Selective attention and visual search: revision of an allocation model and application to age differences.

The present experiments examined a revised version of the Eriksen and Yeh model of attentional allocation during visual search. The results confirmed the assumption of the model that performance represents a weighted combination of focused- and distributed-attention trials, although Ss relied on focused attention more than was predicted. Consistent with the model, predictions on the basis of the assumption of a terminating search fit the data better than predictions on the basis of an exhaustive search. The effects of varying cue validity favored an interpretation of focused attention in terms of a processing gradient rather than a zoom lens. Although the allocation of attention across trials was similar for young and older adults, there was an age-related increase in the time required to allocate attention within individual trials.     

The influence of attention allocation and age on intersection accidents

Many severe accidents occur in urban areas. As part of the research project UR:BAN, this study investigated the causes of driver errors (e.g., inadequate attention allocation) in urban areas when turning left at intersections. As intersection accidents are especially difficult for older drivers, differences between older and younger drivers were examined as well. In a first step, accident protocols of left turn crashes with pedestrians and bicyclists were analysed in detail, since they are the most dangerous ones. Characteristics of the oncoming traffic and the location of crossing bicyclists and pedestrians were identified as possible causes. Accordingly, critical scenarios were implemented in a static driving simulator, varying the characteristics of the oncoming traffic, the direction and location of crossing vulnerable road users. These factors were examined in a within-subject design, with two different aged groups of participants (12 aged 20–35 y, 12 aged 65+ y; between-subjects factor).The results revealed that the presence of the oncoming traffic, which was assumed to capture the drivers’ attention, did not lead to more accidents with vulnerable road users. However, this may be because many drivers waited until the oncoming traffic had passed. Unexpectedly, older drivers had fewer accidents. This may be explained by the more cautious behaviour of older drivers, who drove significantly slower and waited significantly longer at the stop line before turning. Further analyses showed that a more cautious behaviour, independently of the age, predicted accident avoidance better than attention allocation. From these results, warning systems for younger and older drivers, especially for those not driving cautious, need to be developed. This idea will be tested in future studies introducing different warning concepts.     

Adult age differences in attention to semantic context

In three experiments age differences in attention to semantic context were examined. The performance of younger adults (ages 18-29 years) and older adults (ages 60-79 years) on a semantic priming task indicated that both age groups could use information regarding the probability that a prime and target would be related to flexibly anticipate the target category given the prime word (Experiment 1). The timing by which target expectancies were reflected in reaction time performance was delayed for older adults as compared to younger adults, but only when the target was expected to be semantically unrelated to the prime word (Experiment 2). When the target and prime were expected to be semantically related, the time course of priming effects was similar for younger and older adults (Experiment 3). Together the findings indicate that older adults are able to use semantic context and the probability of stimulus relatedness to anticipate target information. Although aging may be associated with a delay in the timing by which controlled expectancies are expressed, these findings argue against an age-related decline in the ability to represent contextual information.     

The associative-memory basis of cognitive skill learning: adult age differences

It has been established that memorizing common problems and their solutions underlies cognitive skill development, and that there are substantial age deficits in the rate of this learning. In a between-groups design, the authors compared learning rates for the same set of problems in skill (SK) training and paired-associate (PA) training. The authors found main effects due to condition (PA problems were acquired earlier) and to age (older adults' learning was delayed), but no condition-by-age interaction. The authors concluded that the age deficit in SK can be accounted for by the age deficit in associative memory; no further explanation is needed. The authors also analyzed fast and slow retrieves in SK and PA, and found that the frequency of fast retrieves did not differ in the two conditions. The overall advantage of PA was due to the occurrence of slow retrieves, which were absent in SK presumably because the skill algorithm displaces slow, explicit memory search in SK, but not fast, familiarity-based retrieval.     

Baseline differences,attention, and age differences in time-sharing performance

The purpose of this experiment was to determine whether age differences noted when two tasks are performed concurrently can be accounted for in terms of age differences in single task baseline performance. Two groups of 12 8-year-olds and one group of 12 13-year-olds performed a compensatory tracking task and an auditory matching task, first alone and then time shared. The 8- and 13-year-old baseline groups performed baseline trials on each task prior to time-sharing trials. Each training group 8-year-old was randomly paired with a 13-year-old and given sufficient single task practice before time sharing to equate the 8- and 13-year-old pair members' baselines on both tasks. Results showed trained 8-year-olds to be indistinguishable from 13-year-olds in time sharing, whereas the 8-year-old baseline group showed significantly greater decrements in time-sharing and higher baseline scores on both tasks. These data provide support for the hypothesis that time-shared performance is directly related to level of baseline performance.     

Individual differences in working memory capacity predict visual attention allocation

To the extent that individual differences in working memory capacity (WMC) reflect differences in attention (Baddeley, 1993; Engle, Kane, & Tuholski, 1999), differences in WMC should predict performance on visual attention tasks. Individuals who scored in the upper and lower quartiles on the OSPAN working memory test performed a modification of Egly and Homa’s (1984) selective attention task. In this task, the participants identified a central letter and localized a displaced letter flashed somewhere on one of three concentric rings. When the displaced letter occurred closer to fixation than the cue implied, high-WMC, but not low-WMC, individuals showed a cost in the letter localization task. This suggests that low-WMC participants allocated attention as a spotlight, whereas those with high WMC showed flexible allocation.     

Decomposing adult age differences in symbol arithmetic

A componential analysis was conducted to determine the locus of adult age differences in symbol arithmetic. Measures of the duration of two proposed components, substitution of digits for symbols and the addition or subtraction of the digits resulting from these substitutions, were obtained from 52 young adults and 52 older adults. Tests of working memory, perceptual speed, motor speed, and associative learning were also administered to all subjects. The results were most consistent with an interpretation postulating that the speed of many different cognitive processes decreases with increased age. Considerable age-related variance remained in the measures of symbol arithmetic performance after statistical control of working memory and associative learning performance, casting doubt on alternative hypotheses of the source of age-related differences in this task.     

Working-memory mediationof adult age differences in integrativereasoning

Three research methods were used to investigate the hypothesized mediational influence of working memory on age-related differences in integrative reasoning. Results from all three procedures were consistent with the hypothesis because (1) statistical control of an index of working memory attenuated the age differences in reasoning accuracy, (2) young adults were more accurate than older adults in a measure reflecting the preservation of information during processing, and (3) young adults performing the task with a concurrent memory load exhibited a qualitative pattern of performance similar to that of older adults performing the task without a concurrent memory load.     

Adult age differences in attentional allocation during memory search.

Young and older adults performed a memory search task in which, before probe onset, a cue indicated which of 4 memory-set items the probe was most likely to be. The results were consistent with an attentional allocation model in which performance represents a weighted combination, across trials, of focused (i.e., selective) versus distributed attention. The model significantly underestimated the reaction time required by miscued trials, probably because of the response inhibition occurring on these trials. The degree to which Ss relied on focused attention was significantly greater for older adults than for young adults. The estimated time required to shift attention between memory-set items was equivalent for the 2 age groups.     

Assessment of adult age differences in task engagement: The utility of systolic blood pressure

The constructs of effort and engagement are central to many theoretical frameworks associated with the study of aging. Age differences in the effort associated with effortful cognitive operations have been hypothesized to account for aging effects in ability, and shifting goals and motivation have been hypothesized to be associated with differential levels of engagement across situations in younger and older adults. Unfortunately, the assessment of effort and engagement—constructs that we view as relatively synonymous—has suffered in the field of aging due to the lack of well-validated measures. We suggest that systolic blood pressure might provide an easy and valid means for examining age differences in mental effort, and present evidence in support of its usage. Existing findings clearly support its potential utility, but further empirical and theoretical work is necessary.     

Age differences in the allocation of study time account for age differences in memory performance

How aging affects the utilization of monitoring in the allocation of study time was investigated by having adults learn paired associates during multiple study-test trials. During each trial, a subject paced the presentation of individual items and later judged the likelihood of recalling each item on the upcoming test; after all items had been studied and judged, recall occurred. For both age groups in Study 1, (1) people’s judgments were highly accurate at predicting recall and (2) intraindividual correlations between judgments (or recall) on one trial, and study times on the next trial were negative, which suggests that subjects utilized monitoring to allocate study time. However, the magnitude of these correlations was less for older than for younger adults. Study 2 revealed that these differences were not due to age differences in forgetting. Results from both studies suggest that older adults do not utilize on-line monitoring to allocate study to the same degree as younger adults do, and that these differences in allocation contribute to age deficits in recall.     

The source of adult age differences in event-based prospective memory: a multinomial modeling approach

Event-based prospective memory involves remembering to perform an action in response to a particular future event. Normal younger and older adults performed event-based prospective memory tasks in 2 experiments. The authors applied a formal multinomial processing tree model of prospective memory (Smith & Bayen, 2004) to disentangle age differences in the prospective component (remembering that you have to do something) and the retrospective component (remembering when to perform the action) of prospective memory performance. The modeling results, as well as more traditional analyses, indicate age differences in the resource-demanding prospective component.     

Adult age differences in strategic and dynamic components of focusing visual attention

Abstract

Changes in the width of a focally attended area were assessed by analysis of changes in reaction time associated with response-incompatible nontarget letters (flankers). In two experiments, the focus of attention widened as an increasing function of stimulus onset asynchrony (SOA). In contrast to the predictions of generalized slowing and inhibition-deficit models, this dynamic change in attention was comparable for young and older adults in both experiments. Evidence accumulation outside the focus of attention was greater for young adults than for older adults when target location varied (Experiment 2). This latter effect, however, was strategic (i.e., independent of SOA). Analyses of the task complexity functions (Brinley plots) indicated a greater contribution of generalized slowing when target location was constant (Experiment 1) than when location varied (Experiment 2).     

Absence of adult age differences in forgetting in the Brown-Peterson Task

Despite some recent evidence to the contrary, no reliable age differences in proactive interference (PI) or retroactive interference (RI) were found in a cross-sectional study of adults aged 18-29 and 63-75. Individual memory span was used as the list length in the Brown-Peterson Task in order to achieve stimulus equivalence of memory loads across individuals and age groups. Data from rehearsers were excluded from the analyses in order to isolate age differences in passive forgetting processes from those in rehearsal. PI was manipulated by presenting categorized or uncategorized memory lists. RI was manipulated, holding distractor task difficulty constant, by using words or tones in a signal detection distractor task. It is concluded that age differences are minimal to nonexistent in passive RI-related processes such as decay and perturbation and in passive PI-related processes such as set effects in semantic encoding.     

Neurophysiological measures of involuntary and voluntary attention allocation and dispositional differences in need for cognition

Need for cognition (NFC) refers to stable individual differences in the intrinsic motivation to engage in and enjoy effortful cognitive endeavors and has been a useful predictor of dispositional differences in information processing. Although cognitive resource allocation conceptualized as cognitive effort is assumed to be the key mediator of NFC-specific processing, to date no research has systematically addressed its underpinnings. Using a neurocognitive paradigm and recording event-related potentials associated with bottom-up and top-down-driven aspects of attention, the present research contributes to filling this gap. In Study 1, high-NFC individuals showed larger P3a amplitudes to contextually novel events, indicating greater involuntary (automatic) attention allocation. This effect was replicated in Study 2, where NFC also was positively correlated with the P3b to target stimuli, indicating voluntary (controlled) processes of attention allocation. Thus, our findings provide first evidence for neurophysiological correlates of NFC and can improve the understanding of NFC-specific processing.     

The development of selective attention: holistic perception versus resource allocation

In two experiments, a speeded sorting task was administered to children. In each sorting, the child was instructed to sort a deck of cards according to values on one dimension while the values of a second irrelevant dimension were held constant, were correlated, or were varied orthogonally. Experiment 1 evaluated developmental changes in perceived structure as compared with such changes in the control of attention. Different groups of kindergarten, 2d-, and 5th-grade children performed the task with spatially integrated vs spatially separated dimensions. The results indicate that with spatially integrated dimensions there is a trend from holistic to featural perception and an increase in attentional control with increasing age. Spatially separate dimensions are perceived dimensionally at all ages, but show a trend in attentional development. In Experiment 2, the spatially integrated dimensions of Experiment 1 were made separable by portraying different targets within a configuration in different colors. The theoretical implications of the results are discussed.     

The vertical nature of dominance-submission: Individual differences in vertical attention

Dominance-submission has been linked to verticality in studies of metaphor, judgment, and online processing. In all cases, dominance has been associated with higher locations in vertical space, whereas submission has been associated with lower locations in vertical space. The present studies sought to extend this class of vertical metaphors to individual differences in spatial attention. Two studies were conducted. In both, dominance-submission was assessed as an individual difference variable and covert spatial attention tasks were used to assess biases in vertical selective attention. As predicted, dominant individuals were faster to respond to higher spatial probes, whereas submissive individuals were faster to respond to lower spatial probes. These results reinforce a vertical theory of dominance-submission, importantly extending it to individual differences and basic processes of selective attention. Findings are discussed in relation to theories of embodiment, metaphor, personality, and attention.     

Recollection and familiarity in recognition memory: adult age differences and neuropsychological test correlates

Dual process theories account for age-related changes in memory by proposing that old age is associated with deficits in recollection together with invariance in familiarity. The authors evaluated this proposal in recognition by examining recollection and familiarity estimates in young and older adults across 3 process estimation methods: inclusion/exclusion, remember/know, and receiver operating characteristics (ROC). Consistent with a previous literature review (Light, Prull, LaVoie, & Healy, 2000), the authors found age invariance in familiarity when process estimates were derived from the inclusion/exclusion method, but the authors found age differences favoring the young when familiarity estimates were derived from the remember/know and ROC methods. Recollection estimates were lower for older adults in all 3 methods. Recollection and familiarity had variable relationships with frontal- and temporal-lobe measures of neuropsychological functioning in older adults, depending on which method was used to generate process estimates. These data suggest that although recollection deficits appear to be the rule in aging, not all estimates of familiarity show age invariance.     

Activity duration and adult age differences in memory for activity performance

Young and elderly subjects performed a series of activities that varied in the duration of their performances (45 s, 90 s, and 180 s). Duration was found to have a negligible effect on the subsequent recall of the activities and on the magnitude of the age deficit in recall. Operationalization of the program for performing an activity seems essential for establishing a memory trace of that activity's performance, but the duration of performing that activity seems to yield no further enhancement of that trace.