Three experiments are reported that investigate the weighting attached to logic and belief in syllogistic reasoning. Substantial belief biases were observed despite controls for possible conversions of the premises. Equally substantial effects of logic were observed despite controls for two possible response biases. A consistent interaction between belief and logic was also recorded; belief bias was more marked on invalid than on valid syllogisms. In all experiments, verbal protocols were recorded and analyzed. These protocols are interpreted in some cases as providing rationalizations for prejudiced decisions and, in other cases, as reflecting a genuine process of premise to conclusion reasoning. In the latter cases, belief bias was minimal but still present. Similarly, even subjects who focus primarily on the conclusion are influenced to an extent by the logic. Thus a conflict between logic and belief is observed throughout, but at several levels of extent.An important debate in cognitive psychology surrounds the notion of rationality with respect to human inference (see Cohen, 1981, and associated commentaries). Recent reviews by Evans (1982) and Nisbett and Ross (1980) have stressed the role of apparently irrational processes in the study of inductive and deductive inference, respectively (see also Pollard, 1982). However, theories favoring a rationalist interpretation of inferential behavior still hold a dominant position in the recent literature (see, for example, the collections of papers edited by Falmagne, 1975, andMayer, 1978).In the case of deductive reasoning, much of the argument centers on the use by subjects of a system of logic, whether of the philosopher's variety (cf. Henle, 1962) or of an alternative "natural" type (e.g., Braine, 1978).The nonlogical or antirational position is sometimes misinterpreted as denigrating man's proven intelligence. What is in fact suggested is an alternative conception of that intelligence. The "rationalist" position entails the supposition that the reasoner proceeds by forming an abstract representation of problem information and applying a general set of inferential rules to its logical structure, regardless of its content. This notion is clearly embodied, for example, in Piaget's theory of formal operations (cf. Inhelder & Piaget, 1958). The alternative argument stressed here is that specific features of problem content, and their semantic associations, constitute the dominant influence on thought (see Evans, 1982, for extended discussion).

This paper reviews the effects on subjects' judgements of a variety of factors that have been included in experimental depictions of rape. The focus is on attribution of responsibility or fault to the victim or attacker and related judgements, particularly regarding guilt and sanctions. Generally, females make more pro-victim judgements than do males, and people with non-traditional sex-role attitudes make more pro-victim judgements than do holders of more traditional views. Other factors covered are various victim characteristics, victim-attacker acquaintance, resistance, and victim attire and a range of behaviours prior to the attack. These are limits to generalization due to populations studied and methods used, and the observed effects of several factors are either minimal or inconsistent. However, some factors have reliable effects on judgements, which it is argued are explainable in terms of their link with traditional beliefs about women's rights and roles. Males have often been found to be more susceptible to these effects. In particular, it appears that if a female engages in any behaviour deemed to be 'incautious' that results in victimization then she may be perceived to be at fault, even though these behaviours would be 'legitimate' for males, and that prior romantic involvement with the attacker mitigates the perceived seriousness of, and may even be seen as supplying justification for, a sexual attack. The existence of these attitudes implies that rape may be tacitly condoned in many situations.

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A statistical test leads to a Type I error whenever it leads to the rejection of a null hypothesis that is in fact true. The probability of making a Type I error can be characterized in the following three ways: the conditional prior probability (the probability of making a Type I error whenever a true null hypothesis is tested), the overall prior probability (the probability of making a Type I error across all experiments), and the conditional posterior probability (the probability of having made a Type I error in situations in which the null hypothesis is rejected). In this article, we show (a) that the alpha level can be equated with the first of these and (b) that it provides an upper bound for the second but (c) that it does not provide an estimate of the third, although it is commonly assumed to do so. We trace the source of this erroneous assumption first to statistical texts used by psychologists, which are generally ambiguous about which of the three interpretations is intended at any point in their discussions of Type I errors and which typically confound the conditional price and posterior probabilities. Underlying this, however, is a more general fallacy in reasoning about probabilities, and we suggest that this may be the result of erroneous inferences about probabilistic conditional statements. Finally, we consider the possibility of estimating the (posterior) probability of a Type I error in situations in which the null hypothesis is rejected and, hence, the proportion of statistically significant results that may be Type I errors.We are grateful to Larry Phillips for his comments on a previous version of this article and to an anonymous reviewer for bringing the article by Carver (1978) to our attention.

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