Growth and pruning of mushroom body Kenyon cell dendrites during worker behavioral development in the paper wasp, Polybia aequatorialis (Hymenoptera: Vespidae)

Adult workers of some social insect species show dramatic behavioral changes as they pass through a sequence of task specializations. In the paper wasp, Polybia aequatorialis, female workers begin adult life within the nest tending brood, progress to maintaining and defending the nest exterior, and ultimately leave the nest to forage. The mushroom body (MB) calyx neuropil increases in volume as workers progress from in-nest to foraging tasks. In other social Hymenoptera (bees and ants), MB Kenyon cell dendrites, axons and synapses change with the transition to foraging, but these neuronal effects had not been studied in wasps. Furthermore, the on-nest worker of Polybia wasps, an intermediate task specialization not identified in bees or ants, provides the opportunity to study pre-foraging worker class transitions. We asked whether Kenyon cell dendritic arborization varies with the task specialization of Polybia workers observed in the field near Monteverde, Costa Rica. Golgi-impregnated arbors in the lip and collar calyces, which receive a predominance of olfactory and visual input, respectively, were quantified using Sholl’s concentric circles and a novel application of virtual spherical probes. Arbors of the lip varied in a manner reminiscent of honeybees, with foragers having the largest and in-nest workers having the smallest arbors. In contrast, arbors of the collar were largest in foragers but smallest in on-nest workers. Thus, progression through task specializations in P. aequatorialis involves subregion specific dendritic growth and regression in the MB neuropil. These results may reflect the sensitivity of Kenyon cell dendritic structure to specialization dependent social and sensory experience.     

When Public Statements Reveal Private Beliefs: Assessing Operational Codes at a Distance

This article uses both public and private documents to measure the operational code of John F. Kennedy in the summer of 1962. Previous operational code research (and indeed, much of content analysis more generally) has relied exclusively on the analysis of public speeches and is thus open to charges that the speeches represent attempts at deception, persuasion, or impression management. This article tests the validity of using public speech data in operational code analysis by comparing the output to the results one gets by analyzing private statements from the same period. The results strongly indicate that one obtains the same results using either the public or the private data, thus providing tentative confirmation of the validity of using public speeches for assessing the operational codes of leaders.     

Consciousness as a Process: From the Loneliness of William James to the Buzzing and Booming Voices of Contemporary Science

This Special Issue of IPBS brings the old metaphor of William James—consciousness as a “stream of thought”—to a contemporary critical inspection. It is demonstrated—based on materials of language (Panksepp 2008; Shanahan 2008), perception (Engelmann 2008) and dialogical self (Bertau 2008) that the classic river metaphor is an inadequate depiction of the multi-level psychological processes that are regulated by the affective systems of the brain and hierarchically integrated through dialogical and semiotic mechanisms.

The effects of expectancy on inhibition of return

This research examined the influence of cue temporal predictability on inhibition of return (IOR). In exogenous attention experiments, the cue that summons attention is non-informative as to where the target will appear. However, it is predictive as to when it will appear. Because in most experiments there are equal numbers of trials for each cue-target interval (SOA--stimulus onset asynchrony), as time passes from the appearance of the cue, the probability of target presentation increases. Predictability was manipulated by using three SOA distributions: non-aging, aging and accelerated-aging. A robust IOR was found that was not modulated by temporal information within a trial. These results show that reflexive effects are relatively protected against modulation by higher volitional processes.     

Interpersonal similarity as a social distance dimension: Implications for perception of others’ actions

Building on the assumption that interpersonal similarity is a form of social distance, the current research examines the manner in which similarity influences the representation and judgment of others’ actions. On the basis of a construal level approach, we hypothesized that greater levels of similarity would increase the relative weight of subordinate and secondary features of information in judgments of others’ actions. The results of four experiments showed that compared to corresponding judgments of a dissimilar target, participants exposed to a similar target person identified that person’s actions in relatively more subordinate means-related rather than superordinate ends-related terms (Experiment 1), perceived his or her actions to be determined more by feasibility and less by desirability concerns (Experiment 3), and gave more weight to secondary aspects in judgments of the target’s decisions (Experiment 2) and performance (Experiment 4). Implications for the study of interpersonal similarity, as well as social distance in general, are discussed.     

Relationship of temporal lobe volumes to neuropsychological test performance in healthy children

Ecological validity of neuropsychological assessment includes the ability of tests to predict real-world functioning and/or covary with brain structures. Studies have examined the relationship between adaptive skills and test performance, with less focus on the association between regional brain volumes and neurobehavioral function in healthy children. The present study examined the relationship between temporal lobe gray matter volumes and performance on two neuropsychological tests hypothesized to measure temporal lobe functioning (visual perception-VP; peabody picture vocabulary test, third edition-PPVT-III) in 48 healthy children ages 5-18 years. After controlling for age and gender, left and right temporal and left occipital volumes were significant predictors of VP. Left and right frontal and temporal volumes were significant predictors of PPVT-III. Temporal volume emerged as the strongest lobar correlate with both tests. These results provide convergent and discriminant validity supporting VP as a measure of the "what" system; but suggest the PPVT-III as a complex measure of receptive vocabulary, potentially involving executive function demands.     

Counselling Australian baby boomers: examining the loss and grief issues facing aging distance-separated sibling dyads

It has long been recognised that mature-aged sibling dyads provide each other with emotional support. What has yet to be determined is whether this support function is maintained within the baby boomer generational cohort of sibling dyads who through economic relocation/migration have become separated by distance. As such, this paper highlights the need for research to be conducted into the experiences of baby boomers dealing with sibling loss and grief-related issues without the support of their nuclear and extended family members.     

Hemispheric asymmetries for temporal information processing: transient detection versus sustained monitoring

This study investigated functional differences in the processing of visual temporal information between the left and right hemispheres (LH and RH). Participants indicated whether or not a checkerboard pattern contained a temporal gap lasting between 10 and 40 ms. When the stimulus contained a temporal signal (i.e. a gap), responses were more accurate for the right visual field-left hemisphere (RVF-LH) than for the left visual field-right hemisphere (LVF-RH). This RVF-LH advantage was larger for the shorter gap durations (Experiments 1 and 2), suggesting that the LH has finer temporal resolution than the RH, and is efficient for transient detection. In contrast, for noise trials (i.e. trial without temporal signals), there was a LVF-RH advantage. This LVF-RH advantage was observed when the entire stimulus duration was long (240 ms, Experiment 1), but was eliminated when the duration was short (120 ms, Experiment 2). In Experiment 3, where the gap was placed toward the end of the stimulus presentation, a LVF-RH advantage was found for noise trials whereas the RVF-LH advantage was eliminated for signal trials. It is likely that participants needed to monitor the stimulus for a longer period of time when the gap was absent (i.e. noise trials) or was placed toward the end of the presentation. The RH may therefore be more efficient in the sustained monitoring of visual temporal information whereas the LH is more efficient for transient detection.