Adult age differences in the effects of sentence context and stimulus degradation during visual word recognition.

I investigated adult age differences in the efficiency of feature-extraction processes during visual word recognition. Participants were 24 young adults (M age?=?21.0 years) and 24 older adults (M age?=?66.5 years). On each trial, subjects made a word/nonword discrimination (i.e., lexical decision) regarding a target letter-string that was presented as the final item of a sentence context. The target was presented either intact or degraded visually (by the presence of asterisks between adjacent letters). Age differences in lexical decision speed were greater for degraded targets than for intact targets, suggesting an age-related slowing in the extraction of feature-level information. For degraded word targets, however, the amount of performance benefit provided by the sentence context was greater for older adults than for young adults. It thus appears that an age-related deficiency at an early stage of word recognition is accompanied by an increased contribution from semantic context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling intrusions and correct recall in episodic memory: Adult age differences in encoding of list context.

A model for correct recall and intrusions in cued recall of word lists is introduced. Intrusions are false responses that were correct in an earlier list. The model assumes 3 exclusive states for memory traces after encoding: with a list tag (i.e., with information about list origin), without list tags, and missing. Across lists, a trace can lose its list tag or its content. For retrieval, an optimal strategy of response selection was assumed. Younger and older laboratory-trained mnemonists participated in 2 experiments in which recall of permutations of a single word list across a single set of cues was held constant with individually adjusted presentation times. With correct recall equated to younger adults, older adults were more susceptible to intrusions. Age differences were restricted to model parameters estimating the probability of generation of list tags. Alternative accounts of age differences in context memory are discussed. (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)     

Semantic priming during sentence processing by young and older adults.

Examined semantic processing of sentences by 30 younger (mean age 25.1 yrs) and 30 older (mean age 68.5 yrs) adults, using a priming technique. Ss read a sentence and then made a lexical decision about a target presented immediately after the sentence. For both age groups, word targets that were instruments implied by the action of the sentence had faster latencies than unrelated word targets. There was no evidence of inhibition of unrelated targets, suggesting that the facilitation of instrument targets involved automatic processes. Results provide no evidence for age-related changes in semantic processing of sentences, including access to implied information. Older Ss did, however, have poorer memory for the sentences on a recognition test. It is suggested that previous findings by G. Cohen (see PA, Vols 63:747 and 67:958) of age deficits in comprehension may depend on techniques that measure what is remembered rather than what is understood. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in short-term memory for serial order: Data and a model.

Age-related deficits in short-term memory have been widely reported, but reduced overall scores could reflect increased order errors, increased omissions, or increased intrusions. Different explanations for reduced short-term memory with aging lead to different predictions. In this study, young (n?=?68; M age?=?20 years) and older (n?=?99; M age?=?65 years) adults were presented with lists of letters and were asked to recall each list immediately in the correct order. Age differences in error patterns were similar for auditory and visual presentation. For example, older adults made more errors of every type, and a greater proportion of the older adults' errors were omissions. An additional condition, in which older adults were encouraged to guess, ruled out an age increase in response threshold as a full explanation for the results. The data were modeled by an oscillator-based computational model of memory for serial order. A good fit to the aging data was achieved by simultaneously altering two parameters that were interpreted as corresponding to frontal decline and response slowing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of perceptual and conceptual processing on memory for words and voice: different patterns for young and old

In two experiments younger and older adults listened to a list of words presented auditorily by two speakers. The subjects processed each word either perceptually (voice judgements) or conceptually (pleasantness judgements), and were then given memory tasks for the words and the presenting voice. In the word-recognition task the two age groups benefited equally from conceptual as opposed to perceptual processing. In the voice memory task, however, conceptual processing improved performance relative to perceptual processing in the younger subjects (significantly so in Experiment 1), but conceptual processing was associated with decreased performance in the older group (significantly so in Experiment 2). These results suggest that whereas older subjects exhibit a trade-off in memory for item and attribute information, younger subjects exhibit a pattern of support, in which conceptual processing benefits memory for both items and their attributes.     

Episodic priming and memory for temporal source: Event-related potentials reveal age-related differences in prefrontal functioning.

Event-related potentials (ERPs) were recorded from young (M?=?25) and older (M?=?71) adults during a recognition memory paradigm that assessed episodic priming. Participants studied two temporally distinct lists of sentences (each with two unassociated nouns). At test, in response to the nouns, participants made old–new, followed by remember (context)–know (familiarity) and source (i.e., list) judgments. Both young and older adults showed equivalent episodic priming effects. However, compared to the young adults, the older adults showed a greater source performance decrement than item memory performance decrement. Both age groups showed equivalent posterior-maximal old-new ERP effects. However, only the young produced a frontal-maximal, late onset old-new effect that differed as a function of subsequent list attribution. Because source memory is thought to be mediated by prefrontal cortex, we conclude that age-related memory differences may be due to a deficit in a prefrontal cortical system that underlies source memory and are not likely to be due to an age-related decline in episodic priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recollective experience, normal aging, and frontal dysfunction.

Examined the nature of verbal recognition memory in young and old Ss. Following presentation of a word list, Ss undertook a yes–no recognition test and indicated whether their decision was based on explicit recollection or assessment of familiarity. Explicit recollection declined with age, and familiarity-based recognition increased. Furthermore, the extent to which older Ss relied on familiarity-based recognition correlated with neuropsychological indices of frontal lobe dysfunction. A further experiment indicated that the change from explicit recollection to familiarity-based responding was unrelated to changes in older Ss' confidence about their memory. The data indicate the central role of frontal dysfunction in understanding age-related memory loss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time course of allocation of visual attention after equating for sensory differences: An age-related perspective.

Adult age differences in the time course of the allocation of visual attention were investigated, in 2 experiments that both included the same 10 younger adults (M?=?22 years) and 10 older adults (M?=?68 years). In Experiment 1, older adults accumulated information about target identity at a slower rate than younger adults, as represented by the rise in accuracy as a function of target duration. To equate performance in a baseline condition in a spatial-cuing paradigm (Experiment 2), target duration was set for each observer on the basis of the data in Experiment 1. Performance for the 2 age groups was comparable, both in the baseline condition and in the time course of attention, as indexed by the function relating accuracy to cue-target onset asynchrony. The authors conclude that, in this spatial-cuing paradigm, an age-related change is evident in sensory processing but not in attentional allocation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The selective effects of alcohol on automatic and effortful memory processes.

Automatic and effortful memory processes were evaluated in a 2-session, within-subjects design involving an alcohol challenge and a no-alcohol condition. Free recall of a 90-word list measured effortful processing. Estimation of word frequency from the same list measured automatic processing. Acute intoxication was hypothesized to diminish effortful but not automatic memory processes. Healthy, male volunteers (n?=?36) completed the 2 conditions 1 week apart. Presentation frequency influenced both free recall and frequency estimation, with both measures increasing as presentation frequency increased. Free recall was significantly lower in the alcohol than in the no-alcohol condition, but frequency estimation was not differentially affected. The data showed that an alcohol challenge dissociated automatic and effortful memory processes in volunteers. The authors discuss potential neurobiological substrates that may account for alcohol's selective disruption of effortful, verbal, episodic memory processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Forgetting rates in modality memory for young, mid-life, and older women.

Administered a mixed-modality (visual and auditory) continuous recognition task, followed immediately by a final recognition test, to 16 women in each of 3 age groups (18–23 yrs, 38–50 yrs, and 60–74 yrs). Ss gave recognition responses for both the words and their presentation modality. Although older Ss remembered less information about input mode than did the 2 younger groups, the age decrement was not the result of faster forgetting of such information by the elderly. When a ceiling effect at the initial lag was taken into account, forgetting rates for both words and input mode were comparable across the adult life span. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Effects of Aging and Divided Attention on Memory for Item and Associative Information.

The present study examined how aging and divided attention influence memory for item and associative information. Older adults and younger adults working under full-attention conditions and younger adults working under divided-attention conditions studied unrelated word pairs. Memory for item information was measured by later recognition of the 2nd word in the pair, and associative information was measured by recognition of the entire pair. Both older adults in the full-attention condition and younger adults in the divided-attention condition performed more poorly than younger adults in the full-attention condition, with the deficit in associative information being greater than the deficit in item information. In addition, a differentially greater associative decrement was found for the older adults, as shown by their heightened tendency to make false-alarm responses to re-paired (conjunction) distractors. The results are discussed in terms of an age-related reduction in processing resources compounded by an age-related increase in older adults' reliance on familiarity in associative recognition memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of age and processing stage on visual word recognition.

Used a lexical-decision task in 3 different experiments to examine whether age differences in word recognition were consistent across processing stage. In all experiments, word frequency and length were manipulated. In Exps 1 and 2, encoding difficulty was varied, and in Exp 3, response selection difficulty was varied. In all 3 experiments, there were no age differences for word frequency. However, in Exps 1 and 2, older adults showed a larger decrement for encoding. In Exp 3, age differences were larger when response selection load increased. These results suggest that age differences in word recognition occur because older adults exhibit primarily peripheral- rather than central-processing decrements. The implications of these data for generalized and localized slowing models are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of talker variability on word recognition in preschool children.

In a series of experiments, the authors investigated the effects of talker variability on children's word recognition. In Experiment 1, when stimuli were presented in the clear, 3- and 5-year-olds were less accurate at identifying words spoken by multiple talkers than those spoken by a single talker when the multiple-talker list was presented first. In Experiment 2, when words were presented in noise. 3-, 4-, and 5-year-olds again performed worse in the multiple-talker condition than in the single-talker condition, this time regardless of order; processing multiple talkers became easier with age. Experiment 3 showed that both children and adults were slower to repeat words from multiple-talker than those from single-talker lists. More important, children (but not adults) matched acoustic properties of the stimuli (specifically, duration). These results provide important new information about the development of talker normalization in speech perception and spoken word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On-line processing of written text by younger and older adults.

Word-by-word reading times were measured for young and elderly adults who read single sentences for immediate recall. The reading strategies of young and old were similar in that both groups allocated time to process word-level and constituent-level features. Young and elderly readers differed mainly in how they allocated time for organizational processing: Whereas younger adults allocated extra processing time at sentence boundaries as well as at major and minor clause boundaries, older adults allocated extra time at major and minor clause boundaries only. Results were generally consistent with the notions that processes that are more microlevel (e.g., word access) become automatic with practice and that age deficits are minimal for such processes. Age differences in organization time allocated at clause boundaries, however, suggested age-related limitations in working memory processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Activity memory and aging: The role of motor retrieval and strategic processing.

Examined the role of retrieval and encoding mechanisms in the magnitude of age differences in the recall of S-performed tasks (SPTs). 80 older (60–79 yrs old) and 80 younger adults (18–26 yrs old) were tested in 1 of 4 conditions by varying modality at both encoding and retrieval. The role of list organization in reducing age differences in SPT recall was also examined. The results suggested that older adults' SPT recall improves when motor processing is enhanced by list organization. Age differences in recall were reduced for an organized list when motor processing occurred during retrieval or encoding, but age differences in recall of an unorganized list remained under most conditions. Discrepant results in the literature concerning the magnitude of age differences in SPT recall could be due in part to differences in list characteristics, such as organization, that have not been fully explored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of divided attention and time course on automatic and controlled components of memory in older adults.

The relation between attention available at encoding and automatic and consciously controlled aspects of memory was investigated within a single task using the process-dissociation procedure (L. L. Jacoby, 1991). Sixty-four older adults and 64 young adults studied a word list in either a full or a divided attention condition. Recall cued with word stems was tested immediately and at 20-minute and 60-minute delays. In contrast to consciously controlled influences of memory, automatic influences of memory (a) showed generally no reliable age differences, (b) remained invariant across the manipulation of attention, and (c) remained relatively invariant across the 60-minute time course. Furthermore, age did not interact with the attentional manipulation or the time course factor. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

General slowing in semantic priming and word recognition.

Analyses of lexical decision studies revealed that (1) older (O) adults' mean semantic priming effect was 1.44 times that of younger (Y) adults, (2) regression lines describing the relations between O and Y adults' latencies in related (O?=?1.54 Y?–?112) and unrelated conditions (O?=?1.50 Y?–?93) were not significantly different, and (3) that there was a proportional relation between O and Y adults' priming effects (O?=?1.48 Y?–?2). Analyses of word-naming studies yielded similar results. Analyses of delayed pronunciation data (D. A. Balota & J. M. Duchek, 1988) revealed that word recognition was 1.47 times slower in O adults, whereas O adults' output processes were only 1.26 times slower. Overall, analyses of whole latencies and durations of component processes provide converging evidence for a general slowing factor of approximately 1.5 for lexical information processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical ambiguity and children's word recognition.

Conducted 2 experiments to examine the word recognition processes of 2nd, 4th, and 6th graders. In Exp I, 72 Ss named target words that were primed by words that had more than 1 meaning. Targets were related either to the more or less frequent sense of the ambiguous prime or were unrelated to it. Findings indicate that older Ss were more likely than younger Ss to restrict processing of ambiguous words to the most frequent meaning. While younger Ss showed approximately equal facilitation for words related to either meaning, regardless of each one's relative frequency, 6th graders apparently retrieved only the most frequent meaning. Exp II, with 36 Ss, was similar to Exp I but included neutral primes and varied the interval between presentation of prime and target. Results show that all groups showed automatic retrieval of both meanings of the ambiguous word. For 6th graders, however, this retrieval was followed by a 2nd stage, in which attention was allocated to the more frequent meaning, maintaining it, while the less frequent meaning was inhibited. Overall data indicate that older children use meaning frequency to narrow the amount of information kept active following word recognition. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory habituation in young and older adults: The verbal transformation effect.

In 3 experiments, auditory massed repetition was used to examine age-related differences in habituation by means of the verbal transformation paradigm. Participants heard 10 words (5 high frequency and 5 low frequency), each presented 180 times, and they reported perceived changes in the repeated words (verbal transformations). In these experiments, older adults reported fewer illusory percepts than young adults. Older adults' loss of auditory acuity and slowing of processing, stimulus degradation (in young adults), and instructions biasing the report of these illusory percepts did not account for the fewer illusory percepts reported by the older adults. These findings suggest that older adults' reduced susceptibility to habituation arises from centrally located declines in the transmission of information within the word recognition pathway. The discussion focuses on the implications that these age-related declines may have on word identification during on-line speech perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)