Distractibility, circadian arousal, and aging: A boundary condition?

Two studies assessed the presence of a synchrony effect between peak circadian arousal and time of testing for both older and younger adults. Participants performed a reading aloud task that included distracting words that were either present or absent and, if present, were either thematically related or unrelated to the target text. As well, the distracting material was presented in either spatially predictable or unpredictable locations. In each experiment, older and younger adults were tested at optimal versus nonoptimal times. Both experiments showed age differences in susceptibility to distraction, replicating earlier findings (e.g., M. C. Carlson, et al; see record 1996-00890-001). Neither showed differences due to time of testing, suggesting a boundary condition for cognitive disruptions associated with circadian arousal patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integration of press-fit implants in cortical bone: a study on interface kinetics

Two studies assessed the presence of a synchrony effect between peak circadian arousal and time of testing for both older and younger adults. Participants performed a reading aloud task that included distracting words that were either present or absent and, if present, were either thematically related or unrelated to the target text. As well, the distracting material was presented in either spatially predictable or unpredictable locations. In each experiment, older and younger adults were tested at optimal versus nonoptimal times. Both experiments showed age differences in susceptibility to distraction, replicating earlier findings (e.g., M. C. Carlson, L. Hasher, R. T. Zacks, & S. L. Connelly, 1995). Neither showed differences due to time of testing, suggesting a boundary condition for cognitive disruptions associated with circadian arousal patterns.     

Preserved Spatial Memory Over Brief Intervals in Older Adults.

Two studies compared young and older adults' memory for location information after brief intervals. Experiment 1 found that accuracy of intentional spatial memory for individual locations was similar in young and older participants for set sizes of 3 and 6. Both groups also encoded individual locations in relation to the larger configuration of locations. Experiment 2 showed that like young adults, older adults' latency to respond to a test probe in a letter working memory task was negatively influenced by spatial information that was irrelevant to the task. This interference effect indicated preserved incidental memory for spatial information in older adults. Together, these data suggest that initial encoding of spatial information for relatively small numbers of items is largely preserved in healthy older adults and that representations of spatial information persist over short intervals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Now you see it, now you don't: Evidence for age-dependent and age-independent cross-modal distraction.

Age-related deficits in selective attention have often been demonstrated in the visual modality and, to a lesser extent, in the auditory modality. In contrast, a mounting body of evidence has suggested that cross-modal selective attention is intact in aging, especially in visual tasks that require ignoring the auditory modality. Our goal in this study was to investigate age-related differences in the ability to ignore cross-modal auditory and visual distraction and to assess the role of cognitive control demands thereby. In a set of two experiments, 30 young (mean age = 23.3 years) and 30 older adults (mean age = 67.7 years) performed a visual and an auditory n-back task (0 ≤ n ≤ 2), with and without cross-modal distraction. The results show an asymmetry in cross-modal distraction as a function of sensory modality and age: Whereas auditory distraction did not disrupt performance on the visual task in either age group, visual distraction disrupted performance on the auditory task in both age groups. Most important, however, visual distraction was disproportionately larger in older adults. These results suggest that age-related distraction is modality dependent, such that suppression of cross-modal auditory distraction is preserved and suppression of cross-modal visual distraction is impaired in aging. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effects of aging, distraction, and response pressure on the binding of actors and actions.

Two experiments provide evidence for an age-related deficit in the binding of actors with actions that is distinct from binding deficits associated with distraction or response pressure. Young and older adults viewed a series of actors performing different actions. Participants returned 1 week later for a recognition test. Older adults were more likely than young adults to falsely recognize novel conjunctions of familiar actors and actions. This age-related binding deficit occurred even when older adults could discriminate old items from new items just as well as could young adults. Young adults who experienced distraction or time pressure also had difficulty discriminating old items from conjunction items, but this deficit was accompanied by a deficit at discriminating old and new items. These results suggest that distraction and response pressure lead to deficits in memory for stimulus components, with any deficits in binding ability commensurate with these deficits in component memory. Aging, in turn, may lead to binding difficulties that are independent of attention-demanding executive processes involved in maintaining individual stimulus components in working memory, likely reflecting declines in hippocampally mediated associative processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examining inhibition of return with multiple sequential cues in younger and older adults.

Studies with younger adults have shown that when multiple peripheral cues are presented sequentially, inhibition of return (IOR) occurs at several locations with the greatest IOR at the most recently cued location and the least at the earliest cued location. The inhibitory ability needed to tag multiple locations requires visuospatial working memory, and it is thought that this type of memory may be vulnerable to the effects of aging. The present experiments examined whether older adults would show less IOR at multiple cued locations than younger adults when placeholders were present (Experiment 1) and absent (Experiment 2). Of interest, in both experiments older adults showed an almost identical pattern of IOR, in both magnitude and number of inhibited locations, to that of younger adults. This finding, in conjunction with research on memory-guided saccades, suggests that there may be a form of visuospatial working memory, specific to oculomotor and visual attention processes, that is relatively resistant to the effects of aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Instance-based automaticity and aging: Acquisition, reacquisition, and long-term retention.

This research examined age differences in the acquisition and reacquisition of instance-based automaticity. In 2 experiments, young and older adults were trained to enumerate targets presented in otherwise empty displays or in displays that contained distractors. Experiment 1 revealed that older adults required more practice to reach asymptote than young adults. For both age groups, modifications of the identities and locations of targets produced substantial disruptions in performance, whereas modifications of the identities or locations of distractors produced little interference. However, no age differences in the representations of instances in memory were obtained in participants who reached asymptote. Experiment 2 revealed age deficits in the long-term retention and rate of reacquisition of instance-based automaticity 18 months after initial training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and the inhibition of spatial location.

Two experiments compared the performance of older and younger adults on a task assessing suppression (or negative priming) for location of distractors. A 3rd experiment compared the 2 age groups on suppression for location and identity of distractors such that location was irrelevant to selection and response. Older and younger adults showed location suppression across all experiments. In Exp 3, identity suppression was found for younger but not older adults. In addition, younger adults revealed an additive effect for suppression of identity and location. Consistent evidence of inhibition of return was not found for either age group. The findings are discussed in terms of the L. Hasher and R. T. Zacks (1988) theory of reduced inhibitory efficiency in the elderly and in terms of neurophysiological evidence that inhibition of identity and location may function separately within the 2 cortical visual systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of gaze on apparent visual responses of frontal cortex neurons

Previous reports have argued that single neurons in the ventral premotor cortex of rhesus monkeys (PMv, the ventrolateral part of Brodmann's area 6) typically show spatial response fields that are independent of gaze angle. We reinvestigated this issue for PMv and also explored the adjacent prearcuate cortex (PAv, areas 12 and 45). Two rhesus monkeys were operantly conditioned to press a switch and maintain fixation on a small visual stimulus (0.2 degree x 0.2 degree) while a second visual stimulus (1 degree x 1 degree or 2 degrees x 2 degrees) appeared at one of several possible locations on a video screen. When the second stimulus dimmed, after an unpredictable period of 0.4-1.2 s, the monkey had to quickly release the switch to receive liquid reinforcement. By presenting stimuli at fixed screen locations and varying the location of the fixation point, we could determine whether single neurons encode stimulus location in "absolute space" or any other coordinate system independent of gaze. For the vast majority of neurons in both PMv (90%) and PAv (94%), the apparent response to a stimulus at a given screen location varied significantly and dramatically with gaze angle. Thus, we found little evidence for gaze-independent activity in either PMv or PAv neurons. The present result in frontal cortex resembles that in posterior parietal cortex, where both retinal image location and eye position affect responsiveness to visual stimuli.     

Inhibition and habituation: Preserved mechanisms of attentional selection in aging and Alzheimer's disease.

Are inhibition and habituation, processes that contribute to selective attention, impaired by aging or Alzheimer's disease (AD)? Younger adults, older adults, and adults with AD read lists of letters presented either alone or paired with distractor letters. Slower reading times for lists containing distractors relative to lists without distractors indexed concurrent interference (distraction). Slower rending times for lists in which distractors subsequently became targets relative to lists in which distractors and targets were unrelated indexed negative priming (inhibition). Faster reading times when distractors were constant in identity or location rather than random indexed repeated distractor effects (habituation). Distraction increased with aging and AD, whereas inhibition and habituation showed no age- or AD-related decline, suggesting that inhibition and habituation still function to aid attentional selection in older adults and adults with AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Affect dynamics, affective forecasting, and aging": Correction to Nielsen, Knutson, and Carstensen (2008).

Reports an error in "Affect dynamics, affective forecasting, and aging" by Lisbeth Nielsen, Brian Knutson and Laura L. Carstensen (Emotion, 2008[Jun], Vol 8[3], 318-330). The first author of the article was listed as being affiliated with both the National Institute on Aging and the Department of Psychology, Stanford University. Dr. Nielsen would like to clarify that the research for this article was conducted while she was a postdoctoral fellow at Stanford University. The copyright notice should also have been listed as "In the Public Domain." (The following abstract of the original article appeared in record 2008-06717-002.) Affective forecasting, experienced affect, and recalled affect were compared in younger and older adults during a task in which participants worked to win and avoid losing small monetary sums. Dynamic changes in affect were measured along valence and arousal dimensions, with probes during both anticipatory and consummatory task phases. Older and younger adults displayed distinct patterns of affect dynamics. Younger adults reported increased negative arousal during loss anticipation and positive arousal during gain anticipation. In contrast, older adults reported increased positive arousal during gain anticipation but showed no increase in negative arousal on trials involving loss anticipation. Additionally, younger adults reported large increases in valence after avoiding an anticipated loss, but older adults did not. Younger, but not older, adults exhibited forecasting errors on the arousal dimension, underestimating increases in arousal during anticipation of gains and losses and overestimating increases in arousal in response to gain outcomes. Overall, the findings are consistent with a growing literature suggesting that older people experience less negative emotion than their younger counterparts and further suggest that they may better predict dynamic changes in affect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Aging, optimal testing times, and negative priming": Correction.

Reports 2 errors in the article "Aging, Optimal Testing Times, and Negative Priming' by M. J. Intons-Peterson, Paola Rocchi, Tara West, Kimberly McLellan, and Amy Hackney (Journal of Experimental Psychology: Learning, Memory, and Cognition, 1998, Vol. 24, No. 2, pp. 362–376; see record 1998-00017-007). On page 370, the sentence beginning on line 6 of the Method section should have read as follows: "the younger adults were fulfilling a partial requirement of their introductory psychology courses, and the older group was drawn randomly from participants who served in the normative study and from more recently tested older individuals.' The final phrase of the sentence has been added to more accurately reflect the number of participants in the older group. The second error is on page 368. The entries in the left column of Table 3 were incorrect. The corrected table is presented. A portion of the original abstract follows: The effects of time-of-day preferences on selective attention were tested in 2 experiments after normative work with 975 younger adults and 143 older adults verified C. P. May, L. Hasher, and E. R. Stoltzfus's (1993) finding that most older adults prefer the morning, whereas younger adults prefer activities later in the day. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial cuing in a stereoscopic display: attention remains "depth-aware" with age

Previous research has demonstrated that spatial attention is "depth-aware": Reaction times (RT) are greater for shifts in depth and two-dimensional (2-D) space than in 2-D space alone. This experiment examined whether the ability to focus attention at a depth location is maintained with advanced age. Twelve younger and 12 older observers viewed stereoscopic displays in which one of four spatial locations was cued. Two of the locations were at a near depth location and two were at a far depth location. When the focus of visual attention was shifted to a new location in space (because of an invalid cue), the cost in RT for switching attention (measured as the difference between RT on valid cue and invalid cue trials) was greater when observers had to switch attention between different depth locations and different locations in 2-D space than for shifts in 2-D space alone. This effect was observed for both younger and older observers, suggesting that the ability to orient attention to a depth location is maintained with age.     

Breaking the waves: Age differences in electrical brain activity when reading text with distractors.

The authors tested whether older adults have greater difficulty than younger adults in ignoring task-irrelevant information during reading as a result of age-related decline in inhibitory processes. Participants were shown target sentences containing distractor words. They were instructed to read aloud each sentence and ignore distractors. The N400 event-related potential (ERP) was used to measure the extent of semantic processing of target and distracting information. It showed that younger adults semantically processed both target and distracting material, whereas online processing of target sentences in older adults was disrupted by the distractors. In older adults, memory for target information related to their susceptibility to distraction and inhibition efficiency. Implications for age-differences in inhibitory control, working memory, and resource capacity are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in shifting focused attention.

Young and older adults performed a choice response task in which 1 of 2 target letters was presented visually at 1 of 4 display locations. In 2 experiments, the validity of a target location cue and the presence of nontarget characters (distractors) were varied. With target-only displays and 40% cue validity (Experiment 1), the estimated time to shift attention between display locations was essentially 0 msec for both age groups. With 70% cue validity, Experiment 2 demonstrated significant increases in the attention shift time as a function of both increased age and the presence of distractors (asterisks). The results suggest that age-related changes in the shifting of focused attention are minimal except when the processing of nontarget information is required. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related binding deficits and the content of false memories.

The authors examined effects of age-related binding deficits on feature information in false memories for imagined objects (e.g., lollipop) that were similar in shape to seen objects (e.g., magnifying glass). In Experiment 1, location memory for seen objects was lower in older than younger adults and lower still in old-old than young-old adults. Imagined objects, when falsely called seen, were less likely to be attributed to the location of similar seen objects (i.e., congruent attributions) by old-old than young-old adults. In Experiment 2, for younger adults, displaying seen objects for less time (1 s vs. 4 s) reduced both location memory for seen objects and congruent attributions for false memories. Thus, binding deficits may influence the specific content of false memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does the Information Content of an Irrelevant Source Differentially Affect Spoken Word Recognition in Younger and Older Adults?

To determine whether older adults find it difficult to inhibit the processing of irrelevant speech, the authors asked younger and older adults to listen to and repeat meaningless sentences (e.g., "A rose could paint a fish") when the perceived location of the masker (speech or noise) but not the target was manipulated. Separating the perceived location (but not the physical location) of the masker from the target speech produced a much larger improvement in performance when the masker was informational (2 people talking) than when the masker was noise. However, the size of this effect was the same for younger and older adults, suggesting that cognitive-level interference from an irrelevant source was no worse for older adults than it was for younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye movements of young and older adults while reading with distraction.

The authors used eye-tracking technology to examine young and older adults' online performance in the reading in distraction paradigm. Participants read target sentences and answered comprehension questions following each sentence. In some sentences, single-word distracters were presented in either italic or red font. Distracters could be related or unrelated to the target text. Online measures, including probability of fixation, fixation duration, and number of fixations to distracting text, revealed no age differences in text processing. However, young adults did have an advantage over older adults in overall reading time and text comprehension. These results provide no support for an inhibition deficit account of age differences in the reading in distraction paradigm, but are consistent with J. Dywan and W. E. Murphy's (1996) suggestion that older adults are less able than the young to distinguish target and distracter information held in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How many locations can be selected at once?

The visual system uses several tools to select only the most relevant visual information for further processing, including selection by location. In the present study, the authors explored how many locations can be selected at once. Although past evidence from several visual tasks suggests that the visual system can operate on a fixed number of 4 objects or locations at once, the authors found that this capacity varies widely in response to the precision of selection required by the task. When the authors required precise selection regions, only 2-3 locations could be selected. But when the selection regions could be coarser, up to 6-7 locations could be selected. The authors discuss potential mechanisms underlying the selection of multiple locations and review the evidence for fixed limits in visual attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)