Children's perceptual organization of seriated displays: evidence against a memory reorganization hypothesis.

The memory for a seriated display and its reorganization over an eight-month interval was examined in educationally subnormal children. By including groups of children who viewed a random display and an array of disordered sticks, it was found that the reorganization into a more seriated drawing after the passage of time was not directly based on the original stimulus. Various controls including copying of the original material, and matching and recognition conditions, give evidence that the child's cognitive level affects encoding of the material as well as its later output. The observed phenomenon of 'memory' improvement may have little to do with stored images, and may instead be linked to the developmental symbolic level of the child which influences original perception as well as 'memory'. It was also found that educationally subnormal children perform like normal children of the same mental age on the seriation task.     

Perceived self-efficacy and pain control: opioid and nonopioid mechanisms

In this experiment, we tested for opioid and nonopioid mechanisms of pain control through cognitive means and the relation of opioid involvement to perceived coping efficacy. Subjects were taught cognitive methods of pain control, were administered a placebo, or received no intervention. Their pain tolerance was then measured at periodic intervals after they were administered either a saline solution or naloxone, an opiate antagonist that blocks the effects of endogenous opiates. Training in cognitive control strengthened perceived self-efficacy both to withstand and to reduce pain; placebo medication enhanced perceived efficacy to withstand pain but not reductive efficacy; and neither form of perceived self-efficacy changed without any intervention. Regardless of condition, the stronger the perceived self-efficacy to withstand pain, the longer subjects endured mounting pain stimulation. The findings provide evidence that attenuation of the impact of pain stimulation through cognitive control is mediated by both opioid and nonopioid mechanisms. Cognitive copers administered naloxone were less able to tolerate pain stimulation than were their saline counterparts. The stronger the perceived self-efficacy to reduce pain, the greater was the opioid activation. Cognitive copers were also able to achieve some increase in pain tolerance even when opioid mechanisms were blocked by naloxone, which is in keeping with a nonopioid component in cognitive pain control. We found suggestive evidence that placebo medication may also activate some opioid involvement. Because placebos do not impart pain reduction skills, it was perceived self-efficacy to endure pain that predicted degree of opioid activation.     

Tail-pinch hyperalgesia and analgesia: Test-specific opioid and nonopioid actions

Reactivity to noxious stimuli in rats is altered following acute exposure to tail-pinch. However, while our laboratory has reported that tail-pinch produces hyperalgesia as measured by the flinch-jump test and attenuates analgesic responses following morphine and cold-water swims, others have found that tail-pinch elicits an opioid-sensitive analgesia on the hot plate test and a nonopioid-sensitive analgesia on the writhing test. The first experiment of the present study examined whether tail-pinch altered responses on two somatic pain tests and showed that tail-pinch significantly decreased both jump thresholds and tail-flick latencies. In assessing whether tail-pinch hyperalgesia on the jump test was mediated by endogenous opioids, the second experiment indicated that low (0.1 and 0.5 mg/kg) doses of naloxone eliminated tail-pinch hyperalgesia by selectively lowering control thresholds and a high (10 mg/kg) dose of naloxone eliminated tail-pinch hyperalgesia by selectively increasing thresholds following tail-pinch. Further, the third experiment showed that morphine-tolerant rats (10 mg/kg morphine daily over 14 days) did not exhibit tail-pinch hyperalgesia on the 15th day, an effect attributable to a selective lowering of control thresholds. The fourth experiment was a direct replication of the observation that tail-pinch produces analgesia on the writhing test which is not antagonized by naloxone. These results demonstrate that the pain test employed and the amount of prior tail-pinch experience are critical variables in determining the direction of tail-pinch effects upon pain perception in rats.     

Parallel processing across neural systems: implications for a multiple memory system hypothesis

A common conceptualization of the organization of memory systems in brain is that different types of memory are mediated by distinct neural systems. Strong support for this view comes from studies that show double (or triple) dissociations between spatial, response, and emotional memories following selective lesions of hippocampus, striatum, and the amygdala. Here, we examine the extent to which hippocampal and striatal neural activity patterns support the multiple memory systems view. A comparison is made between hippocampal and striatal neural correlates with behavior during asymptotic performance of spatial and response maze tasks. Location- (or place), movement, and reward-specific firing patterns were found in both structures regardless of the task demands. Many, but not all, place fields of hippocampal and striatal neurons were similarly affected by changes in the visual and reward context regardless of the cognitive demands. Also, many, but not all, hippocampal and striatal movement-sensitive neurons showed significant changes in their behavioral correlates after a change in visual context, irrespective of cognitive strategy. Similar partial reorganization was observed following manipulations of the reward condition for cells recorded from both structures, again regardless of task. Assuming that representations that persist across context changes reflect learned information, we make the following conclusions. First, the consistent pattern of partial reorganization supports a view that the analysis of spatial, response, and reinforcement information is accomplished via an error-driven, or match-mismatch, algorithm across neural systems. Second, task-relevant processing occurs continuously within hippocampus and striatum regardless of the cognitive demands of the task. Third, given the high degree of parallel processing across allegedly different memory systems, we propose that different neural systems may effectively compete for control of a behavioral expression system. The strength of the influence of any one neural system on behavioral output is likely modulated by factors such as motivation, experience, or hormone status.     

Concurrent performance of two memory tasks: evidence for domain-specific working memory systems

Previous studies of dual-task coordination in working memory have shown a lack of dual-task interference when a verbal memory task is combined with concurrent perceptuomotor tracking. Two experiments are reported in which participants were required to perform pairwise combinations of (1) a verbal memory task, a visual memory task, and perceptuomotor tracking (Experiment 1), and (2) pairwise combinations of the two memory tasks and articulatory suppression (Experiment 2). Tracking resulted in no disruption of the verbal memory preload over and above the impact of a delay in recall and showed only minimal disruption of the retention of the visual memory load. Performing an ongoing verbal memory task had virtually no impact on retention of a visual memory preload or vice versa, indicating that performing two demanding memory tasks results in little mutual interference. Experiment 2 also showed minimal disruption when the two memory tasks were combined, although verbal memory (but not visual memory) was clearly disrupted by articulatory suppression interpolated between presentation and recall. These data suggest that a multiple-component working memory model provides a better account for performance in concurrent immediate memory tasks than do theories that assume a single processing and storage system or a limited-capacity attentional system coupled with activated memory traces.     

Misleading postevent information and memory for events: arguments and evidence against memory impairment hypotheses

The claim that a person's memory for an event may be altered by information encountered after the event has been influential in shaping current conceptions of memory. The basis for the claim is a series of studies showing that subjects who are given false or misleading information about a previously witnessed event perform more poorly on tests of memory for the event than subjects who are not misled. In this article we argue that the available evidence does not imply that misleading postevent information impairs memory for the original event, because the procedure used in previous studies is inappropriate for assessing effects of misleading information on memory. We then introduce a more appropriate procedure and report six experiments using this procedure. We conclude from the results that misleading postevent information has no effect on memory for the original event. We then review several recent studies that seem to contradict this conclusion, showing that the studies do not pose problems for our position. Finally, we discuss the implications of our conclusions for broader issues concerning memory.     

Multiple memory systems: evidence from stroke

In this report, we describe the "fractionation of memory systems" in a 62-yr.-old woman following a left anterior stroke. Despite the presence of a significant, persistent declarative memory (verbal learning) deficit, this patient exhibited relatively intact procedural learning. The latter was manifested over a 4-day period by improved performance on a maze task executed under "mirror-tracing" conditions. By the final set of trials, the patient's performance approximated that of a normal control subject with respect to speed, although not errors. The selective preservation of particular learning abilities in brain-damaged patients has implications for rehabilitative interventions.     

Evaluating the neuropsychological dissociation evidence for multiple memory systems

This article presents a critical evaluation of the logic and nature of the neuropsychological dissociation evidence that has provided one of the essential lines of support for claims of multiple memory systems--specifically, suggesting that amnesia selectively compromises, and an intact hippocampal system selectively supports, a particular form of memory. An analysis of the existing neuropsychological dissociation evidence is offered in which different classes of evidence--different dissociation approaches-are identified and characterized. The logic of these neuropsychological dissociation approaches is evaluated critically in terms of their ability to distinguish among alternative theoretical views. We conclude that although they support a multiple memory systems account, the findings from these types of neuropsychological dissociation, taken individually and without support from other converging lines of cognitive neuroscience evidence, cannot definitively rule out alternative formulations. A more powerful neuropsychological dissociation approach is then outlined, involving dissociation within condition, that, by more effectively limiting the critical domains of difference between the dissociated performances, can successfully rule out alternative accounts. Its application in Ryan, Althoff, Whitlow, and Cohen (2000) is described, providing strong support for the power of the dissociation within condition approach.     

The facilitation of aggression by aggression: evidence against the catharsis hypothesis.

Nnety male subjects were either attacked or treated in a more neutral manner by a male confederate. On a subsequent maze-learning task, one third of the subjects shocked the confederate, one third observed as the experimenter shocked the confederate, and one third waited for a period of time during which the confederate was not shocked. Finally, all subjects shocked the confederate as part of a code-learning task. Subjects who had been attacked and had shocked the confederate during the maze task delivered shocks of greater intensity on the code task did subjects in the other two conditions, and the former subjects also experienced a greater reduction in diastolic blood pressure than did the latter. The results contradict the hypothesis of aggression catharsis and are discussed in terms of feelings of restraint against aggressing that a subject experiences after committing an aggressive act.     

Critical evidence: a test of the critical-period hypothesis for second-language acquisition

The critical-period hypothesis for second-language acquisition was tested on data from the 1990 U.S. Census using responses from 2.3 million immigrants with Spanish or Chinese language backgrounds. The analyses tested a key prediction of the hypothesis, namely, that the line regressing second-language attainment on age of immigration would be markedly different on either side of the critical-age point. Predictions tested were that there would be a difference in slope, a difference in the mean while controlling for slope, or both. The results showed large linear effects for level of education and for age of immigration, but a negligible amount of additional variance was accounted for when the parameters for difference in slope and difference in means were estimated. Thus, the pattern of decline in second-language acquisition failed to produce the discontinuity that is an essential hallmark of a critical period.     

Behavioral evidence for two distinct memory systems in rats

Animal Cognition - Serial reaction time tasks, in which subjects have to match a target to a cue, are used to explore whether non-human animals have multiple memory systems. Predictable...     

Emotional arousal and memory: a test of the poststimulus processing hypothesis

Emotional arousal is believed to enhance memory for details central to an episode but impair memory for peripheral details. However, new research suggests that arousal induced thematically (i.e., through involvement with an unfolding event) produces only memory enhancements. This article examines whether consciously controlled elaborative processing in the aftermath of an arousing experience is responsible. A dual task manipulation was used to prevent participants from ruminating over a video that depicted an abduction and attack. Several indices of recall showed greater memory for emotional event details than for details from a neutral control video, which remained the case when the opportunity for post-stimulus elaboration was prevented. Thus, superior retention of the content of emotional experiences may arise from the way in which arousal is induced rather than through immediate postevent cognitions.     

Color categories: evidence for the cultural relativity hypothesis

The question of whether language affects our categorization of perceptual continua is of particular interest for the domain of color where constraints on categorization have been proposed both within the visual system and in the visual environment. Recent research (Roberson, Davies, & Davidoff, 2000; Roberson et al., in press) found substantial evidence of cognitive color differences between different language communities, but concerns remained as to how representative might be a tiny, extremely remote community. The present study replicates and extends previous findings using additional paradigms among a larger community in a different visual environment. Adult semi-nomadic tribesmen in Southern Africa carried out similarity judgments, short-term memory and long-term learning tasks. They showed different cognitive organization of color to both English and another language with the five color terms. Moreover, Categorical Perception effects were found to differ even between languages with broadly similar color categories. The results provide further evidence of the tight relationship between language and cognition.     

Recognition memory for novel stimuli: the structural regularity hypothesis

Early studies of human memory suggest that adherence to a known structural regularity (e.g., orthographic regularity) benefits memory for an otherwise novel stimulus (e.g., G. A. Miller, 1958). However, a more recent study suggests that structural regularity can lead to an increase in false-positive responses on recognition memory tests (B. W. A. Whittlesea & L. D. Williams, 1998). In the present study the authors attempted to identify the circumstances under which structural regularity benefits old-new discrimination and those under which it leads to an increase in false-positive responses. The highly generalizable tendency shown here is for structural regularity to benefit old-new discrimination. The increase in false-positive responses for structurally regular novel items may be limited to situations in which regularity is confounded with similarity to studied items.     

Stimulus modality and working memory performance in Greek children with reading disabilities: Additional evidence for the pictorial superiority hypothesis

This study investigated the effects of stimulus presentation modality on working memory performance in children with reading disabilities (RD) and in typically developing children (TDC), all native speakers of Greek. It was hypothesized that the visual presentation of common objects would result in improved learning and recall performance as compared to the auditory presentation of stimuli. Twenty children, ages 10–12, diagnosed with RD were matched to 20 TDC age peers. The experimental tasks implemented a multitrial verbal learning paradigm incorporating three modalities: auditory, visual, and auditory plus visual. Significant group differences were noted on language, verbal and nonverbal memory, and measures of executive abilities. A mixed-model MANOVA indicated that children with RD had a slower learning curve and recalled fewer words than TDC across experimental modalities. Both groups of participants benefited from the visual presentation of objects; however, children with RD showed the greatest gains during this condition. In conclusion, working memory for common verbal items is impaired in children with RD; however, performance can be facilitated, and learning efficiency maximized, when information is presented visually. The results provide further evidence for the pictorial superiority hypothesis and the theory that pictorial presentation of verbal stimuli is adequate for dual coding.     

Effects of mood on memory: Experimental tests of a mood-state-dependent retrieval hypothesis and of a mood-congruity hypothesis

Summary In the present experiment a mood-state-dependent retrieval hypothesis and a mood-congruity hypothesis are tested. The first hypothesis states that recall is higher when mood at test matches mood at input than when it does not match. The second hypothesis states that people learn more about events that match their mood state. Both hypotheses are consistent with the network model of mood and memory proposed by Bower and his colleagues. Our study was conducted to test the cited hypotheses with normal subjects (instead of highly hypnotizable subjects as in the studies by Bower et al.) and with a comparatively mild mood-induction technique. Another aim was to test different predictions from the two hypotheses.We experimentally varied mood (happy vs. sad), both at learning and at recall by using the Velten technique. Additionally, the emotional content (pleasant vs. neutral vs. unpleasant) of the text to be learned was manipulated.The empirical evidence with some restrictions favored the mood-state-dependent hypothesis and disagreed with the mood-congruity hypothesis. Possible explanations for the failure to obtain a mood-congruity effect are offered, and the results are discussed with reference to a network model of mood and memory.     

False memory and the discrepancy-attribution hypothesis: the prototype-familiarity illusion

According to the discrepancy-attribution hypothesis (B. W. A. Whittlesea & L. D. Williams, 1998), people experience a feeling of familiarity when they perceive their processing to be surprising, but for an indefinite reason. This hypothesis has been successful in explaining several illusions of familiarity. Here, it is applied to the prototype-familiarity effect, an illusion of remembering that occurs when people are shown prototype words after studying lists of associates. The experiments showed that studying associates enhances semantic, but not perceptual, processing of prototypes. They also showed that claims of recognizing prototypes can be modified by presenting them in predictive or incongruous contexts at test. The evidence suggests that the effect results from an evaluation process that monitors the coherence of processing.     

Semantic memory for metaphor: The conceptual base hypothesis

The idea that people can encode and use an extremely abstract and general form of a complex linguistic (proverb) input-a conceptual base-was examined in two experiments. In Experiment I, each proverb was accompanied by either a conceptually related (good, mediocre, or poor) or an unrelated interpretation. The related interpretations were more effective recall prompts than were the unrelated interpretations, but only for high-imagery proverbs. In Experiment II, subjects wrote interpretations of the proverbs and then received either the proverb subject-noun or a brief story as a prompt. As was the case for the interpretations in Experiment I, the stories did not share any major vocabulary or propositional structure with their proverb source. Nonetheless, the stories were as effective as the nouns. Also, quality of proverb interpretation and of recall performance were positively related, with the correlations involving low-imagery proverbs, and stories, tending to be higher. Both experiments provided support for the conceptual-base notion, and underlined the importance of interpretive context, but more definitive evidence is needed.     

Contrast requirements for picture recognition: converging evidence for a spatial frequency hypothesis

Based upon perceptual studies, the present hypothesis was that different ranges of spatial-frequency information constitute different sources of information for recognition memory. In Experiment 1, 40 subjects were tested with sets of focused and unfocused pictures as inspection and test stimuli. In addition to reporting whether each test picture was believed to be a member of the inspection set or a novel picture, each subject was allowed to adjust the contrast of the stimulus until such a judgment could be made. In Experiment 2, subjects made similar judgments when inspection or test stimuli were flickered (perceptually enhancing low spatial frequencies) or unflickered. Results from both studies were consistent with the experimental hypothesis. Other studies were reviewed, which, together with the present data, lend converging evidence to the spatial-frequency hypothesis.