DifScal: A tool for analyzing difference ratings on an ordinal category scale

An algorithm for analyzing difference scaling results is described. Frequency data on ordered categories that represent perceived differences for a unidimensional psychological attribute are modeled according to Thurstone’s judgment scaling model. The algorithm applies the gradient method for the maximum likelihood estimation of the model parameters. Two ways to calculate the start configuration for the model parameters are elaborated. The algorithm also provides asymptotic values for the standard errors of the estimates and three measures for the goodness of the model fit. An additional feature of DifScal is that it is suited to analyze incomplete data.     

The Relationship Between Dissociation and Religiosity: An Empirical Evaluation of Schumaker's Theory

Dissociation can be broadly understood as alterations in consciousness where integrated processing of psychological and/or sensory information is disrupted. Following Schumaker's (1995) suggestion that dissociation elicited by religious ritual provides the basis for religious beliefs, the current aim was to empirically assess the relationship between dissociation, religious ritual, and religious beliefs. Four samples with varying levels of religious commitment were administered the Dissociative Experiences Scale, the Francis Scale of Attitude Toward Christianity-short form, and the Maranell Religious Ritual Scale. Dissociation scores were highest in the young Catholic sample and lowest in the Fellowship group. However, these results are largely affected by the covariate of age. No relationship was found between dissociation, religious attitude, and religious ritual in the student sample. However, small to moderate significant correlations were found in the Catholic sample. Results are discussed with reference to Schumaker's theoretical proposal and directions are suggested for future assessment of the dissociation-religiosity relationship.     

Theory‐Driven Subgroup‐Specific Evaluation of an Intervention to Reduce Private Car Use1

In the context of a 2‐wave panel study, we used Ajzen's (1991) theory of planned behavior (TPB) as the theoretical framework for deriving and systematically testing hypotheses as to how an intervention (a “free” ticket for public transportation) influences the travelmode choice of students. The empirical results show that this intervention caused a drastic decrease in students' car use. The effect of the intervention on behavior is mediated by the causal chain postulated by the TPB. In the second step, we analyzed whether there were subgroup‐specific reactions to the intervention. Surprisingly, the subgroup analysis shows that students with more negative attitudes toward policy measures restricting car use reacted more strongly to the intervention than did students with a more positive attitude.     

On the heritability of inspection time and its covariance with IQ: a twin study

Using the classical twin design, this study investigates the influence of genetic factors on the large phenotypic variance in inspection time (IT), and whether the well established IT–IQ association can be explained by a common genetic factor. Three hundred ninety pairs of twins (184 monozygotic, MZ; 206 dizygotic, DZ) with a mean age of 16 years participated, and 49 pairs returned approximately 3 months later for retesting. As in many IT studies, the pi figure stimulus was used and IT was estimated from the cumulative normal ogive. IT ranged from 39.4 to 774.1 ms (159±110.1 ms) with faster ITs (by an average of 26.9 ms) found in the retest session from which a reliability of .69 was estimated. Full-scale IQ (FIQ) was assessed by the Multidimensional Aptitude Battery (MAB) and ranged from 79 to 145 (111±13). The phenotypic association between IT and FIQ was confirmed (−.35) and bivariate results showed that a common genetic factor accounted for 36% of the variance in IT and 32% of the variance in FIQ. The maximum likelihood estimate of the genetic correlation was −.63. When performance and verbal IQ (PIQ & VIQ) were analysed with IT, a stronger phenotypic and genetic relationship was found between PIQ and IT than with VIQ. A large part of the IT variance (64%) was accounted for by a unique environmental factor. Further genetic factors were needed to explain the remaining variance in IQ with a small component of unique environmental variance present. The separability of a shared genetic factor influencing IT and IQ from the total genetic variance in IQ suggests that IT affects a specific subcomponent of intelligence rather than a generalised efficiency.     

A meta-analysis of play therapy outcomes

A meta-analysis of play therapy outcomes with children was conducted to determine the overall effectiveness of play therapy and the variables related to effectiveness. Hierarchical linear modelling was used to analyse the data. The analysis showed an average treatment effect of 0.66 standard deviations. A strong relationship between treatment effectiveness and the inclusion of parents in the therapeutic process was reported. The duration of therapy also appeared to be related to treatment outcomes, with maximum effect sizes occurring after approximately 30 treatment sessions. Play therapy appeared to be as effective as non-play therapies in treating children experiencing emotional difficulties. Recommendations for future researchers focus on explaining therapeutic or participant characteristics that are related to treatment effectiveness.     

"When no means no": can reactance augment the theory of planned behavior?

A longitudinal study examined women's clinic attendance for treatment and follow-up after having received an abnormal cervical screening result. Participants (N = 660) completed questionnaire measures of variables specified by the theory of planned behavior and J. Kuhl's (2000) measure of low volitional control--reactance--prior to receiving up to 3 subsequent appointments during the following 15 months. The theory of planned behavior was capable of predicting persistent attendance and discriminated women who kept all of their scheduled appointments from those who dropped out from treatment. Consideration of reactance enhanced prediction of behavior and discriminated between women who delayed appointment keeping and women who ceased attending.     

Emotional availability and psychosocial correlates among mothers in substance‐abuse treatment and their young infants

Emotional availability (EA) was investigated among low‐income mothers enrolled in substance‐abuse treatment and their young infants (n = 21) compared with a demographically matched group of mother–infant pairs who, by self‐report, were not at risk for substance abuse (n = 27). The mother–infant dyads in the treatment group generally demonstrated poorer EA functioning than those in the comparison group, but few differences between the groups on individual dimensions of EA were significant. This finding was notable considering that mothers in treatment reported significantly higher levels of depressive symptoms and psychological stress. Treatment effects may have buffered the negative impact of depression and psychological stress on mothers' EA scores. The clinical implications of the findings are discussed as they relate to substance‐abuse‐treatment services for pregnant and parenting women.