On the form of stimulus generalization curves for visual intensity

Twelve pigeons were given successive discrimination training involving variable-interval reinforcement for key pecking in the presence of one intensity of monochromatic light randomly alternated with extinction for pecking during another intensity. All of the pigeons were then tested in extinction for generalization along the intensity dimension, and all showed a displacement of maximal responding from the positive stimulus in the direction opposite the negative stimulus. For six of the pigeons, for which the test included only three values beyond the positive stimulus, four showed peaked gradients but two did not, showing monotonic gradients with maximal responding to the most extreme test value. For another six pigeons tested over a wider range, all showed peaked gradients. Thus, when a sufficiently wide range of test values is employed, generalization gradients for visual intensity have the same peaked form as do gradients for qualitative visual dimensions such as wavelength or line angle.     

Pathologisches Glücksspiel und Delinquenz

Pathological gambling is characterized by excessive gambling behavior which influences the life and well-being of a person in a dysfunctional way. It often leads to severe consequences in social and family life, career and material matters. This can also include illegal acts. In the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) excessive gambling was classified under impulse-control disorders but was renamed as gambling disorder (GD) and reclassified under the category “substance-related and addictive disorders” in DSM-5, due to parallels to substance use disorders in the clinical characteristics as well as genetic and neurobiological factors. In Germany, approximately 0.5?% of the adult population suffer from GD. Especially gambling machines are associated with an increased risk of gambling-related problems. Common comorbidities are substance-related and affective disorders. The most important risk factors are young age, male gender, a history of migration, gambling-related problems in the family, unemployment, a low educational level and low household income. Delinquent behavior was not considered to be a sufficiently discriminative factor for GD, although there is a correlation between delinquency and gambling behavior. In addition, those GD subjects who show delinquent behavior also show a specific risk profile. Thus, mental health professionals should be aware of possible psychosocial consequences in GD, such as illegal acts, and this should be addressed in the effective treatment strategies, such as cognitive behavioral therapy. Moreover, it is necessary to improve the access routes for affected people into healthcare system in order to ensure early detection and treatment of the disease.     

Social demand characteristics in children's and adults' eyewitness memory and suggestibility: the effect of different interviewers on free recall and recognition

Shortly after viewing a video of a theft, 5‐ and 7‐year‐old children and adults were interviewed with free recall and either misleading or unbiased‐leading questions. After a 2‐day delay, participants were interviewed with free recall and recognition questions administered by either the same or a different interviewer. Results from day 1 replicate previous findings with levels of recall and resistance to suggestibility increasing with age. Counter to predictions, correct recognition performance on day 2 was greater for some participants interviewed by the same as opposed to a different interviewer, and incorrect recognition was greater for all groups of participants for those interviewed by a different as opposed to the same interviewer. Results are discussed in terms of the role of context dependence on memory performance. Copyright © 2000 John Wiley & Sons, Ltd.     

Optimal designs for the generalized partial credit model

Analysing ordinal data is becoming increasingly important in psychology, especially in the context of item response theory. The generalized partial credit model (GPCM) is probably the most widely used ordinal model and has found application in many large-scale educational assessment studies such as PISA. In the present paper, optimal test designs are investigated for estimating persons’ abilities with the GPCM for calibrated tests when item parameters are known from previous studies. We find that local optimality may be achieved by assigning non-zero probability only to the first and last categories independently of a person's ability. That is, when using such a design, the GPCM reduces to the dichotomous two-parameter logistic (2PL) model. Since locally optimal designs require the true ability to be known, we consider alternative Bayesian design criteria using weight distributions over the ability parameter space. For symmetric weight distributions, we derive necessary conditions for the optimal one-point design of two response categories to be Bayes optimal. Furthermore, we discuss examples of common symmetric weight distributions and investigate under what circumstances the necessary conditions are also sufficient. Since the 2PL model is a special case of the GPCM, all of these results hold for the 2PL model as well.