Bayesian inference for psychology. Part II: Example applications with JASP

Bayesian hypothesis testing presents an attractive alternative to p value hypothesis testing. Part I of this series outlined several advantages of Bayesian hypothesis testing, including the ability to quantify evidence and the ability to monitor and update this evidence as data come in, without the need to know the intention with which the data were collected. Despite these and other practical advantages, Bayesian hypothesis tests are still reported relatively rarely. An important impediment to the widespread adoption of Bayesian tests is arguably the lack of user-friendly software for the run-of-the-mill statistical problems that confront psychologists for the analysis of almost every experiment: the t-test, ANOVA, correlation, regression, and contingency tables. In Part II of this series we introduce JASP (http://www.jasp-stats.org), an open-source, cross-platform, user-friendly graphical software package that allows users to carry out Bayesian hypothesis tests for standard statistical problems. JASP is based in part on the Bayesian analyses implemented in Morey and Rouder’s BayesFactor package for R. Armed with JASP, the practical advantages of Bayesian hypothesis testing are only a mouse click away.     

Altered stress responses in children exposed to early adversity: a systematic review of salivary cortisol studies

Pathological stress responses are implicated in numerous disorders. Hypothalamic-pituitary-adrenal axis function is influenced by gene-environment interaction, with early-life environmental adversity having long-lasting effects. We examine the evidence that, in humans, these effects are apparent from infancy. We systematically reviewed published findings on cortisol response to a stressor, in 0-5-year-olds already exposed to adversity. Adversity was defined as a negative environmental influence present post-conception. We searched Ovid MEDLINE (1950-May 2010), EMBASE (1980-May 2010) and PsychINFO (1806-May 2010). We included peer-reviewed, English language studies that analysed salivary cortisol before and after a standardised stressor. We identified 30 studies, of which 27 reported a significant effect of adversity on the cortisol response to stress. Six of these demonstrated an effect of prenatal substance exposure. Thirteen studies found that psychosocial adversity increased cortisol reactivity. Three studies reported that cortisol reactivity could be normalised by intervention programmes. The studies were heterogeneous, both in nature of adversity studied and in stressor used, precluding meta-analysis and assessment of publication bias. Our review presents evidence that adversity disrupts the stress response from an early age. Longitudinal studies are required to determine whether effects persist, alter with time, or are reversible with intervention.     

Accounting for fluctuations in body dissatisfaction

The present study evaluated whether the strength of relationship between contextual cues (presence of company and mood) and state body dissatisfaction varied as a function of individual differences in key trait measures (body shame, body surveillance tendencies, internalization of appearance standards, and trait affect) which have been linked to trait body dissatisfaction. Fifty-five undergraduate women completed a questionnaire containing the trait-based measures and then carried a Personal Digital Assistant (PDA) for a 7-day period. The PDA prompted participants six times daily to self-report their current mood and state body dissatisfaction. Multi-level modeling revealed that individual differences in body shame predicted inter-individual variability in the strength of the relationships between presence of company and state body dissatisfaction, and positive mood and state body dissatisfaction. Trait positive affect also explained variance in the positive mood state-body dissatisfaction relationship. The implications of the findings for prevention of body image disturbances are discussed.     

“The Parallel Dialogue”: Parental experience of their role in the relationship with their child's counsellor/psychotherapist

The parent–therapist relationship is a central consideration in child counselling and psychotherapy, particularly in private practice where parents are typically financially, emotionally and practically invested in the process. The relationship, which can be ambiguous and anxiety-laden on both sides, has historically received scant attention in therapeutic discourse, leading to gaps in practitioner confidence and training. In this context, and seeking to centre parent voices, this study provides an interpretative phenomenological analysis of four mothers' experiences of their role in the relationship with their child's therapist. Key identified themes encompass parental expectation of involvement; the destabilising, disorienting nature of the relationship; the centrality of trust; and critical evaluations of value. Findings are discussed in relation to attachment theory and cultural expectations of parental responsibility. The study concludes that the relationship is a live and potent property with potential to impact the course of the intervention, and recommends that practitioners thoughtfully consider the potential benefits and drawbacks of meeting or frustrating parental involvement expectations.     

An Investigation of the Three-Way Joint Coaching Alliance: A Social Identity Theory Perspective

This study builds upon the previous research that recognised coaching as a triangular political space generating power relationships. We integrate social identity theory into this power negotiation process and consider that the ultimate purpose of coaching is to facilitate a shared coaching identity among all related collaborators. To gain in-depth understanding of factors that promote a three-way joint coaching identity, we conducted 25 critical incident interviews and two levels of Q-sorting (n = 10) with coaches, coachees, and organisational stakeholders. The research results indicated that a workplace coaching identity is a flexible space underpinned by coaches’ attitude, all collaborators’ positions, and the contracting process. Coaches’ accommodated communication techniques determine the relationship climate (instrumental or influential). Coaches’ position in the coaching space regulates their self-interests and motivation to change. Moreover, a transparent contracting process encourages communication flows and psychological exchanges among all collaborators that may gain more support from stakeholders.     

Hippocampal lesions attenuate latent inhibition and the decline of the orienting response in rats

Two experiments using rats assessed the effect of dorsal hippocampal lesions on the orienting response (OR) elicited by a discrete light and on the subsequent associability of that light. In both experiments subjects received extensive nonreinforced exposure to the light, and it was found that the decline in the OR evident in sham-operated animals was severely attenuated by hippocampal lesions. Subsequently the light was paired with condensed milk in Experiment 1, and it was found that conditioning was faster in the lesioned than in the sham-operated group. Experiment 2 used a conditioned inhibition procedure whereby the light was presented in a nonreinforced compound with a tone which, when presented alone, acted as a signal for condensed milk. Again this discrimination was mastered more rapidly by lesioned animals. Relevant control groups indicated no differences between lesioned and sham-operated animals in learning about a novel light. Thus, hippocampal lesions influence both the loss of associability of a stimulus and the decline in the OR it elicits, which, in turn, suggests that the OR acts as an index of stimulus associability.     

Rich contexts do not always enrich the accuracy of personality judgments

We test the common assumption that information ‘rich’ contexts lead to more accurate personality judgments than information ‘lean’ contexts. Pairs of unacquainted students rendered judgments of one another's personalities after interacting in one of three, increasingly rich, contexts: Internet ‘chat’, telephone, or face-to-face. Accuracy was assessed by correlating participants' judgments with a measure of targets' personalities that averaged self and informant ratings. As predicted, the visible traits of extraversion and conscientiousness were judged more accurately than the less visible traits of neuroticism and openness. However, judgment accuracy also depended on context. Judgments of extraversion and neuroticism improved as context richness increased (i.e., from Internet ‘chat’ to face-to-face), whereas judgments of conscientiousness and openness improved as context richness decreased (i.e., from face-to-face to Internet ‘chat’). Our findings suggest that context richness shapes not only the availability of personality cues but also the relevance of cues in any given context.     

Factors Associated with the Participation of Women Doctorates in the Labor Force

Participation in the labor force by 1,547 women doctorates of 1957 and 1958 and the factors associated with their career development and commitment were examined. 91 per cent of the women doctorates of 1957 and 1958 are in the labor force at present, and of those, 81 per cent work full time. When a woman doctorate's family responsibilities are greatest, i.e., during the rearing of her pre-school children, she is not as likely to participate fully in the labor force. However, if the married woman doctorate has demonstrated an early career commitment, she persists likewise later on.     

Event-related potentials in neuropsychological studies of language

Experiments are described in which event-related potentials (ERPs) are employed to study the specialization of functions between and within the cerebral hemispheres during the performance of language and nonlanguage tasks by normal adults. Similar studies of deaf subjects suggest that the functional organization of the brain may be altered after different early language and sensory experiences. Studies of patients with alexia without agraphia suggest that the ERP may be a valuable tool with which to study cerebral reorganization after brain damage.