Forty years of experimentation on class inclusion and its probabilistic relatives have led to inconsistent results and conclusions about human reasoning. Recent research on the conjunction "fallacy" recapitulates this history. In contrast to previous results, we found that a majority of participants adhere to class inclusion in the classic Linda problem. We outline a theoretical framework that attributes the contradictory results to differences in statistical sophistication and to differences in response mode-whether participants are asked for probability estimates or ranks-and propose (...) two precise cognitive algorithms for ranking probabilities. Our framework allows us to make novel predictions about when and why people adhere to class inclusion. Evidence obtained in several studies supports these predictions and demonstrates that the proposed ranking algorithms can account for about three-quarters of participants' inferences in the Linda problem. (shrink)

Several measures of paranormal belief have been developed and employed by researchers of published work. Despite this, there is considerable debate about the nature and structure of paranormal belief. Particularly, authors remain uncertain about which belief subsets should be included within paranormal scales. The current study extended existing research by exploring shared variance across different paranormal measures. An extensive literature review was undertaken in order to identify measures of paranormal belief. The independent scale items were then combined to produce a (...) 124item composite measure. This was distributed in paper form and electronically via the Internet. Respondents were recruited face to face, by email, and by post. In total, 1,481 respondents completed the measure: 548 the paper version and 933 online. Exploratory factor analysis (principal components analysis) was performed, and a nine-factor structure emerged. This contained item clusters measuring belief in: Hauntings, Other Life, Superstition, Religious Belief, Alien Visitation, Extrasensory Perception (ESP), Psychokinesis (PK), Astrology, and Witchcraft. Keywords: paranormal beliefs—Paranormal Belief Scale (PBS)—R-PBS— Paranormal Short Inventory (PSI) —Australian Sheep–Goat Scale (ASGS)—Anomalous Experiences Inventory (AEI). (shrink)

This paper consists of two parts. In the first, we discuss the neuropsychological correlates of belief in a 'paranormal' or magical causation of coincidences. In particular, we review experimental evidence demonstrating that believers in ESP and kindred forms of paranormal phenomena differ from disbelievers with respect to indices of sequential response production and semantic-associative processing. Not only do believers judge artificial coincidences as more 'meaningful' than disbelievers, they also more strongly suppress coincidental productions (i.e. repetitions) in their generation of random (...) sequences. These findings illuminate the cognitive mechanisms underlying the formation and maintenance of paranormal beliefs for which the right cerebral hemisphere is hypothesized to play a central role. These same right hemispheric semantic-associative processing characteristics are centrally implicated in the creative thought process as well as the genesis of delusional (pathological) beliefs (e.g. ideas of reference). (shrink)