A Reevaluation of the 1990 “Minnesota Study of Twins Reared Apart” IQ Study

In 1990, Thomas J. Bouchard, Jr. and colleagues published the widely cited 1990 “Minnesota Study of Twins Reared Apart” (MISTRA) Science IQ study. To arrive at the conclusion that “IQ is strongly affected by genetic factors,” Bouchard and colleagues omitted their control group reared-apart dizygotic twin (“DZA”) IQ-score correlations. Near-full-sample correlations published after the study’s 2000 endpoint show that the reared-apart monozygotic twin (“MZA”) and DZA group IQ correlations did not differ at a statistically significant level, suggesting that the study failed the first step in determining that IQ scores are influenced by heredity. After bypassing the model-fitting technique they used in most non-IQ MISTRA studies, the researchers assumed that the MZA group IQ-score correlation alone “directly estimates heritability.” This method was based on unsupported assumptions by the researchers, and they largely overlooked the confounding influence of cohort effects. Bouchard and colleagues then decided to count most environmental influences they did recognize as genetic influences. I conclude that the MISTRA IQ study failed to discover genetic influences on IQ scores and cognitive ability across the studied population, and that the study should be evaluated in the context of psychology’s replication problem.

The Development of Positive Attributes of Character: On the Embodiment of Specificity, Holism, and Self-System Processes

Positive character involves a system of mutually beneficial relations between individual and context that coherently vary across ontogenetic time and enable individuals to engage the social world as moral agents. We present ideas about the development of positive character attributes using three constructs associated with relational developmental systems (RDS) metatheory: the specificity of mutually beneficial individual<-->context dynamics across time and place; holistic integration of dynamic processes of an individual with both context and all cognitive, affective, and behavioral processes; and integration of the character-system with other facets of the self-system. These features of RDS-based ideas coalesce on the embodiment of positive character development. We discuss the need for more robust interrogation of embodied features of the character development system by suggesting that coaction of morphological/physiological processes with cultural processes become part of a program of the integrated individual<-->contextual processes involved in the description, explanation, and optimization of positive character attribute development. We discuss moments of programmatic research that should be involved in this interrogation and point to the potential contribution of theory-predicated research about the embodied development of positive character attributes of to enhancing the presence of moral agency and social justice in the world.

A Road Map for Navigating Next Steps in the Study of Attachment in Middle Childhood: Commentary on Gastelle and Kerns

NA

A Systematic Review of Representational and Behavioral Measures of Parent-Child Attachment Available for Middle Childhood

A variety of parent-child attachment measures, representing a range of conceptual approaches, have been adapted for use in middle childhood. A recent surge in studies using the new methods makes a comprehensive review of these measures timely. This systematic review of 67 studies covers representational and behavioral measures of parent-child attachment used with children 9-12 years old. This paper aims to evaluate parent-child attachment measurements with an emphasis on understanding their theoretical bases in addition to considering the available validity evidence. Findings identify several independently well-validated representational measures, and they highlight a continued need to investigate direct comparisons of the measures, as very little research has considered how the measures relate to each other, both conceptually and empirically. Behavioral measures of attachment in middle childhood, which are relatively new, are identified as potentially important in developing a better understanding of attachment measurement in this age group.