Age differences in reading with distraction: Sensory or inhibitory deficits?

Two experiments examined how sensory acuity affects age differences in susceptibility to interference in the reading-with-distraction task. In both experiments, older and younger adults read texts in an italic font and were required to ignore distractor words in an upright font. Experiment 1 examined whether the age-related increase in distractibility can be simulated in younger adults by reducing their visual acuity. Experiment 2 investigated whether the age differences in distractibility disappear if visual acuity is equated across all participants in both age groups. Both experiments showed that an impairment in visual acuity leads to increased interference in the reading-with-distraction task. However, older adults were much more impaired by the distractor material than younger adults with reduced visual acuity (Experiment 1). The age differences in the reading-with-distraction task persisted when visual acuity was equated between older and younger adults (Experiment 2). We conclude that the age-related increase in susceptibility to interference in the reading-with-distraction task is not solely due to perceptual deficits of older adults but arises from a deficit in higher cognitive processes such as inhibitory attention. Nevertheless, sensory acuity has to be taken into account as a potential confounding factor in perceptually demanding visual attention tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dilution, not load, affects distractor processing.

Lavie and Tsal (1994) proposed that spare attentional capacity is allocated involuntarily to the processing of irrelevant stimuli, thereby enabling interference. Under this view, when task demands increase, spare capacity should decrease and distractor interference should decrease. In support, Lavie and Cox (1997) found that increasing perceptual load by increasing search set size decreased interference from an irrelevant distractor. In three experiments, we manipulated the cue set size (number of cued locations) independently of the display set size (number of letters presented). Increasing the display set size reduced distractor interference regardless of whether the additional letters were relevant to the task. In contrast, increasing the cue set size increased distractor interference. Both findings are inconsistent with the load explanation, but are consistent with a proposed two-stage dilution account. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Diluting the burden of load: Perceptual load effects are simply dilution effects.

The substantial distractor interference obtained for small displays when the target appears alone is reduced in large displays when the target is embedded among neutral letters. This finding has been interpreted as reflecting low-load and high-load processing, respectively, thereby supporting the theory of perceptual load (Lavie & Tsal, 1994). However, a possible alternative interpretation of this effect is that the distractor is similarly processed in both displays, yet its interference in the large ones is diluted by the presence of the neutral letters. We separated the effects of load and dilution by introducing dilution displays. They contained as many letters as the high-load displays but were clearly distinguished from the target, thus allowing for a low-load processing mode. Distractor interference obtained under both the low-load and high-load conditions disappeared under the dilution condition. Hence, the display size effect traditionally misattributed to perceptual load is fully accounted for by dilution. Furthermore, when dilution is controlled for, it is high load not low load producing greater interference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of perceptual load in negative priming.

Negative priming (NP) effects from irrelevant distractors were assessed as a function of perceptual load in the processing of prime targets. Participants searched for a target letter among a varying number of nontarget letters in the center of the display and ignored an irrelevant peripheral distractor. NP from this distractor was found to depend on the relevant search set size, decreasing as this set size was increased. The authors conclude that exhausting attention in relevant processing reduces irrelevant processing (e.g., N. Lavie, 1995), leaving less distractor processing to produce NP. This conclusion is consistent with recent reactive inhibition views for NP (e.g., G. Houghton, S. P. Tipper, B. Weaver, & D. I. Shore, 1996). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related changes in selective attention and perceptual load during visual search.

Three visual search experiments were conducted to test the hypothesis that age differences in selective attention vary as a function of perceptual load (E. A. Maylor & N. Lavie, 1998). Under resource-limited conditions (Experiments 1 and 2), the distraction from irrelevant display items generally decreased as display size (perceptual load) increased. This perceptual load effect was similar for younger and older adults, contrary to the findings of Maylor and Lavie. Distraction at low perceptual loads appeared to reflect both general and specific inhibitory mechanisms. Under more data-limited conditions (Experiment 3), an age-related decline in selective attention was evident, but the age difference was not attributable to capacity limitations as predicted by the perceptual load theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult Age Differences in the Implicit and Explicit Components of Top-Down Attentional Guidance During Visual Search.

Two experiments investigated adult age differences in the explicit (knowledge-based) and implicit (repetition priming) components of top-down attentional guidance during discrimination of a target singleton. Experiment 1 demonstrated an additional contribution of explicit top-down attention, relative to the implicit effect of repetition priming, which was similar in magnitude for younger and older adults. Experiment 2 examined repetition priming of target activation and distractor inhibition independently. The additional contribution of explicit top-down attention, relative to the repetition priming of distractor inhibition, was greater for older adults than for younger adults. The results suggest that some forms of top-down attentional control are preserved as a function of adult age and may operate in a compensatory manner. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related changes in imitating sequences of observed movements.

Three experiments investigated the size and sources of age-related changes in visual imitation. In Experiment 1, young and older adults viewed sequences of quasi-random movements and then reproduced from memory what they had seen. As expected, older adults made more errors in imitation than their younger counterparts. However, older adults seemed to supplement their memory by exploiting an abstracted representation (gist) of a sequence. Experiments 2 and 3 apportioned the observed age-related changes in imitation performance among several possible causes. Experiment 2 showed that changes in precision of visual perception and motor control together accounted for only a small fraction of age-related changes in imitation quality; Experiment 3 showed that the bulk of the age-related changes arose from the older participants’ reduced ability to accommodate for increases in memory load, likely caused by diminished ability to encode or retain detailed information about movement sequences. Guided by these results, strategies are proposed for enhancing older adults’ imitation learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dilution: A theoretical burden or just load? A reply to Tsal and Benoni (2010).

Load theory of attention proposes that distractor processing is reduced in tasks with high perceptual load that exhaust attentional capacity within task-relevant processing. In contrast, tasks of low perceptual load leave spare capacity that spills over, resulting in the perception of task-irrelevant, potentially distracting stimuli. Tsal and Benoni (2010) find that distractor response competition effects can be reduced under conditions with a high search set size but low perceptual load (due to a singleton color target). They claim that the usual effect of search set size on distractor processing is not due to attentional load but instead attribute this to lower level visual interference. Here, we propose an account for their findings within load theory. We argue that in tasks of low perceptual load but high set size, an irrelevant distractor competes with the search nontargets for remaining capacity. Thus, distractor processing is reduced under conditions in which the search nontargets receive the spillover of capacity instead of the irrelevant distractor. We report a new experiment testing this prediction. Our new results demonstrate that, when peripheral distractor processing is reduced, it is the search nontargets nearest to the target that are perceived instead. Our findings provide new evidence for the spare capacity spillover hypothesis made by load theory and rule out accounts in terms of lower level visual interference (or mere “dilution”) for cases of reduced distractor processing under low load in displays of high set size. We also discuss additional evidence that discounts the viability of Tsal and Benoni's dilution account as an alternative to perceptual load. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual specificity and implicit auditory priming in older and younger adults.

Age differences in perceptual specificity for implicit auditory priming were examined in 3 experiments. All 3 experiments began with a study phase during which participants rated words based on perceptual (shallow encoding) or semantic (deep encoding) attributes. After the study phase, participants were asked to identify filtered versions of repeated and new words (implicit test) and then to make old/new recognition judgments (explicit test). In contrast to earlier findings (D. L. Schacter, B. Church, & D. M. Osowiecki, 1994), older and younger adults were equally sensitive to study-to-test changes in speaking rate (Experiment 1), fundamental frequency (Experiment 2), and voice (Experiment 3). Explicit memory, in contrast, was significantly poorer for older adults but was minimally affected by changes in surface features. Findings from the study are discussed with respect to their implications for establishing the mechanisms mediating perceptual specificity and for their importance in understanding age-related changes in implicit memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Part-Set Cuing Effects in Younger and Older Adults.

In 3 experiments, the authors examined part-set cuing effects in younger and older adults. Participants heard lists of category exemplars and later recalled them. Recall was uncued or cued with a subset of studied items. In Experiment 1, participants were cued with some of the category names, and they remembered fewer never-cued categories than a free-recall condition. In Experiment 2, a similar effect was observed for category exemplar cues. There was also an age difference: By some measures, a small number of cues impaired older adults more than younger. Experiment 3 replicated this result and found that older adults were disproportionately slow in the presence of cues. Across experiments, older adults showed robust part-set cuing effects, and sometimes, they were disproportionately impaired by cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distraction by competing speech in young and older adult listeners.

In 2 experiments, young and older adults heard target speech presented in quiet or with a competing speaker in the background. The distractor consisted either of meaningful speech or nonmeaningful speech composed of randomly ordered word strings (Experiment 1) or speech in an unfamiliar language (Experiment 2). Tests of recall for the target speech showed that older adults, but not younger adults, were impaired more by meaningful distractors than by nonmeaningful distracters, However, on a surprise recognition test, young adults were more likely than older adults to recognize meaningful distractor items. These results suggest that reduced efficiency in attentional control is an important factor in older adults' difficulty in recalling target speech in the presence of a background of competing speech. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in saccadic averaging.

Younger and older adults were asked to saccade to an orientation-defined target that was presented alone, with a more central distractor, or with a more peripheral distractor. Both age groups exhibited saccadic averaging that was more pronounced in the central distractor condition, wherein older adults had the larger effect. These results are relevant to questions of oculomotor control and also have implications for the study of age differences in other visually guided behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The structural organization of the mental lexicon and its contribution to age-related declines in spoken-word recognition.

Three experiments were conducted within the framework of the Neighborhood Activation Model of spoken-word recognition to study how the structural organization of the mental lexicon may contribute to age-related declines in spoken-language processing. Experiment 1 showed that the number and frequency of words that are phonetically similar to a target word had differential effects on perceptual identification in older and younger adults, with older adults being particularly disadvantaged in identifying hard words (words phonetically similar to many other high-frequency words). Experiment 2 showed that age-related deficits in the ability to identify hard words remained under conditions in which performance for a set of easy words (items phonetically similar to relatively few other low-frequency words) was the same for older and younger adults. In Experiment 3, reducing the resources available for identification by changing from single to multiple talkers reduced word recognition more among older than younger adults. Diminished cognitive resources, impaired inhibitory control, and increased general slowing are discussed as explanations for the results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of aging on absolute identification of duration.

Experiments to examine the effects of aging on the ability to identify temporal durations in an absolute identification task are reported. In Experiment 1, older adults were worse than younger adults in identifying a tone's position within a series of 6 tones of varied durations. In Experiment 2, participants were required to identify a tone's position in 9 tones of varied durations. Older adults' performance was again worse than that of younger adults; moreover, they showed a qualitatively different pattern of errors than younger adults. In Experiment 3, in which the tones varied in pitch, the performance of older adults was worse than that of younger adults, but the error patterns of the 2 groups were similar. The results suggest that older adults have distorted memory representations for durations but not for pitch. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identity negative priming in older adults and individuals with dementia of the Alzheimer type.

This study addressed the question of whether dementia of the Alzheimer type (DAT) produces a breakdown in aspects of the inhibitory component underlying selective attention. Two measures of identity negative priming and 2 measures of distractor interference were obtained. In Experiment 1, participants were presented with overlapping picture stimuli, and in Experiment 2, participants were presented with overlapping written word stimuli. The results of both experiments produced reliable and similar size negative priming in young and old adults, but there was no evidence of negative priming in the individuals with DAT. In contrast, the naming latencies of all 3 groups showed a reliable and similar size distractor interference effect. These results suggest that although the inhibitory component underlying selective attention is impaired in individuals with DAT, the ability to differentiate a target from a distractor may be preserved under certain task conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging, source, and decision criteria: When false fame errors do and do not occur.

Two experiments investigated the influence of decision criteria on source memory performance of older adults and younger adults. Experiment 1 used the false fame paradigm, which encourages people to use relatively loose decision criteria when making what are, in essence, source judgments. Consistent with previous research, older adults made more false fame errors than younger adults. Experiment 2 was identical to Experiment 1 except that the fame judgments were made with the traditional source task format that encourages relatively stringent decision criteria when making source judgments: Possible sources were listed, and participants categorized names in terms of their source. In contrast to Experiment 1, older adults reduced their false fame errors to the level of younger adults. Encouraging older adults to use relatively stringent decision criteria when making source discriminations can reduce age differences in source misattributions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and single versus multiple cues in source monitoring.

Participants heard words said by 2 speakers and later decided who said each word. The authors varied the perceptual distinctiveness of the speakers and the distinctiveness of the cognitive operations participants performed on the words. Relative to younger adults, older adults had significantly lower source monitoring scores when perceptual or cognitive operations conditions were similar but not when either cue was more distinctive. Combining cues did not affect source monitoring of younger adults but hurt older adults' performance relative to the distinctive perceptual condition. Evidently, older adults generate cognitive cues at the expense of encoding perceptual cues; any deficit in binding perceptual and semantic information disadvantages them more in source monitoring than in old/new recognition. There was no correlation between neuropsychological tests assessing frontal function and source monitoring in older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Size scaling and spatial factors in visual attention

This study investigates the effect of the visibility of near and far letter distractors on target processing by scaling the size of the distractor letters to compensate for changes in resolution across the visual field. In Experiment 1, scaled and unscaled distractors were presented at varied stimulus onset asynchronies. Results showed that scaling the size of distractor letters in relation to their distance from the target was effective in producing strong compatibility effects. Scaled distractors presented prior to, or simultaneously with, the target were found to interfere with target processing whether they were near or far from the target. Experiment 2 used scaled distractors and varied the presentation location and the amount of time for processing prior to the presentation of the target. Compatibility effects were found to vary by location and by the exposure duration of the distractor. The finding of distance effects at far locations supports a space-based visual-attention mechanism with a wide attention beam (Steinman, Steinman, & Lehmkuhle, 1995).     

Inhibitory attentional mechanisms and aging

Two experiments sought to elicit distractor suppression in older adults. Experiment 1 used a procedure that increased suppression in younger adults, thus creating a more sensitive measure of suppression in older adults. To compensate for older adults' slowed processing, Experiment 2 used a longer stimulus exposure duration. Neither experiment produced suppression in older adults; both experiments, however, included trial types that elicited parallel facilitatory effects for both age groups. Older adults thus seemed to process distractors but failed to engage inhibitory mechanisms in their rejection of distracting stimuli. Finally, both experiments tested the relationships among suppression, interference, and everyday cognitive failure. Neither experiment suggested relationships between reaction time effects and self-reported cognitive lapses. Results are discussed within L. Hasher and R. T. Zacks's (1988) attentional framework.