Motivational properties of spaced food presentation in hungry rats: Long-lasting effects on drinking and eating

Hungry rats were given 60 food pellets either at spaced intervals or massed in one or two presentations, or no food, followed by a consumption test in the home cage. Drinking was higher after spaced food sessions than after massed food or no food sessions (Experiments 1, 2, 3, and 5) and higher after the presentation of standard food pellets than after quinine-flavored pellets (Experiment 2). An effect of spacing was found even with a delay of 1 hr between the end of the food session and the drinking test (Experiment 3). Spaced food presentation also produced an increase in the consumption of quinine-flavored food pellets after the end of the session (Experiment 4). These results suggest that the enhancement of behavior caused by intermittent reinforcement cannot be attributed entirely to the short-term eliciting effects of the reinforcer or to its thirst-inducing properties.     

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.     

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.     

Factors within the 1969 SVIB for women and relationships to Holland's theory

The Basic Interest Scales (BIS) and the Occupational Scales (O-S) of the revised Strong Vocational Interest Blank for Women (TW 398) were assigned Holland codes, and component scores for the BIS and O-S were separately developed, intercorrelated, and evaluated along with standardized composite scores representing each of the 11 O-S Groups on the profile. The dimensionality of the BIS and O-S was similar, and similar in number to Holland's theory, but the components were only partially congruent. Some profile Groups provided relatively good representations of BIS and/or Occupational scale components, and the grouping of the O-S provided important information not otherwise readily available. Holland's dimensions are not uniformly represented in either the BIS or O-S, and despite some similarities, fundamental problems of compatibility appeared to exist in relating the structure of this instrument to Holland's formulations. Women's interests are in need of independent study.     

Teaching autistic children to use extra-stimulus prompts

Autistic children often do not transfer from extra-stimulus prompts, and thus do not utilize a frequent learning aid. It has been hypothesized that this is due to stimulus overselectivity; a failure to respond to simultaneous multiple cues. This study was designed to determine if autistic children who initially respond only to single cues can be taught a set to respond to two cues and subsequently utilize an extra-stimulus (pointing) prompt. Four autistic children were pretested to determine if they could learn a complex visual discrimination by either trial and error or an extra-stimulus prompt fading procedure. Since they did not, the children were then taught to respond to two cues through a multiple-cue training procedure and subsequently tested to determine if they could now utilize a pointing prompt. Results indicated that while all four children initially did not transfer from an extra-stimulus (pointing) prompt, they did so subsequent to multiple-cue training. The results are discussed in terms of implications for treatment (remediating overselectivity) and in relation to normal child development.     

Differences in spatial knowledge acquired from maps and navigation

Models of the spatial knowledge people acquire from maps and navigation and the procedures required for spatial judgments using this knowledge are proposed. From a map, people acquire survey knowledge encoding global spatial relations. This knowledge resides in memory in images that can be scanned and measured like a physical map. From navigation, people acquire procedural knowledge of the routes connecting diverse locations. People combine mental simulation of travel through the environment and informal algebra to compute spatial judgments. An experiment in which subjects learned an environment from navigation or from a map evaluates predictions of these models. With moderate exposure, map learning is superior for judgments of relative location and straight-line distances among objects. Learning from navigation is superior for orienting oneself with respect to unseen objects and estimating route distances. With extensive exposure, the performance superiority of maps over navigation vanishes. These and other results are consonant with the proposed mechanisms.     

Sign-based short-term coding of American Sign Language signs and printed English words by congenitally deaf signers

A short-term serial recall task consisting of lists of five American Sign Language signs and lists of five printed English words was administered to eight congenitally deaf subjects. For both modes of presentation, the stimuli in a given list were (1) high in phonological relatedness, (2) high in cherological relatedness (i.e., they were similar in terms of the formational attributes of their sign-equivalents), or (3) low in both phonological and cherological similarity (control). For both modes of presentation, recall accuracy was significantly lower on cherologically related lists than on both phonologically related lists and control lists. Phonologically related lists did not differ significantly from control lists. These results suggest the possibility that ways of looking at human memory which rely on a preference for phonological coding in short-term memory processes may reflect the audiocentricity of the experimenter rather than the inherent nature of such processes.