Overconfidence in Interval Estimates.

Judges were asked to make numerical estimates (e.g., "In what year was the first flight of a hot air balloon?"). Judges provided high and low estimates such that they were X% sure that the correct answer lay between them. They exhibited substantial overconfidence: The correct answer fell inside their intervals much less than X% of the time. This contrasts with choices between 2 possible answers to a question, which showed much less overconfidence. The authors show that overconfidence in interval estimates can result from variability in setting interval widths. However, the main cause is that subjective intervals are systematically too narrow given the accuracy of one's information-sometimes only 40% as large as necessary to be well calibrated. The degree of overconfidence varies greatly depending on how intervals are elicited. There are also substantial differences among domains and between male and female judges. The authors discuss the possible psychological mechanisms underlying this pattern of findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of mass spectral techniques using organic peroxides related to artemisinin

The mass spectra of three peroxides related to artemisinin (1) are compared in nine different ionization modes. Ion trap mass spectrometry (MS/MS) spectra reveal numerous pathways for the electron impact (EI) decompositions. In the EI mode, the best spectra are obtained by using the ion trap mass spectrometer at low temperatures. Loss of oxygen is observed with the other EI spectrometers, suggesting catalytic decomposition in the ion source. Methane positive and negative chemical ionization (CI) spectra show considerable fragmentation, while isobutane CI spectra show only (M + H)+ for 1 and (M + H - H2O)+ for dihydroartemisinin (2) and (3). An unusually abundant (2M + H)+ is observed for 1 in both positive-ion plasma desorption and fast atom bombardment mass spectra.     

Hillel J. Einhorn (1941–1987).

Presents an obituary for Hillel Einhorn, who died of Hodgkin's disease at the age of 45. Between two battles with cancer, Einhorn contributed greatly to the development of the field of behavioral decision theory. Apart from visiting appointments at Carnegie-Mellon University and the Hebrew University of Jerusalem, Einhorn spent his entire professional career at the University of Chicago. Three themes could be said to underlie his work. First, he sought to integrate psychological principles into models of decision making and to bring decision research into the mainstream of psychology. Second, guided by a strong aesthetic sense, he had a deep appreciation for the latent simplicity, beauty, and efficacy of many natural processes even when observable behaviors seem complex or chaotic. Third, although he greatly admired rigorous experimental work, he was acutely aware that there can be critical differences between decision making under laboratory conditions and decision making in the real world. Einhorn died in 1987. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diagnosis of ectoparasitism

A vacuum cleaner fitted with an in-line filter was used to collect samples from suspected cases of ectoparasitic infestation in animals. Filter samples, including hair, were hydrolyzed in hot potassium hydroxide, and the residue was concentrated by flotation in concentrated sugar and then examined under a microscope. The 206 animals examined yielded fleas, flea feces, forage mites, Cheyletiella, Sarcoptes, Chorioptes, Psoroptes, Otodectes, Demodex and Damalinia spp. The sensitivity of this technique in the diagnosis of ectoparasites was better than that of conventional skin scrapings or direct observation.     

Cue discovery in probabilistic environments: Uncertainty and experimentation.

It is argued that cue discovery is an important part of the task of learning from experience in probabilistic environments. Cue discovery involves the identification of new valid predictive cues, and their incorporation into the learner's mental model. In contrast, previous work in "multiple-cue probability learning" has focused principally on learning the quantitative characteristics of given cue–criterion relations. In two studies presented here, 36 college students learned to predict the behavior of a computer-controlled graphic display. The criterion behavior was a function of four to six cues, including several not explicitly identified. Analyses of test results, verbal reports, and behavior during learning indicate that subjects used outcome feedback to accomplish cue discovery. This process was accomplished more effectively when subjects were permitted to experiment by designing their own learning experiences. A distinction is drawn between a system whose behavior is unpredictable because of the presence of unknown controlling variables, and one that contains "random" error. Cue discovery may be more difficult in the latter case, but is accomplished nonetheless. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition of uncertainty in emotional inferences: Reasoning about emotionally equivocal situations.

Three experiments investigated children's and adults' understanding of the uncertainty inherent in emotionally equivocal situations (i.e., situations that commonly elicit different feelings in different people). Students in 1st grade, 3rd grade, 6th grade, and college heard scenarios in which a peer experienced an emotionally equivocal or unequivocal event. Children, and to some degree adults, were overconfident about how individuals felt in equivocal situations. The tendency to acknowledge only 1 emotional possibility appeared to reflect difficulty in recognizing the plausibility of alternatives. Neither prompting children to give greater consideration to alternatives nor reminding them of the existence of individual differences produced greater discrimination between equivocal and unequivocal situations. In contrast, children recognized uncertainty when there was variability in the situation or within the individual. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Skilled or unskilled, but still unaware of it: How perceptions of difficulty drive miscalibration in relative comparisons.

People are inaccurate judges of how their abilities compare to others'. J. Kruger and D. Dunning (1999, 2002) argued that unskilled performers in particular lack metacognitive insight about their relative performance and disproportionately account for better-than-average effects. The unskilled overestimate their actual percentile of performance, whereas skilled performers more accurately predict theirs. However, not all tasks show this bias. In a series of 12 tasks across 3 studies, the authors show that on moderately difficult tasks, best and worst performers differ very little in accuracy, and on more difficult tasks, best performers are less accurate than worst performers in their judgments. This pattern suggests that judges at all skill levels are subject to similar degrees of error. The authors propose that a noise-plus-bias model of judgment is sufficient to explain the relation between skill level and accuracy of judgments of relative standing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Confirmation, disconfirmation, and information in hypothesis testing.

A number of philosophers and psychologists stress the importance of disconfirmation in reasoning and suggest that people are instead prone to a general deleterious "confirmation bias." In particular, it is suggested that people tend to test those cases that have the best chance of verifying current beliefs rather than those that have the best chance of falsifying them. We show, however, that many phenomena labeled "confirmation bias" are better understood in terms of a general positive test strategy. With this strategy, there is a tendency to test cases that are expected (or known) to have the property of interest rather than those expected (or known) to lack that property. We show that the positive test strategy can be a very good heuristic for determining the truth or falsity of a hypothesis under realistic conditions. It can, however, lead to systematic errors or inefficiencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypothesis testing in rule discovery: Strategy, structure, and content.

Examined hypothesis-testing strategy by using the paradigm of rule discovery introduced by P. C. Wason (see record 1961-01737-001). Ss were given an example of a triple (a set of 3 items) produced by a particular generating rule. Their goal was to determine the rule. To do this, they proposed a new triple and were told whether the triple fit the rule. Ss completed 18 such trials, each time indicating their current best guess about the rule. After the 18th triple, Ss were told whether their guess was correct. Each S received 1 of 18 problems using triples of numbers or cities. Task structure was varied across problems by varying relations between the correct rule and Ss' initial hypotheses. Performance was a function of task structure, task content, and hypothesis-testing strategy. However, results indicate the overall predominance of a positive test strategy, which often leads to hypotheses that are too narrow. In this strategy, Ss look for possible errors by testing instances they believed should fit the rule, with relatively few tests of instances they believe should not. Successful and unsuccessful Ss showed the same predominant strategy. However, successful problem solvers were much more likely to direct their tests toward distinguishing explicit alternative hypotheses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Benjamin Kleinmuntz (1930-2006).

In the 1960s, the idea that clinical judgments should be aided, or even replaced, by computerized algorithms was quite radical. Computerized interpretation of standardized tests is accepted now, although its role remains controversial. Benjamin Kleinmuntz was a pioneer in the study of computers in clinical reasoning and a founder of the field of judgment and decision research. He passed away at his home inWilmette, Illinois, on June 28, 2006, at the age of 76. Although he lived with a transplanted heart for almost 11 years, he died of complications of unrelated abdominal surgery. Ben's early research concerned statistical methods for identifying psychopathologies and interpreting personality profiles. Ben then focused on investigating the use of computers in clinical diagnosis. Ben also wrote or cowrote textbooks on general psychology, abnormal psychology, and personality assessment. He was also a great teacher and advisor, with a unique personal style and an emphasis on both rigor and relevance. He received multiple awards for teaching excellence, and his two all-University teaching awards were as important to him as his many books, publications, and professional recognitions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)