A stochastic model for paired comparisons of social stimuli

A stochastic model for paired comparisons of multiattribute social stimuli is proposed where one objective is to find the relative importance of the attributes for a judge. The model can be conceived as a special strict binary utility model, i.e., a BTL-model, and is related to of the stimuli are linear combinations of functions of the attributes of the stimuli. The model neither assumes that the functions are fixed in advance nor that different judges have the same set of functions. The choice among such functions, however, is admitted only within a finite scope. Within the framework of exponential families, maximum likelihood estimators and tests are derived and applied to data coming from two psychological experiments.     

Do chimpanzees anticipate an object’s weight? A field experiment on the kinematics of hammer-lifting movements in the nut-cracking Taï chimpanzees

When humans are about to manipulate an object, our brains use visual cues to recall an internal representation to predict its weight and scale the lifting force accordingly. Such a long-term force profile, formed through repeated experiences with similar objects, has been proposed to improve manipulative performance. Skillful object manipulation is crucial for many animals, particularly those that rely on tools for foraging. However, despite enduring interest in tool use in non-human animals, there has been very little investigation of their ability to form an expectation about an object’s weight. In this study, we tested whether wild chimpanzees use long-term force profiles to anticipate the weight of a nut-cracking hammer from its size. To this end, we conducted a field experiment presenting chimpanzees with natural wooden hammers and artificially hollowed, lighter hammers of the same size and external appearance. We used calibrated videos from camera traps to extract kinematic parameters of lifting movements. We found that, when lacking previous experience, chimpanzees lifted hollowed hammers with a higher acceleration than natural hammers (overshoot effect). After using a hammer to crack open one nut, chimpanzees tuned down the lifting acceleration for the hollowed hammers, but continued lifting natural hammers with the same acceleration. Our results show that chimpanzees anticipate the weight of an object using long-term force profiles and suggest that, similarly to humans, they use internal representations of weight to plan their lifting movements.     

Prevalence and correlates of ICD-11 adjustment disorder: Findings from the Zurich Adjustment Disorder Study

Background/Objective: The 11th revision of the International Classification of Diseases (ICD-11) will provide a new definition of adjustment disorder (AjD). The aim of the present study is to report on prevalence and correlates of ICD-11 AjD in a high-risk sample. Method: Three hundred thirty persons who had lost their job involuntarily were sampled by local job centres. The Munich Composite International Diagnostic Interview was administered with a new AjD module. Associations between AjD and correlates were investigated with logistic regression analyses. Results: 27.3% of the participants reported the AjD core symptom pattern. 13.8% men and 17.2% women met diagnostic guidelines of ICD-11 AjD. Prevalence increased with age and exposure to multiple stressors. The AjD core symptom pattern was associated with various sociodemographic correlates (e. g., lower financial household budget), whereas the full ICD-11 diagnosis including the exclusion algorithm was not. Regarding work-related factors, AjD occurred with a lower probability if the last job position had higher responsibilities and more general confidence for the future. Conclusions: ICD-11 AjD has a high prevalence among persons who lost their jobs involuntarily. Healthcare professionals should be aware of this problem. Research to investigate the ICD-11 AjD concept in the general populations and other subpopulations is needed.     

Book reviews

Abstract

Oakhill, J. &; Garnham, A. (1988). Becoming a skilled reader, Oxford: Blackwell. Pp. 206. ISBN 0-631-15244X £27.50 (hardback), ISBN 0-631-15776X £8.95 (paperback).

Brewin, C. R. (1988). Cognitive foundations of clinical psychology. London: Lawrence Erlbaum Associates Ltd. Pp. 224. ISBN 0-86377-098-3 £24.50 (hardback), ISBN 0-86377-099-1 £8.95 (paperback).     

Episodic retrieval processes take place automatically in auditory negative priming

Episodic retrieval processes involved in negative priming have been argued to be susceptible to the proportion of attended repetition trials. The more trials with the same prime and probe response, the more beneficial should it be to retrieve the prime episode, particularly its response. Retrieval of the prime episode, however, is task-inappropriate for ignored repetition trials, leading to negative priming. Correspondingly, visual negative priming increases with the proportion of attended repetition trials. We tested whether the same is true for the auditory modality. Three attended repetition proportion groups (0–25–50%) showed the same amount of negative priming. All groups committed more prime response errors in ignored repetition than in control trials, implying that prime response retrieval took place. Thus, retrieval processes in auditory negative priming appear to be automatic and cannot be influenced as easily as in the visual domain. In Experiment 2, the proportion of ignored repetition trials was manipulated (25–50–75%) to test whether auditory negative priming can be strategically manipulated at all. Similar to the visual modality negative priming was reduced with increasing proportion of ignored repetition trials. Differences between visual and auditory short-term memory are discussed to account for the results.     

Dissociating the effects of automatic activation and explicit expectancy on reaction times in a simple associative learning task

After repeated associations between two events, E1 and E2, responses to E2 can be facilitated either because participants consciously expect E2 to occur after E1 or because E1 automatically activates the response to E2, or because of both. In this article, the authors report on 4 experiments designed to pit the influence of these 2 factors against each other. The authors found that the fastest responses to a target in a reaction time paradigm occurred when automatic activation was highest and conscious expectancy lowest. These results, when considered together with previous findings indicating that, under most conditions, the relation between expectancy and reaction times is in the opposite direction, are indicative of a reversed association-an interaction pattern that J. C. Dunn and K. Kirsner (1988) demonstrated to be the only one that unambiguously points to the involvement of independent processes.     

Normal auditory negative priming in schizophrenic patients

Performance of 28 schizophrenic patients and 28 matched controls was compared in an auditory priming task. A large auditory negative priming effect was obtained for the patients as well as for the control group, and the size of the negative priming effect was approximately the same for both groups. Under the same conditions, positive or repetition priming for the patients was enhanced compared to that of the control group. The present findings from an auditory priming task are consistent with a growing body of evidence from the visual domain showing normal rather than reduced or eliminated negative priming in schizophrenic patients.     

Attention, heart rate, and startle response during exposure to trauma-relevant pictures: a comparison of recent trauma victims and patients with posttraumatic stress disorder

Victims of a recent trauma were compared with posttraumatic stress disorder (PTSD) patients and healthy controls to assess whether a specific anxiety response and an attentional bias were evident initially or only in chronic PTSD. Heart rate (HR) and startle response were measured, and a dot-probe task was carried out using trauma-relevant pictures. Severely affected recent trauma victims and chronic PTSD patients showed HR acceleration to trauma-related material, which was the only significant group difference. A bias away from trauma-related material was related to severity of intrusions in recent trauma victims, and the bias toward trauma-related material increased with amplitude of the HR response in PTSD patients. A specific anxiety reaction is present initially in severely affected trauma victims.     

Gender bias in fame judgments: Implicit gender stereotyping or matching study phase fame?

Familiarized names are falsely judgedfamous more often than nonfamiliarized names. Banaji and Greenwald (1995) demonstrated a gender bias in thisfalse fame effect, with the effect being larger for male than for female names. This effect was interpreted as reflecting the operation of a gender stereotype. However, the famous male names were, in fact, better known than the famous female names. Thus, the presence of more famous male names during study may have contributed to the observed male-famous association. If so, there should be no gender bias if the studied famous male and female names are equally famous, and a reversed gender bias should emerge if the famous female names are more famous than the male names. In two experiments, these predictions were corroborated. A “classical” gender bias was found only when the famous males were more famous than the famous females. These findings are consistent with the hypothesis that the gender bias in fame judgments, rather than showing implicit gender stereotyping in the sense of a transsituational judgment bias, reflects the fact that, in test, participants select a proportion of fame judgments to male and female names so that it matches the relative degree of fame of male and female names encountered during study.