Katie T. Kivlighan

The ''trouble'' with salivary testosterone

In a series of studies, we identify several specific issues that can limit the value of integrating salivary testosterone in biosocial research. Salivary testosterone measurements can be substantially influenced during the process of sample collection, are susceptible to interference effects caused by the leakage of blood (plasma) into saliva, and are sensitive to storage conditions when samples have been archived. There are gender differences in salivary testosterone levels and variance, the serum-saliva association, the relationship of salivary testosterone to age and pubertal development, and the stability of individual differences in salivary testosterone levels over time. The findings have important implications at several levels of analysis for research that aims to test biosocial models of testosterone--behavior relationships. Recommendations are provided to steer investigators around these troubles with salivary testosterone.

Salivary cortisol mediates effects of poverty and parenting on executive functions in early childhood.

In a predominantly low-income population-based longitudinal sample of 1,292 children followed from birth, higher level of salivary cortisol assessed at ages 7, 15, and 24 months was uniquely associated with lower executive function ability and to a lesser extent IQ at age 3 years. Measures of positive and negative aspects of parenting and household risk were also uniquely related to both executive functions and IQ. The effect of positive parenting on executive functions was partially mediated through cortisol. Typical or resting level of cortisol was increased in African American relative to White participants. In combination with positive and negative parenting and household risk, cortisol mediated effects of income-to-need, maternal education, and African American ethnicity on child cognitive ability.

Gender differences in testosterone and cortisol response to competition.

This study examined intra-individual change in testosterone, cortisol, and hormone-behavior relationships in response to a rowing ergometer competition. Forty-six members (23 females) of a university crew team provided saliva samples before, 20- and 40-min post-competition, as well as baselines on a non-competition day. Behavioral assessments included measures of previous rowing experience, dominance, competitiveness, bonding with teammates, pre- and post-competition mental state and performance. Mens and womens endocrine responses to this competitive setting were more different than alike and varied by level of competitive experience, the specific phase of the competitive event, and the particular hormone measured. Inter-individual differences in testosterone and cortisol were differentially associated with social affiliation with teammates but rarely with dominance or competitiveness. Theoretically, the findings support the integration of features of the tend and befriend model with the biosocial model of status, and suggest future research directions that may lead to clarification and refinement of those ideas.

Quantifying blood leakage into the oral mucosa and its effects on the measurement of cortisol, dehydroepiandrosterone, and testosterone in saliva

The impact of blood leakage due to microinjury to the oral cavity on the measurement of salivary hormones was examined. Saliva samples were collected before, immediately after, and then every 15 min for 1 h following vigorous tooth brushing. Blood in saliva was quantified by visual inspection of discoloration, Hemastix reagent strips to detect hemoglobin, and an immunoassay for transferrin. The presence of blood in saliva immediately after microinjury was confirmed by all methods. Hemoglobin and transferrin levels remained elevated over baseline for at least 30 min. Levels of salivary testosterone increased over baseline and remained elevated for 30 min in response to microinjury. Microinjury induced change in salivary testosterone was more closely associated with the change in transferrin than hemoglobin levels or discoloration ratings. On average, levels of salivary dehydroepiandrosterone (DHEA) did not increase in response to microinjury. However, individual differences in microinjury induced change in DHEA were associated with discoloration ratings. Salivary cortisol levels, on average, were neither responsive to microinjury, nor were individual differences in cortisol change associated with blood contamination measures. Neither diurnal nor gender-related differences in baseline hormone levels predicted the impact of blood leakage on quantitative salivary measurements. The findings suggest ecologically valid minor-to-moderate level microinjuries to the oral cavity have negligible effects on the measurement of salivary cortisol, but may be important to quantify and control when assessing other hormones especially testosterone.

Salivary α-amylase response to competition : Relation to gender, previous experience, and attitudes

Summary This study examined individual differences in salivary α-amylase response to competition in relation to gender, previous experience, behavior, attitudes, and performance. Participants were 42 (21 women) members of a collegiate crew team. Saliva samples were collected before, 20- and 40-min post-ergometer competition and at the same times on a non-competition day for comparison. Samples were assayed for salivary biomarkers of sympathetic nervous system (α-amylase) and hypothalamic–pituitary–adrenal axis (cortisol) activity. Behavioral assessments included self-reports of dominance, competitiveness, bonding with teammates, competition-related strategic thinking, and performance. On average, salivary α-amylase increased 156% in response to the ergometer competition. By comparison, cortisol increased 87% across the same time period. Salivary α-amylase was higher across the competition for varsity than for novice athletes, and was positively associated with performance and interest in team-bonding. Regression analyses revealed that α-amylase reactivity explained individual differences in dominance and team bonding above and beyond that associated with cortisol reactivity, and that joint inactivation in α-amylase and cortisol reactivity to competition (low–low) was associated with high perceived dominance. The findings are among the first to integrate salivary α-amylase into the study of competition and reveal that intra-individual change in α-amylase may be influenced by a confluence of factors that include contextual, behavioral, and psychological factors and processes.

Integrating the measurement of salivary α-amylase into studies of child health, development, and social relationships

To advance our understanding of how biological and behavioral processes interact to determine risk or resilience, theorists suggest that social developmental models will need to include multiple measurements of stress-related biological processes. Identified in the early 1990s as a surrogate marker of the sympathetic nervous system component of the stress response, salivary-amylase has not been employed to test biosocial models of stress vulnerability in the context of child development until now. In this report, we describe a standard assay that behavioral scientists can use to improve the next generation of studies and specific recommendations about sample collection, preparation, and storage are presented. More importantly, four studies are presented with mother–infant dyads (N= 86), preschoolers (N= 54), children (N = 54), and adolescents (N = 29) to illustrate individual differences in stress-related change in α-amylase levels, that patterns of α-amylase stress reactivity distinctly differ from those measured by salivary cortisol, and associations between individual differences in α-amylase and social relationships, health, negative affectivity, cognitive/academic/behavior problems, and cardiovascular reactivity. We conclude that the integration of measurements of the adrenergic component of the locus ceruleus/autonomic (sympathetic) nervous system, as indexed by salivary α-amylase, into the study of biosocial relationships may extend our understanding of child health and development to new limits.

Maternal and Child Contributions to Cortisol Response to Emotional Arousal in Young Children from Low-Income, Rural Communities.

Relations of maternal and child characteristics to child cortisol reactivity to and recovery from emotional arousal were examined prospectively at approximately 7 months of age (infancy) and then again at approximately 15 months of age (toddlerhood). The sample was diverse and population based (N = 1,292 mother-infant dyads) and included families from predominantly low-income, rural communities. Maternal behavior, family income-to-need ratio and social advantage, and child temperament, attention, and mental development were assessed, and childrens saliva was sampled before and after standardized procedures designed to elicit emotional arousal. Maternal engagement in infancy was associated with greater cortisol reactivity at the infancy assessment and with reduced overall cortisol level at the toddler assessment. Also at the toddler assessment, child attention, mental development, and temperamental distress to novelty were associated with increased cortisol reactivity and regulation, whereas temperamental distress to limitations and African American ethnicity were associated with reduced cortisol reactivity. Findings are consistent with prior work linking early caregiving to the development of the hypothalamic-pituitary-adrenal axis stress response system and with a conceptual model in which developing temperament is characterized by the interplay of emotional reactivity and the emergence of the ability to effortfully regulate this reactivity using attention.

Testosterone and Social Behavior

Popular perceptions of the effect of testosterone on manly behavior are inaccurate. We need to move away from such simplistic notions by treating testosterone as one component along with other physiological, psychological and sociological variables in interactive and reciprocal models of behavior. Several hormones can now be measured in saliva, removing the need for blood samples. Conceptual shifts have moved research from biological determinism to biosocial models in which the social environment plays a key role in understanding behavior-hormones associations. As a result, more social scientists are incorporating testosterone in their studies. Following a primer on testosterone, we describe testosterones link to (a) gaining, maintaining and losing social status, (b) aggression and antisocial behavior, (c) peer and family relationships, and (d) gender similarities and differences. Research needed to take us to the next level of understanding is outlined.

Oxytocin is not a valid biomarker when measured in saliva by immunoassay.

The integration of oxytocin (OT) into behavioral science seems to hold considerable promise for advancing our understanding of human health and development but methodological issues restrict the measurement of OT in large studies, in everyday social settings, or when repeated sampling is required. Measuring OT in saliva could overcome many of these limitations. In this paper, we rigorously evaluate the feasibility of doing so. A series of experiments leads to the conclusion that saliva does not contain oxytocin in measurable amounts, and that OT is not a valid salivary biomarker when measured by currently available immunological methods. Levels of immuno-reactive OT in saliva are primarily due to non-specific interference with antibody-antigen binding. We can state with a high degree of certainty that measurement of OT in saliva does not yield meaningful indices of individual differences or intra-individual change.

Integrating Biological, Behavioral, and Social Levels of Analysis in Early Child Development: Progress, Problems, and Prospects

Integration of noninvasive, biological measures into behavioral research has increased, but the interpretation of biobehavioral findings in relation to developmental outcomes is rarely straightforward. This commentary highlights the need for specific, theoretically derived hypotheses, multiple measures of behavioral and biological processes, and analytical strategies aimed at explaining interindividual differences in intraindividual change. It is suggested here that the next phase of biosocial research needs to move beyond description and toward development of mid-level theories that will enable researchers to specify, test, and refine hypotheses of how biobehavioral processes interact with social-contextual factors to influence development. These mid-level biosocial models will be necessary to determine whether individual differences in childrens adrenocortical activity confer risk or resilience because of early or cumulative exposure to nonparental care.