Believability and syllogistic reasoning

In this paper we investigate the locus of believability effects in syllogistic reasoning. We identify three points in the reasoning process at which such effects could occur: the initial interpretation of premises, the examination of alternative representations of them (in all of which any valid conclusion must be true), and the "filtering" of putative conclusions. The effect of beliefs at the first of these loci is well established. In this paper we report three experiments that examine whether beliefs have an effect at the other two loci. In experiments 1 and 2 subjects drew their own conclusions from syllogisms that suggested believable or unbelievable ones. In the third experiment they evaluated conclusions that were presented to them. The data show that beliefs both affect the examination of alternative models and act as a filter on putative conclusions. We conclude by showing how some types of problem and some problem contents make the existence of alternative models more obvious than others.     

Mental models and probabilistic thinking

This paper outlines the theory of reasoning based on mental models, and then shows how this theory might be extended to deal with probabilistic thinking. The same explanatory framework accommodates deduction and induction: there are both deductive and inductive inferences that yield probabilistic conclusions. The framework yields a theoretical conception of strength of inference, that is, a theory of what the strength of an inference is objectively: it equals the proportion of possible states of affairs consistent with the premises in which the conclusion is true, that is, the probability that the conclusion is true given that the premises are true. Since there are infinitely many possible states of affairs consistent with any set of premises, the paper then characterizes how individuals estimate the strength of an argument. They construct mental models, which each correspond to an infinite set of possibilities (or, in some cases, a finite set of infinite sets of possibilities). The construction of models is guided by knowledge and beliefs, including lay conceptions of such matters as the “law of large numbers”. The paper illustrates how this theory can account for phenomena of probabilistic reasoning.     

Meaning,amount of processing,and memory for words

Two experiments were carried out in order to try to resolve the controversy about whether the semantic processing of a word necessarily involves all the elements of its meaning. In the first experiment, subjects categorized a list of auditorially presented words according to whether or not they were natural consumable solids (e.g., “apple“). They were then given an unexpected test of their ability to recall the whole list, which contained equal numbers of words with none, one, two, or all three of the target components. The results confirmed the prediction that the greater the number of components a word has in common with a target category, the better it will be recalled. The second experiment used a visual presentation of a list of words, which subjects scanned for members of a particular target category. There were four different target categories assigned to independent groups of subjects. The results again confirmed the prediction. On the assumption that memorability in such tasks is determined by amount of processing, we conclude that some elements of the meaning of a word can be processed without having to process all of them.     

Book reviews

Hamilton, Vernon and Veronon, Magdalen D. (Eds). The Development of Cognitive Processes. London and New York: Academic Press. 1976. Pp. 772. £21.00. ISBN 0 12 321750 4.

Miller, G. A, and Johnson-Laird, P. N. Language and Perception. Cambridge University Press. 1976. Pp. viii + 760. £12.50. ISBN 0 521 21242.

Neisser, U. Cognition and Reality. San Francisco: Freeman. 1976. pp. 230. Hardback $11.00; paperback $4.95. ISBN 0 7167 04781.

Norman, D. A. Memory and Attention. Second edition. New York: Wiley. 1976. Pp. 262. £8.45.

Hammond, K. R. and Joyce, C. R. B. (eds). Psychoactive Drugs and Social Judgment: Theory and Research. New York and London: Wiley. 1975. Pp. 278. £9.25. ISBN

Fodor, J. D. Semantics : Theories of Meaning in Generative Grammer. Sussex: Harvester Press. 1977. Pp. 225. £12.95. ISBN 0 85527 500 6.

Plomp, R. Aspects of Tone Sensation. London: Academic Press. 1976. Pp. id + 167. £6.50. ISBN 0 12 558350 8.

Fite, K. V. The Amphibian Visual System. London: Academic Press. 1977. Pp. 374. £20.95. ISBN 0 12 257450 8.

Eliot, J. and Salkind, N. J. Children's Spatial Development. Springfield, Illinois: Charles C. Thomas. 1975. $23.50. Pp. 296. ISBN 0398 03210 6.

Wong, R. Motiviation : A Biobehavioral Analysis of consummatory Activities. London: Collier-Macmillan. 1976. Pp. 326. £ 4.95. ISBN 0 0242 9400 4.     

Co-reference and reasoning

Memory &; Cognition - Co-reference occurs when two or more noun phrases refer to the same individual, as in the following inferential problem: Mark is kneeling by the fire or he is looking at...     

Reasoning from inconsistency to consistency

This article presents a theory of how individuals reason from inconsistency to consistency. The theory is based on 3 main principles. First, individuals try to construct a single mental model of a possibility that satisfies a current set of propositions, and if the task is impossible, they infer that the set is inconsistent. Second, when an inconsistency arises from an incontrovertible fact, they retract any singularly dubious proposition or any proposition that is inconsistent with the fact; otherwise, they retract whichever proposition mismatches the fact. A mismatch can arise from a proposition that has only mental models that conflict with the fact or fail to represent it. Third, individuals use their causal knowledge-in the form of models of possibilities-to create explanations of what led to the inconsistency. A computer program implements the theory, and experimental results support each of its principles.     

A hyper-emotion theory of psychological illnesses

A hyper-emotion theory of psychological illnesses is presented. It postulates that these illnesses have an onset in which a cognitive evaluation initiates a sequence of unconscious transitions yielding a basic emotion. This emotion is appropriate for the situation but inappropriate in its intensity. Whenever it recurs, it leads individuals to a focus on the precipitating situation and to characteristic patterns of inference that can bolster the illness. Individuals with a propensity to psychological illness accordingly reason better than more robust individuals, but only on topics relevant to their illness. The theory is assessed in the light of previous research, a small epidemiological study of patients, and 3 empirical studies.