Counteracting effect of threat on reward enhancements during working memory

Cognitive performance has been shown to be enhanced when performance-based rewards are at stake. On the other hand, task-irrelevant threat processing has been shown to have detrimental effects during several cognitive tasks. Crucially, the impact of reward and threat on cognition has been studied largely independently of one another. Hence, our understanding of how reward and threat simultaneously contribute to performance is incomplete. To fill in this gap, the present study investigated how reward and threat interact with one another during a cognitive task. We found that threat of shock counteracted the beneficial effect of reward during a working memory task. Furthermore, individual differences in self-reported reward-sensitivity and anxiety were linked to the extent to which reward and threat interacted during behaviour. Together, the current findings contribute to a limited but growing literature unravelling how positive and negative information processing jointly influence cognition.     

Recognition without awareness: An elusive phenomenon

Two recent studies described conditions under which recognition memory performance appeared to be driven by nondeclarative memory. Specifically, participants successfully discriminated old images from highly similar new images even when no conscious memory for the images could be retrieved. Paradoxically, recognition performance was better when images were studied with divided attention than when images were studied with full attention. Furthermore, recognition performance was better when decisions were rated as guesses than when decisions were associated with low or high confidence. In three experiments, we adopted the paradigm used in the earlier studies in an attempt to repeat this intriguing work. Our attempts were unsuccessful. In all experiments, recognition was better when images were studied with full attention than when images were studied with divided attention. Recognition was also better when participants indicated high or low confidence in their decision than when they indicated that their decision was a guess. Thus, our results conformed to what typically has been reported in studies of recognition memory, and we were unable to demonstrate recognition without awareness. We encourage others to explore this paradigm, and to try to identify conditions under which the phenomenon might be demonstrated.Declarative memory refers to the capacity to recollect facts and events, and can be contrasted with a collection of nondeclarative memory abilities, including skills, habits, and the phenomenon of priming, which are expressed through performance rather than recollection (Squire et al. 2004). Declarative memory depends on the integrity of medial temporal lobe structures, while the various forms of nondeclarative memory depend on other brain systems (Schacter and Tulving 1994; Eichenbaum and Cohen 2001; Squire 2004). The best-studied example of declarative memory is recognition memory—the ability to judge items as having been encountered previously. Successful recognition is ordinarily accompanied by a conscious experience of familiarity, and sometimes by conscious memory of the prior encounter itself (Gabrieli 1998).One interesting idea that has been explored in some detail is that recognition memory decisions based on familiarity might also benefit from priming. Priming refers to an improved ability to produce or identify an item on the basis of a recent encounter with the same item or a related item, but without a requirement that there be conscious knowledge of the prior encounter (Tulving and Schacter 1990; Schacter and Buckner 1998). In early studies, it was suggested that previously encountered items might be processed more fluently (e.g., with greater speed and with more ease), and that improved fluency might influence familiarity judgments. Specifically, items perceived with greater fluency might tend to be identified as familiar (Mandler 1980; Jacoby and Dallas 1981; Johnston et al. 1991).This idea encountered difficulty when it was found that severely amnesic patients can perform at chance on conventional recognition tests despite exhibiting intact perceptual priming (Hamann and Squire 1997; Stark and Squire 2000). If fluency facilitates recognition, severely amnesic patients who exhibit intact perceptual priming should perform better than chance on recognition memory tests. Thus, it has seemed that the perceptual fluency that mediates priming does not also support familiarity-based recognition judgments, at least not to a measurable degree. Indeed, the contribution of perceptual fluency appears to be too weak to drive recognition performance noticeably above chance (Conroy et al. 2005).Nonetheless, it remains possible that conditions might be found under which recognition decisions can benefit from perceptual fluency, and in this way be linked to nondeclarative memory. Two recent studies (Voss et al. 2008; Voss and Paller 2009) described conditions under which recognition memory appeared to be significantly driven by nondeclarative memory. Participants studied difficult-to-verbalize images (Fig. 1) with either full attention or divided attention. At test, each image was paired with a highly similar new image, and participants made a speeded forced-choice decision. The striking finding was that, under these conditions, accurate recognition memory performance occurred, but without the awareness that ordinarily accompanies successful recognition. Specifically (and paradoxically), performance was better under divided-attention conditions (which ordinarily degrade memory performance) than under full-attention conditions (Fig. 2A). Furthermore, in one study (Voss et al. 2008), recognition was better when participants reported that they were guessing than when they reported conscious memory of the images (combined high- and low-confidence trials) (Fig. 2B). Notably, this phenomenon occurred only when the test was given in a forced-choice format, and not in a yes/no format. The other study (Voss and Paller 2009) reported a similar advantage for guessing in the divided-attention condition. These two reports appear to demonstrate recognition without awareness and a significant contribution of nondeclarative memory to recognition performance.Open in a separate windowFigure 1.In the full-attention condition, participants studied 14 images for 2 sec each (1.5-sec intertrial interval). Alternatively, in the divided-attention condition, participants studied the images while deciding whether a digit heard during the previous trial was odd or even. The forced-choice recognition test probed memory for the middle 10 images presented in the study sequence. Each studied item was presented together with a highly similar new item, and participants selected the old item by responding “left” or “right.” After each response, participants indicated how confident they were in their recognition decision (G, guess; L, low confidence; H, high confidence).Open in a separate windowFigure 2.Data from Experiment 2 in Voss et al. (2008), estimated from their Figure 2. (A) When recognition was probed using a forced-choice format, performance was more accurate in the divided-attention condition than in the full-attention condition. (B) In both conditions, forced-choice recognition was more accurate in trials where participants indicated that their recognition decision was a guess (G) than in trials where participants indicated low or high confidence (L/H) in their decision. Asterisks indicate performance significantly above chance (P < 0.05). Error bars indicate SEM.These findings challenge the conventional view that recognition memory is more effective when full attention is given to a task than when attention is divided (Anderson 1980), that recognition memory is associated with a conscious experience of familiarity (Gabrieli 1998), and that recognition memory accuracy is positively correlated with ratings of confidence (Reed et al. 1997; Mickes et al. 2007). Because the reported findings are exceptional, we explored the phenomenon further in three separate experiments in an attempt to replicate it and identify its boundary conditions. We adopted the same paradigm as was used in the original study (Voss et al. 2008).     

奖赏与自我加工对记忆的影响

【摘 要】目的:从外显和内隐层面探讨奖赏与自我加工对记忆的影响。方法：以大学生为被试,以人格形容词为实验材料,采用R/K范式,测量被试对识记词语的记忆效果。结果：（1）外显记忆层面,奖赏与自我加工均促进了记忆效果;（2）在内隐记忆层面,自我存在记忆的加工优势,但是没有发现奖赏加工对记忆的影响。结论：自我相关刺激促进了内隐和外显记忆的加工,奖赏刺激只对外显记忆有影响,实验结果支持独立平行模型,即在不同记忆层面,奖赏加工与自我参照加工存在不同加工机制。     

Genuine memory bias versus response bias in anxiety

Low and high trait anxiety undergraduates were presented with physical‐threat, ego‐threat, positive, and neutral words. Following an orienting task promoting lexical—but not semantic—processing, unexpected free recall or recognition tests were presented. High anxiety participants showed increased correct recall of both types of threat‐related words, but also increased incorrect recall (intrusions) and incorrect recognition (false alarms) of these words. Furthermore, participants high in anxiety had reduced sensitivity (d′) for ego‐threat words, and reduced cautiousness (β) for physical‐threat words. This tendency to report threat‐related information regardless of prior presentation suggests that there is a response bias rather than a memory bias in anxiety. In addition, this bias is likely to be mediated by depression insofar as physical‐threat information is concerned, although the bias can be attributed to trait anxiety insofar as ego‐threat information is concerned.     

The effects of enactment and intention accessibility on prospective memory performance

The intention-superiority effect denotes faster response latencies to stimuli linked with a prospective memory task compared to stimuli linked with no prospective task or with a cancelled task. It is generally assumed that the increased accessibility of intention-related materials contributes to successful execution of prospective memory tasks at an appropriate opportunity. In two experiments we investigated the relationship between the intention-superiority effect and actual prospective memory performance under relatively realistic conditions. We also manipulated enactment versus observation encoding to further investigate the similarity in representations of enacted and to-be-enacted tasks. Additionally, Experiment 1 included a control condition to investigate the development of the intention-superiority effect over time. Participants were asked to perform prospective tasks at the end of the experiment to prepare the room for the next participant. They studied these preparatory tasks at the beginning of the experiment either by enacting them themselves or by observing the experimenter perform them. In Experiment 2, participants in a control condition did not intend to perform prospective tasks. We observed a smaller intention-superiority effect after enactment encoding than after observation encoding, but only if response latencies were assessed immediately before the prospective memory task. In addition, Experiment 2 suggested that the size of the intention-superiority effect is related to successful prospective memory performance, thus providing evidence for a functional relationship between accessibility and memory.     

Social anxiety and attentional biases: A top-down contribution?

Selective attention toward threatening facial expressions has been found to precipitate and maintain symptoms of social anxiety. However, the automaticity of this bias is under debate. In the present study, we aimed to test whether top-down (controlled) engagement and disengagement of attention toward threatening faces is associated with social anxiety. This was examined by testing the impact of a secondary working memory (WM) load on attentional biases. In a variation of the dot-probe task, participants’ attention was initially cued to the left or right of fixation before an upright face paired with an inverted face was presented (displaying a disgust or neutral expression), and participants responded to a subsequently presented probe. The task was performed under no-load, low-load (one-digit memory task), and high-load (six-digit memory task) conditions. Social anxiety was not found to be associated with delayed disengagement from threat. However, surprisingly, high social anxiety was associated with an engagement bias away from threat, whereas low social anxiety was associated with a bias toward threat. These results were unaffected by the WM load manipulation. This indicates that engagement with threatening facial expressions has minimal contributions from top-down mechanisms, since it is likely that orienting to facial expressions occurs relatively automatically.     

Social importance enhances prospective memory: evidence from an event-based task

Prospective memory performance can be enhanced by task importance, for example by promising a reward. Typically, this comes at costs in the ongoing task. However, previous research has suggested that social importance (e.g., providing a social motive) can enhance prospective memory performance without additional monitoring costs in activity-based and time-based tasks. The aim of the present study was to investigate the influence of social importance in an event-based task. We compared four conditions: social importance, promising a reward, both social importance and promising a reward, and standard prospective memory instructions (control condition). The results showed enhanced prospective memory performance for all importance conditions compared to the control condition. Although ongoing task performance was slowed in all conditions with a prospective memory task when compared to a baseline condition with no prospective memory task, additional costs occurred only when both the social importance and reward were present simultaneously. Alone, neither social importance nor promising a reward produced an additional slowing when compared to the cost in the standard (control) condition. Thus, social importance and reward can enhance event-based prospective memory at no additional cost.     

Through the looking glass: Sex differences in memory for self-facial poses

This study investigated recognition memory of photographs of the subject's own face. Male and female subjects were photographed as they projected sociable faces, trustworthy faces, and intelligent faces. After deciding which face of 10 best represented each characteristic, and judging which photograph best represented their “real self,” a recognition memory test of poses was given. Half of each sex were tested under intentional learning conditions and the remainder were tested under incidental learning conditions. Females demonstrated superior recognition memory of their own facial projections and, in particular, recalled photographs of their “real self” and “most sociable” self most easily. No differences were found between the two learning conditions. Subjects' recognition performance was not related to their confidence of judgments. The results were discussed in terms of sex differences and the role of self in memory.     

Memory for faces: A social learning analysis

Recognition memory for unfamiliar faces was related to locus of control and anxiety. On the basis of Rotter's social learning theory, it was predicted that memory for faces would be associated with more internal locus of control in an unstructured memory task but not when encoding was controlled. In Experiment 1, where no specific instructions about encoding were presented, the predicted relationship was found for males. In addition, better recognition was associated with low anxiety for females. In Experiment 2, where encoding was controlled by having subjects judge the faces, no significant correlations between the personality measures and memory were found. The results are interpreted as supporting predictions made on the basis of social learning theory.     

Cognitive differentiation as a function of information type and its relation to career choice

Although providing occupational information is a common vocational counseling practice, recent research has raised questions about the utility of such information. Cognitive differentiation (the ability to differentiate among job titles on 12 constructs) has been shown to be positively related to an “appropriate” career choice. Differentiation, however, appears to decrease as a function of traditional types of occupational information (e.g., Occupational Outlook Handbook, U.S. Department of Labor, Washington, D.C., 1980). The present study investigated the hypothesis that information related to Holland personality characteristics of persons in various occupations would increase subjects' ability to differentiate among those job titles. One hundred fifty undeclared-major freshman undergraduate students were randomly assigned to one of three condition groups: objective information, personality information, no information. All subjects were administered the Career Decision Scale and Cognitive Differentiation Grid. Results indicated that subjects receiving personality information exhibited a significantly greater degree of differentiation among careers than subjects receiving objective information. These results confirm the major hypothesis of the study and suggest that the provision of personality information may be more useful in promoting career choice than the types of information traditionally provided.     

Spatial memory in rats under restricted viewing conditions

In a procedure devised by J. A. Walker and D. S. Olton (Learning and Motivation, 1979, 10, 73–84), rats were placed on two arms of a four-arm radial maze and then were placed in the center of the maze to test how accurately they could choose the alleys on which they had not been placed. In three experiments, the conditions under which animals viewed the environment from the arms were varied. In Experiment 1, both the extent of spatial view and the exposure time were varied factorially in a within-subjects design; animals viewed the environment down a tunnel or had a 180° or 360° view, and subjects were allowed to view the environment for either 2 or 20 sec. In Experiment 2, a between-subjects design was used, in which different groups of subjects were tested repeatedly under either the tunnel, 180°, or 360° conditions. Both experiments showed that animals could avoid the arms previously visited at no better than a chance level of accuracy in the tunnel viewing condition but could perform with progressively better accuracy at the 180 and 360° viewing conditions. Animals also were more accurate in Experiment 1 after viewing for 20 sec than after viewing for 2 sec. Experiment 3 involved a procedure in which restricted viewing conditions were used both during arm placements and testing. Animals tested under tunnel viewing eventually achieved above-chance performance with this procedure, but did not exceed chance as rapidly as groups tested with 45 and 90° views of the environment. These results suggest that animals can learn about their position in a spatial environment through observation and that an animal's ability to locate its position is directly related to the extent of the surrounding environment it can see and the length of time it is allowed to look. The implications of these findings for list and map hypotheses of spatial memory representation are discussed.     

Object recognition memory and the rodent hippocampus

In rodents, the novel object recognition task (NOR) has become a benchmark task for assessing recognition memory. Yet, despite its widespread use, a consensus has not developed about which brain structures are important for task performance. We assessed both the anterograde and retrograde effects of hippocampal lesions on performance in the NOR task. Rats received 12 5-min exposures to two identical objects and then received either bilateral lesions of the hippocampus or sham surgery 1 d, 4 wk, or 8 wk after the final exposure. On a retention test 2 wk after surgery, the 1-d and 4-wk hippocampal lesion groups exhibited impaired object recognition memory. In contrast, the 8-wk hippocampal lesion group performed similarly to controls, and both groups exhibited a preference for the novel object. These same rats were then given four postoperative tests using unique object pairs and a 3-h delay between the exposure phase and the test phase. Hippocampal lesions produced moderate and reliable memory impairment. The results suggest that the hippocampus is important for object recognition memory.Recognition memory refers to the ability to judge a previously encountered item as familiar and depends on the integrity of the medial temporal lobe (Squire et al. 2007). Tasks that assess recognition memory (and object recognition memory in particular) have become increasingly useful tools for basic and preclinical research investigating the neural basis of memory (Winters et al. 2008). Perhaps the best known of these tasks is the novel object recognition task (NOR) (also known as the visual paired-comparison task in studies with humans and monkeys).Studies of the NOR task in humans with hippocampal damage (McKee and Squire 1993; Pascalis et al. 2004) and in monkeys with selective damage to the hippocampus (Pascalis and Bachevalier 1999; Zola et al. 2000; Nemanic et al. 2004) have resulted in clear and consistent findings. Damage limited to the hippocampus is sufficient to produce impaired recognition memory (Squire et al. 2007, Box 1). In rats and mice, the NOR task has become particularly popular and is currently a benchmark task for assessing recognition memory. Yet despite its widespread use in rodents, the findings are rather mixed. For example, in the rat, although there is agreement that the perirhinal cortex is critically important for normal NOR performance, there is less agreement about the hippocampus (for review, see Winters et al. 2008). Although some of the discrepancies between studies may be attributed to differences in lesion size and in the length of the retention delay (Broadbent et al. 2004), these factors cannot account for all the findings (Squire et al. 2007).Whereas most studies have investigated the effects of hippocampal lesions on postoperative NOR performance, there is also interest in the effects of hippocampal lesions on memory for previously encountered objects. For a number of tasks, hippocampal lesions produce temporally graded retrograde amnesia, such that memory acquired recently is impaired and memory acquired more remotely is spared (for review, see Squire et al. 2004; Frankland and Bontempi 2005). In the case of the single study of retrograde memory that has involved the NOR task, recognition memory was impaired when a 5-wk interval intervened between training and hippocampal surgery (Gaskin et al. 2003). It remains possible that memory might be spared if a longer delay was imposed between training and surgery.The aim of the present study was to assess both the anterograde and retrograde effects of hippocampal lesions on recognition memory using the NOR task. To thoroughly assess the effects of hippocampal lesions we used (1) large groups of animals, (2) multiple tests of NOR memory, (3) a scoring method that allowed object preference to be determined on a second-by-second basis during the recognition tests, and (4) a novel training protocol that permitted the evaluation of recognition memory even after a retention interval as long as 10 wk.     

Predicting Stereotype Threat,Test Anxiety,and Cognitive Ability Test Performance: An Examination of Three Models

As the classroom and workplace, among other contexts, become more diverse in their population characteristics, the need to be aware of specific factors impacting testing outcome issues correspondingly increases. The focus in this study, among other purposes, was to identify possible interactions between examinee's individual-difference characteristics (e.g., personality) and characteristics of the testing environment on test anxiety reactions and cognitive ability test performance. This study assessed reactions and performance in 4 different testing conditions through a path-analytic testing of 3 well-established theoretical models of stress appraisal and coping (i.e., cognitive appraisal, personality trait, and transactional). The transactional model, incorporating both personality and testing condition factors, was best in predicting the variance associated with the cognitive ability test scores, the 3 test anxiety score indexes (i.e., social derogation, physical tenseness, and cognitive obstruction), and the stereotype threat scores. With personality traits, for example, agreeableness was a relatively strong and consistent predictor of all study measures. Regarding testing condition factors, only the manipulation of stereotype threat level (low or high) produced some significant accounting of variance. Higher perceived stereotype threat levels were generally associated with heightened stereotype threat belief perceptions, lower cognitive ability test scores, and, interestingly, reduced feelings of cognitive obstruction in test anxiety.     

The effect of monetary incentives on backward digit span performance

In order to determine if monetary-incentive effects, particularly the detrimental effects of such incentives on human learning and performance, might be mediated by anxiety, 52 college students were administered six backward digit trials in a preexperimental, baseline phase and six trials in an experimental, test phase. Of the 52 subjects, 26 were paid 50 cents following each correct recitation of a backward digit series during the test phase. The remaining 26 were unpaid control subjects. Results showed that the rationale for the study was correct because state anxiety was indeed negatively related to backward digit span performance as previous research had shown, but the offer of reward did not elevate state anxiety scores and, more importantly, the offer of reward led to a significant improvement in backward digit span performance—an effect which is the opposite of what would be predicted by the anxiety hypothesis. The reward effects of theoretical interest in planning this research were those facilitating and detrimental effects that are produced by offering elementary, high school, or college students small amounts of money (typically from $1 to $3) as a superfluous inducement to participate in a study of human learning or performance. The results of this study discredit any explanation of such reward effects which attributes the effects to reward-induced anxiety.     

Extraversion and the orienting reaction habituation rate to visual stimuli

Eysenck's (1967) proposal that introversion is characterized by increased levels of activity in the cortico-reticular loop was treated in a series of experiments which compared high, middle, and low extraversion groups on the basis of OR habituation rate to visual stimulation. Generally, introverts were observed to have longer OR habituation rates to chromatic and word stimulation than extraverts as evidenced by cardiac, electrodermal, and vasomotor indices of habituation rate, a result which endorses Eysenck's hypothesis. Results are also discussed from the standpoint of individual differences in autonomic response.     

Evaluation,self-awareness,and task performance

Two contradictory hypotheses regarding the effect of self-attention or self-awareness on task performance are considered. Recent research on test anxiety indicates that self-awareness interferes with task performance by decreasing the proportion of attention paid to the task. Wicklund and Duval's (1971) theory of objective self-awareness predicts the opposite: that self-awareness will induce a person to try harder and to perform at a higher level. Experimental evidence indicates that both hypotheses are correct, each at a different level of evaluation. The results are discussed in terms of their implications for a unified social-psychological theory of evaluative self-awareness which could account for findings now classed under separate headings such as test anxiety, self-awareness, and social facilitation.     

The effects of delay and imagery training on the recall and recognition of object pairs

The present study represents a further investigation of an imagery training procedure previously developed by the authors (Yuille & Catchpole, 1973). Subjects given a brief training session in the use of an interacting imaginal mnemonic showed significantly higher performance than nontrained Ss on tests of immediate, delayed, and second learning set memory. While both recognition and recall were equally affected by the procedure, with recognition showing its usual superiority, the type of immediate memory test did not affect delayed recall. The findings are interpreted as supporting the preference of young children for visual coding.     

Individual differences in field articulation as a factor in language comprehension

Previous research has suggested that performance differences associated with field independence/field articulation (FA) reflect differences in the efficiency of a limited capacity “working memory” (WM) system. An information-processing analysis of language comprehension suggests the involvement of WM. This experiment tested the hypothesis that performance differences in a language comprehension task could be predicted on the basis of level of FA and the mediating role of WM. Three levels of memory load were established by varying the logical structure of sets of semantically related sentences which subjects were required to integrate. In the low memory load condition, there was no difference between high and low FA subjects on a test of integration (inference) and specific memory (recognition). In the high memory load condition, there was a decline in performance for low FA subjects on both inference and recognition. Other aspects of the results suggested that the breakdown in information processing, for low FA subjects in the high memory load condition, occurred during or shortly after initial encoding of the sentences.     

An analysis of two central stages underlying responding to personality items: The self-referent decision and response selection

A technique for isolating substages in a processing sequence (Sternberg, 1969) was used to examine two central stages in a postulated model of responding to personality items. The Self-Referent Decision (SRD) stage, where item content is compared to stored memory elements, and the Response Selection Stage, where the output of the SRD is mapped into available response alternatives, were analyzed to determine if they could be seen as separate stages. Results indicated that a modular model that viewed these two stages as being separate was supported. These results were also discussed in relation to existing models of item responding processes and the dichotomous/Likert response format issue.     

Familiarity is related to conceptual implicit memory: An examination of individual differences

Explicit memory is thought to be distinct from implicit memory. However, growing evidence has indicated that explicit familiarity-based recognition memory judgments rely on the same process that supports conceptual implicit memory. We tested this hypothesis by examining individual differences using a paradigm wherein we measured both familiarity and conceptual implicit memory within the same participants. In Experiments 1a and 1b, we examined recognition memory confidence ROCs and remember/know responses, respectively, to estimate recollection and familiarity, and used a free association task to measure conceptual implicit memory. The results demonstrated that, across participants, familiarity, but not recollection, was significantly correlated with conceptual priming. In contrast, in Experiment 2, utilizing a similar paradigm, a comparison of recognition memory ROCs and explicit associative cued-recall performance indicated that cued recall was related to both recollection and familiarity. These results are consistent with models assuming that familiarity-based recognition and conceptual implicit memory rely on similar underlying processes.