Blaming the victim: When disease-prevention programs misfire

This study sought to determine whether or not a disease prevention program might have anegative impact on attitudes towards disease victims. Knowledge of, and attitudes towards AIDS and several other serious diseases were assessed before and after college students viewed a filmed educational program on AIDS. Results showed that, compared to a control group, participants who had seen the AIDS film reported significantlygreater fear and dislike of a hypothetical AIDS patient. The film also significantly enhanced participants’ perceptions that AIDS is a preventable disease. Results are discussed in terms of the possibility that health-education programs emphasizing preventability may inadvertently increase peoples’ tendency to blame the victim. Portions of this paper were presented at the Annual Meeting of the American Psychological Society, Dallas, Texas, June 1990.     

On-line syntactic processing under concurrent memory load

Thirty-six university students were tested in a plausibility judgment task using a self-paced listening paradigm under no-interference and two-digit load conditions. Listening times were longer at syntactically more complex portions of syntactically more complex sentences, and greater loads led to increased listening times. However, listening times at syntactically more complex positions in syntactically more complex sentences did not increase more than listening times at comparable positions in syntactically simple sentences under digit load conditions. The results indicate that a concurrent memory load does not reduce the availability of working memory resources used for on-line syntactic processing and, thus, provide evidence that the working memory system used for assigning syntactic structure is separate from that measured by standard working memory tasks.     

An auditory repetition deficit under low memory load

Previous studies of the auditory analogue of repetition blindness have led to different conclusions regarding the nature of the effect (e.g., N. Kanwisher & M. C. Potter, 1989; M. Miller & D. MacKay, 1994). In the present study, recall accuracy for repeated elements was examined with lists of 2 or 3 items presented dichotically under high temporal pressure. When this procedure was used, a repetition deficit in recall was obtained for both vowels (Experiment 1) and consonant-vowel syllables (Experiment 2). Further experiments demonstrated that this deficit decreases as the stimulus onset asynchrony between the 2 critical elements increases (Experiment 3) and showed that the effect also occurs for words and not just nonsense syllables (Experiment 4). In all 4 experiments, estimations of guessing biases showed that responses to unrepeated lists were not artificially favored over responses to repeated lists.     

Independent operation of implicit working memory under cognitive load

Implicit working memory (WM) has been known to operate non-consciously and unintentionally. The current study investigated whether implicit WM is a discrete mechanism from explicit WM in terms of cognitive resource. To induce cognitive resource competition, we used a conjunction search task (Experiment 1) and imposed spatial WM load (Experiment 2a and 2b). Each trial was composed of a set of five consecutive search displays. The location of the first four displays appeared as per pre-determined patterns, but the fifth display could follow the same pattern or not. If implicit WM can extract the moving pattern of stimuli, response times for the fifth target would be faster when it followed the pattern compared to when it did not. Our results showed implicit WM can operate when participants are searching for the conjunction target and even while maintaining spatial WM information. These results suggest that implicit WM is independent from explicit spatial WM.     

Processing of negative stimuli facilitates event-based prospective memory only under low memory load

Event-based prospective memory (PM) is related to the ability to execute a previously planned action at the appropriate situation. Previous literature showed enhanced performance when emotional stimuli are used as PM targets. However, it was entirely unexplored whether this effect is susceptible to prospective memory load (PML), related to the number of target events that are relevant for the pending PM task. Here we presented participants with angry or neutral faces for an identity judgment (ongoing task). A different number of faces, depending on low vs. high levels of PML, served as PM targets. The results showed better PM performance following negative than neutral targets, but only under low levels of PML. This indicates that the bottom-up facilitation driven by negative stimuli serving as PM targets dramatically depends on the available attention resources allocated for monitoring the incoming information.     

Contextual cueing under working memory load: Selective interference of visuospatial load with expression of learning

In a series of experiments, we investigated the dependence of contextual cueing on working memory resources. A visual search task with 50 % repeated displays was run in order to elicit the implicit learning of contextual cues. The search task was combined with a concurrent visual working memory task either during an initial learning phase or a later test phase. The visual working memory load was either spatial or nonspatial. Articulatory suppression was used to prevent verbalization. We found that nonspatial working memory load had no effect, independent of presentation in the learning or test phase. In contrast, visuospatial load diminished search facilitation in the test phase, but not during learning. We concluded that visuospatial working memory resources are needed for the expression of previously learned spatial contexts, whereas the learning of contextual cues does not depend on visuospatial working memory.     

The self and involuntary memory: Identifying with the victim increases memory accessibility for stressful events

Autobiographical memory is intimately linked to the self. However, the relation between the self and involuntary recall has been understudied. Theoretically, the more relevant an event is to the self the more accessible the memory should be. In line with this prediction, the present study tested the hypothesis that self-relevance of a stressor modulates involuntary recall. Healthy student participants viewed distressing film clips and were presented with information that defined the main characters as more or less similar to them, or without any information about the characters. In line with predictions, participants in the high self-relevance condition reported more involuntary memories of the film clips after one week compared to participants in the low self-relevance and control conditions. The findings support the theoretical relation between the self and memory accessibility and extend findings from previous research to the domain of involuntary recall.     

More conservative go/no-go response criterion under high working memory load

Previous work has shown that the efficiency of selective attention depends on the availability of cognitive control functions, including working memory. Here we examined the role of working memory in another task involving executive control, namely, a go/no-go task. Participants performed the Sustained Attention to Response Task, which requires withholding a prepotent response to an infrequent target, when at the same time placing a low or high load on an unrelated working memory task. Working memory load had the effect of reducing accuracy on the go trials, when at the same time increasing accuracy on the no-go trials. We interpret these findings to suggest that high working memory load led to a shift to a more conservative response criterion.     

Ensemble coding remains accurate under object and spatial visual working memory load

A number of studies have provided evidence that the visual system statistically summarizes large amounts of information that would exceed the limitations of attention and working memory (ensemble coding). However the necessity of working memory resources for ensemble coding has not yet been tested directly. In the current study, we used a dual task design to test the effect of object and spatial visual working memory load on size averaging accuracy. In Experiment 1, we tested participants’ accuracy in comparing the mean size of two sets under various levels of object visual working memory load. Although the accuracy of average size judgments depended on the difference in mean size between the two sets, we found no effect of working memory load. In Experiment 2, we tested the same average size judgment while participants were under spatial visual working memory load, again finding no effect of load on averaging accuracy. Overall our results reveal that ensemble coding can proceed unimpeded and highly accurately under both object and spatial visual working memory load, providing further evidence that ensemble coding reflects a basic perceptual process distinct from that of individual object processing.     

Search through complex motion displays does not break down under spatial memory load

Recent work has shown that observers are remarkably effective in searching displays of randomly moving items. In two experiments, we combined working memory tasks with visual search, to test whether search through such complex motion displays, as compared with search through static items, places an extra burden on spatial working memory. In our first experiment, we show that the dual-task interference observed for motion search is specific to spatial working memory, in line with earlier work for static search. In our second experiment, we found dual-task interference for both static and motion search, but no difference between them. The results support the suggestion that the same search process is active during search among static and search among moving items.     

Dissociation of acquisition and expression of fear conditioned responses under working memory load

Previously, it has been suggested that high working memory load (WML) prevents associative learning and, thus, conditioned responses (CRs) during differential-delay fear conditioning. However, previous studies did not distinguish between the effects of WML on the acquisition versus the expression of the CRs. In the present study, we reinvestigated this issue by manipulating WML during either acquisition or postconditioning and showed that the absence of a differential CR under high WML does not indicate the absence of the acquisition of this CR. Thus, a significant CR was observed during a task-free postconditioning phase, and there was no CR during the preceding acquisition phase with high WML. Conversely, a normally acquired CR was impaired by high WML during the postconditioning phase. The results suggest that high WML affects the expression of the CR. If they are not experimentally separated, the effects of WML on the acquisition and expression of the CR may occur together, and the findings may be erroneously interpreted as indicating a lack of associative learning.     

Decision making with the "adaptive toolbox": influence of environmental structure,intelligence, and working memory load

In 2 experiments with a total of 220 participants, the tendency to use simple heuristics such as the take the best heuristic in an adaptive manner was investigated. In a simulated stock market paradigm, the payoff structure of environments was varied, favoring either compensatory or noncompensatory decision strategies in terms of expected long-term payoff. In both experiments, the majority of participants were classified as using strategies that were adequate for the environment, supporting the notion of adaptive strategy selection. These strategy shifts were moderated by intelligence, as measured with common tests. Neither an additional learning phase (Experiment 1) nor working memory load or working memory capacity (Experiment 2) had additional effects on strategy selection.     

Framing effects under cognitive load: The role of working memory in risky decisions

Framing effects occur in a wide range of laboratory and natural decision contexts, but the underlying processes that produce framing effects are not well understood. We explored the role of working memory (WM) in framing by manipulating WM loads during risky decisions. After starting with a hypothetical stake of money, participants were then presented a lesser amount that they could keep for certain (positive frame) or lose for certain (negative frame). They made a choice between the sure amount and a gamble in which they could either keep or lose all of the original stake. On half of the trials, the choice was made while maintaining a concurrent WM load of random letters. In both load and no-load conditions, we replicated the typical finding of risk aversion with positive frames and risk seeking with negative frames. In addition, people made fewer decisions to accept the gamble under conditions of higher cognitive load. The data are congruent with a dual-process reasoning framework in which people employ a heuristic to make satisfactory decisions with minimal effort.     

工作记忆与知觉负载对工作记忆表征引导注意的调节

本研究采用4个眼动实验探讨不同知觉负载条件下的视觉搜索任务中工作记忆负载对基于工作记忆表征的注意引导效应的影响。实验1和实验3采用低知觉负载的视觉搜索任务,结果在视觉工作记忆负载为1和2时观察到了显著的注意引导效应,但当负载增加到4时注意引导效应消失了;实验2和实验4采用高知觉负载的视觉搜索任务,结果发现注意引导效应在工作记忆负载增加到2时就已经消失了。上述结果表明:工作记忆负载和知觉负载都能够通过调控认知资源的方式来影响工作记忆表征对注意的引导,当认知资源充足时,工作记忆能够同时保持多个记忆表征对视觉注意的引导。     

Role of the dorsal hippocampus in object memory load

The dorsal hippocampus is crucial for mammalian spatial memory, but its exact role in item memory is still hotly debated. Recent evidence in humans suggested that the hippocampus might be selectively involved in item short-term memory to deal with an increasing memory load. In this study, we sought to test this hypothesis. To this aim we developed a novel behavioral procedure to study object memory load in mice by progressively increasing the stimulus set size in the spontaneous object recognition task. Using this procedure, we demonstrated that naive mice have a memory span, which is the number of elements they can remember for a short-time interval, of about six objects. Then, we showed that excitotoxic selective lesions of the dorsal hippocampus did not impair novel object discrimination in the condition of low memory load. In contrast, the same lesion impaired novel object discrimination in the high memory load condition, and reduced the object memory span to four objects. These results have important heuristic and clinical implications because they open new perspective toward the understanding of the role of the hippocampus in item memory and in memory span deficits occurring in human pathologies, such as Alzheimer's disease and schizophrenia.     

The effect of memory load on cortical activity in the spatial working memory circuit

Accumulating evidence from electrophysiology and neuroimaging studies suggests that spatial working memory is subserved by a network of frontal and parietal regions. In the present study, we parametrically varied the memory set size (one to four spatial locations) of a delayed-response task and applied time-resolved fMRI to study the influence of memory load upon the spatial working memory circuit. Our behavioral results showed that performance deteriorates (lower accuracy and longer reaction time) as memory load increases. Memory load influenced cortical activity during the cue, delay, and response phases of the delayed-response task. Although delay-related activity in many regions increased with increasing memory load, it also was significantly reduced in the middle frontal gyrus and frontal eye fields and leveled off in the parietal areas when memory load increased further. Delayrelated activity in the left posterior parietal cortex was also lower during the error trials, in comparison with the correct trials. Our findings indicate that the delay period activity in the spatial working memory circuit is load sensitive and that the attenuation of this signal is the neural manifestation of performance limitation in the face of excessive memory load.     

Effects of memory load on visual search

It remains unclear how memory load affects attentional processes in visual search (VS). No effects, as well as beneficial and detrimental effects of memory load, have been found in this type of task. The main goal of the present research was to explore whether memory load has a modulating effect on VS by means of a different attentional set induced by the order of trials (mixed vs. blocked) and by the time presentation of visual display (long vs. short). In Experiment 1, we randomized the order of type of trial (5, 10 and 15 items presented in the display) while it remained constant (10 items) in Experiments 2A and 2B. In the later experiments, we also changed time presentation of visual display (3000 vs. 1300 ms, respectively). Results showed no differential effects of memory load in Experiments 1 and 2A, but they showed up in Experiment 2B: RTs were longer in the attentional task for trials under high memory load conditions. Although our hypothesis of the attentional set is supported by the results, other theoretical implications are also worth discussing in order to better understand how memory load may modulate attentional processes in VS.