Search

Dr. Auke Tellegen, a renowned personality psychologist and clinical investigator, passed away on March 11, 2024. He was known for his development of the Multidimensional Personality Questionnaire (MPQ) and his contributions to the Minnesota Multiphasic Personality Inventory-2 (MMPI-2). Dr. Tellegen's work on twin studies challenged previous beliefs about the influence of shared environments on personality and mate selection. His research indicated that genes play a significant role in personality resemblance among biological relatives. Dr. Tellegen's contributions to the field of psychology will be remembered and celebrated at a memorial ceremony on May 5, 2024, at the University of Minnesota. [Extracted from the article]

Research suggests that sibling--peer connections are important for understanding adolescent problem behaviors. Using a novel behavioral genetic design, the current study investigated peer network overlap in 300 child--child pairs (aged 7-13 years) in 5 dyad types: monozygotic (MZ), dizygotic twins, full siblings (FSs), friend pairs, and virtual twins (i.e., same-aged, genetically unrelated siblings). Genetic relatedness, sex composition, and age differences contributed to peer overlap in sibling dyads. MZ twins showed the highest overlap (82%), opposite-sex FS pairs showed the lowest overlap (27%), and friend pairs (48%) were close to the mean (53%). Social contact variables and self-reported relationship intimacy predicted additional variance in peer overlap. The roles of genotype--environment correlational and shared environmental processes in the sibling--peer connections are discussed. (Contains 6 tables and 1 figure.)

Genetically informative samples can address hereditary and experiential influences on suicide-related behaviors. The frequency of suicide-related behaviors was compared in twins from two survivor groups: (1) those whose co-twins' deaths were suicides (monozygotic [MZ]: n = 47; dizygotic [DZ]: n = 31), and (2) those whose co-twins' deaths were nonsuicides (MZ: n = 347; DZ: n = 170). The frequency of suicide attempts among suicide survivors was significantly higher in MZ than DZ twins, while the frequency of suicide attempts among nonsuicide twin survivors did not differ between MZ and DZ twins. Twin concordance for suicide attempts more likely reflects a genetic predisposition than a behavioral reaction to the loss.

Fluctuating asymmetry (FA) is the non-pathological left-right asymmetry of body traits that are usually left-right symmetrical, such as eye breadths and elbow to wrist lengths in humans, but which can be affected by developmental stressors. It is generally considered throughout biology to be an indicator of developmental instability and thus of lack of overall biological fitness. Several investigators have proposed that deficiencies in general intelligence ("g") may be indicators of the same kind of instability in human brain development. If so, FA and "g" should be negatively correlated. Moreover, because "g" shows substantial genetic influences, FA should also show genetic influences, and the two sets of genetic influences should be correlated. We investigated these propositions in a sample of 263 adults that included 88 pairs of twins. Results indicated genetic influences on FA, but FA and "g" were not correlated at either the observed or genetic levels.