Serotonin: Modulator of a drive to withdraw

Serotonin is a fundamental neuromodulator in both vertebrate and invertebrate nervous systems, with a suspected role in many human mental disorders. Yet, because of the complexity of serotonergic function, researchers have been unable to agree on a general theory. One function suggested for serotonin systems is the avoidance of threat. We propose and review evidence for an alternative hypothesis, that a phylogenetically primitive of function of serotonin is to oppose the activating neuromodulators (particularly noradrenalin and dopamine). The functional effect of this opposition can be seen as applying a drive to withdraw from dangerous, aversive or high stimulation environments. Proposing that serotonin is involved in a drive to withdraw and seek contentment, instead of a drive to avoid, may be compatible with several lines of evidence on serotonin function and may facilitate a better understanding of serotonergic neuromodulation in human psychopathology.     

COMPLIANCE TRAINING AND BEHAVIORAL COVARIATION IN THE TREATMENT OF MULTIPLE BEHAVIOR PROBLEMS

The present study investigated the use of a compliance-training procedure and its effect on untreated deviant child behaviors. Three children, each generally noncompliant to adult requests and with several additional problems, such as crying, aggression, and self-injurious behavior, were trained in the compliance procedure under a multiple-baséline design across therapists. Compliance was defined as the correct response to prespecified requests. Other classes of deviant child behavior were measured continuously throughout the study but not directly reinforced. The results of the study showed that (a) increases in compliance to requests were directly related to the contingencies employed; (b) decreases in untreated deviant behaviors occurred when compliance increased, even though no direct contingencies had been placed on these behaviors; and (c) the relationship between untreated deviant behaviors and compliance appeared to be maintained by a different set of events in each of the three children. The results are discussed in terms of behavioral covariation and generalization.     

Context in selection of men and women in hiring decisions: gender composition of the applicant pool

The hypothesis that the sex composition of an applicant pool affects the hiring probabilities of individual job applicants was tested using gender-distinctive information on accepted and rejected job applicants in The Netherlands. The evidence supports this hypothesis, although the effect sizes are moderate. Both men and women have a lower probability of being hired when the applicant pool contains fewer applicants from their own sex.     

On the origin of functional differences in recollective experience

Abstract

Subjects studied target words that were repeated either immediately (lag0) or after six intervening items (lag6). At retention testing, subjects were required to discriminate targets from distractors and, contingent on a ‘yes' response, to classify each identified item as one that evoked either a ‘remember’ (R) response or a ‘know’ (K) response. An R response indicated recognition based on conscious recollection, and K, recognition without conscious recollection. R responses were significantly greater in lag6 than lag0 whereas the reverse was found for K responses. The data are interpreted as showing that R responses depend on the probability of a target stimulus engaging conscious effortful processing, whereas K responses are increased in the absence of conscious involvement at learning.     

Facial expressions of singers influence perceived pitch relations

In four experiments, we examined whether facial expressions used while singing carry musical information that can be “read” by viewers. In Experiment 1, participants saw silent video recordings of sung melodic intervals and judged the size of the interval they imagined the performers to be singing. Participants discriminated interval sizes on the basis of facial expression and discriminated large from small intervals when only head movements were visible. Experiments 2 and 3 confirmed that facial expressions influenced judgments even when the auditory signal was available. When matched with the facial expressions used to perform a large interval, audio recordings of sung intervals were judged as being larger than when matched with the facial expressions used to perform a small interval. The effect was not diminished when a secondary task was introduced, suggesting that audio-visual integration is not dependent on attention. Experiment 4 confirmed that the secondary task reduced participants’ ability to make judgments that require conscious attention. The results provide the first evidence that facial expressions influence perceived pitch relations.     

Reprocessing as a recognition cue

The use of mental operations as recognition cues was investigated. Two experiments support the hypothesis that processing details are retained in memory and that a re-creation of those processing details can effectively cue recognition. Four subjects performed a mental arithmetic task that emphasized speed and accuracy while discouraging memorization of the numbers. Recognition was cued either by single numbers or by a pair of numbers that, when added, replicated an episode of the original task. Reprocessing an episode was the most effective recognition cue. Of the two single-number cues, the intermediate subtotals were recognized, whereas the numbers that had been physically displayed were not. The study suggests: (1) that the sequence of mental operations is retained in memory, (2) that reprocessing uses this trace to facilitate performance, and (3) that the detection of facilitated reprocessing aids recognition.     

Anxiety modulates the degree of attentive resources required to process emotional faces

The present study contributes to the ongoing debate over the extent to which attentive resources are required for emotion perception. Although fearful facial expressions are strong competitors for attention, we predict that the magnitude of this effect may be modulated by anxiety. To test this hypothesis, healthy volunteers who varied in their self-reported levels of trait and state anxiety underwent an attentional blink task. Both fearful and happy facial expressions were subject to a strong attentional blink effect for low-anxious individuals. For those reporting high anxiety, a blink occurred for both fearful and happy facial expressions, but the magnitude of the attentional blink was significantly reduced for the fearful expressions. This supports the proposals that emotion perception is not fully automatic and that anxiety is related to a reduced ability to inhibit the processing of threat-related stimuli. Thus, individual differences in self-reported anxiety are an important determinant of the attentional control of emotional processing.