Daniel N. Osherson

An invitation to cognitive science

Symbolic processes in the brain - the case of insect navigation, Charles R. Gallistel The mental representation of time - uncovering a biological clock, Seth Roberts The evolution of cognition - questions we will never answer, Richard C. Lewontin Consciousness and the mind - contributions from philosophy, neuroscience, and psychology, Owen Flanagan, Donald T. Dryden Cognitive algorithms - questions of representation and computation in building a theory, Mark Steedman A gentle introduction to Soar - an architecture for human cognition, Jill Fain Lehman et al Learning arithmetic with a neural network - seven times seven is about 50, James a. anderson Models for reading letters and words, Dominic W. Massaro Inferring mental operations from reaction-time data - how we compare objects, Saul Sternberg Models of visual search - finding a face in the crowd, Barbara Anne Dosher Skill acquisition and plans for actions - learning to write with your other hand, Patricia G. Lindenmann, Charles E. Wright Drawing conclusions from data - statistical methods for coping with uncertainty, Thomas D. Wickens Separating discrimination and decision in detection, recognition, and matters of life and death, John A. Swets Discovering mental processing stages - the method of additive factors, Saul Sternberg Brainwaves and mental processes - electrical evidence of attention, perception, and intention, Allen Osman.

On the adequacy of prototype theory as a theory of concepts

Abstract Prototype theory construes membership in a concepts extension as graded, determined by similarity to the concepts “best” exemplar (or by some other measure of central tendency). The present paper is concerned with the compatibility of this view of concept membership with two criteria of adequacy for theories of concepts. The first criterion concerns the relationship between complex concepts and their conceptual constituents. The second concerns the truth conditions for thoughts corresponding to simple inclusions.

Combining prototypes: A selective modification model

Abstract We propose a model that accounts for how people construct prototypes for composite concepts out of prototypes for simple concepts. The first component of the model is a prototype representation for simple, noun concepts, such as fruit, which specifies: (1) the relevant attributes of the concepts, (2) the possible values of each attribute, (3) the salience of each value, and (4) the diagnosticity of each attribute. The second component of the model specifies procedures for modifying simple prototypes so that they represent new, composite concepts. The procedure for adjectival modification, as when red modifies fruit, consists of selecting the relevant attribute(s) in the noun concept (color), boosting the diagnosticity of that attribute, and increasing the salience of the value named by the adjective (red). The procedure for adverbial modification, as in very red fruit, consists of multiplication-by-o-scalar of the salience of the relevant value (red). The outcome of these procedures is a new prototype representation. The third component of the model is Tverskys (1977) contrast rule for determining the similarity between a representation for a prototype and one for an instance. The model is shown to be consistent with previous findings about prototypes in general, as well as with specific findings about typicality judgments for adjective-noun conjunctions. Four new experiments provide further detailed support for the model.

Conceptual Combination with Prototype Concepts

This paper deals with how people combine simple, prototype concepts into complex ones; e.g., how people combine the prototypes for brown and apple so they can determine the typicality of objects in the conjunction brown apple . We first consider a proposal from fuzzy-set theory ( Zadeh, 1965 ), namely, that the typicality of an object in a conjunction is equal to the minimum of that objects typicality in the constituents (e.g., an objects typicality as a brown apple cannot exceed its typicality as a brown or as an apple ). We evaluated this “min rule” against the typicality ratings of naive subjects in two experiments. For each of numerous pictured objects, one group of subjects rated its typicality with respect to an adjective concept, a second group rated its typicality visa-vis a noun concept, and a third group rated its typicality with respect to the adjective-noun conjunction. In both studies, most objects were rated as more typical of the conjunction than of the noun. These findings violate not only the min rule but also other simple rules for relating typicality in a conjunction to typicalities in the constituents. As an alternative to seeking such rules, we argue for an approach to conceptual combination that starts with the prototype representations themselves. We illustrate one version of this approach in some detail, and show how it accounts for the major findings of the present experiments.

Distinct brain loci in deductive versus probabilistic reasoning

Deductive versus probabilistic inferences are distinguished by normative theories, but it is unknown whether these two forms of reasoning engage similar cerebral loci. To clarify the matter, positron emission tomography was applied during deductive versus probabilistic reasoning tasks, using identical stimuli. Compared to a language comprehension task involving the same stimuli, both probabilistic and deductive reasoning increased regional cerebral blood flow (rCBF) bilaterally in the mesial frontal region and in the cerebellum. In the direct comparison, probabilistic reasoning increased rCBF in left dorsolateral frontal regions, whereas deductive reasoning enhanced rCBF in associative occipital and parietal regions, with a right hemispheric prevalence. The results suggest that reasoning about syllogisms engages distinct brain mechanisms, depending on the intention to evaluate them deductively versus probabilistically.

Language and the ability to evaluate contradictions and tautologies

Abstract Children were found to experience difficulty evaluating contradictions of the form p & -p, and tautologies of the form p v -p. It was hypothesized that (a) the difficulty of these statements was not due solely to the logical words occuring in them, (b) part of the difficulty is due to the fact that their truth value derives from their linguistic form rather than from empirical considerations, and (c) the ability to examine language in an objective manner, apart from events and objects to which it refers, is necessary but not sufficient for correct evaluation of contradictions and tautologies. The results of two experiments support the hypothesis.

Typicality and reasoning fallacies

The work of Tversky and Kahneman on intuitive probability judgment leads to the following prediction: The judged probability that an instance belongs to a category is an increasing function of the typicality of the instance in the category. To test this prediction, subjects in Experiment 1 read a description of a person (e.g., “Linda is 31, bright, ... outspoken”) followed by a category. Some subjects rated how typical the person was of the category, while others rated the probability that the person belonged to that category. For categories likebank teller andfeminist bank teller: (1) subjects rated the person as more typical of the conjunctive category (aconjunction effect); (2) subjects rated it more probable that the person belonged to the conjunctive category (aconjunction fallacy); and (3) the magnitudes of the conjunction effect and fallacy were highly correlated. Experiment 2 documents aninclusion fallacy, wherein subjects judge, for example, “All bank tellers are conservative” to be more probable than “All feminist bank tellers are conservative.” In Experiment 3, results parallel to those of Experiment 1 were obtained with respect to the inclusion fallacy.

On the reality of the conjunction fallacy.

Attributing higher “probability” to a sentence of formp-and-q, relative top, is a reasoning fallacy only if (1) the wordprobability carries its modern, technical meaning and (2) the sentencep is interpreted as a conjunct of the conjunctionp-and-q. Legitimate doubts arise about both conditions in classic demonstrations of the conjunction fallacy. We used betting paradigms and unambiguously conjunctive statements to reduce these sources of ambiguity about conjunctive reasoning. Despite the precautions, conjunction fallacies were as frequent under betting instructions as under standard probability instructions.

The boundaries of language and thought in deductive inference

Is human thought fully embedded in language, or do some forms of thought operate independently? To directly address this issue, we focus on inference-making, a central feature of human cognition. In a 3T fMRI study we compare logical inferences relying on sentential connectives (e.g., not, or, if … then) to linguistic inferences based on syntactic transformation of sentences involving ditransitive verbs (e.g., give, say, take). When contrasted with matched grammaticality judgments, logic inference alone recruited “core” regions of deduction [Brodmann area (BA) 10p and 8m], whereas linguistic inference alone recruited perisylvian regions of linguistic competence, among others (BA 21, 22, 37, 39, 44, and 45 and caudate). In addition, the two inferences commonly recruited a set of general “support” areas in frontoparietal cortex (BA 6, 7, 8, 40, and 47). The results indicate that logical inference is not embedded in natural language and confirm the relative modularity of linguistic processes.

Methods for distance-based judgment aggregation

Judgment aggregation theory, which concerns the translation of individual judgments on logical propositions into consistent group judgments, has shown that group consistency generally cannot be guaranteed if each proposition is treated independently from the others. Developing the right method of abandoning independence is thus a high-priority goal. However, little work has been done in this area outside of a few simple approaches. To fill the gap, we compare four methods based on distance metrics between judgment sets. The methods generalize the premise-based and sequential priority approaches to judgment aggregation, as well as distance-based preference aggregation. They each guarantee group consistency and implement a range of distinct functions with different properties, broadening the available tools for social choice. A central result is that only one of these methods (not previously considered in the literature) satisfies three attractive properties for all reasonable metrics.