A series of three experiments replicated and extended earlier research reported by Chase and Simon (1973), de Groot (1965), and Charness (Note 1). The first experiment demonstrated that the relationship between memory for chess positions and chess skill varies directly with the amount of chess-specific information in the stimulus display. The second experiment employed tachistoscopic displays to incrementally "build" tournament chess positions by meaningful or nonmeaningful chunks and demonstrated that meaningful piece groupings during presentation markedly enhance subsequent recall performance. The third experiment tested memory for one of two positions presented in immediate sequence and demonstrated that explanations based on a limited-capacity short-term memory (Chase & Simon, 1973) are not adequate for explaining performance on this memory task.The game of chess provides a useful working environment for the analysis of specialized informationprocessing skills. Skill in chess is acquired only with extensive exposure to the game. From an analysis of verbal protocols, de Groot (1965) established that chess masters and less able players use similar thought processes in analyzing a complex chess position. They consider a similar number of moves (about 35), calculate to similar depths (about 7 plies), make the same number of fresh starts (about 7), and analyze a similar number of moves per minute (about 3). The only major difference de Groot noted was that the masters invariably analyzed stronger moves than the weaker players. This conclusion (i.e., better players are better because they select better moves) was not terribly illuminating.de Groot's (1965) research did indicate that masters differed from weaker players in their ability to recall a chess position from an unfamiliar game after it had been presented for only 5 sec. Masters recalled 93% of 22 pieces, while strong club players recalled about 51%. Chase and Simon (1973) have shown that this recall ability is chess specific by replicating de Groot's result and including a control condition in which the chess pieces were arranged randomly. With a 5-sec exposure of quiet middle-game positions, their master recalled 81% of the 22 pieces, while a novice recalled only 33%. With the randomized positions, all subjects recalled only three to five pieces correctly. This result indicates that the master and novice have similar visual memory capacities for nonmeaningful piece configurations. Thus, the ability to play chess well seems to depend on aThe design and interpretation of these experiments benefited greatly from discussions with Neil Charness, Eliot Hearst, Henry Helff, Michael Humphreys, and Benton J. Underwood. The authors thank Stanton Tripodis for data collection assistance in Experiment I. Reprint requests should be addressed to Peter Frey, Department of Psychology, Northwestern University, Evanston, Illinois 60201. learned perceptual skill rather than on the acquisition of a sophisticated problem-solvingstrategy. EXPERIMENT IOur first study attemp...

This experiment examined the effect of timing of an intimate disclosure and assignment of responsibility for the event disclosed on interpersonal attraction. Subjects were induced to interact with a confederate who in all cases revealed something quite personal about himself. The disclosure occurred either early or near the end of a 10-minute conversation. The confederate accepted responsibility for the event disclosed, did not mention responsibility, or assigned responsibility to external factors. Negative traits were assigned to the early disclosure, and he was liked significantly less than the late discloser. The results are explained in terms of differential attributions made to early and late disclosures. The results for the assignment of responsibility variable were surprising: The confederate who accepted responsibility for the event disclosed elicited more negative reactions than the confederate who blamed other factors or who did not mention responsibility. Some possible reasons for this unexpected finding are discussed.

Narcotics and benzodiazepines are commonly used for sedation for endoscopy in the United States. Propofol has certain advantages over narcotics and benzodiazepines, but its use is often controlled by anesthesia specialists. This report describes our experience with dosage, safety, patient satisfaction, and discharge time with nurse-administered propofol sedation in 9152 endoscopic cases. The study was performed in a private practice ambulatory surgery center in Medford, Oregon. With the assistance of an anesthesiologist, we developed a protocol for administration of propofol in routine endoscopic cases, in which propofol was given by registered nurses under the supervision of endoscopists or gastroenterologists. We then applied the protocol with 9152 patients. There were seven cases of respiratory compromise (three prolonged apnea, three laryngospasm, one aspiration requiring hospitalization), all associated with upper endoscopy. Five patients required mask ventilation, but none required endotracheal intubation. There were seven colonic perforations (<1 per 1000 colonoscopies), of which three may have involved forceful sigmoid disruption. Of patients who had previously received narcotic or benzodiazepine sedation, 84% preferred propofol. Gastroenterologists strongly preferred propofol. The mean time from completion of procedures to discharge in a sample of 100 patients was 18 min.Nurse-administered propofol sedation in an ambulatory surgery center was safe and resulted in high levels of patient satisfaction and rapid postprocedure recovery and discharge.

A 54-year-old woman with obesity, type II diabetes mellitus, hyperlipidemia, and massive hepatomegaly was found to have severe steatosis and cirrhosis on liver biopsy. Complete evaluation led to the diagnosis of fatty cirrhosis associated with obesity and diabetic mellitus. She underwent four months of fasting with a protein-carbohydrate and vitamin-mineral liquid supplement to control her weight and metabolic abnormalities and to evaluate the effect of this diet on her liver disease. She lost 40 pounds to ideal body weight, normalized her serum glucose and lipids, and decreased total liver height by one third. Liver biopsy at the completion of her diet showed inactive cirrhosis and complete resolution of steatosis. Supplemented fasting with only modest weight loss can safely resolve fatty liver in obese diabetics with nonalcoholic steatosis and cirrhosis. Aggressive dietary approaches to achieve long-term weight loss deserve study in this subgroup of diabetics with unexplained chronic liver disease.

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