Electroencephalographic and dichotic indices of cerebral laterality in stutterers

To test the hypothesis that stuttering is the product of faulty cerebral laterality four experiments were performed on each of five adult stutterers and five fluent speakers. These tests were: (1) dichotic listening with consonant-vowel pairs, (2) alpha recording over both hemispheres during the performance of cognitive tasks intended to engage preferentially the left or right hemispheres, (3) contingent negative variation with either an articulatory or bilaterally symmetrical response, and (4) readiness potential with the same responses. The results fail to disconfirm the null hypothesis regarding stutterers and their fluent peers. All subjects showed consistent patterns of cerebral laterality indicative of localization of speech function in the left hemisphere. Suggestions are made regarding a possible contribution of deficient sensorimotor integration in stuttering.     

Reinforcing fluency in stutterers: An experimental study

Subject-specific periods of fluent reading responses of three adult stutterers were positively reinforced with the presentation of a dime. Subjects were run individually through a sequence of two base rate, two experimental, and two extinction sessions, each session lasting 45 min. Periods of fluent reading responses increased during the experimental condition for each of the three subjects. When the reinforcer was withdrawn during the extinction condition, the frequency of fluent periods showed a decrease. Concomitantly, disfluencies decreased during the experimental condition and they increased during the extinction condition. The clinical implications of fluency manipulation as against disfluency manipulation are discussed.     

Organization of short-term verbal memory in language areas of human cortex: Evidence from electrical stimulation

Short-term verbal memory (STVM) performance was measured during electrical stimulation of human left frontal-parietal-temporal cortex, at craniotomy under local anesthesia for the treatment of medically intractable epilepsy. The areas of cortex where stimulation alters language, as measured by object naming, are separate but adjacent to the areas where stimulation alters STVM. There are differential effects of stimulation during input, storage, and output phases of STVM at different cortical sites. These suggest that cortex adjacent to the posterior language area is a site of storage of STVM, while cortex adjacent to anterior language area is involved in retrieval from STVM.     

Modification of the externality effect in young infants.

When presented with two-element geometric stimuli, with one element enclosed within the other, infants under 2 months of age do not appear to detect the internal element and fail to respond to a change in that element. Infants over 2 months of age experience no difficulty in this respect. However, it is established that this “externality effect” does break down under certain circumstances, for example, where there is independent modulation of the internal element. Evidence is presented which appears to run counter to explanations of this effect in terms of information processing limitations, capture of attention by dominant salience, or level of arousal. An alternative explanation based on figure-ground organization is given partial support.     

Cue selection in verbal discrimination learning of retarded subjects.

A series of experiments was conducted to examine cue function in trigram verbal discrimination learning by retarded subjects. The issue was to determine the factors that control attention in this type of learning situation. The two variables of chief interest were trigram meaningfulness and reinforcement history. The major general conclusion was that retarded subjects employ complex cue selection strategies in solving a verbal discrimination involving compound verbal stimuli. Major findings were as follows: (a) Retarded subjects exhibit a response bias in favor of words over nonsense trigrams; (b) relatively little active cue selection based on meaningfulness was observed; (c) a compound stimulus discrimination was more difficult to learn than a discrimination involving single verbal stimuli; (d) compound and single stimuli may be processed differently in original discrimination learning; (e) cue position probably controls attention in compound discrimination learning; and (f) a frequency theory of verbal discrimination learning is supported by these data.     

Regional cerebral blood flow response during rest and memory activation in a patient with global amnesia

A college professor with a classical amnesic syndrome is described. He has a WAIS IQ of 130, but dramatic memory loss for episodes ranging from a few seconds ago all the way back to portions of his childhood. The amnesia was of sudden onset, 2 years prior to the current memory tests and regional cerebral blood flow measurements. The etiology is believed, though not conclusively proven, to be medial thalamic infarction. rCBF measurements were taken on six separate occasions, four resting baseline, one memory activation, using the previous procedure of Wood, Taylor, et al., and one carbon dioxide activation. The resting baseline showed extremely low flows throughout the cortex, with some hyperfrontal response on the first baseline. With CO₂ activation, however, there was brisk, uniform reactivity, with all sites showing increased flow. This suggested that there were no prominent areas of impaired vasomotor control or probable ischemic damage in the cortical surface. During memory activation, there was also a generalized increase in flow, especially in the frontal areas. This was in sharp contrast to the pattern for normals, described by Wood, Taylor, et al., which shows a slight overall decrease in flow from baseline to memory activation. The results are interpreted in light of Talland's proposal that the amnesic syndrome reflects an arousal failure, with premature closure and shutdown of memory processing, especially at retrieval. Here the arousal failure is interpreted as an inadequate restriction or focusing of cortical activation, with resulting pathologically diffuse flow increases.     

Sensitivity in spectral structures

Invariance of matching is shown to be necessary and sufficient for the existence of sensitivity functions that are unique up to multiplication by arbitrary positive real numbers. Examples from auditory and visual psychophysics are discussed.     

Stimulus control over sex-typed play in cross-gender identified boys.

Discriminative stimulus control over masculine and feminine sex-typed play behaviors was investigated in five boys, aged 5–8 yr, with “childhood crossgender identification.” Reliable observational measures of play were obtained with two sets of toys: (a) “dress-up toys” (girls' apparel vs boys' apparel), and (b) “affect toys” (maternal-nurturance play vs masculine-aggression play). With an ABA reversal intrasubject design, certain stimulus conditions (e.g., presence of father, mother, male, or female stranger) were found to be discriminative for reliable changes in sex-typed play. Sex-typed play was found to vary as a function of the social stimulus situation and as a function of the type of play response required. All children played predominantly feminine while alone in the playroom. While no single environmental stimulus was consistently discriminative for masculine play across children, at least one stimulus condition was found for each subject under which he played predominantly masculine.     

Age and overt verbalization in delay-maintenance behavior in children

The influence of overt self-verbalization on the maintenance of self-imposed delay of gratification was investigated in a task in which the child's possession of accumulating candy rewards was made contingent upon the child stopping further accumulation. Preschool girls who verbalized about the goodness of waiting and preschool girls who uttered an irrelevant verbalization waited longer before terminating their delay than did preschool girls who verbalized about the delayed reward or were silent. Second- and third-grade girls who verbalized about the goodness of waiting or who were silent waited longer than girls of the same age who verbalized about the delayed reward.     

The multiple roles of Broca's discovery in the development of the modern neurosciences

Using the classical clinico-anatomical correlation method of the French clinical school, Paul Broca confirmed the localization of "language" in the frontal lobe. He actually discovered the lateralization of language in the left hemisphere. These contributions eventually led to the demise of the older concept of the "sensorium commune," because Broca's ideas implied the presence of motor functions in the hemispheres. Although Broca worked within the theoretical motif of the "faculty" psychology, the reflex-oriented "associationist" psychology soon became the predominant theoretical framework of localization, because it accommodated the motor aspect of hemispheric function. Since Broca's time, the study of the biology of language has proceeded along two parallel but sometimes separate lines in the experimental and clinical traditions.     

Social facilitation in chickens: A different level of analysis

An assumption of the arousal (D × H) model of social facilitation effects is that in an otherwise constant stimulus situation the simple presence or absence of a conspecific has a quantitative influence on the D component, and that the habit hierarchy in the situation (H) is unaffected. However, certain evidence from avian subjects seemed inconsistent with the multiplicative effects predicted by the model, and experiments were conducted with the aim of resolving this discrepancy. In general, chickens were tested for consummatory responses in the company of companions, in isolation, or in the company of strangers. Clear findings emerged from these tests that showed that only the companion conditions were “facilitative”. Under the other test conditions there were qualitative (as opposed to merely quantitative) shifts in responses. Apparently, the different social test conditions evoked qualitatively different response hierarchies, and “facilitation” reflected this sort of shift rather than simple quantitative changes in arousal (D) across conditions. It was argued, therefore, that the appropriate level of analysis for facilitation effects for animals in a free response situation is not within the (D × H) envelope, but rather at the level of S (stimulus situation) in the S → (D × H) → R formulation. Implications for the analysis of social facilitation effects in humans were discussed.     

Analogic and abstraction strategies in synthetic grammar learning: A functionalist interpretation

Subjects learned artificial grammars under two conditions of acquisition: paired-associate learning and observation of exemplars. The former procedure was strongly associated with the establishment of a fairly concrete memorial space consisting of specific items and parts of items and the use of an analogic strategy for making decisions about novel stimuli. The observation procedure was strongly associated with the induction of an abstract representation of the rules of the grammar and the use of a correspondence strategy for decision making. Moreover, this latter procedure led to more robust knowledge and better overall performance. Analyses of both objective response patterns and subjective introspections yielded coordinated data in support of this distinction. The relationships between acquisition condition and cognitive strategy are discussed from a functionalist point of view.     

Control of social desirability in personality inventories: Principal-factor deletion

Rational and statistical techniques for controlling social desirability (SD) in scales derived from self-report inventories are reviewed. The principal-factor deletion technique is explained in detail. It is applied during factor analysis when derived content scales are expected to be tainted with SD. If one principal factor is found to represent social desirability, the implicated factor is dropped and the communalities adjusted before the remaining factors are rotated to a desired simple structure criterion. Subscales derived from resulting factors are free of SD bias. Principal-factor deletion is compared with other approaches including rational techniques, covariate procedures, and target rotation.     

Response and associative phase components of elaborative prompt effects in children's noun-pair learning

The effects of aural and pictorial elaborative prompts were estimated separately for response and associative phase components of children's nounpair learning. A 20-item list of noun pairs was administered individually to 200 second- and third-grade children by the method of paired-associates. Indices of response learning (free verbal recall and pictorial identification) revealed equivalent effects among prompt conditions whereas measures of associative learning (multiple-choice pictorial-recognition tests) demonstrated substantial performance facilitation as a function of both aural and pictorial elaborative prompts. This outcome was regarded as an unequivocal identification of the locus of elaborative prompt effects in children's nounpair learning.     

The roles of event contingencies and reinforcement in human autoshaping and omission responding

Four experiments were conducted to test those features deemed to play an important role in the acquisition and/or maintenance of autoshaping and omission responding with human subjects, viz., event contingencies, reinforcement, stimulus generalization, the type of CS employed, conditioned reinforcement, and response topography. One important aspect of these studies is that the boundary conditions were made to resemble those pertaining to the majority of nonhuman animal studies, i.e., magazine training followed by paired CS-US presentations. The results demonstrated the importance of CS-UR or, alternatively, CS-US contiguity together with generalization and a response-reinforcer contingency for autoshaped response initiation and maintenance, respectively. The conditioned reinforcing effect of CS offset appears to play a part in generating and maintaining some responding during omission training, especially during a response-terminated CS procedure. Similar response topography was observed when the form of the UR was compared to that of the CR or autoshaped response. Taken as a whole the results of these experiments with humans are directly comparable to results previously reported using a wide variety of nonhuman animals.     

Interest differentiation in high school and vocational indecision in college

Vocational indecision was defined as being both a college upperclassman and having no major. In a sample of 1622 students in college for three years, 24% indecisive students were found and compared with vocationally decisive students (having majors) using precollege measures of achievement, aptitude, and interest. Measures of interest differentiation were of particular concern. Indecisiveness was best predicted from present and past achievement measures, e.g., cumulative college GPA or high school mathematics GPA. Interest predictors slightly augmented the multiple correlation including Outdoor interest, Business Contact interest, and interest differentiation. Most important to vocational indecision in these juniors and seniors, however, was lower academic achievement.     

Pauses and syntax in American sign language

Research on spoken languages has shown that the durations of silent pauses in a sentence are strongly related to the syntactic structure of the sentence. A similar analysis of the pauses (holds) in a passage in American Sign Language reveals that sequences of signs are also interspersed with holds of different lengths: long holds appear to indicate the ends of sentences; shorter holds, the break between two conjoined sentences; and the shortest holds, breaks between internal constituents. Thus, pausal analysis is a guide to parsing sentences in ASL.