Age-related differences in lexical access, spreading activation, and simple pronunciation.

An experiment was conducted to address age-related differences in lexical access, spreading activation, and pronunciation. Both young and older adults participated in a delayed pronunciation task to trace the time course of lexical access and a semantic priming task to trace the time course of spreading activation. In the delayed pronunciation task, subjects were presented a word and then, after varying delays, were presented a cue to pronounce the word aloud. Older adults benefited considerably more from the preexposure to the word than did the younger adults, suggesting an age-related difference in lexical access time. In the semantic priming pronunciation task, semantic relatedness (related vs. neutral), strength of the relationship (high vs. low), and prime–target stimulus onset asynchrony (200 ms, 350 ms, 500 ms, 650 ms, and 800 ms) were factorially crossed with age to investigate age-related differences in the buildup of semantic activation across time. The results from this task indicated that the activation pattern of the older adults closely mimicked that of the younger adults. Finally, the results of both tasks indicated that older adults were slower at both their onset to pronounce and their actual production durations (i.e., from onset to offset) in the pronunciation task. The results were interpreted as suggesting that input and output processes are slowed with age, but that the basic retrieval mechanism of spreading activation is spared by age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Part-Set Cuing Effects in Younger and Older Adults.

In 3 experiments, the authors examined part-set cuing effects in younger and older adults. Participants heard lists of category exemplars and later recalled them. Recall was uncued or cued with a subset of studied items. In Experiment 1, participants were cued with some of the category names, and they remembered fewer never-cued categories than a free-recall condition. In Experiment 2, a similar effect was observed for category exemplar cues. There was also an age difference: By some measures, a small number of cues impaired older adults more than younger. Experiment 3 replicated this result and found that older adults were disproportionately slow in the presence of cues. Across experiments, older adults showed robust part-set cuing effects, and sometimes, they were disproportionately impaired by cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The utility of intraindividual variability in selective attention tasks as an early marker for Alzheimer’s disease.

This study explored differences in intraindividual variability in 3 attention tasks across a large sample of healthy older adults and individuals with very mild dementia of the Alzheimer’s type (DAT). Three groups of participants (healthy young adults, healthy older adults, very mild DAT) were administered 3 experimental measures of attentional selection and switching (Stroop, Simon, task switching). The results indicated that a measure of intraindividual variability, coefficient of variation (CoV; SD/M), increased across age and early stage DAT. The CoV in Stroop discriminated the performance of ε4 carriers from noncarriers in healthy older controls and the CoV in task switching was correlated with cerebrospinal fluid (CSF) biomarkers predictive of DAT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming and attentional control of lexical and sublexical pathways during naming.

A modified priming task was used to investigate whether skilled readers are able to adjust the degree to which lexical and sublexical information contribute to naming. On each trial, participants named 5 low-frequency exception word primes or 5 nonword primes before a target. The low-frequency exception word primes should have produced a greater dependence on lexical information, whereas the nonword primes should have produced a greater dependence on sublexical information. Across 4 experiments, the effects of lexicality, regularity, frequency, and imageability were all modulated in predictable ways on the basis of the notion that the primes directed attention to specific processing pathways. It is argued that these results are consistent with an attentional control hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in information-processing rate and amount: Implications for group differences in response latency.

Research on group differences in response latency often has as its goal the detection of Group ?×? Treatment interactions. However, accumulating evidence suggests that response latencies for different groups are often linearly related, leading to an increased likelihood of finding spurious overadditive interactions in which the slower group produces a larger treatment effect. The authors propose a rate-amount model that predicts linear relationships between individuals and that includes global processing parameters based on large-scale group differences in information processing. These global processing parameters may be used to linearly transform response latencies from different individuals to a common information-processing scale so that small-scale group differences in information processing may be isolated. The authors recommend linear regression and z-score transformations that may be used to augment traditional analyses of raw response latencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Against parafoveal semantic preprocessing during eye fixations in reading.

Investigated 2 reading models, focused attention and semantic preprocessing, in which nonfoveal information plays an important role. A reading experiment was conducted with 24 normally seeing members of a university community. Ss' eye movements were recorded as they read sentences, and a display change occurred before they fixated on a critical target word. In the target word location, 1 of 4 alternative previews was initially presented: the target word itself, a word semantically related to it, an unrelated word, and a nonword visually similar to the target. The various visual processes occurring during the experiment and the retinal regions involved are discussed. Results are inconsistent with the semantic preprocessing but consistent with the focused-attention model of reading. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suffix interference in the recall of linguistically coherent speech.

In Exp 1, definitions of low-frequency words were presented for on-line written recall. Each definition was followed by a nonword speech suffix presented in the same voice as the definition, the same nonword presented in a different voice, or a tone. There was a significant reduction in the recall of the terminal words of the definitions in the speech suffix conditions compared with the tone control. This pattern was replicated in Exp 2, in which Ss did not begin their recall until the suffix item or tone was presented, although the magnitude of the suffix effect was reduced in this experiment. In Exp 3, the suffix effect was considerably reduced compared with the suffix effect found with the definitions presented in Exps 1 and 2. This pattern was replicated in Exp 4, in which Ss did not begin their recall of the story sentences until the speech suffix or tone was presented. Results suggest that auditory memory interference can take place for linguistically coherent speech, although the magnitude of the interference decreases as one increases the level of linguistic structure in the to-be-recalled materials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning Facts From Fiction: Effects of Healthy Aging and Early-Stage Dementia of the Alzheimer Type.

Healthy younger and older adults and individuals with very mild or mild dementia of the Alzheimer type (DAT) listened to and read fictional stories containing correct and incorrect facts about the world. Of interest was their use of this story information to answer questions on a later test of general world knowledge. Prior exposure to relatively well-known facts boosted all subjects' ability to correctly answer general knowledge questions. Reading incorrect facts in the stories led to misinformation effects in healthy older adults (although these effects were smaller than those observed in younger adults). DAT individuals showed reduced effects of story exposure; effects were greatest in a situation that reminded DAT individuals that the stories might provide the answers to the questions. Benefits of story reading depended on activation of the semantic network, whereas costs of story reading were more dependent on episodic memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structure versus processing deficits in Alzheimer's disease, a matter of degree: A comment on Storms et al. (2003).

G. Stories, T. Dirikx, J. Saerens, S. Verstraeten, and P. P. De Deyn (2003) argued that multidimensional scaling studies are ill-suited for investigating semantic deficits in individuals diagnosed with dementia of the Alzheimer type (DAT) because such individuals show great inter- and intraindividual variability in their proximity judgments. Discussed in this commentary are (a) the possible role of attentional set in producing inconsistent performance across trials, (b) the implications of attentional factors on the structure versus process debate, and (c) the inevitable semantic degradation following severe progression of the disease. A framework is presented for considering nonlinear performance differences as a function of attentional demands of the task, vulnerability of the semantic representation, and progression of the disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)