A developmental study of semantic effects on recognition memory

Three experiments evaluated color specificity knowledge and related semantic effects on recognition memory. Experiment I provided the necessary baseline data to show that preschool and college students know the appropriate color of objects. Experiment II revealed semantic effects on recognition of children but not adults. In Experiment III a delay was introduced and adults showed semantic effects as well. The chroma of color-specific and non-color-specific items was remembered relatively well, although chroma recognition for these item types was somewhat different. The semantic effects on very young children's memory suggest deep level interpretive processing in children younger than those generally showing deliberate deployment of memory strategies.     

Memory for internally generated words in Alzheimer-type dementia: breakdown in encoding and semantic memory

The "generation effect" is a phenomenon in which words that are generated by the subject are remembered better than words which are read. The present experiments examined this effect in patients with mild-to-moderate dementia of the Alzheimer type (DAT), healthy elderly adults, and young adults under a variety of different encoding and retrieval conditions. Experiment 1 employed an intentional learning task with multiple study/test trials using the same list of words. While both the young and elderly adults exhibited higher recall for internally generated words than read words, the DAT patients failed to demonstrate the effect even after repeated exposures to the same stimulus list. Experiment 2 replicated this same pattern of results using an incidental learning paradigm with both recall and recognition tests. Various explanations as to why the DAT patients failed to show the generation effect were discussed with particular emphasis placed on the role of semantic memory and encoding failure.     

A developmental study of semantic elaboration and interpretation in recognition memory

Two experiments examined semantic elaboration and interpretation in recognition memory of 4-year-olds and college students. Subjects were presented pictures of color-specific and non-color-specific items, and then tested for their recognition of the chroma of the items. In Experiment 1, one-half of the presentation items were black and white and one-half colored, and testing always involved one black and white and one colored choice. In Experiment 2, all of the presentation items were colored, and testing always involved two colored choices. In both studies, the pattern of results of the two age groups was similar. Experiments 1 and 2 indicated that recognition judgments were based on representations that were elaborated with preexperimentally acquired semantic color information, and Experiment 2 also indicated that recognition judgments were based on representations that contained interpretive information about the appropriateness of the colors of the items. The results were considered to support and extend the view that when young children and adults share a common knowledge base, they are likely to engage in similar and extensive semantic processing.     

Causal conditional reasoning and semantic memory retrieval: a test of the semantic memory framework

This study tested and refined a framework that proposes a mechanism for retrieving alternative causes and disabling conditions (Cummins, 1995) during reasoning. Experiment 1 examined the relation between different factors affecting retrieval. The test revealed high correlations between the number of possible alternative causes or disabling conditions and their strength of association and plausibility. Experiment 2 explored the hypothesis that due to a more extended search process, conditional inferences would last longer when many alternative causes or disabling conditions were available. Affirmation of the consequent (AC) and modus ponens (MP) latencies showed the hypothesized pattern. Denial of the antecedent (DA) and modus tollens (MT) inferences did not show latency effects. The experiment also identified an effect of the number of disabling conditions on AC and DA acceptance. Experiment 3 measured efficiency of disabler retrieval by a limited time, disabler generation task. As predicted, better disabler retrieval was related to lower acceptance of the MP and MT inferences.     

Investigating semantic memory impairments: The contribution of semantic priming

Abstract

The semantic priming task is a valuable tool in the investigation of semantic memory impairments in patients with acquired disorders of language. This is because priming performance reflects automatic or implicit access to semantic information, unlike most other tests of semantic knowledge, which rely on explicit, voluntary access. Priming results are important for two main reasons: First, normal priming results may be observed in patients who perform poorly on other semantic memory tests, enabling us to distinguish between loss of, or damage to, information in semantic memory, and voluntary access to that information. Second, we can investigate the detailed pattern of loss and preservation of different types of semantic information, by charting the priming effects for different kinds of words, and different kinds of semantic relations between primes and targets.

We discuss the use of the priming task in this context, and address some of the theoretical and methodological criticisms that have been raised in connection with use of the priming task to address these issues. We then describe two recent studies in which we have employed semantic priming tasks, along with other more traditional methods, to investigate specific questions about the semantic memory deficits of three patients.     

Quantification and semantic memory

Two models are considered for how people verify explicitly quantified sentences, such as All fathers are parents and Some fathers are parents. The models share the same second stage, but have different first-stage mechanisms. In the Predicate Intersection Model, suggested by Meyer (1970), the first stage involves a serial, self-terminating search among names of categories that intersect the predicate category. In the Feature Comparison Model (Smith, Shoben & Rips, 1974a), the first stage involves evaluating the overall relatedness between the subject and predicate categories by comparing their semantic features. To test the models, three reaction time experiments required subjects to verify statements quantified by Some or All. In the first experiment, the semantic relatedness of categories in false Some-statements was varied. Contrary to predictions of the Predicate Intersection Model, related categories increased reaction time for both true and false Some-statements. While the first experiment revealed that All-statements took longer to verify than comparable Some-statements, the second experiment demonstrated that the All-Some difference can be eliminated by presenting both statement types in the same block of trials, also disconfirming the Predicate Intersection Model. Finally, Experiment III examined the meaning of Some-statements in more detail by having subjects interpret the quantifier Some as “some but not all.” With this interpretation, Some-statements took longer to verify than All-statements. Overall the results support the Feature Comparison Model.     

On the existence of semantic working memory: evidence for direct semantic maintenance

Despite widespread acknowledgment of the importance of online semantic maintenance, there has been astonishingly little work that clearly establishes this construct. We review the extant work relevant to short-term retention of meaning and show that, although consistent with semantic working memory, most data can be accommodated in other ways. Using a new concurrent probe paradigm, we then report experiments that implicate a semantic maintenance capacity that is independent of phonological or visual maintenance that may build on a mechanism of direct semantic maintenance. Experiments 1 through 5 established that while subjects maintain the meaning of a word, a novel delay-period marker of semantic retention, the semantic relatedness effect, is observed on a concurrent lexical decision task. The semantic relatedness effect refers to slowed response times when subjects make a lexical decision to a probe that is associatively related to the idea they are maintaining, compared to when the probe is unrelated. The semantic relatedness effect occurred for semantic but not for phonological or visual word-form maintenance, dissipated quickly after maintenance ends, and survived concurrent articulatory suppression. The effect disappeared when subjects performed our immediate memory task with a long-term memory strategy rather than with active maintenance. Experiment 6 demonstrated a parallel phonological relatedness effect that occurs for phonological but not semantic maintenance, establishing a full double dissociation between the effects of semantic and phonological maintenance. These findings support a distinct semantic maintenance capacity and provide a behavioral marker through which semantic working memory can be studied.     

Charting the progression in semantic dementia: Implications for the organisation of semantic memory

Abstract

A patient, JL, with the syndrome of semantic dementia was assessed longitudinally over a two-year period. The data presented here address the controversy concerning the hierarchical organisation of semantic memory. On a range of category fluency tests, when first tested JL was just within the normal range on the broadest categories of animals and household items, but was virtually unable to produce any instances of specific categories such as breeds of dog or musical instruments. Longitudinal fluency data for the animal category demonstrate that while JL continued to produce the most prototypical responses (cat, dog, horse), other animal labels dropped out early from his vocabulary. On the picture-sorting tests from our semantic memory test battery, JL's discrimination between living things and man-made objects was preserved for a substantial time in conjunction with a marked decline in his sorting ability for more specific categories, particularly features or attributes (e.g. size, foreign-ness, or ferocity of animals).

An analysis of naming responses to the 260 Snodgrass and Vanderwart pictures on four occasions suggests a progressive loss of the features of semantic representations that enable discrimination between specific category instances. There was a progressive decline in circumlocutory and category co-ordinate responses with a rise in broad superordinate and cross-category errors. The latter are of particular theoretical interest; on session I, all cross-category errors respected the living/man-made distinction, but by session IV almost half of such errors failed to respect this distinction. The emergence of category prototypes was another notable feature, particularly in the living domain: at one stage, land (or four-legged) animals were all named either cat, dog, or horse. By contrast, within the man-made domain, items were frequently described in terms of their broad use or function, until eventually no defining features were produced. These findings are discussed in the context of competing theories of semantic organisation.     

Accessing short-term memory with semantic and phonological information: A time-course analysis

The time course for accessing short-term memory representations on the basis of item, phonological, and semantic information was measured with a speed-accuracy tradeoff (SAT) variant of a recognition probe task. Subjects studied 5-word lists and then judged whether a test word (1) was in the study list (item judgment); (2) rhymed with a word in the study list (rhyme judgment); or (3) was a synonym of a word in the study list (synonym judgment). Analysis of the SAT retrieval functions demonstrated that judgments based on phonological and semantic information were slower and less accurate than judgments based on composite item representations. The slower retrieval dynamics for rhyme and synonym judgments suggest that judgments based on component properties of the memory trace are mediated by either a generate or recall process distinct from the parallel or direct-access mechanism used in item judgments.     

Modeling semantic memory: Effects of presenting semantic information in different modalities

How is semantic information from different modalities integrated and stored? If related ideas are encountered in French and English, or in pictures and sentences, is the result a single representation in memory, or two modality-dependent ones? Subjects were presented with items in different modalities, then were asked whether or not subsequently presented items were identical with the former ones. Subjects frequently accepted translations and items semantically consistent with those presented earlier as identical, although not as often as they accepted items actually seen previously. The same pattern of results was found when the items were French and English sentences, and when they were pictures and sentences. The results can be explained by the hypothesis that subjects integrate information across modalities into a single underlying semantic representation. A computer model, embodying this hypothesis, made predictions in close agreement with the data.     

The neurobiology of semantic memory

Semantic memory includes all acquired knowledge about the world and is the basis for nearly all human activity, yet its neurobiological foundation is only now becoming clear. Recent neuroimaging studies demonstrate two striking results: the participation of modality-specific sensory, motor, and emotion systems in language comprehension, and the existence of large brain regions that participate in comprehension tasks but are not modality-specific. These latter regions, which include the inferior parietal lobe and much of the temporal lobe, lie at convergences of multiple perceptual processing streams. These convergences enable increasingly abstract, supramodal representations of perceptual experience that support a variety of conceptual functions including object recognition, social cognition, language, and the remarkable human capacity to remember the past and imagine the future.     

Distinguishing the neural correlates of episodic memory encoding and semantic memory retrieval

Episodic memory and semantic memory interact very closely. In particular, episodic memory encoding (EE) tends to elicit semantic memory retrieval (SR), and vice versa. Thus, similar activations for EE and SR in functional neuroimaging studies may reflect shared memory processes, or they may reflect the fact that EE and SR are usually confounded. To address this issue, we used a factorial functional magnetic resonance imaging approach to disentangle the neural correlates of EE and SR. Within the left temporal lobe, the hippocampus was associated with successful EE, whereas a posterior lateral region was associated with successful SR. Within the left inferior prefrontal cortex, a posterior region was involved in SR, a mid region was involved in both SR and EE, and an anterior region was involved in EE, but only when SR was also high. Thus, the neural correlates of EE and SR are dissociable but interact in specific brain regions.     

FOK与情节记忆、语义记忆和内隐记忆关系的研究

实验采用R/K判断和PDP测量技术,研究了FOK判断与情节记忆、语义记忆和内隐记忆关系及其监测强度.实验结果表明FOK判断的准确性程度为R判断＞K判断,即对情节记忆监测的准确性要大于对语义记忆监测的准确性.FOK对于自动加工的预测准确性差异不显著,说明FOK监测对内隐记忆的作用是微弱的,由此推测无记忆是意识最高层面的活动.对记忆监测水平强度是由意识--无意识逐渐减弱的.FOK判断对意识性水平较高的记忆活动监测的准确性较强.     

Getting connected: Both associative and semantic links structure semantic memory for newly learned persons

The present study examined whether semantic memory for newly learned people is structured by visual co-occurrence, shared semantics, or both. Participants were trained with pairs of simultaneously presented (i.e., co-occurring) preexperimentally unfamiliar faces, which either did or did not share additionally provided semantic information (occupation, place of living, etc.). Semantic information could also be shared between faces that did not co-occur. A subsequent priming experiment revealed faster responses for both co-occurrence/no shared semantics and no co-occurrence/shared semantics conditions, than for an unrelated condition. Strikingly, priming was strongest in the co-occurrence/shared semantics condition, suggesting additive effects of these factors. Additional analysis of event-related brain potentials yielded priming in the N400 component only for combined effects of visual co-occurrence and shared semantics, with more positive amplitudes in this than in the unrelated condition. Overall, these findings suggest that both semantic relatedness and visual co-occurrence are important when novel information is integrated into person-related semantic memory.     

The structure of semantic person memory: evidence from semantic priming in person recognition

This paper reviews research on the structure of semantic person memory as examined with semantic priming. In this experimental paradigm, a familiarity decision on a target face or written name is usually faster when it is preceded by a related as compared to an unrelated prime. This effect has been shown to be relatively short lived and susceptible to interfering items. Moreover, semantic priming can cross stimulus domains, such that a written name can prime a target face and vice versa. However, it remains controversial whether representations of people are stored in associative networks based on co-occurrence, or in more abstract semantic categories. In line with prominent cognitive models of face recognition, which explain semantic priming by shared semantic information between prime and target, recent research demonstrated that priming could be obtained from purely categorically related, non-associated prime/target pairs. Although strategic processes, such as expectancy and retrospective matching likely contribute, there is also evidence for a non-strategic contribution to priming, presumably related to spreading activation. Finally, a semantic priming effect has been demonstrated in the N400 event-related potential (ERP) component, which may reflect facilitated access to semantic information. It is concluded that categorical relatedness is one organizing principle of semantic person memory.     

Word associations: Network and semantic properties

A number of properties of word associations, generated in a continuous task, were investigated. First, we investigated the correspondence of word class in association cues and responses. Nouns were the modal word class response, regardless of the word class of the cue, indicating a dominant paradigmatic response style. Next, the word association data were used to build an associative network to investigate the centrality of nodes. The study of node centrality showed that central nodes in the network tended to be highly frequent and acquired early. Small-world properties of the association network were investigated and compared with a large English association network (Steyvers & Tenenbaum, 2005). Networks based on a multiple association procedure showed small-world properties despitebeing denser than networks based on a discrete task. Finally, a semantic taxonomy was used to investigate the composition of semantic types in association responses. The majority of responses were thematically related situation responses and entity responses referring to parts, shape, or color. Since the association task required multiple responses per cue, the interaction between generation position and semantic role could be investigated and discussed in the framework of recent theories of natural concept representations (Barsalou, Santos, Simmons, & Wilson, in press).