The time course of access to semantic information in high-performing older adults: Behavioral evidence for the hemispheric asymmetry reduction in OLDer individuals

ABSTRACT

The possibility that the HAROLD phenomenon (i.e., Hemispheric Asymmetry Reduction in OLDer adults) is manifested in the course of access to semantic information, in particular the meaning of emotional words, was investigated using the visual half-field priming paradigm. The time course of priming was tracked in the cerebral hemispheres across three SOAs: 150, 300, and 750 ms. The results showed older and young adults had the same level of accuracy. While priming occurred unilaterally in young participants, the pattern of priming in older participants appeared to be bilateral whenever it was present, that is, at the 300- and 750-ms SOAs. The delay in the appearance of priming in older adults may be due to an increase in sensory thresholds that causes older adults to need more time to encode stimuli and fully activate their semantic network. It is concluded that the bilateral pattern of priming in the presence of an equivalent level of performance in older adults provides behavioral evidence supporting the compensatory role of the HAROLD phenomenon for this particular task.     

Discriminating Semantic from Episodic Relatedness in Young and Older Adults

ABSTRACT

The ability of young (aged 18–30) and older (aged 60–80) adults to discriminate pre-experimental (semantic) from experimental (episodic) associations was examined. Participants studied a list containing semantically related and unrelated word pairs and then made either associative recognition (Experiments 1a and b) or semantic relatedness (Experiment 2) judgments at various response deadlines. For associative recognition judgments, both young and older adults benefited from semantic relatedness, leading to more hits for related than unrelated pairs, and at the long response deadline, older adults' performance on those pairs matched that of young participants. Also, both young and older adults demonstrated superior discrimination for unrelated lures whose members had originally been studied in related pairs – evidence for recall-to-reject processing in both age groups. In making semantic relatedness judgments, both young and older adults showed an episodic priming effect. When older adults can rely on long-standing associations, their performance resembles that of young adults – both in associative recognition and in episodic priming.     

Attentional modulation of masked repetition and categorical priming in young and older adults

Three experiments examined the effects of temporal attention and aging on masked repetition and categorical priming for numbers and words. Participants' temporal attention was manipulated by varying the stimulus onset asynchrony (i.e., constant or variable SOA). In Experiment 1, participants performed a parity judgment task and a lexical decision task in which categorical priming and repetition priming were, respectively, tested. Experiment 2 used a semantic categorization task testing categorical priming. In Experiment 3, repetition and categorical priming were tested in the same semantic categorization task with the same stimuli. The results of the three experiments showed that masked repetition priming is insensitive to manipulations of temporal attention whereas categorical priming is. Furthermore, no differences were found between young and older adults in repetition priming effects, again contrasting with the categorical priming results for which older adults were more sensitive to attentional manipulations than young adults.     

Predicting semantic priming at the item level

The current study explores a set of variables that have the potential to predict semantic priming effects for 300 prime-target associates at the item level. Young and older adults performed either lexical decision (LDT) or naming tasks. A multiple regression procedure was used to predict priming based upon prime characteristics, target characteristics, and prime-target semantic similarity. Results indicate that semantic priming (a) can be reliably predicted at an item level; (b) is equivalent in magnitude across standardized measures of priming in LDTs and naming tasks; (c) is greater following quickly recognized primes; (d) is greater in LDTs for targets that produce slow lexical decision latencies; (e) is greater for pairs high in forward associative strength across tasks and across stimulus onset asynchronies (SOAs); (f) is greater for pairs high in backward associative strength in both tasks, but only at a long SOA; and (g) does not vary as a function of estimates from latent semantic analysis (LSA). Based upon these results, it is suggested that researchers take extreme caution in comparing priming effects across different item sets. Moreover, the current findings lend support to spreading activation and feature overlap theories of priming, but do not support priming based upon contextual similarity as captured by LSA.     

Predicting semantic priming at the item level

The current study explores a set of variables that have the potential to predict semantic priming effects for 300 prime–target associates at the item level. Young and older adults performed either lexical decision (LDT) or naming tasks. A multiple regression procedure was used to predict priming based upon prime characteristics, target characteristics, and prime–target semantic similarity. Results indicate that semantic priming (a) can be reliably predicted at an item level; (b) is equivalent in magnitude across standardized measures of priming in LDTs and naming tasks; (c) is greater following quickly recognized primes; (d) is greater in LDTs for targets that produce slow lexical decision latencies; (e) is greater for pairs high in forward associative strength across tasks and across stimulus onset asynchronies (SOAs); (f) is greater for pairs high in backward associative strength in both tasks, but only at a long SOA; and (g) does not vary as a function of estimates from latent semantic analysis (LSA). Based upon these results, it is suggested that researchers take extreme caution in comparing priming effects across different item sets. Moreover, the current findings lend support to spreading activation and feature overlap theories of priming, but do not support priming based upon contextual similarity as captured by LSA.     

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.     

Automatic and attentional priming in young and older adults: reevaluation of the two-process model.

Three experiments addressed the distinction between automatic and attentional mechanisms underlying semantic priming effects by factorially crossing prime-target relatedness, expectancy, and SOA in a task (pronunciation) that minimized postlexical checking processes. Also, possible age-related (young vs. older adults) differences in the automatic and attentional mechanisms were addressed. Across all experiments there was evidence of a Relatedness x Expectancy x SOA interaction, which is inconsistent with the notion of independent automatic and attentional mechanisms in semantic priming and the notion of a self-encapsulated modular lexicon. The results also indicated age-related differences in the build-up of the expectancy effect across SOAs when the prime was visually available for only 200 ms, independently of the prime-target SOA (Experiments 1 and 3), but not when the prime was visually available throughout the SOA (Experiment 2).     

Affective priming with pictures of emotional scenes: the role of perceptual similarity and category relatedness

Prime pictures portraying pleasant or unpleasant scenes were briefly presented (150-ms display; SOAs of 300 or 800 ms), followed by probe pictures either congruent or incongruent in emotional valence. In an evaluative decision task, participants responded whether the probe was emotionally positive or negative. Affective priming was reflected in shorter response latencies for congruent than for incongruent prime-probe pairs. Although this effect was enhanced by perceptual similarity between the prime and the probe, it also occurred for probes that were physically different, and the effect generalized across semantic categories (animals vs. people). It is concluded that affective priming is a genuine phenomenon, in that it occurs as a function of stimulus emotional content, in the absence of both perceptual similarity and semantic category relatedness between the prime and the probe.     

The time course of semantic and associative priming effects is different in an attentional blink task

When two targets are presented using rapid serial visual presentation (RSVP) and the interval between the targets is 200–500 ms, report of the second target is impaired, a phenomena known as the attentional blink (AB). This study examined the time course of semantic-only and associate–semantic priming effects during an AB task. Three RSVP experiments were conducted using targets that shared either a semantic-only or an associative–semantic relationship. The results of the three experiments demonstrated semantic-only priming effects at the shortest stimulus onset asynchronies (SOAs). Associative–semantic priming was evident at shorter and longer SOAs. This suggests that priming in an AB task is driven by conceptual overlap facilitating lexical access at short SOAs and with longer SOAs lexical access benefits from word associations links between targets.     

Exploring the identification-production hypothesis of repetition priming in young and older adults

The identification-production hypothesis of age-related differences in repetition priming predicts reduced priming in older adults on indirect memory measures that require stimulus production (production priming) together with age constancy on indirect measures that require stimulus identification, verification, or classification processes (identification priming). Although some evidence is consistent with this hypothesis, comparisons of identification and production priming in young and older adults often confound stimulus, subject, and dependent measure factors across tasks. Consequently, repetition priming has yet to be assessed in healthy young and healthy older adults using identification and production tasks that control for these factors. The identification-production hypothesis was tested using verb generation as a measure of production priming (Experiments 1-3) and semantic classification (Experiment 1) or semantic verification (Experiments 2 and 3) as the measure of identification priming. Contrary to the identification-production hypothesis, no age-related diminutions in identification or production forms of priming were found.     

Semantic priming,not repetition priming,is to blame for false hearing

Contextual and sensory information are combined in speech perception. Conflict between the two can lead to false hearing, defined as a high-confidence misidentification of a spoken word. Rogers, Jacoby, and Sommers (Psychology and Aging, 27(1), 33–45, 2012) found that older adults are more susceptible to false hearing than are young adults, using a combination of semantic priming and repetition priming to create context. In this study, the type of context (repetition vs. sematic priming) responsible for false hearing was examined. Older and young adult participants read and listened to a list of paired associates (e.g., ROW–BOAT) and were told to remember the pairs for a later memory test. Following the memory test, participants identified words masked in noise that were preceded by a cue word in the clear. Targets were semantically associated to the cue (e.g., ROW–BOAT), unrelated to the cue (e.g., JAW–PASS), or phonologically related to a semantic associate of the cue (e.g., ROW–GOAT). How often each cue word and its paired associate were presented prior to the memory test was manipulated (0, 3, or 5 times) to test effects of repetition priming. Results showed repetitions had no effect on rates of context-based listening or false hearing. However, repetition did significantly increase sensory information as a basis for metacognitive judgments in young and older adults. This pattern suggests that semantic priming dominates as the basis for false hearing and highlights context and sensory information operating as qualitatively different bases for listening and metacognition.     

汉语词汇产生中语义、字形和音韵激活的时间进程

通过图画－词汇干扰实验范式探索汉语单字词产生中语义、字形和语音激活的时间进程。实验一和实验二的结果综合表明：当SOA为-300 ms~0 ms时,存在语义抑制效应,当SOA为-100 ms~100 ms时,存在字形促进效应,当SOA为100 ms时,存在语音促进效应。实验结果支持交互激活理论的观点。实验成功地分离了字形促进效应和语音促进效应,确定了语义、字形和语音这三种信息在汉语口语词汇产生中通达的先后次序,讨论了字形信息在词汇产生中的重要作用,以及被试是否在实验中使用了策略。     

Attention constraints of semantic activation during visual word recognition

The reduction of semantic priming following letter search of the prime suggests that semantic activation can be blocked if attention is allocated to the letter level during word processing. Is this true even for the very fast-acting component of semantic activation? To test this, the authors explored semantic priming of lexical decision at stimulus onset asynchronies (SOAs) of either 200 or 1,000 ms. Following semantic prime processing, priming occurred at both SOAs. In contrast, no priming occurred at the long SOA following letter-level processing. Of greatest interest, at the short SOA there was priming following the less demanding consonant/vowel task but not following the more attention-demanding letter search task. Hence, semantic activation can occur even when attention is directed to the letter level, provided there are sufficient resources to support this activation. The authors conclude that the default setting during word recognition is for fast-acting activation of the semantic system.     

再探汉字加工中语音、语义激活的相对时间进程

在Zhou和Marslen-Wilson（2000）基础之上,进一步探讨汉字加工中语音和语义信息激活的相对时间进程及其对汉字加工理论的含义。采用启动范式,用同一目标字与语义相关启动字、同音启动字以及无关控制启动字配对,变化同音启动字读音与其声旁的规则性,变化启动字与目标字呈现之间的时间间隔（SOA,57ms或200ms）,使用两种实验任务（真假字判断和命名）,考察语义、语音效应发生的时间先后与效应量的大小。真假字判断实验发现,不管SOA如何,语义启动效应都非常显著,而同音启动效应则随SOA的增长而逐渐加大,从不显著到显著;同音启动字读音规则性对启动效应没有明显影响。命名实验发现,语义启动、同音启动效应同时存在于长、短SOA条件中。长SOA时,两者在数值上没有显著差异;短SOA时,同音不规则字产生的启动效应等同于语义启动效应,而同音规则字产生的启动效应则大于语义启动效应。结合其它实验发现,这些结果说明,在熟练的汉字加工中,语音信息的激活并不比语义信息早,语音激活也不是语义激活的先决条件;但汉字各种信息激活的相对激活量和时间进程会随任务性质和材料性质而在一定范围内有所改变。     

Lexical processing of ambiguous words: dominance or associative strength?

Four experiments examined the role of meaning frequency (dominance) and associative strength (measured by associative norms) in the processing of ambiguous words in isolation. Participants made lexical decisions to targets words that were associates of the more frequent (dominant) or less frequent (subordinate) meaning of a homograph prime. The first two experiments investigated the role of associative strength at long SOAs (Stimulus Onset Asynchrony) (750 ms.), showing that meaning is facilitated by the targets' associative strength and not by their dominance. The last two experiments traced the role associative strength at short SOAs (250 ms), showing that the manipulation of the associative strength has no effect in the semantic priming. The conclusions are: on the one hand, semantic priming for homographs is due to associative strength manipulations at long SOAs. On the other hand, the manipulation of the associative strength has no effect when automatic processes (short SOAs) are engaged for homographs.     

A speed-accuracy analysis of word recognition in young and older adults

To measure age differences in the rate of semantic priming, studies vary the prime-target interval in lexical decision (LD) tasks. This provides no time limit on the target response. Thus, older adults' greater response times (RTs) could offer them more accumulated priming at the response compared with younger, faster adults. This study used a response deadline procedure in an LD task to equalize processing time across age groups. Although RTs did not significantly differ across age groups, older adults showed larger semantic priming effects than young adults. Semantic priming was also found with response accuracy (d'), but did not differ across age.     

Production and identification repetition priming in amnestic mild cognitive impairment

The experiment reported here examined implicit memory function, as measured through repetition priming, in amnestic mild cognitive impairment (MCI) to examine whether impairments exist in this aspect of memory function. Young adults, healthy older controls, Alzheimer's disease patients, and MCI participants were asked to perform two types of implicit memory tests (word stem completion and threshold identification repetition priming tasks), as well as a recognition test for studied items. As expected, young adults performed better than the other participants on the recognition test and the word stem completion task; there was equivalent priming across groups on the word identification task. While both the older control and MCI participants showed lower levels of priming on the word stem completion task relative to the young adults, the magnitude of priming was equivalent for these two groups, and reliably greater than that of the dementia participants. These results suggest that not all aspects of memory function are impaired in MCI relative to healthy aging.     

Unconscious Semantic Priming Influences Performance of Visuomotor Tasks Differently but the Effects are Similar in Young and Older Adults

We examined the effects of semantic priming of attention on two sequentially presented visuomotor tasks, traffic judgments and saccadic adaptation. Priming was accomplished with the scrambled sentence task: participants formed meaningful sentences from a list of words where a word denoting wide attention focus was involved. The results showed that semantic priming influenced positively saccade adaptation (its’ benefit increased) while it attenuated visuomotor performance in the traffic task (RT of hand movements increased). We found the effects of priming on both tasks’ performance to be comparable in young and older participants. It was suggested that semantic priming effect on visuomotor tasks depended on the cognitive resources which were needful as for the priming as for the primed task.     

Age-related changes in the appreciation of novel metaphoric semantic relations

In the present study we tested the possibility that older adults differ from younger adults in their appreciation of metaphoric semantic relations, and that age-related changes occur due to the perception of novel metaphors. In the first experiment 35 younger (mean age?=?23.1) and 35 older adults (mean age?=?75.3) were asked to rate the plausibility of metaphoric, literal, and unrelated word pairs. Relative to young participants, older participants rated fewer expressions as metaphorically plausible. The second experiment was conducted to examine whether the findings of the first experiment could be accounted for by an age-associated difference in the appreciation of metaphors with different levels of familiarity. In the second experiment, 25 younger (mean age?=?24.4) and 25 older adults (mean age?=?77.5) were asked to rate the familiarity level of the plausible metaphoric expressions. Relative to young participants, older participants rated fewer expressions as novel and more expressions as familiar. The results suggest that novelty plays an important role in appreciating the plausibility of semantic relationships, and age-related changes are associated with the appreciation of the novelty of expressions.     

Production and Identification Repetition Priming in AmnesticMild Cognitive Impairment

ABSTRACT

The experiment reported here examined implicit memory function, as measured through repetition priming, in amnestic mild cognitive impairment (MCI) to examine whether impairments exist in this aspect of memory function. Young adults, healthy older controls, Alzheimer's disease patients, and MCI participants were asked to perform two types of implicit memory tests (word stem completion and threshold identification repetition priming tasks), as well as a recognition test for studied items. As expected, young adults performed better than the other participants on the recognition test and the word stem completion task; there was equivalent priming across groups on the word identification task. While both the older control and MCI participants showed lower levels of priming on the word stem completion task relative to the young adults, the magnitude of priming was equivalent for these two groups, and reliably greater than that of the dementia participants. These results suggest that not all aspects of memory function are impaired in MCI relative to healthy aging.