Remembering "what" brings along "where" in visual working memory

Does a behavioral and anatomical division exist between spatial and object working memory? In this article, we explore this question by testing human participants in simple visual working memory tasks. We compared a condition in which there was no location change with conditions in which absolute location change and absolute plus relative location change were manipulated. The results showed that object memory was influenced by memory for relative but not for absolute location information. Furthermore, we demonstrated that relative space can be specified by a salient surrounding box or by distractor objects with no touching surfaces. Verbal memory was not influenced by any type of spatial information. Taken together, these results indicate that memory for "where" influences memory for "what." We propose that there is an asymmetry in memory according to which object memory always contains location information.     

Memory for "mean" over "nice": the influence of threat on children's face memory

Adults remember faces of threatening over non-threatening individuals. This memory advantage could be indicative of a system rooted deeply in cognitive evolution to track and remember individuals who have been harmful in the past and therefore might be harmful again. Conversely, adults may have learned through experience that it pays to be vigilant. In the present research, we investigated whether attention to threatening individuals is privileged in young children's face memory. In Experiment 1, preschool-age children showed a face recognition memory advantage for individuals who were said to have committed harmful rather than helpful actions. In a further experiment, children did not selectively remember individuals who were described as the recipients of these actions, suggesting that the memory enhancement was produced by threat rather than negative valence. Together, these findings provide evidence for an early-developing system for remembering threatening individuals, consistent with an evolutionary account of its origins.     

Uncovering the structure of a memorist's superior "basic" memory capacity

After extensive laboratory testing of the famous memorist Rajan, Thompson, Cowan, and Frieman (1993) proposed that he was innately endowed with a superior memory capacity for digits and letters and thus violated the hypothesis that exceptional memory fully reflects acquired "skilled memory." We successfully replicated the empirical phenomena that led them to their conclusions. From additional analyses and new experiments, we found support for an alternative hypothesis, namely that Rajan's superior memory for digits was mediated by learned encoding techniques that he acquired during nearly a thousand hours of practice memorizing the mathematical constant pi. Our paper describes a general experimental approach for studying the structure of exceptional memory and how Rajan's unique structure is consistent with the general theoretical framework of long-term working memory (Ericsson and Kintsch, 1995).     

Mixed- versus strong right-handedness is associated with biases towards "remember" versus "know" judgements in recognition memory: role of interhemispheric interaction

Growing evidence supports the hypothesis that episodic versus semantic memories rely primarily on interhemispheric versus intrahemispheric processing, respectively. For example, a recent study found that individuals with presumed greater interhemispheric interaction were superior in episodic recall but inferior at semantic word fragment completion; however, tests of recognition memory yielded no group differences. Interestingly, recognition memory can be based on either explicitly remembering a stimulus or implicitly knowing that a stimulus had been presented. The current experiments administered recognition memory tests to strongly versus mixed handed participants who judged for each recognised item whether their response was based on remembering (episodic memory) or knowing (semantic memory) (Tulving, 1983). Results indicate that strong versus mixed handers are biased towards basing recognition responses on judgements of knowing versus remembering, respectively. As strong versus mixed handedness is associated with greater versus lesser interhemispheric processing, the results support the original hypothesis.     

States of awareness across multiple memory tasks: obtaining a "pure" measure of conscious recollection

Four experiments were conducted to examine the nature of recollective experience across different explicit memory tests. Experiments 1 and 2 showed that the proportion of retrieved items that were given Remember responses were equivalent across free recall, category cued recall, category plus letter cued recall, and recognition memory tests unlike the result reported by Tulving [Can. Psychol. 26 (1985) 1]. Experiments 3 and 4 revealed that Remember judgments are influenced by both conceptual and perceptual variables not only in the recognition task but in other explicit memory tasks as well. Taken together, the empirical evidence from this study demonstrates that explicit memory performance is accompanied by different states of awareness not only in recognition but also across other memory tasks including free recall.     

Short-term memory and time estimation: beyond the 2-second "critical" value.

We showed previously that when time intervals around two seconds (s) are reproduced concurrently with a memory task, intervals are positively related to duration of memory processing. However, some data in research on timing as well as in memory research suggest that 2 s might be a critical duration beyond which different mechanisms or structures would support performance. This implies that the interference observed between memory processing and 2-s productions could be specific to these durations, and would not be obtained with longer durations. In this experiment, intervals ranging from 1.85 to 6.45 s were reproduced by participants, who were searching simultaneously for a memory probe. At all durations, reproductions were positively related to memory set size. These findings have implications with regards to previous research indicating a discontinuity around 2-3 s in time perception. They suggest in particular that the role of memory is similar in reproduction of durations around 2 s and of longer durations.     

"Pulling Teeth and Torture" : Musical Memory and Problem Solving

A concert pianist the second author videotaped herself learning J.S. Bach's Italian Concerto Presto, and commented on the problems she encountered as she practised. Approximately two years later the pianist wrote out the first page of the score from memory. The pianist's verbal reports indicated that in the early sessions she identified and memorised the formal structure of the piece, and in the later sessions she practised using this organisation to retrieve the memory cues that controlled her playing. The practice and recall data supported this account. Both were organised by the formal structure of the music. Practice segments were more likely to start and stop at boundaries of the formal structure than at other locations, and recall was higher for the beginnings of sections than for later portions. Like other forms of expert memory, pianistic memory appears to be based on use of a highly practised retrieval scheme which permits rapid retrieval of information from long-term memory.     

The hippocampus and memory for "what," "where," and "when"

Previous studies have indicated that nonhuman animals might have a capacity for episodic-like recall reflected in memory for "what" events that happened "where" and "when". These studies did not identify the brain structures that are critical to this capacity. Here we trained rats to remember single training episodes, each composed of a series of odors presented in different places on an open field. Additional assessments examined the individual contributions of odor and spatial cues to judgments about the order of events. The results indicated that normal rats used a combination of spatial ("where") and olfactory ("what") cues to distinguish "when" events occurred. Rats with lesions of the hippocampus failed in using combinations of spatial and olfactory cues, even as evidence from probe tests and initial sampling behavior indicated spared capacities for perception of spatial and odor cues, as well as some form of memory for those individual cues. These findings indicate that rats integrate "what," "where," and "when" information in memory for single experiences, and that the hippocampus is critical to this capacity.     

When high-powered people fail: working memory and "choking under pressure" in math

We examined the relation between pressure-induced performance decrements, or "choking under pressure," in mathematical problem solving and individual differences in working memory capacity. In cognitively based academic skills such as math, pressure is thought to harm performance by reducing the working memory capacity available for skill execution. Results demonstrated that only individuals high in working memory capacity were harmed by performance pressure, and, furthermore, these skill decrements were limited to math problems with the highest demands on working memory capacity. These findings suggest that performance pressure harms individuals most qualified to succeed by consuming the working memory capacity that they rely on for their superior performance.     

A reanalysis of the influence of a "friendly visitor" program

A paper in the American Journal of Community Psychology (AJCP), by Reinke, Holmes, and myself, reported the results of a study of the influence of a friendly visitor program on the cognitive functioning and morale of elderly individuals. The program was reported to have had a significant multivariate effect on a combination of cognitive and morale measures and significant univariate effects on memory, self-perceived health, and activity director's ratings. Being intrigued by the memory finding, I conducted a follow-up study to further investigate the effect of a visitation program on cognitive functioning. In this second study the dependent measures included all of the cognitive variables included in the original study as well as some additional memory variables. The visitation program in the follow-up study had no effect on any of these measures. As a result of my failure to obtain a significant memory effect such as that reported in Reinke et al. (1981), I reanalyzed the data from the original study. In my reanalysis, the only significant effect was a borderline univariate effect for self-perceived health; the multivariate effect did not approach significance. On the basis of my inability to produce the results reported in Reinke et al. when I reanalyzed the original data, I must conclude that the friendly visitor program did not have the effects attributed to it in the original report.     

"Blaming the victim" under memory load

When presented with negative outcomes, people often engage in counterfactual thinking, imagining various ways that events might have been different. This appears to be a spontaneous behavior, with considerable adaptive value. Nevertheless, counterfactual thinking may also engender systematic biases in various judgment tasks, such as allocating blame for a mishap, or deciding on the appropriate compensation to a victim. Thus, counterfactuals sometimes require thought suppression or discounting, potentially resource-demanding tasks. In this study, participants made mock-jury decisions about control and counterfactual versions of simple stories. The judgments of two groups of participants, differing in their respective levels of working memory capacity, were compared. In addition, all participants held memory loads during various stages of the primary task. Lower-span individuals were especially susceptible to bias associated with the counterfactual manipulation, but only when holding memory loads during judgment. The results suggest that counterfactual thoughts arise automatically, and may later require effortful, capacity-demanding suppression.     

A "snapshot" of declarative memory: Differing developmental trajectories in episodic and autobiographical memory

Episodic and autobiographical memory are clearly related, yet in both the adult and developmental literatures it is difficult to compare them because of differences in how the constructs are assessed, including differences in content, levels of control, and time since experience. To address these issues, we directly compared children's and adults' autobiographical and episodic memory using the same controlled paradigm. Participants engaged in a photo-taking activity in a museum (autobiographical encoding) and viewed others' photographs of the same museum exhibits (episodic encoding). At test, participants classified photos as ones they took, viewed, or novel. In the autobiographical condition older children and adults performed similarly; younger children's performance was lower than adults'. In contrast, in the episodic condition both groups of children performed more poorly than adults. The findings suggest the developmental primacy of autobiographical relative to episodic memory, and that traditional episodic tasks may underestimate older children's declarative memory abilities.     

Autonomic and behavioral evidence of "implicit" memory in amnesia

A profoundly amnesic patient with a left retrosplenial-fornix lesion was tested on a recognition task that evaluated both verbal and electrodermal aspects of new learning. In addition, "implicit memory" tasks (mirror reading and perceptual identification) were given. The patient displayed strong evidence of learning on all tasks although the results of this learning were not represented in explicit recall or recognition. These findings suggest that autonomic as well as behavioral evidence can index spared memory functions in amnesia. The specific meaning of electrodermal recognition and its possible place in the distinction between implicit and explicit memory is discussed.     

"Remember where you last saw that card": children's production of external symbols as a memory aid

Four experiments examined the age at which children start to use external symbols to aid their memory and how external symbol use affects both their memory performance and information allocation strategies. In Experiment 1, children in Grades 1, 3, 5, and 7 played a memory card game (Concentration) twice, once with the opportunity to make notes to aid performance and once without the opportunity. Grades I and 3 students tended to produce nonmnemonic notations, whereas Grades 5 and 7 students were more likely to produce functional, adultlike notations that aided performance in the task. In Experiments 2a and 2b, unexpected removal of children's notations led to a decrease in performance. suggesting that the spontaneously produced notations were being used as an external store rather than as an aid to encoding information. Experiment 3 examined whether all information was placed in external storage or if some types of information remained in memory. Grade 7 students who had their notations unexpectedly taken away were able to recognize the identity of the cards they had previously seen but had more difficulty remembering their locations. They appeared to place the location information mainly in external storage while retaining the identity information in memory. These results suggest that in mid-childhood, children begin to distribute information actively between internal and external memory storage.     

Explicit memory for unattended words: the importance of being in the "no"

Recognition tests in which participants indicate whether they recognize items using binary yes/no response options have typically yielded "yes" responses at equal rates for unattended old items and new items. Because most responses to unattended stimuli in such tests are "no" responses, we reasoned that a closer examination of "no" responses might reveal memory for unattended items. We modified a classic paradigm to allow participants to indicate high and low levels of confidence in their responses. As in earlier studies, the overall proportion of "yes" responses did not differ between unattended old items and new items. However, there was a crossover effect in the "no" responses: More high-confidence "no" responses were given for new items than for unattended old items, whereas more low-confidence "no" responses were given for unattended old items than for new items. These results indicate explicit memory for unattended material presented under high perceptual load. Our findings suggest that the null effects obtained in previous studies may not have stemmed from failures of perception or memory, but rather may have been due to insufficiently sensitive memory assessment.     

When nothing is "off the record": exploring the theoretical implications of the continuous recording of cognitive process in memory

This theoretical paper explores the idea of acropetal memory; arguing that representations emanating from all stages of processing an individual stimulus can be registered in memory and potentially available for recall. I describe Lansdale's (1998) HELM model of location memory as a suitable candidate theory within which to implement and test this idea. An exemplar model, HELM-2, is presented and examined against available data. This model provides a satisfactory account of the data and an elegant solution to some interesting puzzles. It also suggests that some retrieval failure can be attributed to interference from representations of a stimulus derived from early stages of processing and that this has much broader implications for modelling encoding, forgetting, and false memory.     

The "consciousness problem" is not the problem.

Although the concept of consciousness is not necessary for the behavioral scientist, it is closely related to a number of psychological concepts that are generally believed to be necessary. Consciousness may be defined as the very short-term memory of a just-completed perceptual act. It may thus be understood as a psychological consequence of psychological antecedents. The question of how brain processes result in consciousness is a misleading one and should be replaced by questions concerning the relationships between the brain and perception, memory, and the other psychological processes that precede consciousness.     

Sex differences in a human analogue of the Radial Arm Maze: the "17-Box Maze Test"

This study investigated sex differences in spatial memory using a human analogue of the Radial Arm Maze: a revision on the Nine Box Maze originally developed by called the 17-Box Maze Test herein. The task encourages allocentric spatial processing, dissociates object from spatial memory, and incorporates a within-participants design to provide measures of location and object, working and reference memory. Healthy adult males and females (26 per group) were administered the 17-Box Maze Test, as well as mental rotation and a verbal IQ test. Females made significantly fewer errors on this task than males. However, post hoc analysis revealed that the significant sex difference was specific to object, rather than location, memory measures. These were medium to large effect sizes. The findings raise the issue of task- and component-specific sexual dimorphism in cognitive mapping.     

Amygdala and "emotional" modulation of the relative use of multiple memory systems

The basolateral amygdala modulates the cognitive and habit memory processes mediated by the hippocampus and caudate nucleus, respectively. The present experiments used a plus-maze task that can be acquired using either hippocampus-dependent "place" learning or caudate-dependent "response" learning to examine whether peripheral or intra-basolateral amygdala injection of anxiogenic drugs would bias rats towards the use of a particular memory system. In Experiment 1, adult male Long-Evans rats were trained to swim from the same start point to an escape platform located in a consistent goal arm, and received pre-training peripheral injections of the alpha(2)-adrenoceptor antagonists yohimbine (2.5 or 5.0 mg/kg), RS 79948-197 (0.05, 0.1, or 0.2 mg/kg), or vehicle. On a drug-free probe trial from a novel start point administered 24h following acquisition, vehicle treated rats predominantly displayed hippocampus-dependent place learning, whereas rats previously treated with yohimbine (2.5, 5.0 mg/kg) or RS 79948-197 (0.1 mg/kg) predominantly displayed caudate-dependent response learning. In Experiment 2, rats receiving pre-training intra-basolateral amygdala infusions of RS 79948-197 (0.1 microg/0.5 microl) also predominantly displayed response learning on a drug-free probe trial. The findings indicate (1) peripheral injections of anxiogenic drugs can influence the relative use of multiple memory systems in a manner that favors caudate-dependent habit learning over hippocampus-dependent cognitive learning, and (2) intra-basolateral amygdala infusion of anxiogenic drugs is sufficient to produce this modulatory influence of emotional state on the use of multiple memory systems.