The dissociation of repetition priming and recognition memory in language/learning-disabled children.

Recent research has found that the performance of learning-disabled and non-disabled children is dissociated on explicit and implicit tests of memory (Lorsbach & Worman, 1989). The current study further examined this phenomenon by comparing language/learning-disabled (L/LD) and nondisabled children (NLD) on tasks measuring primed picture-naming and item recognition. Included within the design of the experiment was the manipulation of both presentation format (pictures or words) and retention interval (immediate or 1 day). Children were initially presented with pictures and words. Performance was measured both immediately and following a 1-day retention interval on a picture naming task, an item recognition task, and a supplementary measure of memory for presentation format. The magnitude of facilitation associated with primed picture-naming was found to be independent of item recognition performance. In addition, the effects of population (L/LD and NLD) and retention interval (immediate test or 1 day) each produced dissociations between the magnitude of naming facilitation and item recognition performance. Results were discussed in terms of their implications for our understanding of the nature of memory difficulties in L/LD children.     

Intent to remember briefly presented human faces and other pictorial stimuli enhances recognition memory

Since the early days of psychology, researchers have investigated whether or not intending to remember information affects subsequent memory performance. The literature contains methodological issues and empirical contradictions, with ambiguous effects. In five experiments, a total of 576 participants viewed a rapid series of pictorial stimuli under either incidental- or intentional-memory conditions. Although the methodology was stringent, intent to remember consistently enhanced recognition memory. Recognition was enhanced even when participants viewed a picture of a human face, of an ape face, or of a bird for as little as 0.5-1.0 sec, with no interstimulus interval between it and the next picture. Rehearsal, depth of processing, and attentional allocation are discussed to explain how people might intentionally encode pictorial information to enhance their subsequent recognition memory performance.     

The effects of a target–stimulus reminder on performance in a novel object recognition task

The effects of original training-stimulus pre-test reminders were examined in a novel object recognition (NOR) task. NOR is a task that examines memory for complex stimuli, and is driven by the rats’ tendency to spend significantly more time exploring novel objects over those previously experienced. In this task, a delay is imposed between a training experience during which the animal is allowed to investigate a set of identical objects, and a later test exposure where the animal encounters one of the original objects and a novel object with which it has had no previous experience. Experiment 1 demonstrated that performance at 24 h is significantly worse than at an immediate delay (1 min). In the second experiment, it was demonstrated that neither a 10-s nor a 30-s reminder treatment, in the absence of training, resulted in a level of preference for novelty, a measure of memory for the original object, that was significantly greater than chance. Experiment 3 illustrated significant performance effects of a 30-s training stimulus reminder administered 15 min prior to test with a 24-h retention interval. The final experiment illustrated that the additional 30-s of object exposure is effective in enhancing performance only if it occurs shortly prior to test. Animals receiving the additional 30-s immediately following training did not experience such beneficial effects. It was concluded, based upon these results, that pre-test training-stimulus reminders in this task produce effects similar to those seen in more traditional tasks of learning and memory.     

The fate of ear asymmetries in short-term memory

Recognition memory for word lists presented to left or right ears was tested after filled retention intervals of 0-to 60-sec duration. Experiment 1 showed that the right-ear advantage (REA) for immediate recognition in dichotic listening does not occur after 10 sec delay. In Experiment 2, monaural presentation produced a nonsignificant REA which did not appear to be affected by delay. These data suggest that the REA for immediate report usually observed in the dichotic listening situation is a transient phenomenon which is based on phonetic encoding. The left hemisphere seems to be specialized for the initial reception of verbal information, but not for the storage or retention of such information over time.     

The effects of cholinergic drugs upon recognition memory in rats

This study measured the effects of the muscarinic blocker, scopolamine, upon object recognition. In order to test object recognition, rats were trained to choose between two distinctive goal boxes, one of which was familiar, and the other was novel. Selection of the unfamiliar goal box was always rewarded (nonmatching-to-sample), and new pairs of start/goal boxes were used on every trial.

In the first experiment it was found that injections of 0.05 mg/kg scopolamine hydrochloride and above produced significant impairments on this nonspatial test of working memory. A second experiment examined whether scopolamine caused a loss of retention by comparing the effects of the drug when the interval between stimulus presentation and choice test was increased from just over 0 sec to 60 sec. While the highest dose of scopolamine hydrobromide (0.06 mg/kg) was sufficient to produce a significant impairment on the longer retention interval, there was no evidence that this dose produced faster forgetting of the stimuli. This result suggests that the drug caused a general depression in performance, which may or may not reflect amnesic properties. In contrast, simultaneous tests with the anticholinesterase, physostigmine, indicated that increasing available acetyl choline might attenuate the effects of the retention intervals. A final series of control tests revealed that the rats relied on cues from a variety of sensory modalities in order to perform the nonmatching task.     

感知觉加工与概念加工对联结记忆中图片优势效应的影响

本研究采用联结再认范式考察联结记忆中感知觉水平和概念加工程度对图片优势效应的影响。实验1通过呈现清晰或模糊的词语或图片对操纵了感知觉水平,结果发现只有在清晰条件下图片优势效应才会出现;实验2则在模糊条件下通过要求被试想象两个项目之间的关系操纵了概念加工程度,结果发现在有概念加工条件下,出现了图片优势效应。研究结果表明：（1）降低的感知觉水平会导致联结记忆中的图片优势效应消失;（2）对模糊项目对进行概念加工会使联结记忆中出现图片优势效应。     

Visual recognition memory across contexts

In two experiments, we investigated the development of representational flexibility in visual recognition memory during infancy using the Visual Paired Comparison (VPC) task. In Experiment 1, 6- and 9-month-old infants exhibited recognition when familiarization and test occurred in the same room, but showed no evidence of recognition when familiarization and test occurred in different rooms. In contrast, 12- and 18-month-old infants exhibited recognition irrespective of testing room. Thus, flexibility across a change of room was observed at a younger age than flexibility across a change of background that has previously been seen with the VPC procedure (Robinson & Pascalis, 2004). To determine if limitations in representational flexibility across a change of background could be overcome by experiences during encoding, in Experiment 2, 6-, 9-, 12- and 18-month-old infants were familiarized with a picture on multiple backgrounds. At all ages, infants showed recognition across a change in background at test. These findings indicate that dissociating an item from its context during encoding may be an important factor in understanding the representational flexibility of visual recognition memory in infancy. Developmental changes in representational flexibility are likely driven by changes in the functional maturity of the hippocampal formation, and experience.     

Individual differences in cognitive style,working memory,and semantic integration

In two experiments subjects classified as being either high or low in field articulation (FA) performed a semantic integration task with high-information load. In Experiment 1, differences in performance between high- and low-FA subjects on an inference and recognition test were obtained when sentences were presented for 5 sec a piece but not when they were presented for 10 sec a piece. In Experiment 2, performance differences between high and low-FA subjects were eliminated by presenting only a specific subset of the sentences for 10 sec a piece. The implications of these results for explanations of FA effects in semantic integration are discussed.     

Infants' memory processing of a serial list: list length effects

Six-month-olds, trained with a three-mobile serial list, exhibit a primacy effect 24 h later. In three experiments, we demonstrated that increasing list length impairs their memory for serial order. In all experiments, 6-month-olds were trained with a five-mobile list. In Experiment 1, infants failed to exhibit a primacy effect on a 24-h delayed recognition test, recognizing mobiles from all serial positions. In Experiment 2, infants did exhibit a primacy effect on a reactivation (priming) test, suggesting that they may originally have encoded serial-order information. Experiment 3 confirmed that serial-order information was represented in infants' training memory. After the reactivation treatment, infants were precued with one list member and tested for recognition of another. When precues specified valid order information, infants recognized test mobiles from the later serial positions. The memory dissociation for serial order on delayed recognition and reactivation tests adds to the growing evidence that young infants possess two functionally distinct memory systems.     

Recognition memory for object form and object location: An event-related potential study

In this study, the processes associated with retrieving object forms and object locations from working memory were examined with the use of simultaneously recorded event-related potential (ERP) activity. Subjects memorized object forms and their spatial locations and made either object-based or location-based recognition judgments. In Experiment 1, recognition performance was higher for object locations than for object forms. Old responses evoked more positive-going ERP activity between 0.3 and 1.8 sec poststimulus than did new responses. The topographic distribution of these old/new effects in the P300 time interval was task specific, with object-based recognition judgments being associated with anteriorly focused effects and location-based judgments with posteriorly focused effects. Late old/new effects were dominant at right frontal recordings. Using an interference paradigm, it was shown in Experiment 2 that visual representations were used to rehearse both object forms and object locations in working memory. The results of Experiment 3 indicated that the observed differential topographic distributions of the old/new effects in the P300 time interval are unlikely to reflect differences between easy and difficult recognition judgments. More specific effects were obtained for a subgroup of subjects for which the processing characteristics during location-based judgments presumably were similar to those in Experiment 1. These data, together with those from Experiment 1, indicate that different brain areas are engaged in retrieving object forms and object locations from working memory. Further analyses support the view that retrieval of object forms relies on conceptual semantic representation, whereas retrieving object locations is based on structural representations of spatial information. The effects in the later time intervals may play a functional role in post-retrieval processing, such as recollecting information from the study episode or other processes operating on the products of the retrieval process, and presumably are mediated by right frontal cortical areas. The results support the view of functionally dissociable object and spatial visual working memory systems.     

Forming a stable memory representation in the first year of life: why imitation is more than child's play

Although 9-month-old infants are capable of retaining temporally ordered information over long delays, this ability is relatively fragile. It may be possible to facilitate long-term retention by allowing infants to imitate event sequences immediately after their presentation. The effects of imitation on immediate and delayed recognition and on long-term recall were investigated using event-related potentials (ERPs) and elicited imitation, respectively. Mnemonic facilitation resulting from the opportunity to imitate was apparent using both assessments. ERP assessments at immediate and delayed recognition tests suggested that infants who were allowed to imitate had stronger memory representations of familiar stimuli relative to infants who only viewed the presentation of the events. In addition, infants who were allowed to imitate evidenced higher levels of ordered recall after 1 month relative to infants who only watched the experimenter's demonstration. Therefore, imitation proved to have beneficial effects on explicit memory in 9(1/2)-month-olds, providing evidence of its effectiveness as a tool to augment mnemonic capabilities in infancy.     

Temporal properties of memory for speech in preschool children

The ability of four-year-old children to remember syllables was investigated, both to determine the temporal properties of memory for speech in subjects who do not use sophisticated retention strategies, and to determine what speech memory is available in the late preschool period. In Experiments 1 and 2, children were to remember pairs of nonsense syllables for 5, 10, 15, or 20 sec filled with a silent, manual task. In both experiments there was an apparent decay of one type of speech memory across 10-15 sec. In Experiment 2, strong interference was obtained when there was a final speech suffix item. An additional phase of this experiment verified that children cannot rehearse during the postlist period. However, in Experiments 3 and 4, suffix effects were not obtained with adult subjects in similar tasks. The results suggest that memory for speech persists for at least 10 sec even in preschool children, but that adults, unlike preschool children, engage in an additional type of speech coding that increases the resistance of memory to speech interference.     

Conceptual masking: the effects of subsequent visual events on memory for pictures

Three experiments studied the effects of voluntary and involuntary focus of attention on recognition memory for pictures. Experiments 1 and 3 tested the conceptual-masking hypothesis, which holds that a visual event will automatically disrupt processing of a previously glimpsed picture if that event is new and meaningful. Memory for 112-ms pictures was tested under conditions where the to-be-ignored 1.5-s interstimulus interval contained a blank field; a repeating picture; a new picture; a new, nonsense picture; or a new, inverted picture each time. The blank field, repeating picture, and new, nonsense picture did not disrupt memory as much as a new, meaningful picture, supporting the conceptual-masking hypothesis. Experiment 2 studied voluntary attentional control of encoding by instructing subjects to focus attention on the brief pictures, all pictures, or the long pictures in a sequence. Recognition memory for pictures of both durations showed a striking ability of observers to process pictures selectively. The possible role of these effects in visual scanning are discussed.     

The development of prospective memory in young schoolchildren: The impact of ongoing task absorption,cue salience,and cue centrality

This study presents evidence that 9- and 10-year-old children outperform 6- and 7-year-old children on a measure of event-based prospective memory and that retrieval-based factors systematically influence performance and age differences. All experiments revealed significant age effects in prospective memory even after controlling for ongoing task performance. In addition, the provision of a less absorbing ongoing task (Experiment 1), higher cue salience (Experiment 2), and cues appearing in the center of attention (Experiment 3) were each associated with better performance. Of particular developmental importance was an age by cue centrality (in or outside of the center of attention) interaction that emerged in Experiment 3. Thus, age effects were restricted to prospective memory cues appearing outside of the center of attention, suggesting that the development of prospective memory across early school years may be modulated by whether a cue requires overt monitoring beyond the immediate attentional context. Because whether a cue is in or outside of the center of attention might determine the amount of executive control needed in a prospective memory task, findings suggest that developing executive control resources may drive prospective memory development across primary school age.     

A misleading feeling of happiness: metamemory for positive emotional and neutral pictures

Emotional information is often remembered better than neutral information, but the emotional benefit for positive information is less consistently observed than the benefit for negative information. The current study examined whether positive emotional pictures are recognised better than neutral pictures, and further examined whether participants can predict how emotion affects picture recognition. In two experiments, participants studied a mixed list of positive and neutral pictures, and made immediate judgements of learning (JOLs). JOLs for positive pictures were consistently higher than for neutral pictures. However, recognition performance displayed an inconsistent pattern. In Experiment 1, neutral pictures were more discriminable than positive pictures, but Experiment 2 found no difference in recognition based on emotional content. Despite participants’ beliefs, positive emotional content does not appear to consistently benefit picture memory.     

Representation of the gender of human faces by infants: a preference for female

Six experiments based on visual preference procedures were conducted to examine gender categorization of female versus male faces by infants aged 3 to 4 months. In experiment 1, infants familiarized with male faces preferred a female face over a novel male face, but infants familiarized with female faces divided their attention between a male face and a novel female face. Experiment 2 demonstrated that these asymmetrical categorization results were likely due to a spontaneous preference for females. Experiments 3 and 4 showed that the preference for females was based on processing of the internal facial features in their upright orientation, and not the result of external hair cues or higher-contrast internal facial features. While experiments 1 through 4 were conducted with infants reared with female primary caregivers, experiment 5 provided evidence that infants reared with male primary caregivers tend to show a spontaneous preference for males. Experiment 6 showed that infants reared with female primary caregivers displayed recognition memory for individual females, but not males. These results suggest that representation of information about human faces by young infants may be influenced by the gender of the primary caregiver.     

Long-term memory of pigeons for stimulus-outcome associations involving multiple stimuli, each seen in a single brief trial

Experiment 1 explored performance of pigeons in two versions of a shortterm recognition memory procedure. In one version responding to entirely novel slides was rewarded, and responding to familiar slides (slides seen once, for 10 sec) was not rewarded; in the other version, responding to familiar slides was rewarded. Performance was initially below chance in both versions of the procedure. This result indicated that in this procedure associations were formed between the slides and the outcome (reward or non-reward) that followed their presentation. The result also suggested that the true capacity of pigeon recognition memory cannot be assessed using these procedures, as performance is inevitably disrupted by the bird's associative memory. The tendency of pigeons to form one-trial associations was exploited in Experiment 2. Phase 1 consisted of 16 two-session cycles: in Session 1 of each cycle, birds were shown 20 novel slides and were rewarded for responding to 10 of those slides; in Session 2, the same slides were shown again, with the same reinforcement contingencies. The birds showed significant overnight retention of the one-trial associations formed in Session 1 of each cycle. Phase 2 showed significant retention over periods of more than 20 days of associations involving 320 slides seen twice only. Phase 3 re-exposed for nine daily sessions one of the sets of 20 slides used in Phases 1 and 2; a high level of discrimination emerged rapidly and 4 (of 8) birds showed, by the end of training, no overlap in response rates to positive and negative slides. Comparative implications of the results are discussed.     

Effects of response-shock interval and shock intensity on free-operant avoidance responding in the pigeon

Two experiments investigated free-operant avoidance responding with pigeons using a treadle-pressing response. In Experiment I, pigeons were initially trained on a free-operant avoidance schedule with a response-shock interval of 32 sec and a shock-shock interval of 10 sec, and were subsequently exposed to 10 values of the response-shock parameter ranging from 2.5 to 150 sec. The functions relating response rate to response-shock interval were similar to the ones reported by Sidman in his 1953 studies employing rats, and were independent of the order of presentation of the response-shock values. Shock rates decreased as response-shock duration increased. In Experiment II, a free-operant avoidance schedule with a response-shock interval of 20 sec and a shock-shock interval of 5 sec was used, and shock intensities were varied over five values ranging from 2 to 32 mA. Response rates increased markedly as shock intensity increased from 2 to 8 mA, but rates changed little with further increases in shock intensity. Shock rates decreased as intensity increased from 2 to 8 mA, and showed little change as intensity increased from 8 to 32 mA.