Impact of pediatric traumatic brain injury on components of verbal memory.

This 3-month longitudinal study examined spared and impaired components of verbal learning and memory after pediatric traumatic brain injury (TBI), using the California Verbal Learning Test for Children. School-aged participants with severe or mild-to-moderate TBI were compared to traumatically injured control subjects without head trauma. Participants were initially evaluated approximately 1 month post injury, and again 3 months later. At Times 1 and 2, participants with severe TBI displayed deficits in immediate recall, delayed recall, and recognition accuracy, consistent with a mild encoding deficit. In both evaluations, participants with mild-to-moderate TBI performed similarly to controls. On average, mild verbal encoding deficits appear to be associated with severe, but not mild-to-moderate, pediatric TBI in the first several months post injury.

Maternally rated childhood gender nonconformity in homosexuals and heterosexuals.

Homosexual and heterosexual subjects provided self-ratings of childhood gender nonconformity. Additionally, their mother rated them on several adjectives describing childhood behavior, which included words related to gender nonconformity. Male homosexuals were remembered by their mothers as less masculine and more nonathletic. This finding did not appear to be due to a bias in mothers' memories. Though female homosexuals were recalled as more masculine than female heterosexuals, this appeared to reflect retrospective bias, as mothers who knew of their daughters' homosexuality were more likely to rate them as masculine. Both self-rated and maternally rated childhood gender nonconformity made independent contributions in predicting sexual orientation. Within the homosexual samples, maternal and self-ratings of subjects' childhood gender nonconformity failed to correlate significantly.

An adoption and a cross-fostering study of the Minnesota Multiphasic Personality Inventory (MMPI) Psychopathic Deviate Scale.

The first of two complementary studies compared biological and adoptive parents of teenage adoptees with either higher (n = 21) or low (n = 51) MMPI Psychopathic Deviate (Pd) scale scores. In comparison to biological mothers of the low-Pd adoptees, biological mothers of the high-Pd adoptees obtained significantly higher MMPI scores on six of eight clinical scales. Fewer differences existed between the corresponding groups of adoptive mothers, but adoptive mothers of the high Pd's did obtain significantly higher scores on the Pd and Hypomania scales. Substantial genetic correspondences also existed for Harris-Lingoes content subscales, with fewer correspondences between adoptees and their adoptive mothers. There were indications that adoptive mothers of the high-Pd children had personality traits which may have made them less effective in attenuating early signs of antisocial behavior. The second study employed a cross-fostering design dividing all biological and adoptive mothers (n = 138 each) by their respective median Pd raw scores to examine effects on offspring. Results confirmed the effect of biological mother Pd score, but only a trend suggested an adoptive mother effect, with no hint of an interaction.

A test of the maternal stress theory of human male homosexuality.

Both the neurohormonal theory of sexual orientation and previous research on humans and animals suggest that male homosexuality may arise from prenatal stress during the brain's sexual differentiation. Stress-proneness and retrospective reports of stress during pregnancy were obtained from mothers of male and female heterosexuals, bisexuals, and homosexuals. Each mother also rated pregnancy stress for a heterosexual sibling of the subject. For males, neither between-family nor within-family analyses revealed a maternal stress effect for either sexual orientation or childhood gender nonconformity. However, mothers of effeminate children reported more stress-proneness than other mothers. Male homosexuality nevertheless was strongly familial, suggesting a reconsideration of genetic and familial environmental mechanisms.

Negative symptoms in schizophrenia and nailfold plexus visibility.

Visibility of the nailfold vascular plexus has shown promise as a genetically transmitted marker for liability to schizophrenia. To assess whether this marker is specifically associated with negative or positive symptoms of schizophrenia, we reanalyzed patient data collected 20 years ago, well before interest in the negative/positive symptom distinction. Eighty-four patients, who retrospectively met DSM-III-R criteria for schizophrenia, had been rated for plexus visualization score (PVS) and independently interviewed using the Mental Status Schedule (MSS). Content scales were derived from the MSS to assess negative, positive, and affective symptoms. There was a highly significant correlation between PVS and negative symptoms (including verbal, motor, cognitive and motivational deficits), but not between PVS and positive or affective symptoms. These findings indicate that the negative symptoms of schizophrenia are due to a disease process biologically distinguishable from those causing positive symptoms and that plexus visibility is a risk marker for this pathology.

Heredity, environment, and personality change: evidence from the Texas Adoption Project.

Personality changes over time can be analyzed by the same twin and adoption methods used to analyze the genetic and environmental influences on a trait at a given time. Composite parent rating measures of Extra-version, Socialization, and Stability made on two occasions approximately 10 years apart on 229 adopted and 83 nonadopted children from the Texas Adoption Project were used to illustrate this point in two ways. The first was based on correlations among family members, from which it appeared that by far the chief source of individual change was neither the genes nor shared family environment, but individual experience (and/or measurement error). The second was via a path-analytic approach to changes in the means of adopted and natural children, from which it appeared that, nonetheless, the children were tending to change on the average in the direction of their genetic parents' personalities.

Modeling IQ change: evidence from the Texas Adoption Project.

An analysis of genetic and environmental contributions to intellectual change was carried out by means of a path model applied to IQ data from the Texas Adoption Project, an adoption study in which children were measured on 2 occasions approximately 10 years apart. Included in the model were assortative mating, selective placement, genotype-environment correlation, a measure of socioeconomic status, and alternative hypotheses about cross-generation environmental transmission and the persistence of a trait over time. Some form of environmental transmission across generations was necessary, but either of the 2 forms tested was sufficient. The data were best fit by considering persistence over time to occur at the level of the developed trait. The effect of both genes and family environment was significant at the time of the first measurement, but only the genes made an additional contribution between the first and the second, suggesting the necessity of revising some popular stereotypes about development.

Personality resemblances in adoptive families when the children are late-adolescent or adult.

Members of 220 families who had adopted one or more children from a Texas home for unwed mothers at least 14 years ago completed the California Psychological Inventory and the Thurstone Temperament Schedule. Consistent with other recent adoption studies in Minnesota and Texas, there was very little resemblance between parents and adopted children or between adoptive siblings (average correlations about .05). The presence of a biological relationship raised correlations a little, but only a little, to about .15, suggesting that much of the explanation for personality variation must lie in within-family environmental variation or nonadditive genetic effects. In an earlier study, young adopted children appeared to be better adjusted, on the average, than biological children in the same families. This was no longer true for the late-adolescents and young adults of the present study.

Personality resemblances between unwed mothers and their adopted-away offspring.

In a sample of 300 adoptive families there was a tendency for adopted children to be more extraverted and emotionally stable than biological children. For extraversion there was a low statistically significant resemblance between unwed mothers and their adopted-away children. Paradoxically, however, children of mothers with elevated Minnesota Multiphasic Personality Inventory (MMPI) scores tended to be rated as more emotionally stable than children of mothers with better adjustment on the MMPI. This latter finding was interpreted as suggested an interaction between emotional sensitivity and the early environment. According to this hypothesis, individuals with genotypes making them vulnerable to their environments could thrive in the warm climate of the adoptive families, but turn out relatively badly in the presumably less benign families in which the unwed mothers were reared.

Personality resemblance in adoptive families.

Adoption studies provide an opportunity to check on twin-study inferences about genetic and environmental effects on personality. The Texas Adoption Project obtained personality tests and ratings from members of 300 adoptive families: MMPIs and 16PFs for adults, and Cattell scales and parents' ratings for children. Overall there was little personality resemblance among family members, either biologically or adoptively related. Median correlations were typically positive, but under 0.10. Elimination of a rating bias and the use of multiple correlations did not yield notably higher levels of prediction, but restriction to a subsample of well-measured children provided higher correlations and more evidence of heritability, particularly in the extraversion domain.

Examiner effects in adoption studies of intelligence.

To test the hypothesis that examiner differences influence family correlations in adoption studies of intelligence, data from two recent adoption studies were reanalyzed as a function of whether the same or different examiners tested both members of a pair. While each study yielded trends suggesting examiner effects on correlations, results of the two studies were directly counter to each other. Our conclusion is that examiner effects are not yet predictable and, overall, cannot be demonstrated to bias adoption studies of intelligence.

Intellectual resemblance among adoptive adoptive and biological relatives: the Texas adoption project.

Intellectual and personality measures were available from unwed mothers who gave their children up for adoption at birth. The same or similar measures have been obtained from 300 sets of adoptive parents and all of their adopted and natural children in the Texas Adoption Project. The sample characteristics are discussed in detail, and the basic findings for IQ are presented. Initial analyses of the data on IQ suggest moderate heritabilities. Emphasis is placed on the preliminary nature of these findings.

The aptitude-achievement test distinction: a study of unrelated children reared together.

Unrelated children reared together (N = 156) in 71 different families included in the Texas Adoption Project were compared for similarities on intelligence and achievement tests. The purpose was to see if a distinction between the two types of tests based on their heritabilities could be sustained. Results indicated no substantial differences in correlations for the two types of tests, and hence little or no support for the notion of an aptitude-achievement distinction based on differential heritabilities.