Mechanisms underlying dependencies of performance on stimulus history in a two-alternative forced-choice task

In choice reaction time tasks, response times and error rates demonstrate differential dependencies on the identities of up to four stimuli preceding the current one. Although the general profile of reaction times and error rates, when plotted against the stimulus histories, may seem idiosyncratic, we show that it can result from simple underlying mechanisms that take account of the occurrence of stimulus repetitions and alternations. Employing a simple connectionist model of a two-alternative forcedchoice task, we explored various combinations of repetition and alternation detection schemes in an attempt to account for empirical results from the literature and from our own studies. We found that certain combinations of the repetition and the alternation schemes provided good fits to the data, suggesting that simple mechanisms may serve to explain the complicated but highly reproducible higher order dependencies of task performance on stimulus history.     

Deficits in trace cued fear conditioning in galanin-treated rats and galanin-overexpressing transgenic mice

Galanin inhibits the release of several neurotransmitters and produces performance deficits in a variety of spatial and aversive learning and memory tasks. The experiments in this study investigated the role galanin has in emotional learning and memory using a standard delay cued and contextual fear conditioning task. Rats were administered galanin into the lateral ventricles before training, and scored for freezing behavior in the same context and in a novel context with and without an auditory cue (CS) that had been paired previously with an aversive stimulus (US). Galanin-overexpressing transgenic mice were tested in an identical behavioral protocol. The galanin-administered rats and the transgenic mice were not significantly different from their respective controls on this task. A more challenging trace cued and contextual fear conditioning procedure was administered to separate groups of galanin-treated rats and galanin-overexpressing transgenic mice. Subjects were trained with the same CS and US, however, a 2.5-sec delay was inserted between CS offset and US onset. Following the trace conditioning, rats administered galanin and mice overexpressing galanin both exhibited significantly less freezing to the CS in the novel context as compared with their control groups. These results indicate that the observed disruption of cued fear conditioning was specific to the more difficult trace conditioning task. These findings are the first demonstration that galanin impairs performance on an emotional memory task and support the hypothesis that galanin-induced deficits are specific to more difficult cognitive tasks.     

Putting the partner within reach: a dyadic perspective on felt security in close relationships

The authors argue that felt insecurity in a partner's positive regard and caring stems from a specifically dyadic perception--the perception that a partner is out of one's league. A cross-sectional sample of dating couples revealed that people with low self-esteem feel inferior to their partner and that such feelings of relative inferiority undermine felt security in the partner's regard. Three experiments examined the consequences of reducing such perceived discrepancies by pointing to either strengths in the self or flaws in the partner. Low, but not high, self-esteem participants reacted to new strengths in the self or faults in the partner by reporting greater felt security in their specific partner's positive regard and commitment and more positive, general feelings about their own interpersonal worth. Thus, putting the partner more within the psychological grasp of low self-esteem people may effectively increase felt security in the partner's regard.     

Allocentric coding of object-to-object relations in overlearned and novel environments

R. F. Wang and E. S. Spelke's (2000) finding that disorientation disrupts knowledge is consistent with egocentric but not allocentric coding of object location. The present experiments tested the hypothesis that egocentric coding may dominate early on but that once an allocentric representation is established, then target location is retrieved from it. This hypothesis predicts that disorientation will disrupt configuration knowledge in a novel environment, such as that used by Wang and Spelke, but not in an overlearned environment. Experiments 1 and 2 tested whether disorientation disrupted configuration knowledge of an overlearned environment, and Experiments 3-7 tested whether disorientation disrupted configuration knowledge of a novel, room-sized environment. In none of the experiments did disorientation disrupt configuration knowledge. Hence, in addition to showing allocentric coding of overlearned interlandmark relations, the present findings are consistent with the immediate availability of allocentric location codes in a novel, room-sized environment.     

The role of the locus coeruleus in mediating the attentional blink: a neurocomputational theory

The attentional blink refers to the transient impairment in perceiving the 2nd of 2 targets presented in close temporal proximity. In this article, the authors propose a neurobiological mechanism for this effect. The authors extend a recently developed computational model of the potentiating influence of the locus coeruleus-norepinephrine system on information processing and hypothesize that a refractoriness in the function of this system may account for the attentional blink. The model accurately simulates the time course of the attentional blink, including Lag 1 sparing. The theory also offers an account of the close relationship of the attentional blink to the electrophysiological P3 component. The authors report results from two behavioral experiments that support a critical prediction of their theory regarding the time course of Lag 1 sparing. Finally, the relationship between the authors' neurocomputational theory and existing cognitive theories of the attentional blink is discussed.     

Measuring adult attachment: a construct validation of two self-report instruments

This study reports the Swedish construct validation of two translated attachment style scales. The factor structure of the attachment construct was investigated via exploratory and confirmatory factor analyses of attachment scores from 515 students of a Swedish university. Results supported the expected two-factor solution, but found a three-factor solution to be a viable alternative. In addition, the attachment scales were compared with the Big Five personality inventory (NEO-PI), using a sample of 87 Swedish students, and found to have expected correlation to this scale.     

Trichotillomania (hair pulling) in toddlers

Although the clinical diagnosis of trichotillomania has been observed for more than a century, not until the last decade has there been a focus on this diagnosis in early childhood. This small case series focuses on the clinical evaluation of 10 toddlers, average of 26 mo., presenting at a specialty child and adolescent psychiatry clinic with hair pulling. Authors suggest that hair pulling in this age group might better be conceptualized as an anxiety disorder.     

Invisible overtures: fears of rejection and the signal amplification bias

Four studies demonstrated that fears of rejection prompt individuals to exhibit a signal amplification bias, whereby they perceive that their overtures communicate more romantic interest to potential partners than is actually the case. The link between rejection anxieties and the bias was evident regardless of whether fears of rejection were assessed in terms of chronic attachment anxiety or were induced by reflection on a previous rejection experience. Mediation analyses suggested that the bias stems in part from an expected-augmenting process, whereby persons with strong fears of rejection incorrectly assume that the recipient of their overtures will take their inhibitions into account when interpreting their behavior. Implications for understanding the link between attachment anxiety and loneliness and for designing social skills interventions are discussed.     

Effect of therapist's title on perceived competence

A videotaped segment of a therapist and student/client was shown to groups of male and female undergraduates under four conditions. One group saw the tape with the title "Doctor (the therapist's actual name was used) and Client" superimposed at the bottom. The second group saw the same tape with "Mr. (blank) Client" superimposed, the third group had "Timothy (blank) and Client," while the fourth group had no title at the bottom. The 204 students rated the therapist on 11 variables. Analysis showed no effect for title and no interaction. Men rated the therapist higher on nine of the 11 variables, than did women.