Strength-based criterion shifts in recognition memory

In manipulations of stimulus strength between lists, a more lenient signal detection criterion is more frequently applied to a weak than to a strong stimulus class. However, with randomly intermixed weak and strong test probes, such acriterion shift often does not result. A procedure that has yieldeddelay-based within-list criterion shifts was applied to strength manipulations in recognition memory for categorized word lists. When participants made semantic ratings about each stimulus word, strength-based criterion shifts emerged regardless of whether words from pairs of categories were studied in separate blocks (Experiment 1) or in intermixed blocks (Experiment 2). In Experiment 3, the criterion shift persisted under the semantic-rating study task, but not under rote memorization. These findings suggest that continually adjusting the recognition decision criterion is cognitively feasible. They provide a technique for manipulating the criterion shift, and they identify competing theoretical accounts of these effects.     

Strategies of text retrieval: a criterion shift account.

This study scrutinized people's ability to apply different strategies to randomly intermixed immediate and delayed test items. In three experiments, participants first read one set of stories. Later, they read more stories, and after each one, answered intermixed questions about that story and one of the earlier ones. The experiments cumulatively manipulated amount of delay, test probe plausibility, probe relation (explicit, paraphrase, inference), and testing procedure (mixed versus uniform delay). Using signal detection response criterion as the index of strategy, we contrasted the single criterion hypothesis, according to which one text retrieval criterion is applied to all test items, and a multiple-criterion hypothesis. The results consistently favoured the multiple-criterion hypothesis. The results also indicated that the presence of immediate and delayed probes mutually influence one another: Less extreme signal detection criteria were adopted under mixed than uniform testing. It was concluded that text retrieval strategy is continually calibrated with reference to the quality of the test probes.     

Visual and semantic factors in recognition from long-term memory

In recognition tests, physical and semantic relationships between targets and distractors have been shown, in separate manipulations, to affect the latency of subject's decision. Recognition was tested for distractors which were visually similar or dissimilar to targets and which belonged to the target categories or to nontarget categories in order to examine the interaction of these dimensions. Rejection latency was longer for target category than for nontarget category distractors. Latency was also longer for visually similar than visually dissimilar distractors, but only when combined with target category probes. This interaction can be explained by the hypothesis that word recognition depends on the analysis of several dimensions of the probe stimulus, and rejection can occur before all such analyses have been completed.     

Specifying theories of developmental dyslexia: a diffusion model analysis of word recognition

The nature of word recognition difficulties in developmental dyslexia is still a topic of controversy. We investigated the contribution of phonological processing deficits and uncertainty to the word recognition difficulties of dyslexic children by mathematical diffusion modeling of visual and auditory lexical decision data. The first study showed that poor visual lexical decision performance of reading disabled children was mainly due to a delay in the evaluation of word characteristics, suggesting impaired phonological processing. The adoption of elevated certainty criteria by the disabled readers suggests that uncertainty contributed to the visual word recognition impairments as well. The second study replicated the outcomes for visual lexical decision with formally diagnosed dyslexic children. In addition, during auditory lexical decision, dyslexics presented with reduced accuracy, which also resulted from delayed evaluation of word characteristics. Since orthographic influences are diminished during auditory lexical decision, this strengthens the phonological processing deficit account. Dyslexic children did not adopt heightened certainty criteria during auditory lexical decision, indicating that uncertainty solely impairs reading and not listening.     

Serial position effects in visual short-term memory for words and abstract spatial patterns

Two experiments tested the effects of list postion, and retention-interval in recognition for two distinct stimulus categories in young adults. Stimulus categories were spatial abstract patterns and words presented on a computer screen. At short delay intervals recency effects predominates and at longer delay intervals a primacy effect predominates in both experiments, indicating similar basic memory processes producing the serial position functions for the two different categories of visual stimuli, but as length of retention-interval increases, memory for first list items improves for words and remains constant for abstract patterns. Recency functions are similar for both stimulus categories tested.     

The long-term recency effect in recognition memory

Three classes of theories explain the recency effect: the modal model, single-store models, and the composite view, which integrates the two positions. None could explain the absence of a long-term recency effect in recognition memory in previous studies. We suggest that prior work did not obtain a recency effect because testing used a multiple-probe rather than a single-probe recognition procedure. Here we tested memory using a single-probe recognition procedure. Experimental conditions included an immediate test, a delayed test after a filled interval, and a continuous-distractor paradigm in which the same filled delay preceded the first word and followed every study word. The long-term recency effect in continuous-distractor recognition was equivalent to the recency effect in immediate recognition. Its absence in the delayed recognition condition demonstrated that it was not attributed to the use of a putative short-term memory store. Single-store models and the composite view can account for this novel finding.     

Familiarity and free recall

Using stimulus material drawn from a single category, it is shown that formal recognition tests yield superior performance to recall when the category cannot be completely enumerated by the subjects, but not otherwise. Furthermore, within these categories recognition is superior only if unfamiliar items are selected as stimuli. These findings fit the theory that when recalling subjects attempt to scan the relevant category and “recognize” those items employed as stimuli.     

Effects of list organization and retrieval cues on children's delayed recall.

Developmental differences in recall were investigated as a function of mode of presentation (blocked vs. random), recall condition (cued vs. noncued), and time of recall (immediate vs. delayed). Ninety-six second graders and 96 fourth graders were the subjects, and the stimuli were 20 pictured items from five categories. Data on three dependent variables (item recall, category recall, and clustering score) were analyzed. Immediate recall was better than delayed recall, the fourth graders' overall performance was superior to that of the second graders, and the blocked presentation of items and the presence of retrieval cues at recall enhanced recall and organization in recall. Furthermore, an analysis of a three-way interaction on two dependent measures indicated that, in the noncued condition, immediate recall was better than delayed recall for children in both grades. However, in the cued condition, the fourth graders performed better during delayed recall than during immediate recall, whereas the second graders did better during immediate recall than during delayed recall.     

Education as a Science

Developmental differences in recall were investigated as a function of mode of presentation (blocked vs. random), recall condition (cued vs. noncued), and time of recall (immediate vs. delayed). Ninety-six second graders and 96 fourth graders were the subjects, and the stimuli were 20 pictured items from five categories. Data on three dependent variables (item recall, category recall, and clustering score) were analyzed. Immediate recall was better than delayed recall, the fourth graders' overall performance was superior to that of the second graders, and the blocked presentation of items and the presence of retrieval cues at recall enhanced recall and organization in recall. Furthermore, an analysis of a three-way interaction on two dependent measures indicated that, in the noncued condition, immediate recall was better than delayed recall for children in both grades. However, in the cued condition, the fourth graders performed better during delayed recall than during immediate recall, whereas the second graders did better during immediate recall than during delayed recall.     

A rule-based categorization deficit in Alzheimer's disease?

This study examined the categorization processes that Alzheimer's disease (AD) patients use during assessments of semantic memory. Rule-based categorization involves the careful, analytic processing of strict criteria to determine category membership, particularly for items from graded categories with ambiguous category membership; similarity-based categorization requires an overall comparison of a test stimulus with a prototype or remembered exemplar of the category and is relatively effective for the rapid categorization of items with unambiguous category membership. To assess these processes in AD, patients were asked to decide the category membership of test stimuli for categories with poorly defined or fuzzy boundaries (e.g., VEGETABLE) and for categories with well-defined boundaries (e.g., FEMALE) and then to judge the representativeness of the test stimulus for its chosen category. A subgroup of AD patients demonstrated a typical pattern of impaired semantic memory compared to healthy control subjects; that is, difficulty deciding the category membership of test items from fuzzy categories. Among these patients, we found no deficit in category membership decisions about items taken from well-defined categories. We also found that AD patients and healthy controls do not differ in their representativeness judgments of items within a correctly judged category. These findings are most consistent with the hypothesis that rule-based categorization difficulty limits semantic memory in AD.     

A fuzzy trace analysis of categorical inferences and instantial associations as a function of retention interval

Two experiments on children's inferences and associative memory provided a test of predictions from fuzzy-trace theory. Specifically, it was expected that gist-based false recognitions would increase with age and that false recognitions would be uncorrelated with verbatim memory. In Experiment 1, children in Grades 1 through 5 heard lists of category labels, clustered instances from categories, and individual instances. On an immediate test, children indicated whether or not they had previously heard a series of individually presented test words. This list consisted of old words, new words, or words that were categorically or semantically related to the studied word clusters. Children made more false recognition errors for instances than for categories. Verbatim memory and inferences were unrelated. In Experiment 2, the effect of a test delay on categorical inferences and associated instances was examined with children in Grades 1 to 6. With delay, false recognition of associated instances declined for children at all grade levels. In contrast, categorical inferences increased with delay for older children. Verbatim memory and inferences were uncorrelated under immediate and 1-day delay conditions, but there were some low but significant correlations across grades under the 7-day delay. The results of the two experiments are interpreted as supporting fuzzy-trace theory.     

Category similarity effects in children's semantic memory retrieval

Fourth-, sixth-, and eighth-grade students were required to indicate whether or not a stimulus word belonged in either of two semantic categories that were held in memory. Each category pair was either semantically similar or semantically dissimilar. The results indicated that even for the youngest children, similar categories required less search time than dissimilar categories. It was suggested that while dissimilar categories had to be accessed successively prior to search, subjects were able to consolidate similar categories into a superordinate group which eliminated the time to shift from one category to another during search. The results were contrasted with clustering studies which have demonstrated a minimal amount of memory facilitation in children for conceptually related items over unrelated items.     

Classifying pictures and words: Implications for the dual-coding hypothesis

In deciding that two items come from the same category, subjects were delayed if the items were presented as a word and a picture, as compared with two words or two pictures. Subjects were not delayed if the items were not to be compared. Hence, the delay appears to occur during the retrieval and comparison of know ledge about the items, not during their perceptual analysis. The results suggest that there are two distinct codes involved in the categorization of words and pictures, rather than a single code.     

Semantic activation in the absence of perceptual awareness

Participants performed a semantic categorization task on a target that was preceded by a prime word belonging either to the same category (20% of trials) or to a different category (80% of trials). The prime was presented for 33 msec and followed either immediately or after a delay by a pattern mask. With the immediate mask, reaction times (RTs) were shorter on related than on unrelated trials. This facilitatory priming reached significance at prime-target stimulus onset asynchronies (SOAs) of 400 msec or less and remained unaffected by task practice. With the delayed mask, RTs were longer on related than on unrelated trials. This reversed (strategic) semantic priming proved to be significant (1) only at a prime-target SOA of 400 msec or longer and (2) after the participants had some practice with the task. The present findings provide further evidence that perceiving a stimulus with and without phenomenological awareness can lead to qualitatively different behavioral consequences.     

Effects of retention interval and modality on sensory and semantic trace information

Subjects studied a long list of individual words that were presented either visually or auditorily. Recall was tested immediately or after a filled delay by using either word endings or taxonomic categories as extralist retrieval cues. Two interactions were of particular interest. First, word ending cues were just as effective as taxonomic cues on the immediate test. On the delayed test, however, ending cues were less effective. This result suggests that sensory information encoded about a word decays at a faster rate than semantic information. Second, although modality had no observable influence on the taxonomic cues, word ending cues were more effective when all items were shown visually than when they were presented auditorily. Taken together, these findings indicate that the visual features of words are encoded at study and that this information can be accessed during test if it is recapitulated by the retrieval cue shortly after acquisition.     

The relationship between repetition and depth of processing

The relationship between depth of information processing and stimulus repetitions was investigated using a simultaneous category judgment task. Several levels of processing were defined involving (1) physically identical items, (2) physically different but same-name items, (3) different items from the same semantic category, and (4) items from different categories. Stimulus pairs were represented by words and pictures, and each pair was presented one, three, or five times. Response times for categorization judgments increased with the level of processing and decreased with repetitions. Repetitions produced greater facilitation for decisions at deeper levels of processing. In a final incidental recall task, more items were remembered from category-same trials than from same-item trials, but level of processing did not interact with number of presentations. Repetitions produced an equivalent increase in final recall probability for items involved in all decision types, indicating that distributed repetitions can lead to the formation of stronger memory traces at several levels of processing.     

Semantic cuing and the scale insensitivity of recency and contiguity

In recalling a set of previously experienced events, people exhibit striking effects of recency, contiguity, and similarity: Recent items tend to be recalled best and first, and items that were studied in neighboring positions or that are similar to one another in some other way tend to evoke one another during recall. Effects of recency and contiguity have most often been investigated in tasks that require people to recall random word lists. Similarity effects have most often been studied in tasks that require people to recall categorized word lists. Here we examine recency and contiguity effects in lists composed of items drawn from 3 distinct taxonomic categories and in which items from a given category are temporally separated from one another by items from other categories, all of which are tested for recall. We find evidence for long-term recency and for long-range contiguity, bolstering support for temporally sensitive models of memory and highlighting the importance of understanding the interaction between temporal and semantic information during memory search.     

Effects of relation similarity on part-whole decisions

Subjects were presented with word pairs (e.g., bed-mattress) and timed as they decided whether one word named part of the item named by the other word. Yes responses were facilitated, and no responses were impeded, by relation similarity (i.e., the similarity of the relation between the two stimulus items to the part-whole relation). Item similarity, the similarity of the two stimulus items to each other, had no effect. The results support the view that similarity effects in semantic decision tasks are due to the comparison of elements of the relation between the two stimulus words against relation elements that serve as criteria for the target relation that the subject has been asked to identify.     

Stimulus-form effectsin recognition memory

In two experiments, recognition memory was tested using memorized lists of items containing from 2 to 32 nominal concepts. Stimulus form was manipulated by using the names of the items on word trials and outline drawings of the items on picture trials. In terms of an information processing stage model of recognition memory, stimulus form affected only an identification or encoding stage of processing. Subsequent memory-search, decision, and response processes were largely the same for all stimuli once the words or pictures were encoded. The results are consistent with the hypothesized role of stimulus form in processes underlying long-term recognition. However, our results are inconsistent with those of a number of studies involving stimulus-form effects in short-term recognition memory.     

On the nature of the decision axis in signal-detection-based models of recognition memory

Most models of recognition memory involve a signal-detection component in which a criterion is placed along a decision axis. Older models generally assume a familiarity-decision axis, but newer models often assume a likelihood ratio axis instead because it allows for a more natural account of the ubiquitous mirror effect. In 3 experiments reported here, item strength was differentially manipulated to see whether a mirror effect would occur. Within a list, the items from 1 category were strengthened by repetition, but the items from another category were not. On the subsequent recognition test, the hit rate was higher for the strong category, but the false-alarm rates for the weak and strong categories were the same (i.e., no mirror effect was observed). This result suggests that the decision axis represents a familiarity scale and that participants adopt a single decision criterion that they maintain throughout the recognition test.