An improved respiratory system for curarized rats

A respiratory system is described in which peak expired CO₂ is continuously monitored from curarized rats. Another alteration from previous systems is that an endotracheal tube is used to minimize dead air space. The adequacy of the system was tested by maintaining curarized rats at one level of peak expired CO₂ for varying periods of time and by keeping rats at different peak expired CO₂ levels for a fixed period of time. Results of blood gas analyses indicated that values obtained with this system are similar to values in noncurarized rats, and that manipulation of expired CO₂ is an effective means of altering blood gas values.     

Interactions between spatial and kinetic dimensions in movement aftereffect

In some conditions, the surface of the test figure on which one sees an aftereffect of movement does not fit with that part of the visual field previously adapted to a movement. Such an effect, called kinetic-figural effect, may be conceived of as resulting from an interaction between two perceptual systems, each one giving specific information: one for the kinetic aspects which are spatially defined, the other for the spatial relationship inside the visual field. Experiments are presented which indicated the validity of a “law of location” for a movement aftereffect, together with some effects of the spatial relationships between adapting and test fields upon the movement aftereffect.     

Marriage preparation and marriage enrichment: The preventive approach

Premarital counseling and marriage enrichment are viewed as two areas of a life continuum prevention program. Premarital counseling is seen as the first step in preparation for marriage, to be followed six months to a year after marriage by a neomarital counseling experience. Content and process for the counseling are elaborated. Marriage enrichment groups are recommended at various points during the life of a marriage. Three models for enrichment are presented. Prevention programs are viewed as vital experiences for personal and relationship maintenance and growth.He is also a member of the faculty of Waterloo Lutheran Seminary, Waterloo, Ontario.     

Modification of Delinquent Behavior1

A matched subjects design was employed to assess the effectiveness of an experimental program for the reduction of delinquent behavior in adolescent boys on probation. Youngsters in the experimental group (N= 19) were invited to participate in a series of small group sessions designed on the basis of principles drawn from the theory and research of social psychology. Control group delinquents (N= 19) were not informed of this project and continued their previous association with the probation office. The group experiences arranged for the experimental participants encouraged free and open discussion of their previous delinquent activities, future behavioral intentions, personal values, and life goals. It was found that participants developed high attraction toward the group and involvement in its activities. Frequency of subsequent delinquent behavior was found to be significantly reduced for experimental group participants as compared with their matched controls. In a followup interview 9 months after the last group meeting, it was found that experimental group members showed significantly more internal responses on a modified version of the Rotter I-E scale than did the control subjects.     

Achievement goals and engagement in individual and collective learning activities

The relationship between achievement goals and individual and collective learning activities was examined for 290 university students who completed two questionnaires. One assessed three achievement goals-a mastery goal and two performance goals, namely, approval seeking and advancing. The other questionnaire measured how actively students report engaging in individual and collective learning activities. Regression analyses showed that the adoption of mastery goals was associated with active engagement in both individual and collective learning, while adoption of a performance goal of approval seeking was associated with passive engagement in individual learning activities. These results are discussed in relation to their theoretical implications and in regard to the possible moderating effect of protecting self-worth.     

Clearing the air: identity safety moderates the effects of stereotype threat on women's leadership aspirations

Exposing participants to gender-stereotypic TV commercials designed to elicit the female stereotype, the present research explored whether vulnerability to stereotype threat could persuade women to avoid leadership roles in favor of nonthreatening subordinate roles. Study 1 confirmed that exposure to the stereotypic commercials undermined women's aspirations on a subsequent leadership task. Study 2 established that varying the identity safety of the leadership task moderated whether activation of the female stereotype mediated the effect of the commercials on women's aspirations. Creating an identity-safe environment eliminated vulnerability to stereotype threat despite exposure to threatening situational cues that primed stigmatized social identities and their corresponding stereotypes.     

Effects of visual attentional load on low-level auditory scene analysis

The sharing of processing resources between the senses was investigated by examining the effects of visual task load on auditory event-related brain potentials (ERPs). In Experiment 1, participants completed both a zero-back and a one-back visual task while a tone pattern or a harmonic series was presented. N1 and P2 waves were modulated by visual task difficulty, but neither mismatch negativity (MMN) elicited by deviant stimuli from the tone pattern nor object-related negativity (ORN) elicited by mistuning from the harmonic series was affected. In Experiment 2, participants responded to identity (what) or location (where) in vision, while ignoring sounds alternating in either pitch (what) or location (where). Auditory ERP modulations were consistent with task difficulty, rather than with task specificity. In Experiment 3, we investigated auditory ERP generation under conditions of no visual task. The results are discussed with respect to a distinction between process-general (N1 and P2) and processspecific (MMN and ORN) auditory ERPs.     

Sensory effects on judgments of short time-intervals

Two experiments were conducted to test the effect of nontemporal factors on duration discrimination. In Exp. 1, a forced-choice adaptive procedure with a standard duration of 400 or 800 ms was employed. It was shown that, for both auditory and visual modes, the discrimination is better with empty intervals (a silent period between two brief signals) than with filled intervals (a continuous signal), but only with shorter durations. In a second experiment, where intervals of the same duration range were employed but were presented with a single-stimulus method, discrimination was better with empty than with filled intervals, and this effect applied to both ranges of duration and both sensory modes. In both experiments, discrimination was better in the auditory than in the visual mode. These data are discussed in the context of current models of timing mechanisms. Received: 16 October 1997 / Accepted: 30 April 1998     

Erroneous Perceptions in Generating Sequences of Random Events1

This paper reports the results of 2 studies that examine the perceptions of individuals attempting to generate random sequences. It was hypothesized that erroneous perceptions dominate probability judgment. The first study demonstrated that subjects verbalized significantly more erroneous than accurate perceptions when generating sequences of random binary events. The second study was designed both to replicate these data and to assess the role of motivation on the frequency of misconceptions. Results showed that the total number of erroneous perceptions again outnumbered accurate perceptions but, motivation did not increase the number of misconceptions. A basic error concerned subjects' inability to consider events as being independent of each other. The theoretical and practical implications of these results are discussed in relation to the psychology of gambling.