An account of subjective probability judgment for joint events: Conjunctive and disjunctive

Probability judgment is a vital part of many aspects of everyday life. In the present paper, we present a new theory of the way in which individuals produce probability estimates for joint events: conjunctive and disjunctive. We propose that a majority of individuals produce conjunctive (disjunctive) estimates by making a quasi-random adjustment, positive or negative, from the less (more) likely component probability with the other component playing no obvious role. In two studies, we produce evidence supporting propositions that follow from our theory. First, the component probabilities do appear to play the distinct roles we propose in determining the joint event probabilities. Second, contrary to probability theory and other accounts of probability judgment, we show that the conjunctive-less likely probability difference is unrelated to the more likely disjunctive probability difference (in normative theory these quantities are identical). In conclusion, while violating the norms of probability judgment, we argue that estimates produced in the manner we propose will be close enough to the normative values especially given the changing nature of the external environment and the incomplete nature of available information.

Paranormal belief, thinking style preference and susceptibility to confirmatory conjunction errors

This study examines the extent to which belief in extrasensory perception (ESP), psychokinesis (PK) or life after death (LAD), plus need for cognition (NFC) and faith in intuition (FI), predict the generation of confirmatory conjunction errors. An opportunity sample (n = 261) completed sixteen conjunction problems manipulated across a 2 event type (paranormal vs. non-paranormal) × 2 outcome type (confirmatory vs. disconfirmatory) within subjects design. Three Generalised Linear Mixed Models - one per paranormal belief type - were performed. With respondent gender and age controlled for, ESP, PK and LAD beliefs were all associated with the making (vs. non-making) of conjunction errors both generally and specifically for confirmatory conjunctive outcomes. Event type had no impact. Individuals high in NFC were less likely to commit the fallacy. The role thinking style plays in shaping paranormal believers' susceptibility to confirmatory conjunction biases is discussed. Methodological issues and future research ideas are also considered.

The Missing Link in the Paradox of the Linda Conjunction Problem: Beyond Knowing and Thinking of the Conjunction Rule, the Intrinsic Appeal of Heuristic Processing

Participants who adopted an intuitive-experiential but not an analytical-rational mode of information processing reproduced the usual finding for the Linda conjunction problem of a preference for a heuristic, representativeness over a statistical, conjunction-rule solution. Many who knew and thought of the conjunction rule (the absence of which previously were considered the major reasons for the prevalence of representativeness solutions) preferred a representativeness solution. The widely held belief that people prefer the outcome of their rational more than their intuitive processing when both are equally accessible is of limited generality. The preference by many who know the conjunction rule for a heuristic, representativeness solution can account for both the very high rate of conjunction errors to the Linda problem and their resistance to elimination by training. A finding of a surprisingly strong priming effect suggests that once people engage in a processing mode, it tends to be self-maintaining.

Assessment of Magical Beliefs about Food and Health

The Magical Beliefs About Food and Health scale (MFH) was developed to assess individual differences in the tendency to adopt eating and health instructions that many magazines, health care books and food ideologies regard as valid but which obey universal laws of similarity and contagion. In a study of 216 individuals, the total MFH score showed good internal consistency and it was associated with various validity criteria as hypothesized (e.g. vegetarianism and other ideological commitments to food choice, female gender, increased neuroticism, experiential thinking, positive attitudes towards alternative medicine, low sensation seeking and endorsement of universalism values). Factor analysis yielded two factors: General Magical Beliefs and Animal Products as Food Contaminants. In addition, three other items (the Animal Products as Personality Contaminants scale) cross-loaded on the two factors. The factor structure and test–retest reliability were confirmed with separate samples. The results showed that the total MFH score is a reliable and valid measure of magical food and health beliefs, and that the subscales may prove useful when a multidimensional assessment of magical beliefs is needed.

Is experiential-intuitive cognitive style more inclined to err on conjunction fallacy than analytical-rational cognitive style?

In terms of prediction by Epstein’s integrative theory of personality, cognitive-experiential self-theory (CEST), those people with experiential-intuitive cognitive style are more inclined to induce errors than the other people with analytical-rational cognitive style in the conjunction fallacy (two events that can occur together are seen as more likely than at least one of the two events). We tested this prediction in a revised Linda problem. The results revealed that rational and experiential cognitive styles do not statistically influence the propensity for committing the conjunction fallacy, which is contrary to the CEST’s predictions. Based on the assumption that the rational vs. experiential processing is a personality trait with comparatively stabile specialities, these findings preliminarily indicate that those people who are characterized by “rational thinking” are not more inclined to use Bayes’ deduction than the other people who are labeled by “intuitive thinking” or by “poor thinking.”

Gender differences in the effect of visual sexual stimulation on the perceived covariation between freedom and responsibility

The authors replicated and extended a test of Epstein's cognitive-experiential self-theory (CEST; S. Epstein, 1973, 1980, 1985, 1994, 2003) regarding subjective estimates of the relationship between freedom and responsibility. CEST predicts that information in the form of sexually provocative images is likely to be processed by the experiential system. The authors' hypothesis was that such experiential processing would cause an increase in the likelihood of participants endorsing as true a statement that proposed a negative correlation between freedom and responsibility. University students (N = 97) in introductory psychology classes viewed 25 images of either men or women in provocative clothing, or a control consisting of academic journal covers, after which they responded to 24 statements proposing either a positive, negative, or noncontingent relationship between freedom and responsibility. Judgments were analyzed according to perceiver gender and target gender, as well as the framing of the proposition and its contingency category. The hypothesis was supported for the men and to a lesser extent for the women. Although priming the experiential system by exposing participants to sexually provocative images did not change endorsement rates of positive contingencies, it did lead to an increase in the likelihood of simultaneously endorsing negative contingencies.