The effects of averaging subjective probability estimates between and within judges.

The average probability estimate of J > 1 judges is generally better than its components. Two studies test 3 predictions regarding averaging that follow from theorems based on a cognitive model of the judges and idealizations of the judgment situation. Prediction 1 is that the average of conditionally pairwise independent estimates will be highly diagnostic, and Prediction 2 is that the average of dependent estimates (differing only by independent error terms) may be well calibrated. Prediction 3 contrasts between- and within-subject averaging. Results demonstrate the predictions' robustness by showing the extent to which they hold as the information conditions depart from the ideal and as J increases. Practical consequences are that (a) substantial improvement can be obtained with as few as 2-6 judges and (b) the decision maker can estimate the nature of the expected improvement by considering the information conditions.

Internal structure of the MMPI-2 Addiction Potential Scale in alcoholic and psychiatric inpatients.

Recently, Weed, Butcher, McKenna, and Ben-Porath (1992) introduced two new scales for assessing alcohol and drug abuse with the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989): the Addiction Potential Scale (APS), an empirically derived measure similar to the MacAndrew Alcoholism Scale (MAC; MacAndrew, 1965), and the Addiction Acknowledgement Scale. Like the MAC, the APS was designed to identify the personality dimensions associated with substance abuse. Although there has been evidence to support the discriminative validity of the APS among samples of abusers, nonabusers, and psychiatric inpatients (Greene, Weed, Butcher, Arrendondo, & Davis, 1992; Weed et al., 1992), there has been no attempt to determine the personality dimensions tapped by the APS. Thus our study investigated the internal complexities of the APS. Using MMPI-2 protocols from a sample of alcoholic and psychiatric inpatients, we subjected the APS to a principal components analysis with subsequent varimax rotation. Both qualitative and quantitative methods were used to name the components that were identified. Five components consistently emerged across settings: Satisfaction/Dissatisfaction with Self, Powerlessness/Lack of Self-Efficacy, Antisocial Acting-Out, Surgency, and Risk-Taking/Recklessness, Clinical advantage gained from a knowledge of the internal structure of the APS was illustrated using 6 patients from the alcoholic sample. A rational approach to validating the empirical structure of the APS was discussed as a potential avenue for future research.

Meal patterns and macronutrient intake after peripheral and PVN injections of the alpha 2-receptor antagonist idazoxan.

Studies with idazoxan (IDA), a specific alpha 2-noradrenergic receptor antagonist, demonstrate effects on feeding behavior opposite to those observed with norepinephrine in the paraventricular nucleus (PVN) and peripheral injection of the alpha 2 agonist clonidine. Administration of IDA, both intraperitoneally (IP) and into the PVN at the onset of the nocturnal feeding cycle, caused a dose-related, selective suppression of carbohydrate intake 90 min after injection. To characterize further the impact of this antagonist on macronutrient intake, we examined in IDA-injected animals the macrostructure of feeding using computer-assisted analyses of meal patterns. Both IP and PVN administration of IDA produced a selective suppression of carbohydrate intake, primarily during the first meal of the feeding cycle. This effect occurred through significant reductions in meal size, diet composition, feeding time, and feeding rate for this nutrient. Idazoxan administration into the PVN continued to decrease carbohydrate intake in the next two meals and reduced the satiating impact of this nutrient. In contrast to this immediate change in carbohydrate intake, PVN IDA reduced protein intake after a latency of 4 h. although fat intake was suppressed only after a latency of 7 h. An increase in total meal number and a decrease in the average meal size across the 12-h dark cycle were seen after PVN IDA administration. These results, showing effects of peripheral and PVN-injected IDA on carbohydrate intake, suggest a possible physiological role of endogenous PVN alpha 2-noradrenergic receptors in modulating natural patterns of carbohydrate feeding at the onset of the dark period.