Aging, selective attention, and inhibitory processes: A psychophysiological approach.

Investigated the efficiency with which younger and older adults allocate attention to relevant and irrelevant stimuli. The model of attention guiding this research links the orienting response with the allocation of attention and habituation with the inhibition of the allocation of attention. The authors adapted a paradigm developed by W. G. Iacono and D. T. Lykken (1983) in which Ss are instructed unambiguously either to attend or to ignore a series of innocuous tones, and the skin conductance orienting response elicited by each tone is measured. Results revealed that young Ss instructed to ignore the tones habituated more quickly than did those instructed to attend to the tones. However, older adults exhibited nondifferential orienting across the 2 instruction conditions. These results suggest an age-related deficit in the ability to inhibit attention to irrelevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-Related Differences in Localized Attentional Interference.

Attentional selection of an object in the visual field degrades processing of neighboring stimuli in young adults. A pair of experiments examined the effects of aging on such localized attentional interference. In Experiment 1, younger and older observers made speeded same-different judgments of target shapes that varied in spatial separation. Performance declined for both age groups as the distance between targets decreased, but an Age x Distance interaction indicated that the magnitude of this effect was larger for older adults. Experiment 2 ruled out sensory masking as an explanation for these findings. Results indicate that older observers experience losses in the ability to attend to multiple spatially proximal stimuli within the visual field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of higher order auditory processes in younger and older adults.

The authors conducted 3 experiments investigating the effects of aging on higher order auditory processes. They compared younger and older adults with respect to (a) their auditory channel capacity, (b) the extent of their top-down control over auditory gain, and (c) their ability to focus attention on a narrow band of frequencies. To ensure that subclinical cochlear processing deficits in older adults (e.g., higher thresholds, poorer discrimination of frequency and intensity differences) did not limit performance, the authors used only stimuli that were perfectly discriminable by all participants. No age differences were found in any of these experiments, suggesting that some higher order auditory processes (e.g., top-down control over auditory gain, auditory attention) are preserved in normal aging, despite numerous age-related declines in peripheral auditory functionality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relational Integration, Inhibition, and Analogical Reasoning in Older Adults.

The difficulty of reasoning tasks depends on their relational complexity, which increases with the number of relations that must be considered simultaneously to make an inference, and on the number of irrelevant items that must be inhibited. The authors examined the ability of younger and older adults to integrate multiple relations and inhibit irrelevant stimuli. Young adults performed well at all but the highest level of relational complexity, whereas older adults performed poorly even at a medium level of relational complexity, especially when irrelevant information was presented. Simulations based on a neurocomputational model of analogical reasoning, Learning and Inference with Schemas and Analogies (LISA), suggest that the observed decline in reasoning performance may be explained by a decline in attention and inhibitory functions in older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiologic indices of Stroop and Garner interference reveal linguistic influences on auditory and visual processing

The purpose of this study was to examine linguistic influences on the auditory and visual processing of words both behaviorally and electrophysiologically. Our task yielded measures of the effect of irrelevant semantic content (Stroop interference) and of the effect of irrelevant linguistic variability (Garner interference). The behavioral results allow us to assess whether the linguistic and nonlinguistic dimensions of verbal stimuli are processed dependently or independently. The electrophysiologic results allow us to determine where any processing interactions are arising, particularly regarding perceptual versus postperceptual underpinnings, and to evaluate the similarity and dissimilarity between the two interference effects. Results show pronounced Stroop and Garner interference both behaviorally and electrophysiologically, indicating linguistic influences on auditory and visual processing. Subjects could not ignore the irrelevant linguistic dimension and attend selectively to the physical dimension of either spoken or written words. The results indicate that the physical and linguistic dimensions of words are not processed independently. With regard to the stage of processing underlying the interference effects, our results suggest that both Stroop and Garner interference involve multiple stages of processing. The two interference effects are not duplicate measures, however, and different electrophysiologic signatures were observed. Stroop interference is characterized by perceptual and postperceptual components. Similar electrophysiologic patterns within the auditory and visual modalities suggest that each interference effect is tapping similar processes for spoken and written stimuli.     

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)     

Success and failure at dual-task coordination by younger and older adults.

Dual-task processing was explored in younger and older adults in 2 experiments that used a tone discrimination and a letter discrimination task. To encourage parallel processing if that was possible, the authors presented the stimuli for the 2 tasks simultaneously, and participants were instructed to withhold their responses until both were ready. The authors found no evidence for parallel processing and no evidence that the management of central processing of dual tasks is qualitatively different in older adults than it is in younger adults. When one response was verbal and the other manual, the 2 responses closely coincided. When both responses were manual, the authors did find that the first response was not delayed enough to coincide with the 2nd and that this underestimation was greater in older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of age on cross-modal emotion perception.

Efficient navigation of our social world depends on the generation, interpretation, and combination of social signals within different sensory systems. However, the influence of healthy adult aging on multisensory integration of emotional stimuli remains poorly explored. This article comprises 2 studies that directly address issues of age differences on cross-modal emotional matching and explicit identification. The first study compared 25 younger adults (19–40 years) and 25 older adults (60–80 years) on their ability to match cross-modal congruent and incongruent emotional stimuli. The second study looked at performance of 20 younger (19–40) and 20 older adults (60–80) on explicit emotion identification when information was presented congruently in faces and voices or only in faces or in voices. In Study 1, older adults performed as well as younger adults on tasks in which congruent auditory and visual emotional information were presented concurrently, but there were age-related differences in matching incongruent cross-modal information. Results from Study 2 indicated that though older adults were impaired at identifying emotions from 1 modality (faces or voices alone), they benefited from congruent multisensory information as age differences were eliminated. The findings are discussed in relation to social, emotional, and cognitive changes with age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory temporal order perception in younger and older adults

This investigation examined the abilities of younger and older listeners to discriminate and identify temporal order of sounds presented in tonal sequences. It was hypothesized that older listeners would exhibit greater difficulty than younger listeners on both temporal processing tasks, particularly for complex stimulus patterns. It was also anticipated that tone order discrimination would be easier than tone order identification for all listeners. Listeners were younger and older adults with either normal hearing or mild-to-moderate sensorineural hearing losses. Stimuli were temporally contiguous three-tone sequences within a 1/3 octave frequency range centered at 4000 Hz. For the discrimination task, listeners discerned differences between standard and comparison stimulus sequences that varied in tonal temporal order. For the identification task, listeners identified tone order of a single sequence using labels of relative pitch. Older listeners performed more poorly than younger listeners on the discrimination task for the more complex pitch patterns and on the identification task for faster stimulus presentation rates. The results also showed that order discrimination is easier than order identification for all listeners. The effects of hearing loss on the ordering tasks were minimal.     

Does audiovisual speech offer a fountain of youth for old ears? An event-related brain potential study of age differences in audiovisual speech perception.

The current study addressed the question whether audiovisual (AV) speech can improve speech perception in older and younger adults in a noisy environment. Event-related potentials (ERPs) were recorded to investigate age-related differences in the processes underlying AV speech perception. Participants performed an object categorization task in three conditions, namely auditory-only (A), visual-only (V), and AVspeech. Both age groups revealed an equivalent behavioral AVspeech benefit over unisensory trials. ERP analyses revealed an amplitude reduction of the auditory P1 and N1 on AVspeech trials relative to the summed unisensory (A + V) response in both age groups. These amplitude reductions are interpreted as an indication of multisensory efficiency as fewer neural resources were recruited to achieve better performance. Of interest, the observed P1 amplitude reduction was larger in older adults. Younger and older adults also showed an earlier auditory N1 in AVspeech relative to A and A + V trials, an effect that was again greater in the older adults. The degree of multisensory latency shift was predicted by basic auditory functioning (i.e., higher hearing thresholds were associated with larger latency shifts) in both age groups. Together, the results show that AV speech processing is not only intact in older adults, but that the facilitation of neural responses occurs earlier in and to a greater extent than in younger adults. Thus, older adults appear to benefit more from additional visual speech cues than younger adults, possibly to compensate for more impoverished unisensory inputs because of sensory aging. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Narrative comprehension and aging: The fate of completed goal information.

Previous research has shown that older adults are able to use situation models in a manner similar to younger adults. However, other areas of cognition have shown that older adults are less able to remove irrelevant information from the current stream of processing. Accordingly, the authors tested whether older and younger adults would differ in reducing the availability of information about a completed goal in a situation model during narrative comprehension. In 2 experiments, memory probes tested for the availability of protagonist goal information during reading when it was either failed goal, completed goal, or neutral information. The results for both age groups showed that goal information was most available in the failed goal condition, less available in the completed goal condition, and least available in the neutral condition. No reliable differences between younger and older adults in the pattern of response times were observed. Reading time data were also examined to explore the possibility that older adults engage in a longer wrap-up period after a goal is completed, but no such difference was found. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overriding age differences in attentional capture with top-down processing.

Two experiments investigated the influence of top-down information on adult age differences in the ability to search for singleton targets using spatial cues. In Experiment 1, both younger and older adults were equally able to use target-related top-down information (target feature predictability) to avoid attentional capture by uninformative (25% valid) cues. However, during informative (75% valid) cue conditions, older adults demonstrated less efficient use of this cue-related top-down information. The authors extended these findings in Experiment 2 using cues that were either consistent or inconsistent with top-down feature settings. Results from this second experiment showed that although older adults were capable of avoiding attentional capture when provided with top-down information related to target features, capture effects for older adults were notably larger than those of younger adults when only bottom-up information was available. The authors suggest that older adults' ability to use top-down information during search to avoid or attend to cues may be resource-limited. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Listening to discourse in distracting settings: The effects of aging.

Younger and older adults listened to discourse in quiet and in conversational noise, before answering questions concerning the material. Some questions required listeners to recall specific details; others were of a more integrative nature. When the listening situation was adjusted for individual differences in hearing, younger and older adults were equally adept at remembering the gist of the passages in both quiet and in two levels of noise. The two age groups also did not differ with respect to memory for specific details when listening in quiet or in a moderate level of noise, even when required to perform a concurrent task. Only at the loudest noise level did younger adults tend to recall more detail than older adults. However, when no adjustments were made to compensate for the poorer hearing of older adults (all participants tested under identical listening conditions), older adults could not recall as much detail as younger adults, either in quiet or in noise. The results indicate that the speech-comprehension difficulties of older adults primarily reflect declines in hearing rather than in cognitive ability. (PsycINFO Database Record (c) 2010 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)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing the age-related effects of proactive interference on working memory tasks using the Rasch model.

Inhibition-reduction theory (L. Hasher & R. Zacks, 1988) hypothesizes that the age-related decline in working memory (WM) span is a result of a decrease in the ability to inhibit irrelevant information in WM. Using the Rasch psychometric model, this study found that later trials on 2 WM span tasks were more difficult for older adults than for younger adults, consistent with inhibition-reduction theory's hypothesis that older adults are more susceptible to the effects of proactive interference (PI). Furthermore, after accounting for differential susceptibility to the effects of PI, age-related variance in WM span was reduced by about half. These results suggest that differential susceptibility to PI may account for a substantial portion, although not all, of the age-related decline in WM span. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Renal and hepatic 1 alpha-hydroxylation of 25-hydroxyvitamin D3 in piglets suffering from pseudo vitamin D-deficiency rickets, type I

Research has shown that speech articulated in a clear manner is easier to understand than conversationally spoken speech in both the auditory-only (A-only) and auditory-visual (AV) domains. Because this research has been conducted using younger adults, it is unknown whether age-related changes in auditory and/or visual processing affect older adults' ability to benefit when a talker speaks clearly. The present study examined how speaking mode (clear vs conversational) and presentation mode (A-only vs AV) influenced nonsense sentence recognition by older listeners. Results showed that neither age nor hearing loss limited the amount of benefit that older adults obtained from a talker speaking clearly. However, age was inversely correlated with identification of AV (but not A-only) conversational speech, even when pure-tone thresholds were controlled statistically.     

Why do older adults have difficulty following conversations?

Age-related declines in understanding conversation may be largely a consequence of perceptual rather than cognitive declines. B. A. Schneider, M. Daneman, D. R. Murphy, and S. Kwong-See (2000) showed that age-related declines in comprehending single-talker discourse could be eliminated when adjustments were made to compensate for the poorer hearing of older adults. The authors used B. A. Schneider et al.'s methodology to investigate age-related differences in comprehending 2-person conversations. Compensating for hearing difficulties did not eliminate age-related differences when the 2 talkers were spatially separated by 9° or 45° azimuth, but it did when the talkers' contributions came from one central location. These findings suggest that dialogue poses more of a problem for older than for younger adults, not because of the additional cognitive requirements of having to follow 2 talkers rather than 1, but because older adults are not as good as younger adults at making use of the auditory cues that are available for helping listeners perceptually segregate the contributions of 2 spatially separated talkers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and involuntary attention capture: Electrophysiological evidence for preserved attentional control with advanced age.

The present study examined whether people become more susceptible to capture by salient objects as they age. Participants searched a target display for a letter in a specific color and indicated its identity. In Experiment 1, this target display was preceded by a non-informative cue display containing one target-color box, one ignored-color box, and two white boxes. On half of the trials, this cue display also contained a salient-but-irrelevant abrupt onset. To assess capture by the target-color cue, we used the N2pc component of the event-related potential, thought to reflect attentional allocation to the left or right visual field. The target-color box in the cue display produced a substantial N2pc effect for younger adults and, most importantly, this effect was not diminished by the presence of an abrupt onset. Therefore, the abrupt onset was unable to capture attention away from the target-color cue. Critically, older adults demonstrated the same resistance to capture by the abrupt onset. Experiment 2 extended these findings to irrelevant color singleton cues. Thus, we argue that the ability to attend to relevant stimuli and resist capture by salient-but-irrelevant stimuli is preserved with advancing age. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Visual search for change in older adults.

Previous research has demonstrated that younger adults are surprisingly poor at detecting substantial changes to visual scenes. Little is known, however, about age differences in this phenomenon. In the 2 experiments reported here, older adults were slower than younger adults in detecting changes to simple visual stimuli. This age difference was beyond what would be expected given known age-related changes in processing speed. Examination of eye movement behavior during the search for change suggested that age-related changes in the useful field of view and degree of cautiousness play a significant role. Speed of processing and 3 age-related eye movement behaviors explained 85% of the variance in change detection latency, eliminating the effect of age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)