Categorization of multidimensional geometrical figures by chickens (Gallus gallus f. domestica): fit of basic assumptions from exemplar, feature and prototype theory

Five hens, experienced in discrimination of two categories of multidimensional geometrical figures presented in fixed pairs in a simultaneous discrimination, were tested with familiar figures arranged as new pairs to assess the dependence of categorization performance on learned relational or configural cues. Test performance did not differ from training: relational or configural cues still influenced discrimination performance. It was suggested that – in accordance with exemplar theories – this influence depended on differences between pairs of probe exemplars that facilitate retrieval of learned category members. To test whether exemplar, feature or prototype theory was most suitable to explain categorization by chickens, the rates of pecking at exemplars were analysed using principal components analysis (PCA). The distribution of the exemplars' component loads on the single component obtained was examined in the light of the conditions dictated by the three types of theories on how representative category exemplars should be. The least constraining theory, i.e. the exemplar theory, was most suitable. Defining factors of classificatory behaviour are discussed with a special emphasis on the characteristics of category-defining stimulus attributes. Accepted after revision: 29 May 2001 Electronic Publication     

Resistance in group psychotherapy

The authors view resistance generally as healthy and a sign of a more or less intact ego. A brief review of the psychoanalytic literature and the group therapy literature presents resistance as a mechanism that closes off aspects of the internal and external world seen as potentially dangerous. Patient resistances are identified as coming from cultural values, fear of strangers, fear of regression, and resentment toward the therapist. Clinical vignettes of group patients and group interaction are presented. Finally, resistance of therapists and indications of such resistance are also explored.     

Asking Difficult Questions: Task Complexity Increases the Impact of Response Alternatives

In providing behavioural frequency reports, respondents use the range of the response alternatives as a frame of reference, resulting in higher estimates on scales that offer high rather than low values. The present study demonstrates that the size of this effect increases with increasing question difficulty.     

Response scales as frames of reference: The impact of frequency range on diagnostic judgements

In social and psychological research, respondents are often asked to report the frequency of a behaviour by checking the appropriate alternative from a list of response categories provided to them. Previous research indicated that respondents extract comparison information from the range of the response alternatives, assuming that the average respondent is represented by values in the middle range of the scale, and that the extremes of the scale represent the extremes of the distribution. Extending this line of research, the present studies demonstrate that the users of a respondent's report are also likely to use the range of the response alternatives as a frame of reference in evaluating the implications of the report. Specifically, subjects are found to draw different conclusions about the respondent's personality (Experiment l ), or the severity of his or her medical condition (Experiment 21, from the same absolute frequency report, depending upon the range of the response scale on which the frequency was checked. Moreover, experienced medical doctors were as likely to be influenced by scale range as first-year medical students, suggesting that the phenomenon is of considerable applied importance. Implications for the use of response alternatives in psychological research and diagnostic judgement are discussed.     

Die psychiatrische Vorgeschichte schizophrener Maßregelpatienten -Rahmenbedingungen der Deliktprävention durch die Allgemeinpsychiatrie

Background

People suffering from schizophrenic disorders are at increased risk of committing violent crimes. In the present study, we investigated the conditions of preventing offences by general inpatient psychiatric services.

Method

The sample enclosed 75 patients treated at forensic hospitals in Baden-Württemberg, Germany. Data on frequency and date of previous delinquency and general psychiatric treatments were collected from the clinical records and from the psychiatric expertise provided for the sentencing.

Results

Prior to the severe offence leading to forensic detainment, eighty-three per cent of the cases had been treated at least once at a general psychiatric hospital while indications of a risk of delinquency were already present. Even if more specific risk indicators were used and patients with only one general psychiatric treatment episode were excluded, nearly two thirds of cases remain as target group for prospective general psychiatric prevention programs. On average, six inpatient treatments during the course of six years would have provided opportunities to prevent delinquency. However, in twenty-five per cent of the cases, the crime leading to admission to a forensic unit took place within an institutional environment (wards, penal institution). Of the offences that were committed outside of an institution, fifty per cent occurred during the first year after a general psychiatric treatment. Two thirds of the sample had committed an offence before first admission to general psychiatric treatment. On average, the first offence preceded the first admission by 4,6 years.

Conclusions

General psychiatric services provide promising opportunities to prevent delinquency among schizophrenics at risk for criminal offending. Specific programs that are effective beyond discharge from a general psychiatric ward should be developed and evaluated.     

Fast and frugal heuristics are plausible models of cognition: reply to Dougherty, Franco-Watkins, and Thomas (2008)

M. R. Dougherty, A. M. Franco-Watkins, and R. Thomas (2008) conjectured that fast and frugal heuristics need an automatic frequency counter for ordering cues. In fact, only a few heuristics order cues, and these orderings can arise from evolutionary, social, or individual learning, none of which requires automatic frequency counting. The idea that cue validities cannot be computed because memory does not encode missing information is misinformed; it implies that measures of co-occurrence are incomputable and would invalidate most theories of cue learning. They also questioned the recognition heuristic's psychological plausibility on the basis of their belief that it has not been implemented in a memory model, although it actually has been implemented in ACT-R (L. J. Schooler & R. Hertwig, 2005). On the positive side, M. R. Dougherty et al. discovered a new mechanism for a less-is-more effect. The authors of the present article specify minimal criteria for psychological plausibility, describe some genuine challenges in the study of heuristics, and conclude that fast and frugal heuristics are psychologically plausible: They use limited search and are tractable and robust.     

Group communication and decision-making strategies

In daily life, people frequently make inferences about current and future states of the world. Most of these inferences are not made individually, but by exchanging information about which strategies could be used with other people. In an experiment, we analyzed whether exchanging information socially increased the probability of selecting the most adaptive strategy. In our experiment, take-the-best (TTB; Gigerenzer & Goldstein, 1996), a simple heuristic that employs one-reason decision making, achieved the highest payoff. Results showed that the fit of TTB increased substantially across trial blocks when participants were allowed to exchange information with other group members. In contrast, when participants made inferences individually, they did not select the most adaptive strategy even after seven trial blocks. Overall, our results support the hypothesis that group communication increases the likelihood that participants select the most adaptive strategy for making inferences.