Emotionality vs. Other Biobehavioural Traits: A Look at Neurochemical Biomarkers for Their Differentiation

This review highlights the differential contributions of multiple neurochemical systems to temperament traits related and those that are unrelated to emotionality, even though these systems have a significant overlap. The difference in neurochemical biomarkers of these traits is analysed from the perspective of the neurochemical model, Functional Ensemble of Temperament (FET) that uses multi-marker and constructivism principles. Special attention is given to a differential contribution of hypothalamic–pituitary hormones and opioid neuropeptides implicated in both emotional and non-emotional regulation. The review highlights the role of the mu-opioid receptor system in dispositional emotional valence and the role of the kappa-opioid system in dispositional perceptual and behavioural alertness. These opioid receptor (OR) systems, microbiota and cytokines are produced in three neuroanatomically distinct complexes in the brain and the body, which all together integrate dispositional emotionality. In contrast, hormones could be seen as neurochemical biomarkers of non-emotional aspects of behavioural regulation related to the construction of behaviour in fast-changing and current situations. As examples of the role of hormones, the review summarised their contribution to temperament traits of Sensation Seeking (SS) and Empathy (EMP), which FET considers as non-emotionality traits related to behavioural orientation. SS is presented here as based on (higher) testosterone (fluctuating), adrenaline and (low) cortisol systems, and EMP, as based on (higher) oxytocin, reciprocally coupled with vasopressin and (lower) testosterone. Due to the involvement of gonadal hormones, there are sex and age differences in these traits that could be explained by evolutionary theory. There are, therefore, specific neurochemical biomarkers differentiating (OR-based) dispositional emotionality and (hormones-based) body’s regulation in fast-changing events. Here we propose to consider dispositional emotionality associated with OR systems as emotionality in a true sense, whereas to consider hormonal ensembles regulating SS and EMP as systems of behavioural orientation and not emotionality.

Temperament and Visual Category Learning Strategy Use

Transient affective states have been shown to affect cognition, including category learning, but less is known about the role of stable temperament traits and categorization. We examined affective temperament traits to see whether the tendency to experience negative and positive affect is predictive of category learning performance and strategy use. Working memory and attentional control were measured as covariates. Participants first completed the Adult Temperament Questionnaire (Evans & Rothbart, 2007) including two affective temperament factors and an attentional control factor. Then they completed a memory task followed by either a conjunctive rule-based (CR) or an information integration (II) category learning task. Results showed that people who tend to experience more positive affect and less negative affect achieved higher accuracy and were more likely to find the optimal strategy in the II task compared to people who tend to experience more negative affect and less positive affect. However, no performance or strategy use difference was seen in the CR task across different temperament profiles. These results extend prior literature and provide additional insights on the effects of stable traits on category learning.

Temperament Trait Changes in Japanese Black Cows Under Grazing and Confined Conditions

The objective of the present study was to reveal the effects of grazing on the temperament traits of cows. Nine Japanese Black cows [344 ± 32 kg body weight (BW), 7.7 ± 3.0 year of age], which had various experiences, such as tethering, handling, and grazing, were used in this experiment. Five of the nine cows were grazed for 3 months on a 1.8-ha field composed of a sown pasture with forestland. The remaining cows were fed in confinement. On days 38, 52, 72, and 86 after the start of grazing, the temperament traits observed in various situations, such as moving to the body weight scale, weighing, handling, moving to the stock for blood sampling, holding in the stock, and obtaining a blood sample, were assessed with a visual analog scale (VAS: 1–10) or score (1–5). During weighing and handling, the intensity of resistance exhibited by the grazing cows, as evaluated by head movement, walking/stepping, tail flicking, rope tension, and overall movement, was lower than that exhibited by confined cows (P < 0.05). The resistance score exhibited by the grazing cows during blood sampling was also lower than that exhibited by confined cows (P < 0.01). These results suggest that grazing enhances docility in cows with various experiences in different situations encountered in daily management.

A person-centered approach to understanding child temperament at ages 3 and 6

Person-centered analyses, such as latent profile analysis, provide an approach to assessing individual differences in child temperament that aligns with typological theory and is well positioned for translation to applied settings. In a community sample, latent profile analysis was conducted using seven temperament traits assessed through laboratory observation when children were three- and six-years-old. At age 3, a four-class model fit best and subgroups were labeled “typical,” “sluggish,” “surgent,” and “dysregulated,” based on the pattern of class-specific means. A five-class model fit best at age 6 and subgroups were labeled “typical,” “sluggish,” “outgoing,” “active-impulsive” and “negative affect.” Associations between class membership and mother-reported temperament traits, concurrently assessed, were mostly consistent with the class identities. Comparison of subgroup membership across waves generally demonstrated patterns of continuity across groups characterized by similar trait patterns. This paper provides an illustrative guide for temperament researchers in the implementation of latent profile analysis, addressing important methodical considerations. Increased utilization of person-centered approaches like latent profile analysis could lead to important advances in the study of child temperament, such as improved understanding of the continuity of temperamental styles and more targeted risk assessment.