counting of difficult-to-find targets. In Experiment 1, young and older adults enumerated targets (Os) with and without distractors (Qs). Without distractors, the usual subitization-counting function occurred in both groups, with the same subitization span of 3.3 items. Subitization disappeared with distractors; older adults were slowed more overall by their presence but enumeration rates were not slowed by ageing either with or without distractors. In contrast, search rates for a single target (O among Qs) were twice as slow for older as for young adults. Experiment 2 tested and ruled out one account of age-equivalent serial enumeration based on the need to subvocalize numbers as items are enumerated. Alternative explanations based on the specific task differences between detecting and enumerating stimuli are discussed.

Adolescent↗

PubMed2005

Effects of Alzheimer's disease on visual enumeration.

Speeded enumeration of visual objects typically produces fast and accurate performance for up to 3 to 4 items (subitization) but slower and less accurate performance thereafter (counting). We investigated enumeration ability in patients with Alzheimer's disease (AD) and in age-matched controls. AD patients were slower overall than controls. The subitizing span was significantly reduced in AD patients compared with controls (2.3 vs 3.5 items) and counting rate was significantly slower (451 vs 349 ms/item). Error rates were similar in the two groups except at numerosity 3, when AD patients made errors but controls did not (consistent with their subitizing spans). Within the AD patient group, several aspects of performance correlated significantly with Mini-Mental State Examination scores. Together, the results provide a striking contrast with studies showing preservation of enumeration ability in normal aging.

Afterimage↗

PubMed2005

Motor control in old age: evidence of impaired low-level inhibition.

In the masked prime task, responses to supraliminal targets are influenced by previously presented subliminal primes. When targets follow primes immediately, positive compatibility effects are obtained such that performance is better when prime and target are compatible (mapped to the same response) than when they are incompatible (mapped to opposite responses). In young adults, this pattern reverses with longer interstimulus intervals (negative compatibility effect). These effects reflect an activation-followed-by-inhibition process: Primes trigger an initial activation of their corresponding motor response, which is subsequently inhibited. The present study demonstrates that healthy older adults (M = 76 years) show a substantial positive compatibility effect with a short prime-target interval, but they fail to produce reliable negative compatibility effects with longer intervals, indicating an age-related impairment in low-level motor control.

Adult↗

PubMed2003

Habitual prospective memory in schizophrenia.

BACKGROUND: Prospective memory (PM), the act of remembering that something has to be done in the future without any explicit prompting to recall, provides a useful framework with which to examine problems in internal-source monitoring. This is because it requires distinguishing between two internally-generated processes, namely the intention to perform an action versus actual performance of the action. In habitual tasks, such as taking medicine every few hours, the same PM task is performed regularly and thus it is essential that the individual is able to distinguish thoughts (i.e., thinking about taking the medicine) from actions (i.e., actually taking the medicine). METHODS: We assessed habitual PM in patients with schizophrenia by employing a laboratory analogue of a habitual PM task in which, concurrently with maneuvering a ball around an obstacle course (ongoing activity), participants were to turn over a counter once during each trial (PM task). After each trial, participants were asked whether they had remembered to turn the counter over. RESULTS: Patients with schizophrenia made a disproportionate number of errors compared to controls of reporting that a PM response had been made (i.e., the counter turned over) after an omission error (i.e., the counter was not turned over). There was no group difference in terms of reporting that an omission error occurred (i.e., forgetting to turn over the counter) when in fact a PM response had been made. CONCLUSION: Patients with schizophrenia displayed a specific deficit distinguishing between two internally-generated sources, attributable to either poor source monitoring or temporal discrimination.

Adult↗

PubMed2003

The Prospective and Retrospective Memory Questionnaire (PRMQ): Normative data and latent structure in a large non-clinical sample.

The Prospective and Retrospective Memory Questionnaire (PRMQ; Smith, Della Sala, Logie, & Maylor, 2000) was developed to provide a self-report measure of prospective and retrospective memory slips in everyday life. It consists of sixteen items, eight asking about prospective memory failures, and eight concerning retrospective failures. The PRMQ was administered to a sample of the general adult population (N = 551) ranging in age between 17 and 94. Ten competing models of the latent structure of the PRMQ were derived from theoretical and empirical sources and were tested using confirmatory factor analysis. The model with the best fit had a tripartite structure and consisted of a general memory factor (all items loaded on this factor) plus orthogonal specific factors of prospective and retrospective memory. The reliabilities (internal consistency) of the Total scale and the Prospective and Retrospective scales were acceptable: Cronbach's alpha was 0.89, 0.84, and 0.80, respectively. Age and gender did not influence PRMQ scores, thereby simplifying the presentation and interpretation of normative data. To ease interpretation of scores on the PRMQ, tables are presented for conversion of raw scores on the Total scale and Prospective and Retrospective scales to T scores (confidence limits on scores are also provided). In addition, tables are provided to allow users to assess the reliability and abnormality of differences between an individual's scores on the Prospective and Retrospective scales.

Adolescent↗

PubMed2002

Aging and enumeration: a selective deficit for the subitization of targets among distractors.

The term subitization has been used to refer to the fast and accurate enumeration of up to about 4 items. Beyond 4 items, enumeration becomes more serial and less accurate, with each additional item adding to the total enumeration time. The effects of aging on visual enumeration of targets (Os) were assessed with and without the presence of distractors (Xs). Young participants (n = 30; 18-27 years) showed the usual subitization-counting enumeration function, both with and without the presence of distractors. In contrast, for older participants (n = 35; 65-79 years), evidence for subitization was found only when distractors were absent. This occurred even though they could detect an individual target among distractors in parallel across the field. The results are discussed in relation to recent theories of visual selection and enumeration.

Adolescent↗

PubMed2002

Preserved olfactory cuing of autobiographical memories in old age.

The authors investigated whether olfactory cues can facilitate memory retrieval and whether they retain their effectiveness in old age. In Phase 1, 57 young and 57 old adults (mean ages of 21 and 84 years, respectively) were asked to recall autobiographical memories associated with each of six cue words. In Phase 2, the same words were presented again with instructions to recall new memories; on this second occasion, half of the words were accompanied by their appropriate odors. Both age groups recalled more than twice as many memories in Phase 2 with the odor than without the odor, providing evidence for substantial olfactory cuing that is remarkably intact in old age.

Adult↗

PubMed2002

Does performance on theory of mind tasks decline in old age?

In the first reported study of theory of mind (ToM; the ability to attribute mental states) in old age, Happe, Winner, and Brownell (1998) observed better performance on ToM tasks in older participants (mean age 73 years) than in young participants (mean age 21 years). We present two experiments exploring the generality of this finding. Experiment 1 compared young, young-old, and old-old age groups (mean ages 19, 67, and 81 years, respectively) on their understanding of ToM stories both with and without the need to remember the information, and control studies that did not require the ability to attribute mental states. For ToM stories with a memory load, the young group performed significantly better than both the young-old and old-old groups; without a memory load, the young and young-old groups performed significantly better than the old-old group. In Experiment 2, young and old-old age groups (mean ages 21 and 81 years, respectively) were compared on their understanding of ToM and control stories without the need to remember the information. Again, the young group performed significantly better than the old-old group on ToM stories. There were no significant age differences in performance on the control stories in either experiment. The age deficit on ToM stories remained significant after taking account of measures of vocabulary and processing speed (Experiments 1 and 2), and measures of executive functioning (Experiment 2).

Adolescent↗

PubMed2002

Prospective and retrospective memory in normal aging and dementia: an experimental study.

Two experiments investigated the effects of normal aging and dementia on laboratory-based prospective memory (PM) tasks. Participants viewed a film for a later recognition memory task. In Experiment 1, they were also required either to say "animal" when an animal appeared in the film (event-based PM task) or to stop a clock every 3 min (time-based PM task). In both tasks, young participants were more successful than older participants, who were, in turn, more successful than patients with Alzheimer's disease (AD). For successful remembering in the time-based task, older participants and AD patients checked the clock more often than did young participants. In Experiment 2, participants were asked to reset a clock either when an animal appeared in the film (unrelated cue-action) or when a clock appeared in the film (related cue-action). Responses were faster in the related condition than in the unrelated condition. Again, there were differences in PM performance between young and older participants, and between older participants and AD patients. The observed deficits were not due to the forgetting of the PM task instructions in either experiment. Retrospective memory (RM) tasks (digit span, sentence span, free recall, and recognition) were more impaired by AD than were the PM tasks. Factor analysis revealed separate factors corresponding to RM and PM.

Adult↗