On the psychological reality of a natural rule of syllable structure

If natural rules in phonology, such as the rule which deletes a word final consonant before a consonant, are frequently found in unrelated languages, it must be because they tap universal features of production and/or perception. The present experiment employed a learning task to see whether naive subjects have a predisposition for the natural rule as opposed to its converse (consonant deletion before a vowel). The Ss first learned four novel words (nouns) - two beginning with a consonant, two with a vowel - as paired associates to English ‘translations’. Then three novel adjectives were combined with each of the four nouns, following the natural rule for one group of Ss, the unnatural rule for the other. The twelve phrases were cued by their English translations and the S had to respond to each with the phonologically correct sequence of adjective and noun; confirmation followed each response. The Ss learning the unnatural corpus had a strong tendency to give natural responses, whereas the converse was not true. Consequently they made many more errors en route to mastery than their natural counterparts, even when the operative rule was displayed on the first trial by presenting in turn each adjective with its four following nouns. It appears that our Ss had implicit knowledge of the natural rule, even though it does not operate to any significant extent in English.     

Family resemblances: Studies in the internal structure of categories

Six experiments explored the hypothesis that the members of categories which are considered most prototypical are those with most attributes in common with other members of the category and least attributes in common with other categories. In probabilistic terms, the hypothesis is that prototypicality is a function of the total cue validity of the attributes of items. In Experiments 1 and 3, subjects listed attributes for members of semantic categories which had been previously rated for degree of prototypicality. High positive correlations were obtained between those ratings and the extent of distribution of an item's attributes among the other items of the category. In Experiments 2 and 4, subjects listed superordinates of category members and listed attributes of members of contrasting categories. Negative correlations were obtained between prototypicality and superordinates other than the category in question and between prototypicality and an item's possession of attributes possessed by members of contrasting categories. Experiments 5 and 6 used artificial categories and showed that family resemblance within categories and lack of overlap of elements with contrasting categories were correlated with ease of learning, reaction time in identifying an item after learning, and rating of prototypicality of an item. It is argued that family resemblance offers an alternative to criterial features in defining categories.     

Immediate and delayed reinforcers for flavor preferences in rats

When rats received, on alternate days, one flavored saccharin solution for 5 min and a differently-flavored saccharin solution for 60 min, they showed no consistent preference between the flavors. On the other hand, when they received one flavor in a concentrated saccharin solution and a different flavor in a dilute one, they preferred the first flavor in tests with saccharin concentration held constant; also, rats learned to prefer a flavor immediately followed by a concentrated saccharin solution to one followed by nothing. They showed no consistent preference, however, between a flavor followed 30 min later by a concentrated saccharin solution and one followed by nothing; but they learned to prefer a flavor followed 30 min later by a dextrose solution to one followed by nothing. In other words, consummatory responding did not reinforce flavor preference, sweet taste did so with immediate but not delayed reinforcement, and nutrition did so even with delayed reinforcement.     

One-way characteristic performance of rats under two-way signaled avoidance conditions

In Experiment 1, the conflict in a two-way active avoidance was reduced by allowing rats to avoid one of two levels of shock by running onto a safe platform which covered one half of the grid floor. Performance characteristics of one-way avoidance were obtained regardless of the shock intensity. Groups with no platform showed poor performance. Experiment 2 suggested that the facilitatory effect of the platforms was not due to the cue associated with platform removal. These results suggest that (a) rats can quickly learn to enter a spatially aversive location, (b) fast avoidance learning may be obtained in a two-way setting, and (c) rats seem capable of selective association of environmental and aversive stimuli.     

Storage and retrieval processes in sentence memory

Two experiments investigated how much time Ss take to verify a sentence with respect to a set of subject-verb-object (SVO) propositions they had learned. Three triplets of SVOs provided differing degrees of equivocation, including (1) unique SVOs, (2) a V with 3 SOs, and (3) an SV with 3 Os. A general class of models was proposed regarding the representation of prepositional trees in memory and an algorithm by which a probe tree might be verified against a set of trees in memory. In Expt I, verification times were least for Condition (1), slower and equal for Conditions (2) and (3). In Expt II, a fourth condition, an SO with 3 Vs, produced verification times as slow as those in Condition (3). Of several models considered, the closest-fitting one assumed parallel search processes proceeding simultaneously from S, V, and O positions of the probe, scanning through memory trees structered according to the HAM (Human Associative Memory) theory of Anderson and Bower.     

Basic objects in natural categories

Categorizations which humans make of the concrete world are not arbitrary but highly determined. In taxonomies of concrete objects, there is one level of abstraction at which the most basic category cuts are made. Basic categories are those which carry the most information, possess the highest category cue validity, and are, thus, the most differentiated from one another. The four experiments of Part I define basic objects by demonstrating that in taxonomies of common concrete nouns in English based on class inclusion, basic objects are the most inclusive categories whose members: (a) possess significant numbers of attributes in common, (b) have motor programs which are similar to one another, (c) have similar shapes, and (d) can be identified from averaged shapes of members of the class. The eight experiments of Part II explore implications of the structure of categories. Basic objects are shown to be the most inclusive categories for which a concrete image of the category as a whole can be formed, to be the first categorizations made during perception of the environment, to be the earliest categories sorted and earliest named by children, and to be the categories most codable, most coded, and most necessary in language.     

Classes and collections: Internal organization and resulting holistic properties

This work presents an analysis of a type of concept, the collection, not readily characterized by class inclusion models. Collections, the referents of collective nouns (e.g., pile, family, bunch), are argued to differ from classes in (a) how membership can be determined, (b) part-whole relationships, (c) internal structure, and (d) the nature of the higher order units they form. From this analysis, it is hypothesized that the psychological integrity of collections is greater than that of classes. Collections and objects, in contrast to classes, both require specified relationships among the parts and both result in a coherent psychological unit. It was suggested that objects form a relatively more stable unit than collections. Corresponding to this analysis the degree of psychological integrity is hypothesized to lead to different degrees of difficulty in making part-whole comparisons for objects, collections, and classes in modified Piagetian class-inclusion paradigms. The hypothesized difference in performance was found for collections and classes and an alternative linguistic explanation for the greater success with collections was eliminated. However, children performed equally well on tasks involving collections and objects, raising the possibility that when elements are organized into collections, they form psychological units which are as coherent as objects.     

A note on the use of A′ as a measure of sensitivity

The use of A′, a nonparametric measure of sensitivity in tests of recognition memory, is discussed. In particular, two formulas for computing A′ are considered. One formula, which was reported in a recent paper by Berch (1975), should be used only when the observed hit rate is greater than or equal to the false alarm rate. A second formula is presented for computing A′ when the hit rate is less than the false alarm rate.