Human vocal development occurs through two parallel interactive processes that transform infant cries into more mature vocalizations, such as cooing sounds and babbling. First, natural categories of sounds change as the vocal apparatus matures. Second, parental vocal feedback sensitizes infants to certain features of those sounds, and the sounds are modified accordingly. Paradoxically, our closest living ancestors, nonhuman primates, are thought to undergo few or no production-related acoustic changes during development, and any such changes are thought to be impervious to social feedback. Using early and dense sampling, quantitative tracking of acoustic changes, and biomechanical modeling, we showed that vocalizations in infant marmoset monkeys undergo dramatic changes that cannot be solely attributed to simple consequences of growth. Using parental interaction experiments, we found that contingent parental feedback influences the rate of vocal development. These findings overturn decades-old ideas about primate vocalizations and show that marmoset monkeys are a compelling model system for early vocal development in humans.

In humans, vocal turn-taking is a ubiquitous form of social interaction. It is a communication system that exhibits the properties of a dynamical system: two individuals become coupled to each other via acoustic exchanges and mutually affect each other. Human turn-taking develops during the first year of life. We investigated the development of vocal turn-taking in infant marmoset monkeys, a New World species whose adult vocal behaviour exhibits the same universal features of human turn-taking. We find that marmoset infants undergo the same trajectory of change for vocal turn-taking as humans, and do so during the same life-history stage. Our data show that turn-taking by marmoset infants depends on the development of self-monitoring, and that contingent parental calls elicit more mature-sounding calls from infants. As in humans, there was no evidence that parental feedback affects the rate of turn-taking maturation. We conclude that vocal turn-taking by marmoset monkeys and humans is an instance of convergent evolution, possibly as a result of pressures on both species to adopt a cooperative breeding strategy and increase volubility.

Parenting stress is relevant to the development, maintenance, and amelioration of youth mental, emotional, and behavioral health issues. This Evidence Base Update evaluates the empirical literature on the measurement of parenting stress to guide future research and inform clinical decision-making. After a comprehensive literature search, we identified eight well-studied measures of parenting stress, to which we applied the criteria put forth by Hunsley and Mash (2008) and extended by Youngstrom et al. (2017) to evaluate the evidence base for norms, validity, and utility. All measures were rated adequate, good, excellent, or no evidence on 11 psychometric categories (e.g., internal consistency, treatment sensitivity). Overall, the ability of identified measures to accurately and reliably assess parenting stress was strong. Although the psychometrics vary across measures, the aggregated findings support the existence of a parenting stress construct and further confirm the relevance of parenting stress to family functioning, youth psychopathology, and mental health interventions.

Treatment delay and non-adherence in first episode psychosis is a pressing public health problem. Ambivalence regarding psychiatric intervention and labeling among young people with psychosis is a contributing factor. For these individuals, caregivers often facilitate the pathway to care and support ongoing engagement and adherence. Caregivers describe distress and burden associated with this role. This manuscript describes the development and pilot feasibility testing of a motivational interviewing-derived communication training for caregivers of individuals with untreated or under-treated early course psychosis. Individuals with lived experience were consulted in the intervention development process. The training consisted of four 60-min sessions teaching the philosophy and basic skills of motivational interviewing as well as two brief practice calls. Feasibility was assessed with regard to study enrollment, retention, and completion. Satisfaction was assessed through the Client Satisfaction Questionnaire and qualitative feedback. Thirty-one caregivers consented to this pilot feasibility trial and participated via telehealth over the course of 5 months. Intervention completion and reported satisfaction were high, with 94% of consented participants completing at least three training sessions and 84% reporting that they would “definitely” recommend the training to a friend in similar circumstances. There were no between-clinician differences in MILO session attendance (F[2] = 0.53, p = 0.596) or satisfaction total scores (F[2] = 1.03, p = 0.371). Brief motivational interviewing skills training appears to be a feasible and valued intervention for caregivers of individuals with poorly managed early course psychosis.Clinical Trial Registration:ClinicalTrials.gov Identifier: NCT04010747

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