On realizable biorders and the biorder dimension of a relation

The paper discusses the mathematical foundations of a technique of multidimensional scaling, generalizing Guttman scaling, in which the structure of the embedding space relies only on ordinal concepts. An empirical relation is represented as an intersection of a minimal number (called bidimension) of Guttman relations. Fairly complete results are given for the cases of bidimensions 1 and 2. In the general case, the main results are based on the equivalence between the bidimension and the dimension of a certain partial order. A characterization of the bidimension as the chromatic number of some hypergraph is also provided.     

A test of the quasi-circumplex structure of human values

Schwartz’s value system (SVS) has been widely used in different disciplines (e.g., psychology, management, and marketing). Although the value structure seems to be validated when data are analyzed through multidimensional scaling, we show that the quasi-circumplex structure of human values is not supported when confirmatory analysis approaches (e.g., CIRCUM and constrained confirmatory factor analysis) are used. Based on two samples of French and Swiss respondents, confirmatory tests of SVS provide little support for its quasi-circumplex structure, mainly due to problems of construct and discriminant validity resulting from multicollinearity between value types.     

Comparing Nouns and Verbs in a Lexical Task

We analyzed the differential processing of nouns and verbs in a lexical decision task. Moderate and high-frequency nouns and verbs were compared. The characteristics of our material were specified at the formal level (number of letters and syllables, number of homographs, orthographic neighbors, frequency and age of acquisition), and at the semantic level (imagery, number and strength of associations, number of meanings, context dependency). A regression analysis indicated a classical frequency effect and a word-type effect, with latencies for verbs being slower than for nouns. The regression analysis did not permit the conclusion that semantic effects were involved (particularly imageability). Nevertheless, the semantic opposition between nouns as prototypical representations of objects, and verbs as prototypical representation of actions was not tested in this experiment and remains a good candidate explanation of the response time discrepancies between verbs and nouns.     

Attentional bias in post-traumatic stress disorder diminishes after symptom amelioration

Background

Avoidance and hypervigilance to reminders of a traumatic event are among the main characteristics of post-traumatic stress disorder (PTSD). Attentional bias toward aversive cues in PTSD has been hypothesized as being part of the dysfunction causing etiology and maintenance of PTSD. The aim of the present study was to investigate the cognitive strategy underlying attentional bias in PTSD and whether normal cognitive processing is restored after a treatment suppressing core PTSD symptoms.

Methods

Nineteen healthy controls were matched for age, sex and education to 19 PTSD patients. We used the emotional stroop and detection of target tasks, before and after an average of 4.1 sessions of eye movement desensitization and reprocessing (EMDR) therapy.

Results

We found that on both tasks, patients were slower than controls in responding in the presence of emotionally negative words compared to neutral ones. After symptoms removal, patients no longer had attentional bias, and responded similarly to controls.

Conclusion

These results support the existence of an attentional bias in PTSD patients due to a disengagement difficulty. There was also preliminary evidence that the disengagement was linked to PTSD symptomatology. It should be further explored whether attentional bias and PTSD involve common brain mechanisms.     

Increasing compliance with medical examination requests directed to children with autism: effects of a high-probability request procedure

The purpose of this study was to evaluate the effectiveness of a high-probability (high-p) request sequence as a means of increasing compliance with medical examination tasks. Participants were children who had been diagnosed with autism and who exhibited noncompliance during general medical examinations. The inclusion of the high-p request sequence effectively increased compliance with medical examination tasks. In addition, the procedure was efficient, could be implemented by parents and medical professionals, and did not involve aversive procedures.     

Recasting (the near-miss to) Weber's law

The authors argue mathematically that a common, power-function model of the just-noticeable difference in stimulus intensities is logically inconsistent with an exponent other than 1 in those frequent situations in which a particular averaging over experimental conditions has taken place. The authors show that an alternative power-law model, one which does not share this logical inconsistency, provides a good fit to many well-known, psychoacoustic intensity discrimination data. They also show that the exponent in this alternative model must be nonconstant with the discrimination criterion in experiments implementing this averaging of data.     

Ageing-related stereotypes in memory: When the beliefs come true

Age-related stereotype concerns culturally shared beliefs about the inevitable decline of memory with age. In this study, stereotype priming and stereotype threat manipulations were used to explore the impact of age-related stereotype on metamemory beliefs and episodic memory performance. Ninety-two older participants who reported the same perceived memory functioning were divided into two groups: a threatened group and a non-threatened group (control). First, the threatened group was primed with an ageing stereotype questionnaire. Then, both groups were administered memory complaints and memory self-efficacy questionnaires to measure metamemory beliefs. Finally, both groups were administered the Logical Memory task to measure episodic memory, for the threatened group the instructions were manipulated to enhance the stereotype threat. Results indicated that the threatened individuals reported more memory complaints and less memory efficacy, and had lower scores than the control group on the logical memory task. A multiple mediation analysis revealed that the stereotype threat effect on the episodic memory performance was mediated by both memory complaints and memory self-efficacy. This study revealed that stereotype threat impacts belief in one's own memory functioning, which in turn impairs episodic memory performance.