Selective attention and the processing of integral and nonintegral dimensions: A developmental study

In two experiments, first- and fourth-grade subjects (age 6 and 9 years) performed a speeded card-sorting task with either integral or nonintegral dimensions. The dimensions were so arranged that subjects sorted on three types of task: (1) single dimension, (2) correlated dimensions, and (3) orthogonal dimensions. Results of the first experiment indicate that both first- and fourth-grade subjects sorted integral dimensions in a manner not qualitatively different from that of the adult (Garner & Felfoldy, Cognitive Psychology, 1970, 1, 225–241). In comparison with single-dimension tasks, performance was facilitated on the correlated-dimensions tasks and interference was observed on the orthogonal-dimensions tasks. Performances with nonintegral dimensions revealed an age-related processing difference. Fourth graders sorted nonintegral dimensions like the adult; no differences in performance were observed between the tasks. In contrast, first-graders sorted nonintegral dimensions as if they were integral. Interference was consistently observed on orthogonal-dimensions tasks. On correlated-dimensions tasks, interference was observed on easy tasks and redundancy facilitated difficult tasks. In the second experiment, first graders showed consistent facilitation on the correlated-dimensions task; all other results were indentical to those of Experiment I. The results were interpreted as consistent with perceptual learning theory (Gibson, Principles of perceptual learning and development. New York: Appleton-Century-Crofts, 1969).     

Observing behavior in monkeys (Macaca arctoides): Support for the information hypothesis

A single lever, discrete-trials observing procedure was used with stumptailed monkeys (Macaca arctoides). Lever-presses during a trial produced colored key lights (IS⁺ and IS^?) which signaled whether the trial would end with response-independent food or without food. During the baseline period, both IS⁺ and IS^? were produced on a variable-interval (VI) 15-sec schedule which began operating at the onset of the trial. The two experimental conditions involved a combination of this VI schedule and a DRL schedule. In one of these conditions, only a response that both met the VI requirement and was preceded by at least 6 sec of nonresponding could produce IS^? on nonfood trials, while the schedule for IS⁺ on food trials remained VI 15 sec. In the other experimental condition, the schedules for producing the two stimuli were the reverse. All subjects eventually learned to produce either IS⁺ or IS^? on the combined VI-DRL schedule. These data support an information hypothesis of observing in monkeys and contrast with data from pigeons which support a conditioned reinforcement hypothesis.     

Short-term memory for time intervals

The effect of intertrial interval, preset interval, and retention interval on the performance of rats in a time estimation task was described. On each trial a signal was presented for a duration of 2 to 8 sec. Eighteen rats were trained to press one lever (the short response) if the signal was shorter than 4 sec, and another lever (the long response) if the signal was longer than 4 sec. When trials were massed (Experiment 1), the percentage long response was affected by the classification of the previous signal, but not by its actual duration. This suggests that the animals remembered the response made on the previous trial, but not the signal duration. If a response was not permitted on the previous trial (Experiment 2), the duration or classification of the previous signal had no effect on performance. This supports the conclusion from the first experiment and suggests that an animal can reset its internal clock in less than 2 sec. In Experiment 3, the difference limen of the psychophysical function increased with the duration of the retention interval, but the point of subjective equality did not change. This suggests that resetting of the internal clock occurs on a non-time dimension.     

Information need,affect, and cognition of autonomic activity

Several studies have shown that bogus feedback of physiological change induces a greater liking for attractive stimuli. Other research suggests that the affective change induced by bogus feedback requires an opportunity to visually search change-associated stimuli for information which can account for its purported physiological effect. While there is considerable agreement among theorists that a greater disliking should obtain when the stimuli are unattractive (but a lack of data supporting this contention), there is disagreement about whether information searching is directed equally toward change-associated stimuli and no-change stimuli, or toward change-associated stimuli alone.Results of the present study support the contention that stimulus features determine the kind of affect experienced: change-associated slides depicting nudes are rated as more attractive than no-change-associated nudes, and change-associated slides depicting accident vitctims are rated as more repulsive than no-change-associated victims. Information seeking data are more consistent with the contention that information needs exist after both types of feedback.     

The role of instrumental responding and contiguity of stimuli in the development of infant secondary reinforcement

Ten-month-old infants received contingent pairings of a tone (T+) and food reinforcer. Groups S^r and S^D received the food on an FI 23-sec schedule for target touching, the former group receiving T+ immediately after the response and 1.5 sec prior to food and the latter group receiving T+ at the end of the intertrial interval. Group SC received food reinforcers 1.5 sec after T+ with no response required. A second tone (Tⁿ) was heard by all groups once during each intertrial interval, at randomly determined points. All groups subsequently were given a spatial discrimination task, receiving T+ for one alternative and Tⁿ for the other. Group S^r gave significantly more responses for T+ than for Tⁿ, but neither of the other two groups produced a superiority for T+. Thus, both contiguity with a primary reinforcer and the presence of an operant during training appear to be necessary for a neutral signal to acquire the ability to enhance responding.     

Rats learn the relationship between responding and environmental events: An expansion of the learned helplessness hypothesis

Previous research has shown that preexposure to inescapable shock interferes with subsequent acquisition of escape responding, while pretraining with escapable shock facilitates subsequent acquisition of a different escape response. It has also been demonstrated that interference and facilitation persist when the aversive event is changed between the two phases of training. The present experiment extended these findings, showing generalized learning from an appetitive to an aversive situation. Six groups of rats received the following treatment in the presence of discriminative stimuli: One group was trained to nose press for food, a second to chain pull for food, and a third to chain pull to escape or avoid shock. Two groups received either signalled free food or inescapable shock, and a naive control group received no pretreatment. All groups were then tested in a nose-press escape-avoidance situation. The three groups with prior response training acquired responding most rapidly, and at the same rate. The naive controls acquired responding slowly, and the two groups with response-independent histories did not acquire responding during the 5 days of training. It was concluded that rats learn the relationship between responding and environmental events and that such learning strongly influences subsequent learning.     

Hominid evolution, supralaryngeal vocal tract physiology, and the fossil evidence for reconstructions.

The functional, physiologic aspects of the human supralaryngeal vocal tract, which follow from the equal length of the oral and pharyngeal cavities and their right angle orientation are discussed. Sounds like the vowels [i] and [u], which only the human supralaryngeal vocal tract can produce in a Quantal mode, provide a selective advantage for vocal communication and the evolution of the human vocal tract and matched neural property detectors. The dissimilarity between Neanderthal skulls and specimens of anatomically modern Homo sapiens and other fossil skulls is discussed in relation to the reconstruction of the Neanderthal supralaryngeal vocal tract. The absence of some of the innate neural property detectors that play a part in the perception of human speech can be inferred in Neanderthal hominids from the reconstruction of their supralaryngeal vocal tract.     

Knowledge of one's own responding and the relation of such knowledge to learning: A developmental study

First-, third-, fifth-grade children, and college students (ages 6, 8, 10, and 19 years) acquired a paired-associate list under the study-test procedure to a one error-less trial criterion. In addition, as each pair was presented the individual indicated whether he/she had that pair correct on the immediately preceding trial (postdiction responses). The data were interpreted in terms of a discrimination-utilization hypothesis which postulates that individuals discriminate their own correct and incorrect responses on a given trial and use this information for distributing processing effort on the subsequent trial. Analyses involving the accuracy of postdiction responses, the relation of postdiction accuracy to acquisition, and the consideration of the acquisition data in terms of a two-stage model led to the conclusion that older children and adults may use the discrimination-utilization strategy but younger children tend not to use it, probably because of both mediation and production deficiencies.     

The use of the cumulative rehearsal strategy: A developmental study

This study was designed to address two issues: (1) At what age do children spontaneously use a cumulative rehearsal strategy; and (2) What effect does the use of the strategy have on their performance?Twenty-eight children at each of five grade levels (nursery, kindergarten, 1, 3, and 5) were tested in a serial-position recall task. Stimuli were pictures of common objects and animals whose labels were one or two syllables in length. Following testing, the children were asked to report the memory strategy they had used.The assumption was made that children who were using a cumulative rehearsal strategy would perform better on series of one-syllable items than on series of two-syllable items. As predicted, nursery, kindergarten, and first-grade subjects correctly recalled as many two-syllable as one-syllable items: Both third- and fifth-graders recalled significantly more one-syllable than two-syllable items. Results indicated that (1) young children do not spontaneously use a cumulative rehearsal strategy until after first grade, and (2) the use of rehearsal did not facilitate overall performance of the rehearsers relative to the nonrehearsers at any grade level. Results are discussed in terms of their theoretical implications for the study of memory development.     

Variations in hand position, cerebral lateralization, and reading ability among right-handed children

A group of 121 right-handed children between the ages of 7 and 9 with a range of hand positions between normal and inverted were assessed for verbal and visuospatial lateralization and reading comprehension. Results indicate that (a) children with a normal hand position tended to be more verbally lateralized than children with nonnormal positions, although the effect was not strong or always consistent, (b) the closer the child was to the normal position, the higher the child's reading scores, and (c) poor readers were as lateralized for verbal and visuospatial functions as were good readers. Coupled with the results of previous research, these findings suggest that hand position indexes both maturation and lateralization, and that the relationship between hand position and reading is primarily mediated by the former.     

A developmental study of the role of word order in comprehending Hebrew

Monolingual Hebrew-speaking subjects, 3, 4, 5, 6, 7, and 11 years old, as well as adults, were asked to interpret utterances consisting of two nouns and a verb. Some utterances included only word order cues while others included direct object marker and subject-verb gender agreement cues. Even though Hebrew word order is relatively free, when subjects used word order as an interpretive cue they generally assigned sentence relations according to the dominant SVO order of modern Hebrew. This trend was less strong for the interpretations of NNV utterances than of NVN and VNN utterances. There was no evidence of a developmental sequence for word order strategies. In addition, there was no evidence that word order, for any age group, was necessarily a dominant cue for assigning sentence relations when other linguistic information was available.     

The role of distinctive features in the dichotic perception of vowels

A dichotic listening experiment was conducted to determine if vowel perception is based on phonetic feature extraction as is consonant perception. Twenty normal right-handed subjects were given dichotic CV syllables contrasting in final vowels. It was found that, unlike consonants, the perception of dichotic vowels was not significantly lateralized, that the dichotic perception of vowels was not significantly enhanced by the number of phonetic features shared, and that the occurrence of double-blend errors was not greater than chance. However, there was strong evidence for the use of phonetic features at the level of response organization. It is suggested that the differences between vowel and consonant perception reflect the differential availability of the underlying acoustic information from auditory store, rather than differences in processing mechanisms.     

A developmental study of schedule-induced polydipsia in the rat

Rats 30, 60, 90, and 120 days of age were fed 105 45-mg food pellets on a noncontingent VT 70-sec schedule during 14 daily 2-hr sessions. Every animal became polydipsic on this schedule when compared with a schedule in which 105 pellets were presented at the beginning of the session. Mean polydipsic ratios (schedule intake/control intake) ranged from 2.9–5.4. Water intakes (milliliters per 100g body weight) did not differ during the last five sessions as a function of age. The results are discussed with respect to the generality of the class of adjunctive behaviors.     

Passing markers: A theory of contextual influence in language comprehension

Most Artificial Intelligence theories of language either assume a syntactic component which serves as “front end” for the rest of the system, or else reject all attempts at distinguishing modules within the comprehension system. In this paper we will present an alternative which, while keeping modularity, will account for several puzzles for typical “syntax first” theories. The major addition to this theory is a “marker passing” (or “spreading activation”) component, which operates in parallel to the normal syntactic component.     

The nature and structure of infant form categories

The nature of form categories in 3 to 4-month infants was studied using the visual preference for novelty in the familiarization-novelty paradigm. Novelty preference indicates habituation to and recognition of the familiar. In a series of experiments employing three form categories composed of dot patterns, generalized habituation to new category members was used to assess categorization behavior in the recognition of visual forms. At 3 to 4 months of age, infants did not initially show any systematic preferences for “good” or symmetrical examples of a category relative to “distorted” examples (Experiment 1) and this was true for all three form categories used (i.e., square, triangle, and diamond). Evidence for categorization was seen in the recognition performance of 3- to 4-month infants (Experiment 2). Infants showed generalized habituation to the previously unseen category prototypes following exposure to six exemplars within each of the three form categories. Given evidence that infants could discriminate between the prototype and other category members (Experiment 3), “inability to discriminate” was ruled out as an explanation for this form categorization or generalized habituation effect. Four subsequent experiments were conducted to determine whether infants exhibit a prototypicality structure for their remembered categories and whether certain conditions which have been shown to enhance prototypicality effects with adults have similar effects with infants. No evidence of a prototypicality structure was found for the form categories of infants when the number of exemplars during familiarization was limited to 6 and the test for form recognition followed immediately (Experiment 4). However, a prototypicality structure for the remembered form categories was found when a 3-min delay was introduced between familiarization and tests for form recognition (Experiment 5), when 12 exemplars were presented during familiarization (Experiment 7), or when the prototype was included as one of the six exemplars during the familiarization period (Experiment 6).     

A developmental study of choice reaction time: the effect of two forms of stimulus degradation on encoding.

To assess the effects of environmental enrichment, 156 normal, full-term institutionalized infants were randomly assigned to Group I (30 min per day of supplementary vestibular stimulation), Group II (30 min per day of supplementary vestibular-plus-verbal stimulation), or Group III (untreated controls). Stimulation began at about the age of 12 days and continued until the children were adopted, approximately 6 weeks later. Children were assessed at regular intervals on the Gesell Developmental Schedules, until the age of 27 months. Group comparisons revealed no significant treatment effects.     

A direct comparison of four methods for eliminating a response

Thirty-two rats pressed one lever (lever A) on a VI 30-sec schedule of food reinforcement and were then shifted to one of four procedures for eliminating the lever A response: extinction, differential reinforcement of other behavior, reinforcement of a different response (pole pushing), and reinforcement of a similar response (pressing lever B). Effectiveness of a response-elimination procedure was measured by (1) how quickly lever A response rate fell to a low level when the procedure was in effect, (2) how much lever A responding recovered when the procedure was discontinued, and (3) how resistant lever A responding was to reinstatement when the VI reinforcement schedule was reimposed. No one method was superior by all three measures. Extinction produced the most variable behavior, while differential reinforcement of other behavior produced the least. Reinforcing alternative behavior produced the greatest recovery in the original lever A response when the response-elimination procedure was discontinued.     

Fear reduction in rats through avoidance blocking

Rats trained to avoid an electric shock in an alley were divided into two groups depending on their behavior during 25 min of response blocking. Subjects demonstrating exploratory behavior while blocked were put in one group, while subjects demonstrating agitation, freezing or grooming were placed in another. Fear measures, when subsequently exposed to the CS. were taken on experimental subjects and compared to controls. The results confirmed the hypothesis that response blocking can lead to fear reduction and that the fear reduction is related to the behavior of the subject during blocking.     

Conditional reasoning following contradictory evidence: A developmental analysis

Recent evidence suggests that young adults do not correctly understand the logical relationship of the conditional (if p the q) as it applies to hypothesis testing, and most training procedures have not been productive. However, the introduction of contradictory evidence following faulty inferences has led to accurate inferences with conditional statements. Third and seventh grade and college studients (9, 13, and 21 years of age, respectively) were tested to assess developmental differences in improvement following contradiction training and to test whether improved performance transfers to other conditional reasoning tasks. Significant improvement in conditional reasoning was found for the young adult group following the introduction of contradictory evidence, and the positive effect of the treatment transferred across tasks. The third grade students showed no effects from the introduction of the contradiction, but the seventh graders were often confused by the introduction of the contradiction. Seventh grade and college student performances were generally worse than that of the third graders for the positive instances (p · q), but while the contradiction training improved college studients' performance it did not affect the seventh graders. The results are discussed in terms of changes in cognitive structures.     

Memory span and short-term memory capacity: A developmental study

A memory span task involving series conditions comprised of several different types of material was administered to children from three grade levels (7–12 years of age). As expected, age differences were strongly affected by type of material, with two conditions (consonant letters, words) intended to restrict opportunities for chunking yielding age differences that were negligible, and one condition (consonant-vowel letters) constructed to maximize sequential probability yielding age differences that were large. This finding renders less plausible the popular notion that capacity increases with age, and suggests that age differences in memory span reflect chunking processes. Additional findings, which indicate that age differences in memory span are affected by method of presentation and stage of practice, suggest that these variables should be considered in studies aimed at estimating children's memory capacity.