Contribution of the speech musculature to apparent human EEG asymmetries prior to vocalization

Vocalizations are preceded by slow EEG waves over inferior frontal scalp regions, but some controversy exists as to whether these slow potentials are left-lateralized as a function of speech. In this study both speech and non-speech vocalizations were studied, under conditions of repetitive and variable production. Averaged responses over the speech musculature, including the temporalis, masseter, orbicularis oris, and mylohyoid muscles, as well as the eyes and tongue, were calculated simultaneously with scalp EEG averages. The responses of the temporalis and masseter muscles, as well as that of the tongue, were correlated with EEG sites at specific latencies prior to speech, suggesting that no part of the inferior frontal EEG record was free from myogenic confounds. In addition, all significant EEG differences between speech and non-speech conditions were subsequently eliminated by covariance analysis, using selected muscle channels as covariates. Previous reports of asymmetrical “speech potentials” in the EEG probably reflected a combination of several myogenic confounds.     

Testing hypotheses regarding rape: Exposure to sexual violence,sex differences,and the “normality” of rapists

Three hypotheses on the subject of rape were addressed empirically. The first concerns the effects of exposure to sexual violence on reactions to rape. Males and females were first exposed to either a sadomasochistic or a nonviolent version of the same sexual passage and then to a portrayal of rape. Responses to the rape showed interactions between gender and previous exposure: In comparison to males who had read the nonviolent version, males exposed to the sadomasochistic story were more sexually aroused to the rape depiction and more punitive toward the rapist whereas females evidenced differences in the opposite direction. Simple effects analyses for each gender, however, yielded significant differences for the punitiveness measure only and for males only. In addressing the second hypothesis, gender differences were found in the perception of rape. Third, the assertion that rape may be an extension of normal sexual patterns was explored. Subjects were found to believe that a high percentage of men would rape if assured of not being punished and that a substantial percentage of women would enjoy being victimized. While both genders shared these beliefs, very few women believed that they personally would derive pleasure from victimization. Surprisingly, more than half of the males indicated some likelihood that they themselves would rape if assured of not being punished. The association between this self-report and general attitudes toward rape revealed a pattern that bears striking similarity to the callous attitudes often held by convicted rapists.     

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.     

The propensity to recall another's completed and uncompleted tasks as a consequence of varying social relationships

Two laboratory experiments are reported. Each investigates the bias that social relationships exert on a subject's propensity to recall another's completed and uncompleted tasks. Using closed circuit television, subjects in both experiments observed a bogus other working on a set of puzzles. The person working completed only one-half of the puzzles. In three of the six experimental conditions in both experiments, subjects believed that the remaining puzzles could be completed at a later time. In the first experiment, a subject's relationship to the other was determined by cooperative, competitive, or individualistic economic incentives. In the second, the relationship was determined simply by their similarity or dissimilarity on a bogus personality test. Utilizing a combination of Lewinian assumptions and contemporary theory about memory, we hypothesized that the opportunity to resume work would result in an increased propensity to recall uncompleted tasks in the competitive (or dissimilar) conditions and a decreased propensity to do so in the cooperative (or similar) conditions. Results confirmed this hypothesis. Additional data in both experiments suggest that subjects' relationships with the bogus other altered the accessibility of this information. Theoretical implications of these findings and their relationship to research on prosocial behavior are discussed.     

Three experiences affecting spatial discrimination learning by ambulatory children

Children 1 and 3 years of age were given a two-choice spatial discrimination task. They were placed in front of a barrier and encouraged to walk around it; one route around the barrier was blocked. Three experiments studied the effects of different types of experience with this spatial problem. The first examined trial and error experience, in which the child was allowed to walk the route he or she had chosen. Although most children readily learned to choose the open route, the pattern of choices indicated that 3-year-olds were more likely to achieve a learning criterion after an error than 1-year-olds. A second experiment looked at the effects of showing the children the layout of the problem prior to trial and error experience. The 3-year-olds were again more likely than the 1-year-olds to achieve criterion after an error; furthermore, they were likely to know the correct route on the first trial. The third experiment let the children watch their parents take the correct route. This procedure eliminated age differences in performance. The initial choices of the 1-year-olds indicated that they were likely to know the correct route, and if they did not, they were just as likely to learn from their mistakes as the 3-year-olds. The data were interpreted within a mathematical model of learning. Based upon these analyses, we propose two developmental trends. One involves a growth in sensitivity to the consequences of a choice of route. The other is a progression from social learning to more independent and ideational methods of spatial problem solving.     

Stimulus control of defensive burying in the rat

Rats shocked once through a wire-wrapped stationary prod mounted on the wall of a test chamber incorporated the bedding material covering the chamber floor into a defensive reaction. When tested 1 min later, they approached the prod and buried it. Evidence was provided by three separate studies of this burying response that rats had learned about the association of both the position and brightness of the prod with shock after this single conditioning trial. In Experiment 1, the amount of burying decreased if either the position or brightness of the prod had been changed prior to the test. In Experiments 2 and 3, rats were shocked through one of two prods (white or black) mounted on opposite walls of the test chamber. When the positions of the prods were unchanged for the test, almost every subject buried the prod through which it had been shocked, even when the conditioning-test interval was 24 hr; whereas, each rat directed substantial amounts of bedding material at both prods when the positions of the two prods were reversed. Thus, discriminated “avoidance” learning can be rapid, reliable, and enduring when shock is administered “by” a clearly defined stimulus object, i.e., when cue and consequence are spatially contiguous.     

Sequences of phonemic approximations in aphasia

The trends of sequences of phonemic approximations to a single target were studied in three types of aphasia (Broca's, conduction, and Wernicke's), as gathered in five tasks (spontaneous speech, repetition of meaningful words, repetition of nonsense words, reading aloud, and automatized sequences). A phonemic error ratio was defined in order to quantify the distance between each approximation of a given sequence and its target. The results of a computer analysis based on this ratio were analyzed according to three parameters. A study of three types of patients revealed that conduction aphasics exhibited the most regular trend toward the target in sequences of phonemic approximations; the analysis of the various tasks indicated that sequences produced in repetition by conduction aphasics form an exception to the regularity of this trend, and an examination of the various lengths of sequences indicated that longer sequences showed a less decisive trend toward the target than shorter sequences. The discussion bears on some theoretical aspects of the phonological production mechanism and its control: the initial strength and permanence of the internal representation of the target emerge as important factors required for the good functioning of this mechanism.     

Intelligence and short-term memory: A clandestine relationship

Five possible mechanisms are considered as being responsible for the systematic variation of serial STM with IQ, namely rehearsal maintenance, chunking, access, encoding of item and/or order information, and trace persistence. A STM/IQ correlational study is reported. It was concluded from analysis of a correlation matrix, and from earlier reported data, that the encoding of items-in-order into an already loaded store appears to be the critical mechanism in determining IQ-related individual differences in STM performance, at least in children. The implications of individual difference data for models of STM are also discussed.     

Phonological processing in Broca's aphasics

Phonological processing was investigated in nine Broca's aphasics. A receptive phonological task examined knowledge of phonotactic rules. Three lists of “word” pairs, phoneme sequences, were constructed such that one member was possible in English and the other was not. The lists varied in distance from English or phonemic structure (CCVC vs. CCVCC). Following auditory presentation, the aphasic was required to indicate which of the two “words” was possible in English. The productive task was an articulation test for monosyllabic and polysyllabic words. The high positive correlation between receptive and productive scores suggested that, rather than motor speech sequencing problems being exclusively involved, more general phonological-articulatory processes were disrupted. Several hypotheses were advanced to describe the nature of this disruption.