Synapses,Schizophrenia, and Civilization: What Made Homo Sapient?

Progress in technology has allowed dynamic research on the development of the human brain that has revolutionized concepts. Particularly, the notions of plasticity, neuronal selection, and the effects of afferent stimuli have entered into thinking about brain development. Here I focus on development from the age of four years to early adulthood, during which a 30 percent reduction in some brain synapses occurs that is out of proportion to changes in neuronal numbers. This corresponds temporally with changes in normal child behavior from the loose‐associative, almost schizoid, thinking and art of the four‐year‐old to the more trained, or disciplined, or acculturated—and restrained—personality of the young adult. I propose that the synaptic changes can best be thought of as a winnowing process likely subject to environmental influences. Acquisition of language and the ability to link linguistic cognition to the plastic development of the brain provide a potentially powerful means of explaining the evolutionally explosive development of human cognition and culture. Schizophrenia, a disease that can be envisioned as representing a derangement of synaptic maturation, may provide an entry into the search for genes controlling the processes mediating the unprecedented development of Homo sapiens over the past 40,000 to 70,000 years. The recently completed mapping of the genome of the chimpanzee provides a new frame of reference that may speed the search.     

Death by 1000 ‘true fans’: Do marketing laws apply to music listening?

The advice to musicians and marketers is to focus on what they love: a truism for practitioners is to find 1000 ‘true fans’ and make $100 from each of them (Kelly, 2008. 1000 True fans. The Technium). If this advice is correct, we should see musicians with loyal user bases engaging more with their favourite artists and less with other music, suggesting a narrow targeting strategy would suffice. On the other hand, the established marketing laws indicate that the listeners of very different genres should overlap more than conventional wisdom would suggest, supporting the need for a much broader approach to targeting potential audiences. Given these conflicting views, musicians need to know if they should market to their existing listeners, the listeners of music similar to theirs (i.e., the same genre), or if they should try to reach a much wider audience. We turn to established choice patterns from the marketing literature to address these questions in the music context. This study examines 84,000,000 observations of music listening from 27,000 unique global users between 2013 and 2014 and survey data from 2019 containing music listening from over 1000 representative respondents in the United States. The results show that listening follows the Duplication of Purchase law for genres, artists, albums, and songs, at an annual, 6-months, 3-months, 1-month, and 1-week period, with no indication of partitioned music listening. The implication is that musicians should try to reach all potential listeners, regardless of what they already listen to. These findings contribute to the theoretical knowledge about duplication analyses of various durations, extend the contexts of choice behaviour that exhibit this pattern, and managerially, to knowledge about the extent of potential audiences and ‘share of ear’ competition.     

The ‘Collective Pierre Rivière’: Using collective biography and ambling conversational methods to interrogate and re-present pivotal moments from the Pierre Rivière narratives

Collective biography is a research strategy that works at the level of bodily and emotional knowledge and moves beyond individualized versions of the subject, towards subjects-in-process and subjects-in-relation (Davies and Gannon, 2006). In this paper we, the authors, reflect upon and describe our experiences of using collective biography practices as a way of interrogating and writing our way into ‘pivotal moments’ within the Pierre Rivière texts (both book and film). The collective writing about ‘pivotal moments’ that our research group generated during workshops held at a university, exploring the ‘Pierre Rivière’ narratives have then been further reworked into a reflective, layered account, through an ambling conversational process.     

Modeling error variance in job specification ratings: the influence of rater, job, and organization-level factors

The authors modeled sources of error variance in job specification ratings collected from 3 levels of raters across 5 organizations (N=381). Variance components models were used to estimate the variance in ratings attributable to true score (variance between knowledge, skills, abilities, and other characteristics [KSAOs]) and error (KSAO-by-rater and residual variance). Subsequent models partitioned error variance into components related to the organization, position level, and demographic characteristics of the raters. Analyses revealed that the differential ordering of KSAOs by raters was not a function of these characteristics but rather was due to unexplained rating differences among the raters. The implications of these results for job specification and validity transportability are discussed.     

Learning and production of movement sequences: behavioral, neurophysiological, and modeling perspectives

A wave of recent behavioral studies has generated a new wealth of parametric observations about serial order behavior. What was a trickle of neurophysiological studies has grown to a steady stream of probes of neural sites and mechanisms underlying sequential behavior. Moreover, simulation models of serial behavior generation have begun to open a channel to link cellular dynamics with cognitive and behavioral dynamics. Here we review major results from prominent sequence learning and performance tasks, namely immediate serial recall, typing, 2 x N, discrete sequence production, and serial reaction time. These tasks populate a continuum from higher to lower degrees of internal control of sequential organization and probe important contemporary issues such as the nature of working-memory representations for sequential behavior, and the development and role of chunks in hierarchical control. The main movement classes reviewed are speech and keypressing, both involving small amplitude movements amenable to parametric study. A synopsis of serial order models, vis-a-vis major empirical findings leads to a focus on competitive queuing (CQ) models. Recently, the many behavioral predictive successes of CQ models have been complemented by successful prediction of distinctively patterned electrophysiological recordings. In lateral prefrontal cortex, parallel activation dynamics of multiple neural ensembles strikingly matches the parallel dynamics predicted by CQ theory. An extended CQ simulation model--the N-STREAMS neural network model--exemplifies ongoing attempts to accommodate a broad range of both behavioral and neurobiological data within a CQ-consistent theory.     

Sexual Priming, Gender Stereotyping, and Likelihood to Sexually Harass: Examining the Cognitive Effects of Playing a Sexually-Explicit Video Game

The present study examines the short-term cognitive effects of playing a sexually explicit video game with female “objectification” content on male players. Seventy-four male students from a university in California, U.S. participated in a laboratory experiment. They were randomly assigned to play either a sexually-explicit game or one of two control games. Participants’ cognitive accessibility to sexual and sexually objectifying thoughts was measured in a lexical decision task. A likelihood-to-sexually-harass scale was also administered. Results show that playing a video game with the theme of female “objectification” may prime thoughts related to sex, encourage men to view women as sex objects, and lead to self-reported tendencies to behave inappropriately towards women in social situations.     

Shyness and sociability: a dangerous combination for illicit substance use in adolescent males?

Researchers have hypothesized that behavioral problems are accentuated when a shy person wants to be with other people. This need to be with others--sociability--is a related but separate construct from shyness. The purpose of the present study was to examine the relationship of shyness and sociability to illicit substance use in a sample of 654 male high school students. It was found that, in general, shy male adolescents were significantly more likely to use illicit substances when compared to those who were not shy. Those who were shy and highly sociable were significantly more likely to use hallucinogenic substances than were those who were shy and low to moderate in sociability as well as those who were not shy. Although not significant, there was a trend toward more cocaine and marijuana use among those who were shy and highly sociable. The implications of these findings for those who work with adolescents are discussed.     

Sensitivity reductions in false recognition: a measure of false memories with stronger theoretical implications

Signal detection analyses of recognition memory indicate that a bias to respond "old" is large for critical words that are centrally related with previously encoded word lists, is small for words that are less related, and is not observed for unrelated words. Also, recognition sensitivity has not been previously shown to differ between those conditions, which has focused debate over how to explain false recognition on the bias differences. In 3 experiments, critical-word sensitivity was lower than sensitivity for other word types, but related-word sensitivity was not lower than sensitivity for unrelated words. Extant models that predict reduced critical-word sensitivity also predict lower sensitivity for related words than for unrelated words. These results provide crucial new constraints on theoretical explanations of false memories.