While there has been an increase in studies investigating the relationship between endogenous oxytocin (OXT) concentrations and human social interactions over the past decades, these studies still seem far from converging, both in methodological terms and in terms of their results. This systematic review and meta-analysis were aimed at a comprehensive evaluation and synthesis of empirical evidence on the relationship between endogenous OXT concentrations and human social interactions by reviewing studies published between 1970 and July 2020 and addressing various related methodological and analytical limitations. Sixty-three studies were included in the qualitative synthesis, and results from 51 studies were pooled in a meta-analysis (n = 3,741 participants). The results indicated that social interaction did not lead to an expected hormonal response in causal designs, either in a pre-post design (g = 0.079) or when comparing experimental conditions with and without social interaction (g = 0.256). However, in correlational designs, the overall mean effect size (ES) of the correlations between indicators of social interaction and OXT concentrations was significantly different from zero (z = 0.137). In both designs, subgroup analyses revealed that studies involving either parent-child interactions, or the utilization of the enzyme-linked immunosorbent assay method for OXT analysis, or unrestricted eating, drinking, or exercise before biofluid collection showed significantly higher than zero mean ESs. This review exposes the observed inconsistencies and suggests that standardized, replicable, and reliable approaches to assessing social interaction and measuring OXT concentrations need to be developed to study neurochemical mechanisms of sociality in humans. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

To perform quick assessments, welfare practitioners may focus on specific behavioral indicators of welfare, which can lead to challenges in interpretation. Anticipatory behavior has been suggested as a potentially graded indicator of well-being in animals. However, there are difficulties in assessing variations in this class of behavior quantitatively. Here, we propose an analytical approach for identifying and comparing the intensity of anticipatory behavior across different conditions. We evaluated the changes in the behavior of a sea lion at the San Francisco Zoo before and after daily training sessions, the start time of which had differing degrees of predictability. We show that anticipatory behavior is a complex suite of behaviors that can show multi-directional changes prior to an anticipated event. Additionally, we show that the methods utilized here can distinguish among differing intensities of anticipation directed toward daily husbandry events. We suggest that this approach may be broadly applicable for applying measures of anticipatory behavior as a graded welfare indicator.

Visitor effect studies have been of keen interest for decades, but there have been only anecdotal opportunities to investigate the impact of the prolonged absence of visitors on animal welfare in zoos. In some zoos, bears are actively involved in animal–visitors interaction through begging, which gives them some degree of control over gaining food rewards throughout the day when visitors are present. Prolonged visitor absence may, therefore, represent a loss of control and have a negative impact on the bears’ welfare. In this study, we investigate the behavior of four brown bears (Ursus arctos) in three zoos to see how the animals’ behavior changed depending on the presence and absence of the public during zoo closures in 2020 related to the COVID-19 pandemic. The bears’ behavior was assessed using activity budget analysis and novel object tests. The results showed that the bears behavior varied between facilities and that there was no effect of visitor presence for the individuals who had access to indoor holding space. The results of the study are discussed in terms of choice and control and their impact on the wellbeing of bears in zoos.

Under conditions of suboptimal parental care, children with specific temperamental features have been shown to be especially vulnerable to the effects of stress. Most studies of temperamentally vulnerable children have been conducted using parental questionnaires, which are unfortunately not completely objective. An alternative approach, the use of objective methods for assessing temperament in childhood, can and should be used to study the impact of poor parenting quality on children's stress levels, an important factor in child development. Although studies using such objective methods exist, they are quite rare. A PubMed search identified twelve articles reviewed here. Existing data indicate that, in general, higher basal cortisol and cortisol stress response are associated with “reactive” temperament: shyness, fearfulness, behavioral inhibition, and negative affectivity. Furthermore, child temperament interacts with the quality of parental care to predict cortisol levels in early childhood. Accordingly, in the context of inadequate parental care, temperamentally vulnerable children with “reactive” temperaments are particularly at risk for negative effects of stress. Studies of stress‐by‐parental‐care‐interactions are essential for preventing long‐term mental problems and problems with physical health that could occur in temperamentally vulnerable children who receive suboptimal parental care.