Visual search through color displays: Effects of target-background similarity and background uniformity

The effects of target-background similarity and background uniformity were investigated in two experiments in which subjects reported the presence or absence of an achromatic target item in arrays containing irrelevant chromatic items. In Experiment 1, both “present” and “absent” decision times were an increasing function of the similarity of a predefined target item to the background, and were shortened when the interitem similarity of the background set was increased. In Experiment 2, the effects of target-background similarity on the “present” decision were replicated when subjects were not informed on each trial as to which member of the target set might appear in the array, and the “absent” decision was faster when each row of the array comprised background items of a single color than when these items were allocated randomly to array locations. The results are interpreted in terms of the role of pre-attentive grouping operations.     

Sequences of phonemic approximations in aphasia

The trends of sequences of phonemic approximations to a single target were studied in three types of aphasia (Broca's, conduction, and Wernicke's), as gathered in five tasks (spontaneous speech, repetition of meaningful words, repetition of nonsense words, reading aloud, and automatized sequences). A phonemic error ratio was defined in order to quantify the distance between each approximation of a given sequence and its target. The results of a computer analysis based on this ratio were analyzed according to three parameters. A study of three types of patients revealed that conduction aphasics exhibited the most regular trend toward the target in sequences of phonemic approximations; the analysis of the various tasks indicated that sequences produced in repetition by conduction aphasics form an exception to the regularity of this trend, and an examination of the various lengths of sequences indicated that longer sequences showed a less decisive trend toward the target than shorter sequences. The discussion bears on some theoretical aspects of the phonological production mechanism and its control: the initial strength and permanence of the internal representation of the target emerge as important factors required for the good functioning of this mechanism.     

Evolutionary function of dreams: A test of the threat simulation theory in recurrent dreams

proposed an intriguing and detailed evolutionary theory of dreams which stipulates that the biological function of dreaming is to simulate threatening events and to rehearse threat avoidance behaviors. The goal of the present study was to test this theory using a sample of 212 recurrent dreams that was scored using a slightly expanded version of the DreamThreat rating scale. Six of the eight hypotheses tested were supported. Among the positive findings, 66% of the recurrent dream reports contained one or more threats, the threats tended to be dangerous and aimed at the dreamer, and when facing a threat, the dreamer tended to take defensive or evasive actions that were possible and reasonable. However, less than 15% of the recurrent dreams depicted realistic and probable situations critical for one's physical survival or reproductive success and the dreamer rarely succeeded in fleeing the threat despite important and appropriate efforts. The findings thus provide mixed support for the threat simulation theory.     

Transient and enduring spatial representations under disorientation and self-rotation

Current theories of environmental cognition typically differentiate between an online, transient, and dynamic system of spatial representation and an offline and enduring system of memory representation. Here the authors present additional evidence for such 2-system theories in the context of the disorientation paradigm introduced by R. F. Wang and E. S. Spelke (2000). Several experiments replicate the finding that disorientation results in a decrease in the precision of people's estimates of relative directions. In contrast to the typical interpretation of this effect as indicating the primacy of a transient spatial system, the present results are generally more consistent with an interpretation of it as indicating a switch from a relatively precise online representation to a relatively coarse enduring one. Further experiments examine the relative precision of transient and enduring representations and show that switching between them does not require disorientation, but can also be produced by self-rotations as small as 135 degrees .     

Assessing text representations with recognition: The interaction of domain knowledge and text coherence

Readers construct at least 2 interrelated mental representations when they comprehend a text: a textbase and a situation model. Two experiments were conducted with recognition memory to examine how domain knowledge and text coherence influence readers' textbase and situation-model representations. In Experiment 1, participants made remember-know judgments to text ideas. Knowledge and coherence interacted to influence remember judgments differently than know judgments. In Experiment 2, the authors used the process-dissociation procedure to obtain recollection and familiarity estimates. Knowledge and coherence interacted to influence recollection estimates but not familiarity estimates. The authors claim that recollection and familiarity can be used as markers of the different processes involved in constructing a textbase and a situation model.     

Impulsive-compulsive sexual behavior

Impulsive-compulsive sexual behavior is a little studied clinical phenomenon which affects approximately 5% to 6% of the population. In the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-Text Revision, it is classified as an impulse control disorder not otherwise specified or a sexual disorder not otherwise specified. It may be placed in a possible new category in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition called substance and behavioral addictions. This clinical entity is reviewed and the merit of classifying it as an addiction is assessed. Information is presented regarding its diagnostic criteria, epidemiology, types of behavior it can involve, relationship to hypersexuality, comorbidities, treatment, and etiology. The data regarding this disorder and its overlap with chemical addiction is limited. If the two disorders are to be grouped together, further data are needed.     

Using FMRI to study the neural correlates of virtual reality analgesia

Excessive pain during medical procedures, such as burn wound dressing changes, is a widespread medical problem and is especially challenging for children. This article describes the rationale behind virtual reality (VR) pain distraction, a new non-pharmacologic adjunctive analgesia, and gives a brief summary of empirical studies exploring whether VR reduces clinical procedural pain. Results indicate that patients using VR during painful medical procedures report large reductions in subjective pain. A neuroimaging study measuring the neural correlates of VR analgesia is described in detail. This functional magnetic resonance imaging pain study in healthy volunteers shows that the large drops in subjective pain ratings during VR are accompanied by large drops in pain-related brain activity. Together the clinical and laboratory studies provide converging evidence that VR distraction is a promising new non-pharmacologic pain control technique.     

Anatomy of a decision: striato-orbitofrontal interactions in reinforcement learning, decision making, and reversal

The authors explore the division of labor between the basal ganglia-dopamine (BG-DA) system and the orbitofrontal cortex (OFC) in decision making. They show that a primitive neural network model of the BG-DA system slowly learns to make decisions on the basis of the relative probability of rewards but is not as sensitive to (a) recency or (b) the value of specific rewards. An augmented model that explores BG-OFC interactions is more successful at estimating the true expected value of decisions and is faster at switching behavior when reinforcement contingencies change. In the augmented model, OFC areas exert top-down control on the BG and premotor areas by representing reinforcement magnitudes in working memory. The model successfully captures patterns of behavior resulting from OFC damage in decision making, reversal learning, and devaluation paradigms and makes additional predictions for the underlying source of these deficits.     

Self-benefiting in the allocation of scarce resources: leader-follower effects and the moderating effect of social value orientations

Previous research on the allocation of scarce resources suggests that people who are assigned to higher positions (e.g., leaders) are more likely to make self-benefiting allocations than people who are assigned to lower positions (e.g., followers). In this article, the authors investigated the proposition that these findings would be moderated by people's social value orientations. In two experimental studies, the authors assigned participants either to the role of leader or follower and assessed the participants' social value orientations. In agreement with predictions, the findings show that position effects are moderated by social value orientation. Social value orientations only affected the allocation behavior of the leaders: Proself leaders allocated more resources to themselves than did prosocial leaders. Additional analyses indicate that these effects are mediated by feelings of entitlement.