Visual discrimination learning in the killer whale (Orcinus orca)

Trial-and-error and errorless training procedures were used to train two killer whales on a simple visual discrimination problem. Both whales demonstrated difficulties in solving the problem under trial-and-error training. The relative effectiveness of the two training procedures is evaluated.     

Monkeys are rational!

Five squirrel monkeys showed a significant Symbolic Distance Effect (SDE) when tested on procedures designed to incorporate reaction time (RT) measures within the five-term series (“transitive inference”) task. Taken together with the high levels of transitive choice obtained by these subjects, this result shows that monkeys have met choice and reaction time criteria perceived by many as indexical of “linear representation”. Explicit evaluation of the representational implications of the SDE was subsequently undertaken in three-choice transfer tests, which initially revealed consistent deviations from the ranks predicted on a linear model. Extensive testing with the triadic method, however, elicited spontaneous improvement in overall choice ranking according to a linear principle. Further decomposition of the RT data showed that the irregularities in the initial transfer behaviour are by no means paradoxical. The ordinal separation data structure, from which the SDE is derived, masks two separate populations of scores--one fast and relatively undifferentiated, the other slow and based on judgements with poorly encoded items. And it is these factors, not inter-item distance, which, we argue, are the main determiners of the SDE. Whilst this phenomenon is thus only weakly indexical of principled linear representation, we contend that new (triad-based) ranking evidence suggests that monkeys may be capable of seriation as well as transitivity.     

Plasticity associated with escalated operant ethanol self-administration during acute withdrawal in ethanol-dependent rats requires intact matrix metalloproteinase systems

Repeated cycles of ethanol intoxication and withdrawal associated with dependence induce neuroadaptations in a variety of brain systems. Withdrawal-induced negative emotional states can be ameliorated by ethanol consumption; a learned process termed negative reinforcement. Accordingly, a dependence-induced phenotype is escalated ethanol self-administration. Matrix metalloproteinases (MMPs) are proteolytic enzymes which degrade the extracellular matrix to allow for synaptic reorganization and plasticity. To test the hypothesis that an intact MMP system is required for animals to learn about the negative reinforcing effects of ethanol and display escalated self-administration during acute withdrawal when ethanol-dependent, male Wistar rats were trained to self-administer ethanol and then assigned to either acute or chronic MMP inhibition treatment groups. The chronic treatment group received intracerebroventricular (ICV) infusions of the broad spectrum MMP inhibitor FN-439 or artificial cerebrospinal fluid (aCSF) via osmotic minipumps during a 1 month ethanol dependence induction period and subsequent post-dependence induction self-administration sessions that occurred during acute withdrawal. The acute treatment group only received ICV FN-439 or aCSF on the day of self-administration sessions following dependence induction during acute withdrawal. The results showed that inhibition of MMPs attenuated escalated ethanol self-administration following chronic and acute exposure conditions. Furthermore, once learning (i.e., plasticity) had occurred, MMP inhibition had no impact on escalated response patterns and animals previously subjected to MMP inhibition that did not escalate evidenced normal escalations in operant ethanol self-administration once FN-439 treatments were terminated. Thus, the present data identified that an intact MMP system is required for the escalated responding that occurs during acute withdrawal in dependent animals and implicate such escalation as a learned response.     

A preliminary examination of the effect of massage on state body image

Evidence suggests positive effects of massage on psychological health; however, little is known about the effects of massage on body image. This research examined the effect of massage on state body image as well as relations between trait body image and attitudes toward massage. Forty-nine female university students were randomly assigned to either a massage condition or a control condition. It was hypothesized that participants in the massage condition would report improved state body image following the intervention when compared to participants in the control condition. As predicted, participants in the massage condition reported a more favorable state body image than participants in the control condition post-manipulation. Certain body image evaluations were moderately associated with views that massage is pleasurable, with the link between Body Areas Satisfaction and viewing massage as pleasurable reaching significance. Research is needed to determine the mechanism/s through which massage improves body image.     

The mini-IPIP scales: tiny-yet-effective measures of the Big Five factors of personality

The Mini-IPIP, a 20-item short form of the 50-item International Personality Item Pool-Five-Factor Model measure (Goldberg, 1999), was developed and validated across five studies. The Mini-IPIP scales, with four items per Big Five trait, had consistent and acceptable internal consistencies across five studies (= at or well above .60), similar coverage of facets as other broad Big Five measures (Study 2), and test-retest correlations that were quite similar to the parent measure across intervals of a few weeks (Study 4) and several months (Study 5). Moreover, the Mini-IPIP scales showed a comparable pattern of convergent, discriminant, and criterion-related validity (Studies 2-5) with other Big Five measures. Collectively, these results indicate that the Mini-IPIP is a psychometrically acceptable and practically useful short measure of the Big Five factors of personality.     

Oddities in Kirkpatrick, et al.'s study of children of lesbian mothers

Kirkpatrick, et al.'s 1976 study of what happened to 20 lesbians' children has received considerable attention, apparently later being matched with 20 heterosexuals' children. In 2004, Kirkpatrick generally acknowledged Schumm's caution that her findings are less impressive than are needed, yet, Kirkpatrick stated her "early findings have been reinforced" and that "no evidence of differences in the children grouped by the mother's sexual orientation" have been documented by subsequent research. Close examination of the data of these studies indicates that children from 13 lesbian mothers were compared with children from 13 divorced heterosexuals. Further, there are contradictions between the published reports regarding the nature of samples and various findings. Analysis of Kirkpatrick, et al.'s study suggests that children do less well when raised by homosexual parents.     

The impact of frontal and non-frontal brain tumor lesions on Wisconsin Card Sorting Test performance

Several lesion and imaging studies have suggested that the Wisconsin Card Sorting Test (WCST) is a measure of executive dysfunction. However, some studies have reported that this measure has poor anatomical specificity because patients with either frontal or non-frontal focal lesions exhibit similar performance. This study examined 25 frontal, 20 non-frontal low-grade brain tumor patients, and 63 normal controls (NC) on the WCST. The frontal patients were also assigned to either a left frontal (n=10) group or a right frontal group (n=15) and compared with the non-frontal group and NC. It was hypothesized that the frontal brain tumor patients would display greater deficits on categories achieved and a higher number of perseverative errors than non-frontal brain tumor patients on the WCST. Finally, it was predicted that right frontal brain tumors would result in greater executive functioning deficits than left frontal or non-frontal brain tumors. Results indicated that the left frontal group achieved the fewest categories and committed the most perseverative errors compared to the other patient and normal control groups. In addition, the left frontal group committed significantly more perseverative errors than the right frontal group. These results suggest that the WCST is sensitive to the effects of low-grade brain tumors on executive functioning.     

An information-processing model of the BOLD response in symbol manipulation tasks

Two imaging experiments were performed—one involving an algebraic transformation task studied by Anderson, Reder, and Lebiere (1996) and the other an abstraction symbol manipulation task studied by Blessing and Anderson (1996). ACT-R models exist that predict the latency patterns in these tasks. These models require activity in an imaginal buffer to represent changes to the problem representation, in a retrieval buffer to hold information from declarative memory, and in a manual buffer to hold information about motor behavior. A general theory is described about how to map activity in these buffers onto the fMRI blood oxygen level dependent (BOLD) response. This theory claims that the BOLD response is integrated over the duration that a buffer is active and can be used to predict the observed BOLD function. Activity in the imaginal buffer is shown to predict the BOLD response in a left posterior parietal region; activity in the retrieval buffer is shown to predict the BOLD response in a left prefrontal region; and activity in the manual buffer is shown to predict activity in a motor region. More generally, this article shows how to map a large class of information-processing theories (not just ACT-R) onto the BOLD response and provides a precise interpretation of the cognitive significance of the BOLD response.     

Power,approach, and inhibition

This article examines how power influences behavior. Elevated power is associated with increased rewards and freedom and thereby activates approach-related tendencies. Reduced power is associated with increased threat, punishment, and social constraint and thereby activates inhibition-related tendencies. The authors derive predictions from recent theorizing about approach and inhibition and review relevant evidence. Specifically, power is associated with (a) positive affect, (b) attention to rewards, (c) automatic information processing, and (d) disinhibited behavior. In contrast, reduced power is associated with (a) negative affect; (b) attention to threat, punishment, others' interests, and those features of the self that are relevant to others' goals; (c) controlled information processing; and (d) inhibited social behavior. The potential moderators and consequences of these power-related behavioral patterns are discussed.