Visual control of action without retinal optic flow

In everyday life, the optic flow associated with the performance of complex actions, like walking through a field of obstacles and catching a ball, entails retinal flow with motion energy (first-order motion). We report the results of four complex action tasks performed in virtual environments without any retinal motion energy. Specifically, we used dynamic random-dot stereograms with single-frame lifetimes (cyclopean stimuli) such that in neither eye was there retinal motion energy or other monocular information about the actions being performed. Performance on the four tasks with the cyclopean stimuli was comparable to performance with luminance stimuli, which do provide retinal optic flow. The near equivalence of the two types of stimuli indicates that if optic flow is involved in the control of action, it is not tied to first-order retinal motion.     

Perception of heading without retinal optic flow

How do we determine where we are heading during visually controlled locomotion? Psychophysical research has shown that humans are quite good at judging their travel direction, or heading, from retinal optic flow. Here we show that retinal optic flow is sufficient, but not necessary, for determining heading. By using a purely cyclopean stimulus (random dot cinematogram), we demonstrate heading perception without retinal optic flow. We also show that heading judgments are equally accurate for the cyclopean stimulus and a conventional optic flow stimulus, when the two are matched for motion visibility. The human visual system thus demonstrates flexible, robust use of available visual cues for perceiving heading direction.     

Trade-offs and individual differences in evolved traits

Comments on Evolutionary psychology: Controversies, questions, prospects, and limitations (see record 2010-02208-001) by Confer et al. We applaud Confer et al.'s (February-March 2010) clarifications of the many misconceptions surrounding the use of evolutionary analyses in psychology. As they noted, such misunderstandings are common and result in a curious tendency of some of our colleagues to criticize evolutionary psychology without a firm understanding of evolution itself. Confer et al. also did an admirable job acknowledging current unresolved issues among evolutionary psychologists (e.g., the relative importance of group selection on humans). The above said, we disagree with their view that a current limitation of evolutionary psychology is its inability to explain phenomena "that appear to reduce an individual's reproductive success, and cannot be explained by mismatches with, or hijacking of, our psychological mechanisms by modern-day novel inputs" (Confer et al., 2010, p. 122). Mismatches between modern environments and environments of evolutionary adaptedness are only one set of explanations for seemingly maladaptive traits (Nesse, 2005). Another set involves evolutionary trade-offs.     

Mathematics anxiety affects counting but not subitizing during visual enumeration

Individuals with mathematics anxiety have been found to differ from their non-anxious peers on measures of higher-level mathematical processes, but not simple arithmetic. The current paper examines differences between mathematics anxious and non-mathematics anxious individuals in more basic numerical processing using a visual enumeration task. This task allows for the assessment of two systems of basic number processing: subitizing and counting. Mathematics anxious individuals, relative to non-mathematics anxious individuals, showed a deficit in the counting but not in the subitizing range. Furthermore, working memory was found to mediate this group difference. These findings demonstrate that the problems associated with mathematics anxiety exist at a level more basic than would be predicted from the extant literature.     

Therapist Grief and Functional Analytic Psychotherapy: Strategic Self-Disclosure of Personal Loss

Functional Analytic Psychotherapy (FAP), a behavioral approach that focuses on the development of genuine and meaningful therapeutic relationships including the strategic use of disclosure, provides a framework for therapist self-disclosure during times of personal loss. This article briefly outlines FAP and provides an example of FAP in practice following the death of the first author’s mother. Qualitative data from a client questionnaire on the impact of this disclosure are presented, which suggest that the disclosure was a positive experience for most but not all clients. The article concludes with clinical guidelines that can enhance therapeutic effectiveness whether or not therapists choose to disclose loss to their clients and general precautions for treading in this emotionally intense territory.     

A joke is just a joke (except when it isn't): cavalier humor beliefs facilitate the expression of group dominance motives

Past research reveals preferences for disparaging humor directed toward disliked others. The group-dominance model of humor appreciation introduces the hypothesis that beyond initial outgroup attitudes, social dominance motives predict favorable reactions toward jokes targeting low-status outgroups through a subtle hierarchy-enhancing legitimizing myth: cavalier humor beliefs (CHB). CHB characterizes a lighthearted, less serious, uncritical, and nonchalant approach toward humor that dismisses potential harm to others. As expected, CHB incorporates both positive (affiliative) and negative (aggressive) humor functions that together mask biases, correlating positively with prejudices and prejudice-correlates (including social dominance orientation [SDO]; Study 1). Across 3 studies in Canada, SDO and CHB predicted favorable reactions toward jokes disparaging Mexicans (low-status outgroup). Neither individual difference predicted neutral (nonintergroup) joke reactions, despite the jokes being equally amusing and more inoffensive overall. In Study 2, joke content targeting Mexicans, Americans (high-status outgroup), and Canadians (high-status ingroup) was systematically controlled. Although Canadians preferred jokes labeled as anti-American overall, an underlying subtle pattern emerged at the individual-difference level: Only those higher in SDO appreciated those jokes labeled as anti-Mexican (reflecting social dominance motives). In all studies, SDO predicted favorable reactions toward low-status outgroup jokes almost entirely through heightened CHB, a subtle yet potent legitimatizing myth that "justifies" expressions of group dominance motives. In Study 3, a pretest-posttest design revealed the implications of this justification process: CHB contributes to trivializing outgroup jokes as inoffensive (harmless), subsequently contributing to postjoke prejudice. The implications for humor in intergroup contexts are considered.     

Acute and chronic effects of cocaine on the spontaneous behavior of pigeons

The present experiment examined the effects of acute and daily cocaine on spontaneous behavior patterns of pigeons. After determining the acute effects of a range of doses, 9 pigeons were divided into three groups that received one of three doses of cocaine daily, either 1.0, 3.0, or 10.0 mg/kg cocaine. Measures were taken of spontaneous locomotion, pecking, preening, and emesis. Under daily administration, cocaine induced consistent and substantial enhancements of its locomotor effects in all 9 pigeons, consistent with the phenomenon of locomotor sensitization. The maximum locomotor output did not differ according to the size of the daily dose. Locomotion was not elevated following tests of the saline vehicle, suggesting the effect was due to cocaine, not to a change in baseline or reactivity to the injection procedure. Cocaine dose‐dependently decreased preening when given acutely, and those effects were not altered by repeated cocaine administration. Pecking occurred at very low rates and was unresponsive to cocaine treatment. Cocaine‐induced emesis showed a dose‐dependent increase under initial tests with cocaine, and those effects were attenuated following daily exposure. In a final condition, cocaine was replaced with daily saline for 30 days to assess the persistence cocaine‐related increases in locomotion. Approximately half of the pigeons continued to show enhanced effects even after 30 days without cocaine, so although persistence was obtained, it showed marked intersubject variability. The data indicate that the effects of repeated cocaine administration on the behavior of pigeons shows parallels with many effects commonly reported with rodents (i.e., increased locomotion following repeated treatment, decrease in preening or grooming, persistence following drug withdrawal).