Reduced prefrontal and increased subcortical brain functioning assessed using positron emission tomography in predatory and affective murderers

There appear to be no brain imaging studies investigating which brain mechanisms subserve affective, impulsive violence versus planned, predatory violence. It was hypothesized that affectively violent offenders would have lower prefrontal activity, higher subcortical activity, and reduced prefrontal/subcortical ratios relative to controls, while predatory violent offenders would show relatively normal brain functioning. Glucose metabolism was assessed using positron emission tomography in 41 comparisons, 15 predatory murderers, and nine affective murderers in left and right hemisphere prefrontal (medial and lateral) and subcortical (amygdala, midbrain, hippocampus, and thalamus) regions. Affective murderers relative to comparisons had lower left and right prefrontal functioning, higher right hemisphere subcortical functioning, and lower right hemisphere prefrontal/subcortical ratios. In contrast, predatory murderers had prefrontal functioning that was more equivalent to comparisons, while also having excessively high right subcortical activity. Results support the hypothesis that emotional, unplanned impulsive murderers are less able to regulate and control aggressive impulses generated from subcortical structures due to deficient prefrontal regulation. It is hypothesized that excessive subcortical activity predisposes to aggressive behaviour, but that while predatory murderers have sufficiently good prefrontal functioning to regulate these aggressive impulses, the affective murderers lack such prefrontal control over emotion regulation. © 1998 John Wiley & Sons, Ltd.     

“There is Nothing Good About this Work:” Identity and Unhappiness Among Nicaraguan Female Sex Workers

In a study of life satisfaction in Nicaragua, Cox (2012) found that female sex workers had dramatically low subjective well-being (SWB) relative to other marginalized groups in Nicaragua. Moreover, the SWB of these female sex workers was possibly the lowest recorded in the life satisfaction literature. A novel theory linking life satisfaction with life stories is proposed, and a method not heretofore used in SWB research is employed, the life story interview, in order to better understand the dramatic unhappiness of this sample. Seeing life satisfaction as an identity invoking process, the sample’s dramatically low life satisfaction judgments are framed within the larger context of narrative identity. Thematic analysis of the stories revealed a prototypical narrative arc: early family conflict, departure from home, a series of unsuccessful romantic relationships, birth of multiple children, dire economic crises, entry into sex work, and hope for a future exit from sex work. The life stories of these participants provided an identity and life course context to understand the dramatic unhappiness of this sample.     

Intelligence and changes in regional cerebral glucose metabolic rate following learning

Positron emission tomography (PET) studies of brain glucose metabolic rate (GMR) in normal volunteers report inverse correlations between GMR and scores on the Raven's Advanced Progressive Matrices (RAPM) and verbal fluency. A new study in eight normal men reports widespread significant GMR decreases following learning a complex task (the computer game “Tetris”). The purpose of this study is to ascertain the correlations between GMR changes following learning “Tetris” and psychometric intelligence scores (RAPM and WAIS-R) to determine whether high-ability subjects show the largest GMR decreases, as predicted by a brain efficiency hypothesis. This hypothesis is supported with significant correlations between the magnitude of GMR change and intelligence scores in many brain areas that changed with learning. Some implications for the role of attention, memory, and speed of processing are discussed in view of the specific brain areas involved.     

Contrast effects on the auditory evoked response and its relation to psychophysical judgments

An auditory average evoked response (AER) procedure was used to search for a physiological counterpart of the contrast effect-the tendency for a S’s judgment of the intensity of a stimulus to be modified by the intensity of prior stimulation. When a tone was preceded by a softer tone, its AER amplitude increased; conversely, when a tone followed a louder tone, amplitude decreased. Irregular intervals between tones decreased the AER contrast effect, as did increasing the interval between tones. Further, significant correlations were found between individual scores on the AER contrast procedure and performance on a battery of psychophysical tasks.     

Demand awareness, subject sophistication, and the effectiveness of a verbal "reinforcement"

A cognitive or problem-solving interpretation of verbal conditioning was extended by making explicit the role of demand awareness and cooperation motivation in mediating the behavior. It was found that the word “reinforcement” itself was effective in producing verbal conditioning, and as predicted there was a highly significant difference between subjects who had taken a course in psychology and those who had not Postexperimental measures of contingency awareness, demand awareness and cooperation motivation all correlated with experimental performance That the strongest association was obtained when demand awareness plus cooperation motivation were considered was interpreted as indicating the crucial importance of these variables in mediating so-called verbal conditioning Data were interpreted as questioning the appropriateness of using the concepts of instrumental appetitive conditioning to describe so-called verbal conditioning. The effect seems to be an artifact of subjects cooperating with experimental demand characteristics     

Psychological type of American Evangelical missionary candidates

Sending missionaries into the field requires an enormous up-front investment on the part of the candidate as well as the sending organisation. An effective candidate selection process can limit the significant financial and emotional effects of a bad fit for a field placement. The present study seeks to analyse the typology of missionary candidates, using the Myers–Briggs Type Indicator (MBTI). A sample of 475 American Evangelical missionary candidates took the MBTI as part of their candidacy process. Results indicate that there were significant differences on 12 of the 16 MBTI typologies of the missionary candidates compared to the national representative sample. The ENFJ (14.1%) and ENFP (14.1%) typologies were significantly overrepresented in the sample. The personality types most underrepresented were ISTP (1.1%) and ISFP (1.7%). Comparisons with similar religious populations are discussed. Implications for how missionary candidates may adjust to field work based on type are considered.     

Compensatory neoplasia: Chronic erythrocytosis and neuroblastic tumors

There are a large number of exogenous biological and chemical substances with known neoplastic or carcinogenic potential. However, it has also been postulated that external stimuli can influence the body's internal milieu, and thereby induce compensatory excessive growth of cells in the form of hyperplasia or neoplasia. In a recent study, we observed a strong association between chronic hypoxic states and the occurrence of peripheral neuroblastic tumors, a relatively uncommon group of neural neoplasms. In this report we review those findings and formulate an hypothesis to explain why conditions which lead to chronic erythrocytosis may also cause compensatory neoplasia of neural tissues.