Carving nature at its joints: Paul Meehl's development of taxometrics

This article presents a brief summary of Paul Meehl's development of taxometrics. Of special concern is the question, Why did Paul Meehl develop taxometrics? It is shown that taxometrics played an integral role in Meehl's broader research program on the genetics of schizotaxia.     

Sexual sadism and sadistic personality disorder in sexual homicide

Controversies exist about the diagnostic validity of sexual sadism and its relation to sadistic personality disorder in sex offenders. The aim of this study was to investigate which diagnostic, developmental, and criminal characteristics differentiate sexual sadistic from non-sadistic sexual homicide perpetrators. Psychiatric court reports on 166 men who had committed a sexual homicide were evaluated regarding psychiatric, sexual and criminal history. Sixty-one offenders (36.7%) with sexual sadism (SeSd) were compared with 105 (63.3%) offenders without this diagnosis (NSeSd). Besides the sexual sadistic symptoms, there were seven factors that discriminated best between the two groups (sexual masochism, sadistic personality disorder, isolation in childhood, multiple sexual homicide, previous rape, previous tendencies for similar behavior, and long duration of the homicidal act). Sexual sadism is connected with circumscribed other characteristics and has to be considered in risk assessment and treatment of sex offenders.     

The selection of grammatical features in word production: the case of plural nouns in German

Two experiments investigate the effect of number congruency using picture-word interference. Native German participants were required to name pictures of single objects (Nase 'nose') or two instances of the same object (Nasen 'noses') while ignoring simultaneously presented distractor words. Distractor words either had the same number or were different in number. In addition, the type of plural formation (same or different inflectional plural suffix) and the semantic relationship (same or different semantic category) between target and distractor were varied in Experiments 1 and 2. Results showed no effect of number congruency in either experiment. Furthermore, the type of inflectional suffix did not exert an influence on naming latencies in Experiment 1, but semantic relationship led to a significant interference effect in Experiment 2. The results indicate that selection of the number feature diacritic in noun production is not a competitive process. The implications of the results for models of lexical access are discussed.     

Biological motion shown backwards: the apparent-facing effect

We examined how showing a film backwards (reverse transformation) affects the visual perception of biological motion. Adults and 6-year-old children saw first a point-light quadruped moving normally as if on a treadmill, and then saw the same display in reverse transformation. For other groups the order of presentation was the opposite. Irrespective of the presentation mode (normal or reverse) and of the facing of the point-light figure (rightward or leftward), a pronounced apparent-facing effect was observed: the perceptual identification of a display was mainly determined by the apparent direction of locomotion. The findings suggest that in interpreting impoverished point-light biological-motion stimuli the visual system may neglect distortions caused by showing a film backwards. This property appears to be robust across perceptual development. Possible explanations of the apparent-facing effect are discussed.     

The influence of stimulus array on training of a speeded response

We conducted two experiments to study the training of speeded responses to stimuli in a clock face array. Participants were trained on one clock face and later tested on either the same or a different clock face. The clock faces varied along 3 dimensions of change (left-right flip, up-down flip, and 180 degrees rotation). Skill acquisition was reflected in decreases in overall, initiation, and movement response times in the training and test phases except that movement time reached an asymptote during training and did not decrease further during test. Test performance was best when training and test used the same clock face and worst when the training to test change involved an up-down flip. The transition to different clock faces was consistent with an interpretation based on the violation of expectations about target positions acquired during training. Consistent trial-by-trial feedback led to better initiation time but not movement time during training than periodic feedback, but this effect did not persist into the test phase.     

The effects of social change within a group on membership preferences: to leave or not to leave?

Two studies examined immediate (Study 1) and long-term (Study 2) behavioral consequences of previously documented asymmetries in cognitive and evaluative reactions to change in majority and minority positions within a group. Study 1 found an overall decrease in preferences for group membership immediately following change, which was preceded by decategorization and devaluation of the group in response to loss, together with lack of categorization and positive evaluation in response to gain of the majority position. Study 2 found a gradual increase in preference to stay with (vs. exit) the group among former minorities with prolonged interactions that confirmed their gained majority position. A gradual increase in preference for group membership was paralleled with gradual increases in perception of both inclusion within and differentiation from the group.     

Social anxiety and interpersonal perception: a social relations model analysis

Cognitive models of social phobia posit that an individual's negative beliefs about the way he or she is perceived by others (metaperceptions) are a core feature of the disorder. The social relations model () was used to analyze interpersonal perception data collected following unstructured social interactions in 62 socially anxious (SA) and 62 not socially anxious (NSA) individuals. Using this model, the interpersonal perceptions were analyzed to evaluate whether pathological levels of social anxiety are associated with self-perceptions, metaperceptions, and perceptions from others. SA participants saw themselves negatively and believed others saw them negatively. Although seen as more nervous by others, SA participants were not seen as less likeable. A mediational model demonstrated that the negative metaperceptions of SA individuals were more a function of their own self-perceptions than the negative perceptions of others. These findings were not attributable to depressive symptoms. Implications for theory and treatment of social phobia are discussed.     

Strength-is-Weakness: The (ir)relevant relation between resources and payoffs in coalition formation

A key observation in coalition formation is that bargainers who control many resources are often excluded from coalitions by bargainers who control few resources, the Strength-is-Weakness effect. We argue that this effect is contingent on whether resources provide a legitimate claim to be included in a coalition. Across three incentivized coalition experiments (n = 2745; 915 triads), three participants (player A had four resources, player B had three resources, player C had two resources) negotiated about a payoff of 90 monetary units. Depending on condition, these resources were obtained randomly, earned, or earned and proportionally linked to the payoff. Results showed player As were less included when resources were obtained randomly and more often included in coalitions when resources were earned and/or proportionally linked to the payoff. This provides evidence that the Strength-is-Weakness is contingent on the legitimacy of the resources.     

The emergence of knowledge systems thinking: A changing perception of relationships among innovation,knowledge process and configuration

As agriculture develops, policy and management decisions increasingly focus on agricultural innovation emerging from utilizing knowledge and/or technology. This paper considers models for underpinning knowledge and technology policy and management. It describes the emergence of knowledge systems thinking. The system construct is applied to actors (individuals, networks and institutions) involved in knowledge processes. These actors potentially form a highly articulated and complex whole. Knowledge policy and management focus on measures that enhance the synergy between actors. Knowledge systems are viewed as “soft systems,” i.e., they only become systems as a result of active construction and joint learning. The soft systems perspective facilitates the identification of various knowledge system models, which have consequences for policy and management decisions with respect to investment, design, and training. In an attempt to create a unifying theory for these models, it is posited that these models are consistent combinations of innovation, knowledge process and structural configuration. Currently, he is the director of an international program on “Comparative research in knowledge systems in support of sustainable agriculture.”