Caroline L. Bokhorst

In Search of Shared and Nonshared Environmental Factors in Security of Attachment: A Behavior-Genetic Study of the Association between Sensitivity and Attachment Security.

The current article presents results from a twin study of genetic and environmental components of maternal sensitivity and infant attachment and their association. The sample consisted of 136 twin pairs from 2 sites: Leiden, the Netherlands, and London, UK. Maternal sensitivity was assessed in the home at 9-10 months, and infant attachment security was observed in the laboratory at 12 months. The study yielded little evidence that genetic factors are involved in variations between twins in maternal sensitivity ratings but did find that shared variance in maternal sensitivity was able to account for some of the similarity between twins in attachment security. Weak nonshared associations between sensitivity and attachment appeared to suppress the magnitude of the correlation between attachment and sensitivity in twin children. The results could indicate that the attachment security of one twin may depend on the relationship the parent has with the other twin. The results are brought to bear on the validity of attachment theory as a theory of primarily shared environmental effects in childrens development and the continuing challenge posed to attachment theory by within-family differences in socioemotional processes.

A prepared speech in front of a pre-recorded audience: Subjective, physiological, and neuroendocrine responses to the Leiden Public Speaking Task

This study describes a new public speaking protocol for youth. The main question asked whether a speech prepared at home and given in front of a pre-recorded audience creates a condition of social-evaluative threat. Findings showed that, on average, this task elicits a moderate stress response in a community sample of 83 12- to 15-year-old adolescents. During the speech, participants reported feeling more nervous and having higher heart rate and sweatiness of the hands than at baseline or recovery. Likewise, physiological (heart rate and skin conductance) and neuroendocrine (cortisol) activity were higher during the speech than at baseline or recovery. Additionally, an anticipation effect was observed: baseline levels were higher than recovery levels for most variables. Taking the anticipation and speech response together, a substantial cortisol response was observed for 55% of participants. The findings indicate that the Leiden Public Speaking Task might be particularly suited to investigate individual differences in sensitivity to social-evaluative situations.

Age and puberty differences in stress responses during a public speaking task: Do adolescents grow more sensitive to social evaluation?

During adolescence pubertal development is said to lead to an increase in general stress sensitivity which might create a vulnerability for the emergence of psychopathology during this period. However, the empirical evidence for increasing stress sensitivity is scarce and mixed. Biological responses (salivary cortisol and alpha-amylase) were investigated during a social-evaluative stressor, the Leiden Public Speaking Task, in 295 nine to 17-year olds. Specific attention was paid to different elements of the task, that is anticipation to and delivery of the speech. Biological reactivity to the speech task increased with age and puberty, particularly during anticipation. Current findings support the idea that biological stress sensitivity increases during adolescence, at least in response to a social-evaluative situation. The increasing stress sensitivity appears related to both age and pubertal maturation, but unique contribution could not be distinguished. The importance of measuring anticipation is discussed.

The importance of shared environment in infant-father attachment: A behavioral genetic study of the Attachment Q-Sort

In this first behavior genetic study on infant-father attachment, we estimated genetic and environmental influences on infant-father attachment behaviors and on temperamental dependency, both assessed with the Attachment Q-Sort (AQS; B. E. Vaughn & E. Waters, 1990; E. Waters, 1995). Mothers of mono- and dizygotic twins (N = 56 pairs) sorted the AQS with a focus on the infants behaviors in the presence of the father. Genetic modeling showed that attachment was largely explained by shared environmental (59%) and unique environmental (41%) factors. For dependency, genetic factors explained 66% of the variance, and unique environmental factors including measurement error explained 34%. Attachment to father appears to be, to a significant degree, a function of the environment that twins share.

Social fears during adolescence: Is there an increase in distress and avoidance?

Mid-adolescence is considered as the time of onset for social phobia and is assumed to be related to a normative increase of social fears. People diagnosed with social phobia, however, do not only experience high levels of fear or distress, but also report avoidance behavior. Little attention has been paid to the development of avoidance behavior during adolescence. In the current study, a community sample with 9-17 year olds (n=260) completed a questionnaire derived from the Anxiety Disorders Interview Schedule for Children (ADIS-C) [Silverman, W. K., & Albano, A. M. (1996). Anxiety disorders interview schedule for DSM-IV child version, child interview schedule. San Antonio: The Psychological Corporation]. They rated their levels of distress and avoidance in a variety of social situations. The results showed an age related increase for formal speaking and interaction situations in both avoidance and distress, with a stronger increase in avoidance than in distress. The same pattern was found for girls for situations regarding observation by others. No effects were observed for informal speaking and interaction situations.

Resistance and conformity

Resistance to peer influence, or the ability to resist making choices or adopting views under the implicit or explicit influence of your peers, is expected to undergo changes during adolescence. Two developmental trajectories have emerged from the field. On the one hand, adolescents show a temporary decrease in resistance to peer influence when it comes to antisocial situations, whereas on the other hand, adolescents seem to grow more resistant to neutral peer influence. Studies that have investigated age and gender differences in self-reported resistance to peer influence will be reviewed. In addition, relationships between resistance to peer influence and neuromaturational changes, both functional and structural, will be discussed. Finally, possibilities for future strands of research are suggested to further the field of resistance to peer influence. The current essay will discuss a range of studies that investigated resistance to peer influence over the past decades. Special attention will be paid to effects of used setting in which peer influence is assessed on the conclusions that are drawn about the development of resistance to peer influence. The negative framework for studying resistance to peer influence will be contrasted with a neutral framework. The negative framework refers to the fact that many researchers have investigated resistance to peer influence in relation to antisocial activities (e.g., delinquency) and adolescent problem behavior (e.g., alcohol abuse and smoking). On the other hand, neutral resistance to peer influence has been the subject of more recent research studies. The term neutral resistance to peer influence is used here to indicate peer influence that does not occur in an antisocial setting but is assessed in relation to a neutral context. For instance, the value attached to being an individual rather than part of the crowd or the willingness to change your ideas to more closely reflect those of your peers. These are studies that have explicitly tried to minimize the negative connotations in their methodology. In addition to reviewing studies that have investigated age differences in self-reported resistance to peer influence, a new avenue of research will be discussed. These studies conducted by among others Paus and colleagues (e.g., Grosbras et al. 2007; Paus et al. 2008) have investigated the relationship between neuromaturational changes and the development of resistance to peer influence. Finally, future strands of research are suggested for the study of resistance to peer influence.