Bayesian PTSD-Trajectory Analysis with Informed Priors Based on a Systematic Literature Search and Expert Elicitation

There is a recent increase in interest of Bayesian analysis. However, little effort has been made thus far to directly incorporate background knowledge via the prior distribution into the analyses. This process might be especially useful in the context of latent growth mixture modeling when one or more of the latent groups are expected to be relatively small due to what we refer to as limited data. We argue that the use of Bayesian statistics has great advantages in limited data situations, but only if background knowledge can be incorporated into the analysis via prior distributions. We highlight these advantages through a data set including patients with burn injuries and analyze trajectories of posttraumatic stress symptoms using the Bayesian framework following the steps of the WAMBS-checklist. In the included example, we illustrate how to obtain background information using previous literature based on a systematic literature search and by using expert knowledge. Finally, we show how to translate this knowledge into prior distributions and we illustrate the importance of conducting a prior sensitivity analysis. Although our example is from the trauma field, the techniques we illustrate can be applied to any field.     

Narrative skill and testimonial accuracy in typically developing children and those with intellectual disabilities

Children must describe maltreatment coherently for their testimony to be influential in court. We know little about how well children with intellectual disabilities (CWID) describe their experiences relative to typically developing (TD) children, despite CWID's vulnerability to maltreatment. We investigated children's reports of an experienced event and compared coherence in CWID (mild to moderate impairment: 7–11 years) with TD children matched for mental (4–10 years) or chronological age (7–11 years). All children included important markers of narrative coherence in their reports. Children with lower mental ages, particularly those with an intellectual disability, included fewer markers of narrative coherence in their reports than children with higher mental ages. Individual markers of narrative coherence, particularly recall of content, predicted accuracy of testimony and resistance to suggestion even when disability and mental age were taken into account. These findings highlight the importance of helping children to describe their experiences coherently.     

Propagation of innovations in networked groups

A novel paradigm was developed to study the behavior of groups of networked people searching a problem space. The authors examined how different network structures affect the propagation of information in laboratory-created groups. Participants made numerical guesses and received scores that were also made available to their neighbors in the network. The networks were compared on speed of discovery and convergence on the optimal solution. One experiment showed that individuals within a group tend to converge on similar solutions even when there is an equally valid alternative solution. Two additional studies demonstrated that the optimal network structure depends on the problem space being explored, with networks that incorporate spatially based cliques having an advantage for problems that benefit from broad exploration, and networks with greater long-range connectivity having an advantage for problems requiring less exploration. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

Measuring Hong Kong Undergraduate Students’ Attitudes Towards Transpeople

Hill and Willoughby’s (Sex Roles, 53:531–544, 2005) Genderism and Transphobia Scale (GTS), originally developed in Canada, was examined with a Hong Kong sample. Undergraduate students, 82 female and 121 male (total n?=?203), completed a Chinese version of the instrument. Overall scores and factor structure of the Hong Kong sample were compared with Hill and Willoughby’s Canadian data. Gender differences in transphobia were investigated, both in terms of the participants’ gender as well as the gender of the gender variant persons to whom GTS items referred. Transphobia was higher in Hong Kong than in Canada. The factor structure for Hong Kong differed from Canada. Five factors were identified (with a gender effect on Factors II and V). They were: I, Anti Sissy Prejudice; II, Anti Trans Violence; III, Trans Unnaturalness; IV, Trans Immorality; and V, Background Genderism. Hong Kong men were more transphobic than women. Gender variance in men was viewed less favourably than in women.     

Visuotactile apparent motion

This article compares the properties of apparent motion between a light and a touch with apparent motion between either two lights or two touches. Visual and tactile stimulators were attached to the tips of the two index fingers that were held apart at different distances. Subjects rated the quality of apparent motion between each stimulus combination for a range of stimulus onset asynchronies (SOAs). Subjects reported perceiving apparent motion between all three stimulus combinations. For light—light visual apparent motion, the preferred SOA and the direction threshold SOAs increased as the distance between the stimuli increased (consistent with Korte’s third law of apparent motion). Touch—touch apparent motion also obeyed Korte’s third law, but over a smaller range of distances, showing that proprioceptive information concerning the position of the fingers is integrated into the tactile motion system. The threshold and preferred SOAs for visuotactile apparent motion did not vary with distance, suggesting a different mechanism for multimodal apparent motion.     

The care-system for homeless youth in The Netherlands: perceptions of youngsters through a peer research approach

The aim of this study was to examine the perceptions of homeless youth of the care they receive. Since we wanted to involve homeless youth as participants in this project, we adopted the approach of peer-research. This form of collaborative research has a major role for homeless youth in making an inventory of the problems. A parallel is drawn between the parent-adolescent relationship and the relationship between social worker and homeless adolescent.     

Observer Influences on Fathers and Mothers: An Experimental Manipulation of the Structure and Function of Parent – Infant Conversation

From studies over the past 20 years four contrasting hypotheses can be made about the nature of parent–infant communication: (1) mothers and fathers display similar skills to their infants and do not exert a differential influence on their development; (2) fathers are less sympathetic to their infants' level of development and therefore inadvertently stretch the child's development more than mothers; (3) both parents differentially socialize their sons' and daughters' early communicative skills; (4) any apparent differences between parents reflect their expectations about being observed. To examine these hypotheses together, this experiment records the communication of 10 mother–infant and 10 father–infant dyads in two conditions: when an observer was present or absent. The analysis revealed two patterns. Firstly, in keeping with most research on parent–child communication, mothers and fathers both simplified their speech to their infants in similar ways. Secondly, both the structure and function of parental communication showed differences between the two conditions and many of these differences were moderated by interactions between condition and sex of parent or child. The data thus provide more support for the first and fourth hypotheses cited above. It is suggested that analyses of parent–infant interaction should move away from simple assumptions about parental ‘influences’ upon children's development to consider the subtleties of different parental styles in different settings.     

Conceptualism and the (Supposed) Non-Transitivity of Colour Indiscriminability

In this paper, I argue that those who accept the conceptualist view in the philosophy of perception should reject the traditional view that colour indiscriminability is non-transitive. I start by outlining the general strategy that conceptualists have adopted in response to the familiar ‘fineness of grain’ objection, and I show why a commitment to what I call the indiscriminability claim seems to form a natural part of this strategy. I then show how together, the indiscriminability claim and the non-transitivity claim –the claim that colour indiscriminability is non-transitive –entail a further, suspicious-looking claim that I call the problematic claim. My argument then splits into two parts. In the first part, I show why the conceptualist does indeed need to reject the problematic claim. Given that this claim is jointly entailed by the indiscriminability claim and the non-transitivity claim, the conceptualist is then left with a straight choice: reject the indiscriminability claim, or reject the non-transitivity claim. In the second part, I then explain why the conceptualist should choose the latter option.