Elizabeth A. Maylor

Inhibitory component of externally controlled covert orienting in visual space.

Four experiments are reported that investigate an inhibitory effect associated with externally controlled orienting and first identified by Posner and Cohen (1980, 1984). The effect takes the form of an inability to respond quickly to a stimulus appearing in the same location in the visual periphery as a previous one that produced covert orienting. Several characteristics of the effect are revealed that eliminate possible explanations in terms of response inhibition, masking, and sensory habituation. The inhibitory component of orienting occurs whether or not the first stimulus requires a response (Experiment 1), lasts at least a second (Experiments 1, 2, and 3), affects not only the originally stimulated location but also nearby locations (Experiment 2), is determined by environmental coordinates (Experiment 3), and occurs both in the periphery and at the fovea (Experiment 4). It is concluded that inhibition may act together with an early facilitatory component (Posner & Cohen, 1984) in directing the attention and eye movement systems in order to maintain efficient spatial sampling.

Prospective and retrospective memory in normal ageing and dementia: A questionnaire study

Frequency of prospective memory and retrospective memory failures was rated on a 16-item questionnaire by 862 volunteers, from five groups: patients with Alzheimer Disease (rated by carers), carers of Alzheimer Disease patients, elderly, young, and a group of married couples. Reported memory failures were highest for Alzheimer Disease patients, and lowest for carers, with elderly and young controls in between. More prospective memory than retrospective memory failures were reported in all groups, although the difference was small for Alzheimer Disease patients who were rated near ceiling for both. Prospective memory failures of Alzheimer Disease patients were reported as more frustrating for carers than retrospective memory failures; prospective memory and retrospective memory failures frustrated Alzheimer Disease patients equally. Data from the couples indicated that there were no biases resulting from rating on behalf of someone else. These results suggest that: (1) normal ageing has no greater effect on self-reported retrospective memory than prospective memory failures, (2) the relatively small number of memory failures reported by carers may result from comparing themselves with the Alzheimer Disease patients in their care, and (3) prospective memory failures have a greater impact on the lives of the carers and are therefore more likely to be reported as early indicants of the disease.

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: Cronbachs 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 individuals scores on the Prospective and Retrospective scales.

Age and prospective memory

This paper reports an investigation into the effects of age, intelligence, and retrospective memory on performance in a prospective memory task in which subjects aged between 52 and 95 were required to telephone once a day either between two times or at an exact time. The most important influence on performance was how subjects chose to remember to make the telephone calls. The best performance was from subjects who telephoned either in conjunction with another routine event or engaged in some form of advanced planning of the daily schedule. The worst performance was from those who relied on internal cues from their own memory. Performance was intermediate from those who used external cues such as notes or diary entries. Subjects in the between condition were less likely to choose internal cues than those in the exact condition, possibly because the task appeared more difficult, and this resulted in their showing superior performance. The effect of age was influenced by the cue used. For subjects using internal cues, those who forgot were older than those who remembered, whereas for subjects using the other cues, those who forgot were younger than those who remembered. Regardless of cue, self-ratings of cognitive failures were related to performance such that those who reported more minor everyday mistakes were indeed more likely to forget to telephone. While there was some indirect effect of general intelligence on performance in the task, there was no relationship between retrospective memory scores and whether or not subjects remembered to telephone.

Age-related impairment in an event-based prospective-memory task

Slides of famous people were presented to participants with the instructions to name each face and circle the trial number if the person was wearing glasses (prospective-memory target event). Participants in their 50s and 60s (n = 56) were more successful than participants in their 70s and 80s (n = 59) at both the naming an prospective-memory tasks. An age-related increase in the probability of forgetting replicated an earlier prospective-memory study (E. A. Maylor, 1993); in the present case, there was also an age-related decrease in the probability of recovery. These effects of age remained significant after other measures of current ability were taken into account, including intelligence, speed, and naming performance. For participants who were in both the earlier study (E. A. Maylor, 1993) and this study (n = 65), the correlation between prospective-memory performance on the 2 occasions was significant but only for younger participants. Performance in the prospective-memory task was entirely unrelated to performance in the naming task.

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.

Effects of spatial and nonspatial cognitive activity on postural stability.

Is postural stability controlled automatically, or is it affected by concurrent cognitive activity? Are the effects influenced by the nature of the cognitive activity required, and do they increase in old age? To address these questions, 70 participants aged 20-79 years were asked to stand as still as possible on a force platform (postural control task) while performing (a) no cognitive task, (b) a spatial memory task, and (c) a nonspatial memory task. The memory tasks were also performed while seated as a comparison condition. Both spatial and nonspatial memory recall declined with increasing age but were unaffected by position (standing vs. seated). Postural stability declined with age; moreover, there was support for an earlier finding that age decline was greatest when performing the spatial memory task. Each recording period was split into two phases which, for the spatial and nonspatial memory tasks, corresponded to encoding and maintaining the stimuli. In comparison with no task, participants were more stable when encoding stimuli (particularly in the spatial task), but they were less stable when maintaining stimuli (particularly in the nonspatial task). The results suggest that postural stability can be affected by cognitive activity in complex ways, depending on the age of participants, the type of cognitive task (spatial vs. nonspatial), and the cognitive processing required (encoding vs. maintenance).

The influence of perceptual load on age differences in selective attention

The effect of perceptual load on age differences in visual selective attention was examined in 2 studies. In Experiment 1, younger and older adults made speeded choice responses indicating which of 2 target letters was present in a relevant set of letters in the center of the display while they attempted to ignore an irrelevant distractor in the periphery. The perceptual load of relevant processing was manipulated by varying the central set size. When the relevant set size was small, the adverse effect of an incompatible distractor was much greater for the older participants than for the younger ones. However, with larger relevant set sizes, this was no longer the case, with the distractor effect decreasing for older participants at lower levels of perceptual load than for younger ones. In Experiment 2, older adults were tested with the empty locations in the central set either unmarked (as in Experiment 1) or marked by small circles to form a group of 6 items irrespective of set size; the 2 conditions did not differ markedly, ruling out an explanation based entirely on perceptual grouping.

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.

Developmental changes in time estimation: comparing childhood and old age.

Participants from ages 5 to 99 years completed 2 time estimation tasks: a temporal generalization task and a temporal bisection task. Developmental differences in overall levels of performance were found at both ends of the life span and were more marked on the generalization task than the bisection task. Older adults and children performed at lower levels than young adults, but there were also qualitative differences in the patterns of errors made by the older adults and the children. To capture these findings, the authors propose a new developmental model of temporal generalization and bisection. The model assumes developmental changes across the life span in the noisiness of initial perceptual encoding and across childhood in the extent to which long-term memory of time intervals is distorted.