Equivalence class establishment, expansion, and modification in preschool children

Preschool children were taught four two-choice match-to-sample conditional discriminations with 10 arbitrary visual stimuli. For 6 participants, 2 of the 10 stimuli served as the sample, or conditional, stimuli in all discriminations. For 5 additional participants, the same pair of stimuli served as the discriminative, or comparison, stimuli in all discriminations. Equivalence classes were established with more participants in the latter group, replicating prior research with participants with retardation. Four participants, in whom equivalence classes were established and who were available for further participation, were exposed to new conditional discriminations without trial-by-trial feedback and involving some novel and some familiar stimuli. Consistent conditional responding was observed, and tests for inclusion of the novel stimuli in the original classes showed class expansion. Training to reverse the unreinforced conditional performances produced a reversal of class membership in 3 of 4 participants, an outcome not consistent with other studies. The results are discussed with respect to the interaction of class structure and size.     

A discrimination analysis of training-structure effects on stimulus equivalence outcomes.

Experiments designed to establish stimulus equivalence classes frequently produce differential outcomes that may be attributable to training structure, defined as the order and arrangement of baseline conditional discrimination training trials. Several possible explanations for these differences have been suggested. Here we develop a hypothesis based on an analysis of the simple simultaneous and successive discriminations embedded in conditional discrimination training and testing within each of the training structures that are typically used in stimulus equivalence experiments. Our analysis shows that only the comparison-as-node (many-to-one) structure presents all the simple discriminations in training that are subsequently required for consistently positive outcomes on all tests for the properties of equivalence. The sample-as-node (one-to-many) training structure does not present all the simple discriminations required for positive outcomes on either the symmetry or combined transitivity and symmetry (equivalence) tests. The linear-series training structure presents all the simple discriminations required for consistently positive outcomes on tests for symmetry, but not for symmetry and transitivity combined (equivalence) or transitivity alone. Further, the difference in the number of simple discriminations presented in comparison-as-node training versus the other training structures is larger when the intended class size is greater than three or the number of classes is larger than two. We discuss the relevance of this analysis to interpretations of stimulus equivalence research, as well as some methodological and theoretical implications.     

The role of self-esteem in the misinformation effect

Previous research using the Gudjonnson suggestibility scale has suggested a role for self-esteem in suggestibility, with participants low in self-esteem being more suggestible than participants high in self-esteem. Four experiments are presented examining the role of self-esteem in the misinformation effect and whether enhanced suggestibility effects in participants low in self-esteem reflect genuine memory impairment. In Experiments 1 and 4 participants completed a standard recognition test. In Experiment 2 participants completed the modified recognition test. In Experiment 3 participants completed a free recall test. In Experiments 1 and 4 participants low in self-esteem demonstrated greater misinformation effects than participants high in self-esteem. In Experiment 3 a 3-day retention interval was employed with the modified test and no differences were found between the two groups on the reporting of the new item. The findings suggest that participants low in self-esteem are particularly sensitive to demand characteristics and post-event suggestion but do not suffer from genuine memory impairment.     

Motor proficiency and emotional/behavioural disturbance in autism and Asperger's disorder: another piece of the neurological puzzle?

The relationship of motor proficiency with emotional/behavioural disturbance, autistic symptoms and communication disturbance was investigated in children diagnosed with autism and Asperger's disorder (AD). The Movement Assessment Battery for Children was used as a measure of motor impairment, and the Developmental Behavioural Checklist was used as a measure of emotional/behavioural disturbance in the following groups: AD (n?=?22), high functioning autism (HFA) (n?=?23), LFA (n?=?8) and typically developing children (n?=?20). The HFA group had more difficulty with motor items, such as ball skills and balance, than did the AD group. There were significant positive correlations between impairments in motor proficiency (in particular ball skills and balance) and emotional/behavioural disturbance, autistic symptoms and communication disturbance. These findings are consistent with the hypothesis that there are qualitative and quantitative differences in the motor profile between autism and AD. In addition, the association between motor proficiency impairment and emotional/behavioural disturbance in autism and AD emphasizes the importance for screening of co-occurring emotional/behavioural symptoms in individuals with motor difficulties. These findings have implications for the potential use of adjunct motor measures in the diagnosis and definition of autism spectrum disorders.     

Driver performance, rewards and motivation: A simulator study

It has been suggested that effort invested in a task may be moderated by the perception of the nature of reward offered, e.g., whether social or financial in nature. If levels of payment for empirical work meaningfully influence the effort invested in tasks by participants, the implications may be serious and wide-ranging for the reliability and validity of published data. The study reported in this paper, examines this thesis in a driving context. Thirty-six participants were allocated to either a No payment, Low payment or Medium payment condition in a driving simulator. They undertook both easy and difficult driving scenarios in which performance was measured. Subjective workload and performance results indicated that task difficulty was successfully manipulated with the study. However, in contrast to the previous research in non-driving contexts, participants not receiving rewards were found to perform more poorly and experience increased time pressure.     

Initial development of a brief measure of psychological distress

This paper addresses the preliminary development, construct validity, and psychometric properties of a brief self-report measure of psychological distress. 40 items were originally generated by doctoral level psychologists for use in the preliminary clinical sample. Inpatients from a psychiatric unit (N = 125) completed the items, and a principal-components analysis with a direct oblimin rotation was used to evaluate construct validity. The study indicated a four-factor solution, using the constructs of Depression, Hopelessness, Anxiety, and Anger, with good estimates of reliability. After evaluation of factor structure, item analyses, and reliability estimates, a redacted 19-item scale was identified.     

Taxometric Investigation of PTSD: data from two nationally representative samples

Current psychiatric nosology depicts posttraumatic stress disorder (PTSD) as a discrete diagnostic category. However, only one study has examined the latent structure of PTSD, and this study suggested that PTSD may be more accurately conceptualized as an extreme reaction to traumatic life events rather than a discrete clinical syndrome. To build on the existing literature base, the present research examined the latent structure of posttraumatic stress reactions by applying three taxometric procedures (MAXEIG, MAMBAC, and L-Mode) to data collected from large nationally representative samples of women (ns = 2684 and 3033) and adolescents (n = 3775). Results consistently provided evidence for a dimensional PTSD solution across samples and statistical procedures. These findings have important implications for the theory, assessment, and investigation of posttraumatic stress reactions.     

Maternal Knowledge and Behaviors Regarding Discipline: The Effectiveness of a Hands-on Education Program in Positive Guidance

This study examined which method is most effective in supporting parents to use positive guidance techniques, a lecture-based only parent training series or a lecture-based plus hands-on parent training series. Maternal characteristics of depression, stress level, and attitudes towards positive guidance were explored as possible moderators. In this sample of 49 mother–child dyads, results indicated that the cognitive understanding of the use of positive guidance over time of the participants in the lecture-based only versus the lecture-based plus hands-on groups did not significantly differ. However, both groups improved in their cognitive understanding of positive guidance over time. Results also indicated that the behavioral use of positive guidance over time of the participants in both groups significantly differed. Further investigation revealed that, although the two groups did not differ in their behavioral use of positive guidance before the program, the lecture-based plus hands-on group improved over time whereas the lecture-based only group did not. Depression, stress level, and attitudes towards positive guidance did not moderate the effects of being in either group on participants’ behavioral use of positive guidance. Findings showed that all participants gained a better understanding of effective parenting techniques, but a hands-on component in parent training programs may be necessary for parents to incorporate these strategies into their parenting behaviors. The results have implications for early childhood professionals working with parents to address children’s behavior issues, as well as for the design of parent-support programs.