Verbal and Numerical Expressions of Probability: "It's a Fifty-Fifty Chance"

When estimating risks, people may use "50" as an expression of the verbal phrase "fifty-fifty chance," without intending the associated number of 50%. The result is an excess of 50s in the response distribution. The present study examined factors determining the magnitude of such a "50 blip," using a large sample of adolescents and adults. We found that phrasing probability questions in a distributional format (asking about risks as a percentage in a population) rather than in a singular format (asking about risks to an individual) reduced the use of "50." Less numerate respondents, children, and less educated adults were more likely to say "50." Finally, events that evoked feelings of less perceived control led to more 50s. The results are discussed in terms of what they reveal about how people express epistemic uncertainty. Copyright 2000 Academic Press.     

Characterizing the Imaginative Attitude

Abstract

Three thoughts strongly influence recent work on sensory imagination, often without explicit articulation. The image thought says that all mental states involving a mental image are imaginative. The attitude thought says that, if there is a distinctive imaginative attitude, it is a single, monolithic attitude. The function thought says that the functions of sensory imagination are identical or akin to functions of other mental states such as judgment or belief. Taken together, these thoughts create a theoretical context within which eliminativism appears attractive. Eliminativism is the idea that we need not refer to a distinctive attitude in order to characterize sensory imagination: the attitudes involved in other states provide all the resources we need. Peter Langland-Hassan’s account of sensory imagination provides an example of such eliminativism. Via close examination of this account, I make manifest the three thoughts and their collective tendency to support eliminativism. I argue that all three are dubious, and that we should reject eliminativism; we need a distinctive imaginative attitude if we are to adequately explicate sensory imagination.     

Imaginative Suggestibility and Hypnotizability

More than a half-century of research aimed at identifying the predictors of hypnotic responding has been described as investigations of 'hypnotizability'. Most of that research, however, has disregarded the well-established findings that (a) people respond to suggestion without being hypnotized almost as much as they do following a hypnotic induction, and (b) nonhypnotic and hypnotic suggestibility are highly correlated. More recent studies have provided the first empirical data on predictors of individual differences in response to the induction of hypnosis. These studies indicate that individual differences in hypnotic suggestibility can be accounted for completely by nonhypnotic suggestibility, expectancy, motivation, and reaction time. Because the amount of variance accounted for is as great as the reliability of the hypnotic-suggestibility scale, and because nonhypnotic suggestibility has been controlled, no additional variables are necessary to account for hypnotic suggestibility.     

Chance and the Continuum Hypothesis

This paper presents and defends an argument that the continuum hypothesis is false, based on considerations about objective chance and an old theorem due to Banach and Kuratowski. More specifically, I argue that the probabilistic inductive methods standardly used in science presuppose that every proposition about the outcome of a chancy process has a certain chance between 0 and 1. I also argue in favour of the standard view that chances are countably additive. Since it is possible to randomly pick out a point on a continuum, for instance using a roulette wheel or by flipping a countable infinity of fair coins, it follows, given the axioms of ZFC, that there are many different cardinalities between countable infinity and the cardinality of the continuum.     

Illusions of Sense in the Tractatus: Wittgenstein and Imaginative Understanding

Certain expositors of the Tractatus have tried to make sense of Wittegnstein's curious revocation of its propositions by suggesting that although they lack content, they nonetheless express ("show," but do not say) some ineffable truths about reality. Such a view Cora Dimaond labels "chickening out." I attempt to diagnose the lingering attraction of the 'chicken' (in this case an attraction to an illusion of sense) by condsidering a (false) parallel with the case of perceptual illusion. To this end, I make a brief excursion into the work of Gareth Evans in order to draw out what the parallel would look like and more specifically how the chicken might be tempted to think that there is indeed such a parallel. In this way, I hope to better 'understand' the chicken and her seduction, and in the process make a plea for not "chickening out." I then turn to a positive consideration of how we should in fact read this work. In particular, I consider Diamond's idea that the Tractatus requires an "imaginative understanding" of its reader, an ability to 'think' oneself into certain philosophical illusions of sense in order to dismantle them from within. I explore exactly what such an imagination involves. In particular, I suggest that it presupposes a kind of 'metaphysical' thesis of its own about the nature of human beings and their innermost tendencies, a position, I argue, that Wittegnstein held.     

再认记忆中的概率学习效应:加工分离框架

采用加工分离程序(PDP)与多项加工树模型,对比检验PDP与背景鉴别模型的构思效度;操纵加工水平与项目比例,考察再认记忆中的内隐学习效应。结果表明:(1)包含和排除测验都表现出加工水平效应,包含测验具有视听通道效应。(2)在单一操作中分离出意识回忆和自动加工两种过程。(3)在语义编码条件下出现了概率学习效应,自动加工可能具有情境依存性。未发现支持背景鉴别模型的结果。     

Chance and Counterfactuals1

Suppose the world is chancy. The worry arises that most ordinary counterfactuals are false. This paper examines David Lewis' strategy for rescuing such counterfactuals, and argues that it is highly problematic.     

Context Sensitivity and Chance

‘Chance’ is arguably a context-sensitive expression, a fact that some have thought bears upon the debate about the compatibility of determinism with objective, non-trivial chances (chances with values other than 0 or 1). In this paper, I argue that this attempted move from context sensitivity to compatibilism is misguided, for a number of reasons. First, it relies on a theory of context sensitivity that we have independent reason to reject. Second, the resulting compatibilist position leaves unanswered precisely the sorts of questions we reasonably expect a metaphysical account of chance to answer.     

Bloch's Paradox and the Nonlocality of Chance

I show how an almost exclusive focus on the simplest case—the case of a single particle—along with the commonplace conception of the single‐particle wave function as a scalar field on spacetime contributed to the perception, first brought to light by I. Bloch, that there existed a contradiction between quantum theory with instantaneous state collapses and special relativity. The incompatibility is merely apparent since treating wave‐function values as hypersurface dependent avoids the contradiction. After clarifying confusions which fueled the perception of a paradox, I elaborate on an analysis of the wave function due to Wayne Myrvold to show that nothing special, or ad hoc, is required in treating wave‐function values, even in the single‐particle case, as hypersurface–dependent; rather, the hypersurface dependence of these values is the natural development of nonlocal entanglement in the context of the relativity of simultaneity. Properly understood, what Bloch’s paradox reveals is that the combination of nonlocal entanglement together with a hypersurface‐dependent process of state collapse conflicts with the thesis of spatiotemporal separability and, in particular, with the idea that chances are local matters of fact.     

Imaginative suggestibility and hypnotizability: an empirical analysis.

Hypnotic and nonhypnotic suggestibility were investigated in 2 experiments. In Experiment 1, nonhypnotic suggestibility was suppressed when measured after hypnotic suggestibility, whereas hypnotic suggestibility was not affected by the order of assessment. Experiment 2 confirmed a small but significant effect of hypnosis on suggestibility when nonhypnotic suggestibility was measured first. Nonhypnotic suggestibility was correlated with absorption, fantasy proneness, motivation, and response expectancy, but only expectancy predicted suggestibility when the other variables were controlled. Behavioral response to hypnosis was predicted by nonhypnotic suggestibility, motivation, and expectancy in a model accounting for 53% of the variance. Experiential response to hypnotic suggestion was predicted only by nonhypnotic suggestibility. Unexpectedly, hypnosis was found to decrease suggestibility for a substantial minority of participants.     

Probability Theory and Probability Semantics

Book Information Probability Theory and Probability Semantics. By P. Roeper and H. Leblanc. University of Toronto Press. Toronto. 1999. Pp. xii + 240. Hardback, US$65.00.