Peter H. Venables

Low Resting Heart Rate at Age 3 Years Predisposes to Aggression at Age 11 Years: Evidence From the Mauritius Child Health Project

OBJECTIVE Previous studies indicate that low resting heart rate is probably the best-replicated biological correlate of childhood antisocial and aggressive behavior. Nevertheless, there have been few longitudinal tests of this relationship, little control over potential confounds and mediators, and no test of its cross-cultural generalizability. This study tests the hypothesis that low resting heart rate at age 3 years predicts aggression at age 11 years. METHOD Resting heart rate at age 3 years was assessed in 1,795 male and female children from Mauritius. Aggressive and nonaggressive forms of antisocial behavior were assessed at age 11 years using the Child Behavior Checklist. RESULTS Aggressive children had lower heart rates than nonaggressive children (p < .001). Conversely, those with low heart rates were more aggressive than those with high heart rates (p < .003). There were no interactions with gender or ethnicity. Evidence was found for specificity of low heart rate to aggressive forms of antisocial behavior. Group differences in heart rate were not attributable to 11 biological, psychological, and psychiatric mediators and confounds. CONCLUSIONS It is concluded that low resting heart rate, a partly heritable trait reflecting fearlessness and stimulation-seeking, is an important, diagnostically specific, well-replicated, early biological marker for later aggressive behavior.

Early educational and health enrichment at age 3–5 years is associated with increased autonomic and central nervous system arousal and orienting at age 11 years: Evidence from the Mauritius Child Health Project

Little is known about the effects of environmental enrichment on psychophysiological measures of arousal and orienting in humans. This study tests the hypothesis that early educational and health enrichment is associated with long-term increases in psychophysiological orienting and arousal. One hundred children were experimentally assigned to a two-year enriched nursery school intervention at ages 3-5 years and matched at age 3 years on psychophysiological measures, gender, and ethnicity to 100 comparisons who received the normal educational experience. Children were retested 6-8 years later at age 11 years on skin conductance (SC) and electroencephalogram (EEG) measures of arousal and attention during pre- and postexperimental rest periods and during the continuous performance task. Nursery enrichment was associated with increased SC amplitudes, faster SC rise times, faster SC recovery times, and less slow-wave EEG during both rest and CPT conditions. This is believed to be the first study to show that early environmental enrichment is associated with long-term increases in psychophysiological orienting and arousal in humans. Results draw attention to the important influence of the early environment in shaping later psychophysiological functioning.

Classical conditioning and socialization—A biosocial interaction

While Eysenck (1977) has argued that socialization is in part determined by classical conditioning, there is little difinitive evidence to support this hypothesis. Close inspection of investigations carried out to date reveal most to contain conceptual or methodological flaws which invalidate their results as a strict test of Eysencks theory. An attempt was made to circumvent these problems by testing Eysencks undersocialization-poor conditionability prediction on a sample of 101 15-year-old male schoolchildren using self-report and teacher rating measures of socialization in conjuction with skin conductance measures of classical conditioning. This study also investigated the more specific hypothesis that biological predispositional factors are of particular relevance in determining antisocial conduct in the higher social classes (Mednick et al., 1977). Results of the first analysis provided no support for Eysencks theory. In a second analysis an undersocialization-poor conditionability relationship was uncovered in the high-class children, a relationship which was reversed in the low classes. This result contradicts Eysencks general prediction, is not readily interpretable by Mednicks analysis, but is explained by Eysencks suggestion that in more criminogenic environments, superior conditionability facilities antisocial behaviour. These results suggest that the interaction between conditionability and social milieu needs to play a much more central role in the explanation of antisocial conduct than hitherto.

Association of Poor Childhood Fear Conditioning and Adult Crime

OBJECTIVE Amygdala dysfunction is theorized to give rise to poor fear conditioning, which in turn predisposes to crime, but it is not known whether poor conditioning precedes criminal offending. This study prospectively assessed whether poor fear conditioning early in life predisposes to adult crime in a large cohort. METHOD Electrodermal fear conditioning was assessed in a cohort of 1,795 children at age 3, and registration for criminal offending was ascertained at age 23. In a case-control design, 137 cohort members with a criminal record were matched on gender, ethnicity, and social adversity with 274 noncriminal comparison members. Statistical analyses compared childhood fear conditioning for the two groups. RESULTS Criminal offenders showed significantly reduced electrodermal fear conditioning at age 3 compared to matched comparison subjects. CONCLUSIONS Poor fear conditioning at age 3 predisposes to crime at age 23. Poor fear conditioning early in life implicates amygdala and ventral prefrontal cortex dysfunction and a lack of fear of socializing punishments in children who grow up to become criminals. These findings are consistent with a neurodevelopmental contribution to crime causation.

Early temperamental and psychophysiological precursors of adult psychopathic personality

Emerging research on psychopathy in children and adolescents raises the question of whether indicators, such as temperament or psychophysiology, exist very early in life in those with a psychopathic-like personality in adulthood. This study tests the hypothesis that individuals who are more psychopathic in adulthood would be less fearful and inhibited and more stimulation seeking/sociable at age 3 and that they would also show reduced age 3 skin-conductance (SC) responsivity. In a community sample of 335 3-year-olds, behavioral measures of temperament were taken and electrodermal activity was recorded in response to both orienting and aversive tones. R. D. Hares (1985) Self-Report Psychopathy scale (SRP-II) was administered at follow-up at age 28. Individuals scoring higher on the measure were significantly less fearful and inhibited, were more sociable, and displayed longer SC half-recovery times to aversive stimuli compared with controls at age 3. Contrary to predictions, they also showed increased autonomic arousal and SC orienting. Findings appear to be the first to suggest that a prospective link may exist between temperament and psychophysiology in very young children and psychopathic personality in adulthood.

Reduced electrodermal activity in psychopathy-prone adolescents

This study tests the hypothesis that psychopathy-prone adolescents show reduced anticipatory skin conductance responding. Electrodermal activity was recorded while participants anticipated and responded to a 105 dB signaled or unsignaled white-noise burst. Using an extreme groups design, the authors used Child Psychopathy Scale (D. R. Lynam, 1997) scores from a community sample of 335 male adolescents (age 16) to form control (n = 65) and psychopathy-prone (n = 65) groups. Significantly more psychopathy-prone participants were nonresponders in the signaled anticipatory (p = .014), signaled responsivity (p = .037), and unsignaled responsivity (p = .003) conditions compared with controls. Anticipatory hyporesponsivity of psychopathy-prone adolescents similar to the electrodermal hyporesponsivity found in psychopathic adults suggests that this autonomic impairment is present by adolescence and may predispose individuals to adult psychopathy.

Heart rate and skin conductance in behaviorally inhibited Mauritian children.

This study tested predictions that inhibited versus uninhibited children exhibit higher heart rate (HR) and skin conductance (SC) arousal. Mauritian children (N = 1,795) were tested at age 3 and classified as inhibited, middle, or uninhibited on the basis of social behavior. HR level and several SC measures were obtained immediately before or during a tone task. Inhibited children displayed significantly higher HR and SC levels and longer SC latency relative to uninhibited children. Results remained regardless of ethnicity, gender, height, weight, respiratory complaints, or crying behavior. Findings suggest that HR and SC levels may be early indicators of inhibited or uninhibited behavior at age 3 and support the notion of heightened sympathetic reactivity due to limbic arousal in inhibited children.

Spatial but not verbal cognitive deficits at age 3 years in persistently antisocial individuals

Previous studies have repeatedly shown verbal intelligence deficits in adolescent antisocial individuals, but it is not known whether these deficits are in place prior to kindergarten or, alternatively, whether they are acquired throughout childhood. This study assesses whether cognitive deficits occur as early as age 3 years and whether they are specific to persistently antisocial individuals. Verbal and spatial abilities were assessed at ages 3 and 11 years in 330 male and female children, while antisocial behavior was assessed at ages 8 and 17 years. Persistently antisocial individuals (N = 47) had spatial deficits in the absence of verbal deficits at age 3 years compared to comparisons (N = 133), and also spatial and verbal deficits at age 11 years. Age 3 spatial deficits were independent of social adversity, early hyperactivity, poor test motivation, poor test comprehension, and social discomfort during testing, and they were found in females as well as males. Findings suggest that early spatial deficits contribute to persistent antisocial behavior whereas verbal deficits are developmentally acquired. An early-starter model is proposed whereby early spatial impairments interfere with early bonding and attachment, reflect disrupted right hemisphere affect regulation and expression, and predispose to later persistent antisocial behavior.

Locus of control and socialization

Abstract On the basis of classical association theory, it was predicted that an external locus of control would characterize undersocialization. This hypothesis was tested on a random sample of secondary school children, using a battery of self-report “socialization-delinquent personality” measures to assess degree of socialization. Factorial validity for the use of these measures was obtained from a factor analysis which uncovered a general factor of socialization, while evidence for convergent validity was derived from the relationship between these scales and teacher ratings of refractory behavior. Scores from the Child Nowicki-Strickland Internal-External Scale were found to predict undersocialization in the expected direction. Several possible interpretations of this relationship were suggested and a biosocial explanation was advanced to account for the possible simultaneous development of both externality and undersocialization.

Better Autonomic Conditioning and Faster Electrodermal Half-Recovery Time at Age 15 Years as Possible Protective Factors Against Crime at Age 29 Years.

This prospective study tests the hypothesis that antisocial adolescents who desist from adult crime show better classical conditioning and faster skin conductance half-recovery times at age 15 compared with antisocial adolescents who go on to become adult criminals at age 29. Measures were assessed in 101 unselected 15-year-old male school children. Of these, 17 antisocial adolescents who desisted from adult crime (desistors) were matched with 17 antisocial adolescents who became criminal by age 29 (criminals) and 17 nonantisocial noncriminals (controls). Desistors had significantly better conditioning and faster recovery times than both criminals and controls. These initial findings suggest that better conditioning and enhanced information processing to emotion-relevant events may constitute biological protective factors against crime development.