PubMed Health⌕ Search

Biomedical subjects

L Willerman

Publications and source records attributed to L Willerman.

At least 19 recordsLinked to original sources
PubMed1992

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.

Adolescent↗
PubMed1991

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.

Adolescent↗
PubMed1991

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.

Female↗
PubMed1990

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.

Adoption↗
PubMed1989

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.

Adolescent↗
PubMed1985

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.

Adolescent↗
PubMed1979

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.

Adolescent↗
PubMed1977

Sex differences in WAIS item performance.

Although the WAIS IQ scores of males and females differ only negligibly, significant sex differences do exist on many WAIS subtests. The purpose of the present investigation was to identify any WAIS items within these subtests that showed reliable sex differences. Within a cross-validation methodology that employed 521 adults (264 males; 257 females), 21 items were found to show reliable sex differences. A reanalysis by age groups provided similar results. The nature of the items was discussed, and an index of stereotyped sex-role experiences was proposed.

Adult↗
PubMed1977

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.

Achievement↗
PubMed1976

Personality correlates of WAIS performance.

The relationships between two of Cattell's second-stratum factors, Cortertia and Temperamental Independence, and WAIS scores were investigated for 122 men and 127 women. For men, both Cortertia and Temperamental Independence were related significantly to WAIS scores. For women, Temperamental Independence, but not Cortertia, correlated significantly with WAIS scores. The variability in the degree of relationship between the individual subtests and the personality factors was noted, and the cross-lagged panel correlation methodology was suggested as a possible approach to investigate the causal connections between personality factors and abilities.

Adult↗
PubMed1976

Resemblance in appearance and the equal environments assumption in twin studies of personality traits.

The equal environments hypothesis of twin methodology was examined for the variable of similarity of appearance as it affects the personality ratings of young twins. There were two separate samples, the first with 95 pairs of same-sex twins and the second with 111 pairs. The average age of the twins in both samples was 3-1/2 years. Mothers rated their twins on four personality traits and on confusability of appearance. Not surprisingly, identical twins were markedly more similar in appearance than fraternal twins. The effect of this inequality on the personality ratings of the two types of twins was examined by correlating ratings of similarity of appearance with the absolute difference on the four personality traits for each pair of twins. None of the correlations was significant for the identical twins, suggesting that greater resemblance in appearance in identical twins does not make them more similar in personality. Indeed, the data suggested a contrast effect in which identical twins who were easily mistaken in appearance tended to be rated as less similar in personality. Thus, although similarity of appearance may create unequal environments for the two types of twins, it does not appear to bias twin studies in the direction of inflated heritabilities, at least for rating studies of the personality of young twins.

Child, Preschool↗
PubMed1976

Nature-nurture and intelligence: the twin and adoption studies agree.

A large-scale adoption study is underway at the University of Texas where IQ test scores are available for over 1200 women who gave up their children for adoption immediately following delivery. The adopted children and their adoptive families are now being located and tested and, if current trends continue, complete data should eventually be available on over 400 families. About half of these families will contain two or more adopted children or both adopted and natural children. At present, data are available for 89 families. The results are consistent with twin data and support a genetic hypothesis. The biological mother-adopted child correlation is 0.37 whereas the adoptive mother-adopted child and adoptive father-adopted child correlations are only 0.22 and 0.04 respectively. There are 59 pairs of unrelated children reared together in this sample and the IQ correlation for these children is only 0.13.

Adoption↗
PubMed1976

Retention of learned temperature changes during problem solving.

In 2 studies (ns = 10, 9) college students were trained using biofeedback to lower or to raise finger temperature. Successful subjects were then asked to do distracting intellectual tasks, while simultaneously retaining the learned temperature changes. Results indicated that these changes could be maintained without detectable decreases in problem-solving efficiency in terms of either time or number of errors. These findings suggested that it might be possible for subjects to function efficiently outside the laboratory in their everyday activities while simultaneously exercising voluntary control over some autonomic processes.

Adult↗