Individual differences in susceptibility to inattentional blindness.

Inattentional blindness refers to the finding that people do not always see what appears in their gaze. Though inattentional blindness affects large percentages of people, it is unclear if there are individual differences in susceptibility. The present study addressed whether individual differences in attentional control, as reflected by variability in working memory capacity, modulate susceptibility to inattentional blindness. Participants watched a classic inattentional blindness video (Simons & Chabris, 1999) and were instructed to count passes among basketball players, wherein 58% noticed the unexpected: a person wearing a gorilla suit. When participants were accurate with their pass counts, individuals with higher working memory capacity were more likely to report seeing the gorilla (67%) than those with lesser working memory capacity (36%). These results suggest that variability in attentional control is a potential mechanism underlying the apparent modulation of inattentional blindness across individuals. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The effects of attention on age-related relational memory deficits: Evidence from a novel attentional manipulation.

Healthy aging is often accompanied by episodic memory decline. Prior studies have consistently demonstrated that older adults show disproportionate deficits in relational memory (RM) relative to item memory (IM). Despite rich evidence of an age-related RM deficit, the source of this deficit remains unspecified. One of the most widely investigated factors of age-related RM impairment is a reduction in attentional resources. However, no prior studies have demonstrated that reduced attentional resources are the critical source of age-related RM deficits. Here, we used qualitatively different attention tasks and tested whether reduced attention for relational processing underlies the RM deficit observed in aging. In Experiment 1, we imposed either item-detection or relation-detection attention tasks on young adults during episodic memory encoding and found that only the concurrent attention task that involves relational processing disproportionately impaired RM performance in young adults. Moreover, by ruling out the possible confound of task difficulty on the disproportionate RM impairment, we further demonstrated that reduced relational attention is a key factor for the age-related RM deficit. In Experiment 2, we replicated the results from Experiment 1 by using different materials of stimuli and found that the effect of relational attention on RM is material general. The results of Experiment 2 also showed that reducing attentional resources for relational processing in young adults strikingly equated their RM performance to that of older adults. Thus, this study documents the first evidence that reduced attentional resources for relational processing are a critical factor for the relational memory impairment observed in aging. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The Effects of Age and Dementia of the Alzheimer's Type on Phonological False Memories.

The authors conducted 3 experiments that examined the effects of age and dementia of the Alzheimer's type (DAT) on phonological false memories. In addition, the study was designed to investigate the role of inhibitory control in mediating phonological false memories. In Experiment 1, both young-old and old-old participants exhibited increased susceptibility to false remembering, compared with young adults. In Experiment 2, auditory Stroop interference was used as an index of inhibitory abilities and was found to account for a significant percentage of the variance in false recollection. Experiment 3 provided converging evidence for the importance of inhibitory control in phonological false memories by demonstrating that DAT patients are more susceptible to false recall and recognition than healthy older adults. The results are discussed within the inhibitory deficit framework of cognitive aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Flexible feature-based inhibition in visual search mediates magnified impairments of selection: Evidence from carry-over effects under dynamic preview-search conditions.

Evidence for inhibitory processes in visual search comes from studies using preview conditions, where responses to new targets are delayed if they carry a featural attribute belonging to the old distractor items that are currently being ignored—the negative carry-over effect (Braithwaite, Humphreys, & Hodsoll, 2003). We examined whether inhibition was applied in the same manner across different types of displays or whether the inhibitory weighting applied to different features varied with their utility for the search task. To test this, we present the first empirical investigation of negative carry-over effects under the ecologically valid conditions of dynamic visual search. Experiment 1 investigated preview search using dynamic moving and static displays. Detection was very poor when new targets carried the color of the old distractors, and this negative carry-over effect was significantly exaggerated with moving, compared with static, displays. Experiments 2a and 2b demonstrated that this effect could not be attributed to an increased role of preattentive grouping between new and old items for dynamic displays. Collectively, the findings suggest that feature-based inhibition contributes strongly to preview search through dynamic displays, and this leads to an amplified attentional blindness to new targets. The data specifically indicate that inhibitory processes in search differentially weight color and location in moving and static displays, and that feature-based inhibition may underlie many instances of sustained inattentional blindness in everyday life. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Attentional selection is biased toward mood-congruent stimuli.

One can exert significant volitional control over the attentional filter so that stimuli that are consistent with one's explicit goals are more likely to receive attention and become part of one's conscious experience. Here we pair a mood induction procedure with an inattentional blindness task to show that one's current mood has a similar influence on attention. A positive, negative, or neutral mood manipulation was followed by an attentionally demanding multiple-object tracking task. During the tracking task, participants were more likely to notice an unexpected face when its emotional expression was congruent with participants' mood. This was particularly true for the frowning face, which was detected almost exclusively by participants in the sad mood induction condition. This attentional bias toward mood-congruent stimuli provides evidence that one's temporary mood can influence the attentional filter, thereby affecting the information that one extracts from, and how one experiences the world. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Age-related differences in irrelevant-speech effects.

Three experiments examined age-related differences in irrelevant-speech effects. Younger and older adults were required to recall short prose texts or lists of semantically related words presented visually together with distractor speech. In all experiments, older adults made more semantically related intrusion errors from the irrelevant speech than younger adults. Results of a source memory test suggested that these age-related differences in interference are most likely due to both inhibitory deficits and source-monitoring problems. The results lend partial support to the inhibition deficit theory of cognitive aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and interference in verbal working memory.

According to inhibitory views of working memory, old adults should have particular problems deleting irrelevant information from working memory, leading to greater interference effects compared with young adults. The authors investigated this hypothesis by using variations of an A-B, C-D retroactive interference paradigm in working memory with young and old adults. They used a recognition measure of memory, assessing both accuracy and reaction time. The primary finding was that senior adults consistently exhibited proportionally greater retroactive interference effects compared with young adults when interfering word pairs that had been read aloud had to be rejected. Patterns of recognition and reaction time data suggested that old adults' activation of target material is similar to young adults, but they experience sustained activation of irrelevation material that has entered working memory. Theoretical implications of these findings for inhibitory deficit (R.T. Zacks & L. Hasher, 1998) and source memory deficit accounts of cognitive aging are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential Age Effects on Attention-Based Inhibition: Inhibitory Tagging and Inhibition of Return.

The purpose of this study was to determine whether 2 forms of attentional inhibition, inhibition of return (IOR) and inhibitory tagging, are differentially affected by the aging process. The authors tested 24 younger adults (mean age = 22 years) and 24 older adults (mean age = 69 years) on a combined IOR and Stroop task (Vivas & Fuentes, 2001). As predicted, younger adults' performance was consistent with inhibitory tagging of objects at inhibited locations. Although older adults demonstrated intact IOR, there was no evidence of inhibitory tagging. The results suggest that age deficits in inhibition are selective. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context processing in older adults: Evidence for a theory relating cognitive control to neurobiology in healthy aging.

A theory of cognitive aging is presented in which healthy older adults are hypothesized to suffer from disturbances in the processing of context that impair cognitive control function across multiple domains, including attention, inhibition, and working memory. These cognitive disturbances are postulated to be directly related to age-related decline in the function of the dopamine (DA) system in the prefrontal cortex (PFC). A connectionist computational model is described that implements specific mechanisms for the role of DA and PFC in context processing. The behavioral predictions of the model were tested in a large sample of older (N = 81) and young (N = 175) adults performing variants of a simple cognitive control task that placed differential demands on context processing. Older adults exhibited both performance decrements and, counterintuitively, performance improvements that are in close agreement with model predictions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences and similarities in the effects of cues and prompts.

A series of 6 experiments investigated the use of cues and prompts by younger and older adults. Cues provide useful information about an impending target, even though the information is not always valid. Prompts provide an instruction about what aspect of the target is to be responded to. The costs and benefits of cues were most consistent with models in which the attentional resources that are shifted in response to the cue were as large or larger in older adults as they were in younger adults. The results with both cues and prompts converged on the conclusion that the time course of processing and using a cue or prompt is the same in younger and older adults. The attentional resources tapped by these procedures cannot be the diminished processing resource to which many age differences in cognitive performance are attributed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differences in the functional neuroanatomy of inhibitory control across the adult life span.

Inhibitory control, the ability to suppress irrelevant stimuli, is a fundamental cognitive function that deteriorates during aging, but little is understood about the bases of decline. Thus, we used event-related functional magnetic resonance imaging (fMRI) to study inhibitory control in healthy adults aged 18 to 78. Activation during "successful inhibition" occurred predominantly in right prefrontal and parietal regions and was more extensive, bilaterally, and prefrontally, in the older groups. Presupplementary motor area was also more active in poorer inhibitory performers. Therefore, older adults activate areas that are comparable to those activated by young adults during inhibition, as well as additional regions. The results are consistent with a compensatory interpretation and extend the aging neuroimaging literature into the cognitive domain of inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention set for number: Expectation and perceptual load in inattentional blindness.

Inattentional blindness is the failure to detect unexpected events when attention is otherwise engaged. Previous research indicates that inattentional blindness increases as perceptual demands intensify. The authors present 6 cuing experiments that manipulated both the perceptual demands of a primary letter-naming task and the expectations of the individual. Inattentional blindness was greatest for individuals who held a numerical expectation that was consistent with the number of primary-task items presented. Expectation also affected detection differentially at various levels of perceptual load: Detection at moderate and high perceptual load was significantly affected by expectation, whereas detection at low perceptual load was not. The authors suggest that at moderate to high levels of perceptual load, individuals whose numerical expectations are fulfilled terminate processing when the primary task is complete, at the expense of the unexpected visual event. These experiments provide compelling evidence that expectations do affect detection of an unexpected stimulus, and they are the first to demonstrate that individuals set their attention for the number of items to be detected and are vulnerable to inattentional blindness whenever their primary-task numerical expectation is fulfilled. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and inhibition: Beyond a unitary view of inhibitory processing in attention.

The authors examined the question of whether a decrease in the efficiency of inhibitory processing with aging is a general phenomenon. Thirty elderly and 32 young adults performed a series of tasks from which the authors could extract measures of inhibitory function. The tasks and task components included response compatibility, negative priming, stopping, spatial precuing, Wisconsin Card Sorting Test (WCST), and the Cognitive Failures Questionnaire (CFQ). Only limited evidence for age-related differences in inhibitory function was obtained. Old adults had more difficulty than young adults in stopping an overt response and adopting new rules in a categorization task. However, elderly and young adults produced equivalent negative priming effects, response compatibility effects, spatial precuing effects, and self-reported cognitive failures. The findings are discussed in terms of the relationship between aging, inhibitory processes, and neuroanatomical and physiological function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methodology and validity in the construction of computational models of cognitive deficits following brain damage

Over recent years, neural network models of several cognitive neuropsychological disorders have been developed. These include word recognition difficulties, face recognition difficulties, attentional deficits, visual processing impairments, semantic deficits, and aphasia. These models are useful in various ways. Firstly, they require detailed specifications of theories, and can focus attention on critical assumptions. Secondly, they can query alternative theories, and provide predictions which can be verified by testing patients. In this paper, issues relating both to the methodology and validity of attempts to model cognitive deficits using neural networks will be discussed, providing examples from several studies. Issues discussed will include the requirement for models to perform normally prior to damage, and to show potential effects of rehabilitation or partial recovery following damage. A single model should be able to incorporate multiple symptoms of a deficit and ideally also multiple syndromes when different lesions are introduced. The model must also be able to handle variability between patients with the same syndrome, and even with the same patient at different test sessions.     

Effects of aging and prospective memory on recognition of item and associative information.

Older adults typically perform worse than younger adults on tasks of associative, relative to item, memory. One account of this deficit is that older adults have fewer attentional resources to encode associative information. Previous researchers investigating this issue have divided attention at encoding and then have examined whether associative and item recognition were differentially affected. In the current study, we used a different cognitive task shown to tax attentional resources: event-based prospective memory. Although older adults demonstrated worse associative, relative to item, memory, the presence of the prospective memory task at encoding decreased item and associative memory accuracy to the same extent in both age groups. These results do not support the resource account of age-related associative deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object-based attentional selection and aging.

The authors conducted 2 studies which examined potential age-related differences in object-based attentional selection. Participants were briefly presented with pairs of wrenches and were asked to make 1 response if both target properties (i.e., an open end and a hexagonal end) were present and another response if only a single target property was present in the display. The critical manipulation was whether the target properties were present on 1 wrench or distributed between 2 wrenches. Space-based models of selective attention predict no difference in performance between these conditions. However, object-based attentional selection models predict better performance when both target properties appear on a single object. The results from both of the studies were consistent with object-based models of attentional selection. Furthermore, both young and old adults showed similar performance effects, suggesting the object-based attentional selection is insensitive to normal aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The attentional blink provides episodic distinctiveness: Sparing at a cost.

The attentional blink (J. E. Raymond, K. L. Shapiro, & K. M. Arnell, 1992) refers to an apparent gap in perception observed when a second target follows a first within several hundred milliseconds. Theoretical and computational work have provided explanations for early sets of blink data, but more recent data have challenged these accounts by showing that the blink is attenuated when subjects encode strings of stimuli (J. Kawahara, T. Kumada, & V. Di Lollo, 2006; M. R. Nieuwenstein & M. C. Potter, 2006; C. N. Olivers, 2007) or are distracted (C. N. Olivers & S. Nieuwenhuis, 2005) while viewing the rapid serial visual presentation stream. The authors describe the episodic simultaneous type, serial token model, a computational account of encoding visual stimuli into working memory that suggests that the attentional blink is a cognitive strategy rather than a resource limitation. This model is composed of neurobiologically plausible elements and simulates the attentional blink with a competitive attentional mechanism that facilitates the formation of episodically distinct representations within working memory. In addition to addressing the blink, the model addresses the phenomena of repetition blindness and whole report superiority, producing predictions that are supported by experimental work. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and inhibition processes: The case of metaphor treatment.

The inhibitory deficit hypothesis has often been cited as a possible explanation for cognitive changes related to age. The aim of this study was to develop a new procedure for evaluating effortful inhibition on the basis of the comprehension of metaphors. Our experiment was carried out on younger and older adults, in whom we also measured inhibitory capacity, working memory, and processing speed. The results show that older participants required a longer time and made more frequent errors in rejecting metaphors versus literally false statements. The interference effect was predicted by the psychometric tests designed to evaluate inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Different storage and retrieval deficits in normal aging and mild cognitive impairment: A multinomial modeling analysis.

The authors compared patients with mild cognitive impairment with healthy older adults and young control participants in a free recall test in order to locate potential qualitative differences in normal and pathological memory decline. Analysis with an extended multitrial version of W. H. Batchelder and D. M. Riefer's (1980) pair-clustering model revealed globally decelerated learning and an additional retrieval deficit in patients with mild cognitive impairment but not in healthy older adults. Results thus suggest differences in memory decline between normal and pathological aging that may be useful for the detection of risk groups for dementia, and they illustrate the value of model-based disentangling of processes and of multitrial tests for early detection of dementia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using the attention cascade model to probe cognitive aging.

Young and older adults searched for 2 digit targets among black letter distractors in rapid serial visual presentation. Unsurprisingly, relative to the young, the older adults performed worse on both targets and exhibited greater and longer attentional blink. The data of each group were computationally accounted for by the attention cascade model (Shih, 2008) with 7 parameters; the optimum values and 95% confidence intervals of the parameters were based on 10,000 bootstrap samples. There was no age effect on the width of the attention window or on the capacity of the consolidation processor. However, relative to the young, the older adults suffered more masking effects of the salient (and brighter) stimulus, required longer consolidation duration, and had greater and more widespread decision noise. The processing rate prior to working memory was numerically slower in older adults. Both age groups adopted inefficient strategy during the task—engaging the consolidation processor for an unnecessarily long period. Further simulations suggest that varying the duration can emulate strong or weak blinkers or nonblinkers. The attention cascade model appears a useful tool for the investigation of cognitive aging and other comparative studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)