Stimulus context and duration discrimination

The ability of human observers to discriminate duration was assessed in two types of tasks: (1) pulse tasks, in which the observer compared the duration of two brief increments in an ongoing sinusoid, and (2) gap tasks, in which the observer compared the duration of two brief interruptions in an ongoing sinusoid. Performance in these tasks was assessed in three different contexts: noise alone, noise plus continuous sinusoids, and noise plus continuous sinusoids chosen to induce a pitch segregation effect. Performance in the pulse task was independent of the changes in context; however, performance in the gap task changed as a function of context condition. There was a large decrement in the observers’ ability to discriminate duration when the stimulus ensemble induced the pitch segregation effect. The results are discussed in terms of the relationship between duration discrimination and stimulus variations which do not carry duration information.     

THE EFFECTS OF A GOOD-BEHAVIOR CONTRACT ON THE CLASSROOM BEHAVIORS OF SIXTH-GRADE STUDENTS1

The effects of a good-behavior contract on the on-task behavior, disruptive behavior, daily assignment completion, and weekly grades of four sixth-grade students were examined in a public school classroom. The contract consisted of presenting the students with a list of good conduct and assignment completion goals and a list of disruptive behaviors coupled with a list of rewards and penalties that could be earned. The rewards and penalties made use of existing facilities and classroom privileges. At the beginning of each morning work period, the teacher negotiated the good-behavior contract with each experimental subject. During the negotiations, the teacher emphasized student self-management and encouraged each student to earn a reward by achieving the good-conduct goals and completing the contract assignments. An isolated work area was provided to allow students the opportunity to remove themselves from their desks for a fixed period of 15 min. At the end of the work period, the teacher determined whether each student earned a choice of reward or penalty dependent on assignment completion and whether the teacher had observed disruptive behaviors. Thus, the contract permitted the student to negotiate the goal behaviors and contingencies with the teacher. Throughout the study, the students were in agreement with the teacher on whether a choice of reward or penalty had been earned. The contract was introduced for different children at different times, constituting a multiple-baseline analysis. On-task behavior and daily assignment completion increased, weekly grades were higher, and disruptive behavior decreased when the contract was in effect. Three contrast subjects were selected from the class as model students who consistently produced acceptable assignments and who did not engage in high rates of disruptive and/or off-task behaviors. When the contract was in effect for the experimental subjects, their performance compared favorably with the contrast subjects, who never received the daily contract. The results demonstrated that the contract was effective within the confines of the facilities and contingencies readily available in a public school classroom setting.     

Self-monitoring and self-reinforcement processes in a pre-transsexual boy

Young boys with normal male physical status who manifest feminine gender-role behavior and verbalize a cross-gender identity are high-risk for later adult sexual adjustment problems, e.g., transsexualism and homosexual conflicts (Bakwin, 1968; Lebovitz, 1972; Stoller, 1968; Zuger, 1966). In the only published experimental treatment studies on child gender disturbance in which replication procedures were used, Rekers and his colleagues empirically demonstrated external stimulus control and reinforcement control over pronounced feminine behavior in young boys with serious gender identity and behavior disturbance (Rekers and Lovaas, 1974; Rekers, Lovaas and Low, 1974; Rekers, Willis, Yates, Rosen and Low, in press; Rekers, Yates, Willis, Rosen and Taubman, 1976). To potentially minimize the previously reported stimulus specificity of the extrinsic reinforcement effects, this study introduces, for the first time, behavioral self-control strategies to decrease feminine behavior in a cross-gender identified boy. A 6-year-old boy was taught to self-monitor his own sex-role behavior, and then to self-reinforce gender-appropriate responding. A behavioral cueing procedure was used during the initial phases of the training of self-monitoring.     

Object disappearance and error in Piaget's Stage IV task

Piaget attributes perseverative error in infant manual search to the failure of the infant to conceive of objects as permanent entities which retain their identity when hidden at successive locations A and B. An experiment was performed to test this explanation in which search was compared under three conditions: when the object was hidden at A and B, when the object was covered but visible at A and B, and when the object was visible and uncovered at A and B. Errors occurred under all three conditions taking the form of a conflict in which infants searched persistently either at A or at B. The conflict was at a maximum when the object was hidden, but was evident even when the object was visible but covered. It is suggested that errors may reflect lack of coordination between egocentric and visual frames of reference in relation to which the object is located.     

Sex,masculinity—feminity,and intelligence

Masculine and feminine subgroups of males and females were selected from samples of high school and college students on the basis of composite scores from several M—F scales. They were compared on intelligence as measured by a verbal test, Terman's Concept Mastery Test, and a nonverbal test, D-48. Results did not support previous findings of sex differences in intelligence but showed that masculine subgroups of both sexes scored higher of the nonverbal test.     

Comparison of child and adult vibrotactile thresholds as a function of frequency and duration

Psychophysical thresholds for the detection of sinusoidal vibration of the thenar eminence of the hand were determined for children and adults. The subjects in the child group were between 8 and 11 years old, and the adults were between 20 and 39 years old. Measurements were made for vibration frequencies ranging from 18 to 700 Hz and stimulus durations ranging from 28 to 1,000 msec. For both children and adults, thresholds were a Il-shaped function of stimulus frequency. However, the exact form of the function was influenced by the age of the subjects. At frequencies above 200 Hz, thresholds were virtually identical for children and adults, but below this frequency children were more sensitive than adults. This finding, in combination with known changes in the anatomy of the Pacinian corpuscle with age, is in agreement with a filter model of this cutaneous receptor. Furthermore, variation of stimulus duration resulted in data in agreement with the theory that two classes of mechanoreceptors, Pacinian and non-Pacinian, mediate the perception of vibration.     

Syllabic structure and the acquisition of consonants: The great conspiracy in word formation

The syllabic structure and phonemic inventory of one child were analyzed at the beginning of word production and compared with similar records reported in the literature. The data appear to favor an interactionist view of lexical development which recognizes the contribution of particular syllabic forms to the acquisition of consonantal phonemes and the role these phonemes play in expanded syllabic form. The discussion argues for the primacy of CV as the dominant unit of production and identifies a number of constraints on syllabic forms and a set of conspiratorial rules which assure the production of these forms. Further, it is argued that certain strategies operating within the constraints to particular syllabic forms result in the ordered development of syllabic structures.     

Biasing power law exponents by magnitude estimation instructions

This study investigates the influence of attention loading on the established intersensory effects of passive bodily rotation on choice reaction time (RT) to visual motion. Subjects sat at the center of rotation in an enclosed rotating chamber and observed an oscilloscope on which were, in the center, a tracking display and, 10° left of center, a RT line. Three tracking tasks and a no-tracking control condition were presented to all subjects in combination with the RT task, which occurred with and without concurrent cab rotations. Choice RT to. line motions was inhibited (p < .001) both when there was simultaneous vestibular stimulation and when there was a tracking task; response latencies lengthened progressively with increased similarity between the RT and tracking tasks. However, the attention conditions did not affect the intersensory effect; the significance of this for the nature of the sensory interaction is discussed.