Age-related increase in top-down activation of visual features

Previous research suggests that, during visual search and discrimination tasks, older adults place greater emphasis than younger adults on top-down attention. This experiment investigated the relative contribution of target activation and distractor inhibition to this age difference. Younger and older adults performed a singleton discrimination task in which either an E or an R target (colour singleton) was present among distractor letters. Relative to a baseline condition in which the colours of the targets and distractors remained constant, an age-related slowing of performance was evident when either the colour of the target or that of the distractors varied across trials. The age-related slowing was more pronounced in response to target colour variation, suggesting that older adults place relatively greater emphasis on the top-down activation of target features.     

Age-related increase in top-down activation of visual features

Previous research suggests that, during visual search and discrimination tasks, older adults place greater emphasis than younger adults on top-down attention. This experiment investigated the relative contribution of target activation and distractor inhibition to this age difference. Younger and older adults performed a singleton discrimination task in which either an E or an R target (colour singleton) was present among distractor letters. Relative to a baseline condition in which the colours of the targets and distractors remained constant, an age-related slowing of performance was evident when either the colour of the target or that of the distractors varied across trials. The age-related slowing was more pronounced in response to target colour variation, suggesting that older adults place relatively greater emphasis on the top-down activation of target features.     

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.     

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.     

Aging and visual search: automatic and controlled attentional bias to threat faces

Using a visual search paradigm, we investigated how age affected attentional bias to emotional facial expressions. In Experiments 1 and 2, participants searched for a discrepant facial expression in a matrix of otherwise homogeneous faces. Both younger and older adults showed a more effective search when the discrepant face was angry rather than happy or neutral. However, when the angry faces served as non-target distractors, younger adults' search was less effective than happy or neutral distractor conditions. In contrast, older adults showed a more efficient search with angry distractors than happy or neutral distractors, indicating that older adults were better able to inhibit angry facial expressions. In Experiment 3, we found that even a top-down search goal could not override the angry face superiority effect in guiding attention. In addition, RT distribution analyses supported that both younger and older adults performed the top-down angry face search qualitatively differently from the top-down happy face search. The current research indicates that threat face processing involves automatic attentional shift and a controlled attentional process. The current results suggest that age only influenced the controlled attentional process.     

Age differences in visual search: target and distractor learning.

Age differences in a semantic category visual search task were investigated to determine whether the age effects were due to target learning deficits, distractor learning deficits, or a combination thereof. Twelve young (mean age 20) and 12 older (mean age 70) adults received 2,400 trials each in consistent and varied versions of the search task. Following training, a series of transfer-reversal manipulations allowed the assessment of target learning and distractor learning both in isolation and in combination. The pattern of data suggests that older adults have a deficit in their ability to increase the attention-attraction strength of targets and to decrease the attention-attraction strength of distractors. The results are interpreted in terms of a strength-based framework of visual search performance.     

Sexual distractors boost younger and older adults' visual search RSVP performance

Do sexual words have high attentional priority? How does the ability to ignore sexual distractors evolve with age? To answer these questions, two experiments using Rapid Serial Visual Presentation (RSVP) were conducted. Experiment 1 showed that both younger and older participants were better at identifying a target (the name of a colour) when it was preceded by 336 ms by a sexual word rather than by a musical word. Strikingly, the sexual‐word advantage was more pronounced for older adults than for younger adults. Experiment 2 showed that introducing a variable delay between the distractor and the target eliminated the sexual‐word advantage. This finding suggests that the sexual‐word advantage found in Experiment 1 was due to learning to utilize the sexual word as a temporal cue with a fixed duration between the distractor and the target. Contrary to previous research [Arnell et al., 2007, Emotion, 7, 465), neither experiment showed that sexual words produce an attentional blink.     

Age-related effects in inter-trial inhibition of attention

Young and older adults indentified the shape of a color oddball in a visual search task, and both showed faster and more accurate responses when the distractor color was passively viewed in the preceding target-absent trial than when the target color was previewed. This inter-trial effect, known as the distractor previewing effect (DPE), reflects an attentional bias that prevents attention from focusing on recently inspected features that failed to produce a target. The results showed that the DPE pattern was preserved across the lifespan, and that the age-related increase in the magnitude of the DPE appeared rooted in age-related slowing, suggesting substantial sparing of this inhibitory effect in old age.     

Age-related effects in inter-trial inhibition of attention

ABSTRACT

Young and older adults indentified the shape of a color oddball in a visual search task, and both showed faster and more accurate responses when the distractor color was passively viewed in the preceding target-absent trial than when the target color was previewed. This inter-trial effect, known as the distractor previewing effect (DPE), reflects an attentional bias that prevents attention from focusing on recently inspected features that failed to produce a target. The results showed that the DPE pattern was preserved across the lifespan, and that the age-related increase in the magnitude of the DPE appeared rooted in age-related slowing, suggesting substantial sparing of this inhibitory effect in old age.     

Age differences in the distractor-ratio effect as a function of contrast level

Latencies (RT) and eye movement measures were used to examine the effects of age and contrast on the distractor-ratio effect (DRE) in visual search. Younger and older adults performed a contrast x orientation conjunction search task where the ratios of white to black distractors and luminance contrast levels were varied. The distractor-ratio manipulation had similar effects for older and younger adults on both RT and the number of fixations required to find the target. Both measures were largely independent of distractor ratio on target-present trials, while both RTs and the fixation number increased with the number of items sharing the target's contrast polarity on target-absent trials. A more detailed analysis of eye movements suggested that younger adults were a bit more adept at attending to the smaller set of distractors, which presumably facilitated both overt and covert search. Generalized slowing can account for the age differences in RT, but the fixation number data speak to another mechanism, perhaps increased cautiousness on the part of the elderly when signal strength is low.     

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.     

Modulation of distraction in ageing

A cueing paradigm was employed to examine modulation of distraction due to a visual singleton. Subjects were required to make a saccade to a shape‐singleton target. A predictive location cue indicated the hemifield where a target would appear. Older adults made more anticipatory saccades than younger adults, and were less accurate for making an eye movement in the vicinity of a target. However, younger and older adults likewise benefited from the cue; distraction was reduced when the distractor singleton appeared in an uncued hemisphere. The ability to compensate for problems with distraction in older and younger adults through use of the precue suggests that attention to a general region of space, rather than a specific location, may be enough to modulate distraction.     

Age Differences in the Distractor-Ratio Effect as a Function of Contrast Level

ABSTRACT

Latencies (RT) and eye movement measures were used to examine the effects of age and contrast on the distractor-ratio effect (DRE) in visual search. Younger and older adults performed a contrast × orientation conjunction search task where the ratios of white to black distractors and luminance contrast levels were varied. The distractor-ratio manipulation had similar effects for older and younger adults on both RT and the number of fixations required to find the target. Both measures were largely independent of distractor ratio on target-present trials, while both RTs and the fixation number increased with the number of items sharing the target's contrast polarity on target-absent trials. A more detailed analysis of eye movements suggested that younger adults were a bit more adept at attending to the smaller set of distractors, which presumably facilitated both overt and covert search. Generalized slowing can account for the age differences in RT, but the fixation number data speak to another mechanism, perhaps increased cautiousness on the part of the elderly when signal strength is low.     

The role of working memory capacity and interference resolution mechanisms in task switching

Theories of task switching have emphasized a number of control mechanisms that may support the ability to flexibly switch between tasks. The present study examined the extent to which individual differences in working memory (WM) capacity and two measures of interference resolution, response–distractor inhibition and resistance to proactive interference (PI), account for variability in task switching, including global costs, local costs, and N-2 repetition costs. A total of 102 young and 60 older adults were tested on a battery of tasks. Composite scores were created for WM capacity, response–distractor inhibition, and resistance to PI; shifting was indexed by rate residual scores, which combine response time and accuracy and account for individual differences in processing speed. Composite scores served as predictors of task switching. WM was significantly related to global switch costs. While resistance to PI and WM explained some variance in local costs, these effects did not reach significance. In contrast, none of the control measures explained variance in N-2 repetition costs. Furthermore, age effects were only evident for N-2 repetition costs, with older adults demonstrating larger costs than young adults. Results are discussed within the context of theoretical models of task switching.     

Developmental changes in the control of saccadic eye movements in response to directional eye gaze and arrows

We investigated developmental differences in oculomotor control between 10-year-old children and adults using a central interference task. In this task, the colour of a fixation point instructed participants to saccade either to the left or to the right. These saccade directions were either congruent or incongruent with two types of distractor cue: either the direction of eye gaze of a centrally presented schematic face, or the direction of arrows. Children had greater difficulties inhibiting the distractor cues than did adults, which revealed itself in longer saccade latencies for saccades that were incongruent with the distractor cues as well as more errors on these incongruent trials than on congruent trials. Counter to our prediction, in terms of saccade latencies, both children and adults had greater difficulties inhibiting the arrow than the eye gaze distractors.     

Developmental changes in the control of saccadic eye movements in response to directional eye gaze and arrows

We investigated developmental differences in oculomotor control between 10-year-old children and adults using a central interference task. In this task, the colour of a fixation point instructed participants to saccade either to the left or to the right. These saccade directions were either congruent or incongruent with two types of distractor cue: either the direction of eye gaze of a centrally presented schematic face, or the direction of arrows. Children had greater difficulties inhibiting the distractor cues than did adults, which revealed itself in longer saccade latencies for saccades that were incongruent with the distractor cues as well as more errors on these incongruent trials than on congruent trials. Counter to our prediction, in terms of saccade latencies, both children and adults had greater difficulties inhibiting the arrow than the eye gaze distractors.     

Visual word recognition without central attention: evidence for greater automaticity with advancing age

The present experiments examined the automaticity of word recognition. The authors examined whether people can recognize words while central attention is devoted to another task and how this ability changes across the life span. In Experiment 1, a lexical decision Task 2 was combined with either an auditory or a visual Task 1. Regardless of the Task 1 modality, Task 2 word recognition proceeded in parallel with Task 1 central operations for older adults but not for younger adults. This is a rare example of improved cognitive processing with advancing age. When Task 2 was nonlexical (Experiment 2), however, there was no evidence for greater parallel processing for older adults. Thus, the processing advantage appears to be restricted to lexical processes. The authors conclude that greater cumulative experience with lexical processing leads to greater automaticity, allowing older adults to more efficiently perform this stage in parallel with another task.     

Specific exemplar retention and prototype abstraction in young and old adults

The effects of age differences in retention of information about specific concept members on the ability to abstract central tendency information were examined. Young and older adults were presented with a series of visual patterns that were organized around a prototype. They were then presented with these same patterns plus a set of new patterns varying in prototype similarity in a recognition test. It was found that young adults retained more information about specific acquisition set exemplars, which resulted in slightly different recognition responses for new patterns. However, the recognition behavior of both young and older adults appeared to be governed by the same rules. It is suggested that the organization of conceptual information does not change with age, but the poorer retention of specific item information in older adults may result in a less complete representation.     

The impact of emotional faces on younger and older adults’ attentional blink

ABSTRACT

The attentional blink (AB) is the impaired ability to detect a second target (T2) when it follows shortly after the first (T1) among distractors in a rapid serial visual presentation (RSVP). Given questions about the automaticity of age differences in emotion processing, the current study examined whether emotion cues differentially impact the AB elicited in older and younger adults. Twenty-two younger (18–22 years) and 22 older adult participants (62–78 years) reported on the emotional content of target face stimulus pairs embedded in a RSVP of scrambled-face distractor images. Target pairs included photo-realistic faces of angry, happy, and neutral expressions. The order of emotional and neutral stimuli as T1 or T2 and the degree of temporal separation within the RSVP systematically varied. Target detection accuracy was used to operationalise the AB. Although older adults displayed a larger AB than younger adults, no age differences emerged in the impact of emotion on the AB. Angry T1 faces increased the AB of both age groups. Neither emotional T2 attenuated the AB. Negative facial expressions held the attention of younger and older adults in a comparable manner, exacerbating the AB and supporting a negativity bias instead of a positivity effect in older adults.     

Conflict monitoring and adaptation to affective stimuli as a function of ageing

The current study investigated whether preference for positive affect would be observed in the context of a higher order control process with increasing age given the premise of affective prioritization with ageing. The study examined how affect interacted with cognitive control mechanisms across young, middle-aged and older adults. Conflict monitoring and adaptation for affective stimuli was examined with a face-word Stroop task using happy and fearful facial expressions. The participants’ task was to detect the emotional expression (Happy or Fear) of the face shown with a distractor word (Happy or Fear) written across the face. Reaction time and accuracy data was analysed to compare adaptation effect and Stroop interference as a function of age, valence and previous trial congruence. The results demonstrated a stronger adaptation effect for negative affect in young adults and for positive affect in middle-aged adults and older adults. These results can be explained in terms of the socio-emotional selectivity theory of affective bias in the elderly and the involvement of attentional control mechanisms. This study empirically demonstrates shifts in affective bias towards positive affect with ageing through the implicit recruitment of cognitive control.