Contribution of ankle, knee, and hip joints to the perception threshold for support surface rotation

The purpose of the present experiment was to investigate the extent to which subjects can perceive, at very slow velocities, an angular rotation of the support surface about the medio-lateral axis of the ankle, knee, hip, or neck joint when visual cues are not available. Subjects were passively displaced on a slowly rotating platform at .01, .03, and .05 deg/sec. The subjects’ task was to detect movements of the platform in four different postural conditions allowing body oscillations about the ankle, knee, hip, or neck joint. In Experiment 1, subjects had to detect backward and forward rotation (pitching). In Experiment 2, they had to detect left and right rotations of the platform (rolling). In Experiment 3, subjects had to detect both backward/forward and left/right rotations of the platform, with the body fixed and the head either fixed or free to move. Overall, when the body was free to oscillate about the ankle, knee, or hip joints, a similar threshold for movement perception was observed. This threshold was lower for rolling than for pitching. Interestingly, in these postural conditions, an unconscious compensation in the direction opposite to the platform rotation was observed on most trials. The threshold for movement perception was much higher when the head was the only segment free to oscillate about the neck joint. These results suggest that, in static conditions, the otoliths are poor detectors of the direction of gravity forces. They also suggest that accurate perception of body orientation is improved when proprioceptive information can be dynamically integrated.     

Sexually dimorphic effect of an acute smoking manipulation on skin resistance but not on heart-rate during a cognitive verbal task

In a two-day, two-session experiment where smokers male and female college-student subjects worked on a cognitive verbal task during either the first or second day, and on a cognitive spatial task on the second or first day, smoking was manipulated as an acute independent variable by requiring 10+ hours of pre-experimental abstention, and providing a cigarette during the 15-minute rest period between the two sessions. Non-smoker female and male subjects underwent the same experiment, and hence served as controls for the effects of this acute-smoking manipulation. Overall adaptation (decreased arousal) to the experiment was manifested in a significant increase in skin resistance level (SRL) in all subjects, but when this adaptation effect was statistically controlled, there was a significant smokers by sex interaction during the verbal task only, such that SRL was increased by the cigarette in males, but decreased in females. In contrast, the same analysis indicated only a marked increase in heart-rate (HR) due to smoking, which was unaffected either by sex or by whether the task was the verbal or the (easier) spatial one. We interpret the SRL results as reflecting a sex difference in the direction of transient psychological arousal, and discuss it in relation to evidence in the literature based on self reports, and to evidence (based on HR in this study and on blood pressure in other studies) on physiological (cardiovascular) arousal.     

The role of motion in children's categorization of objects.

Perceptual cues play a fundamental role in early categorization of objects. What is meant by perceptual cues in the literature, however, is not always clear. It is fair to say that they are typically understood to be static shape cues. A number of recent studies have suggested that dynamic perceptual cues, such as motion, may also be important in early categorization. The study presented here explored the role that motion plays in children's categorization of animal and non-animal kinds, such as geometric figures. Motion was directly pitted against shape as a cue for categorization. Results showed that 4-year-old children, confronted with a choice between shape and motion, significantly used motion cues over shape cues to categorize objects, regardless of whether they were animals or geometric figures. Seven-year-olds also tended to use motion more often to categorize animals but not when dealing with geometric figures. Older children, who have been found to have a clearer natural kind/artifact distinction, seem to appreciate the uniqueness of movement to animals and see motion as more relevant to their categorization but relatively less so to categorize geometric figures. This developmental shift in the categorization of animals and geometric figures based on motion was further confirmed by testing adults on the same tasks. Adults were found to base their judgements significantly more often on motion for animals but not for geometric figures. These findings support the view that children are initially guided by motion in object categorization, suggesting that motion plays an overriding role that is central in the process of concept acquisition and in the mechanisms by which concepts are later structured.     

Be is a raising verb: Psycholinguistic evidence

Psycholinguistic evidence is reported supporting the proposal from theoretical linguistics that the D-structure representation of English copular sentences likeJohn is a fool, The man is happy, etc., is [S [NP e] [vp BE [sc NP XP]]], containing a small clause (SC), rather than [s NP [vp BE XP]], in other words, thatbe is a raising verb. Response times to lexical targets following unaccusative, passive, intransitive, and transitive sentences were compared with response times to lexical targets following corresponding copular sentences. A raising analysis of copular sentences specifies a post-verbal NP-trace of the (raised) NP subject at S-structure. This trace should facilitate the response time to a post-sentence presentation of the head noun of the subject NP, causing copular sentence response times to pattern with the response times for corresponding unaccusatives and passives, which also contain such traces. A traditional nonraising analysis specifies no trace at S-structure. Response times to copular sentences should then pattern with corresponding intransitives and transitives, which also do not contain traces. The observed response-time patterns confirmed the raising analysis.This study was conducted at the National Technical Institute for the Deaf at Rochester Institute of Technology, in the course of an agreement with the U.S. Department of Education.     

A method for determining the aversive threshold in the rat using repeated measures: Tests with morphine sulfate

The procedure described here provides an objective automated technique for the psychophysical assessment of the aversive threshold and allows the animal Ss to serve as their own controls. Sensitivity to drug effects, as well as comparisons between drugs, using the same animals are possible also. Using a rectangular tilt cage, the aversive threshold to grid shock was defined as that intensity avoided 75% of the time. Each shock intensity (30, 60, 90, 120, and 150 microA) was presented for 5 min on one side of the cage and then switched to the other side for 5 min, thereby forcing the animal to sample each shock intensity. Aversive thresholds were determined daily for each rat. The analgesic effects of morphine sulfate were compared to saline. Animals were tested for 3 days at each morphine dose level (2, 4, 8, and 16 mg/kg). Each 3-day morphine series alternated with 3 days of testing under saline. Significant differences were detected between saline and morphine at 4, 8, and 16 mg/kg.     

A comparative study of proprietary and nonproprietary vocational training graduates

Questionnaires were sent to 13,549 graduates of four types of proprietary and nonproprietary vocational training programs in four selected metropolitan areas of the United States. Initial responses were received from 5,215 graduates, a response rate of 38.5%. The survey featured an intensive follow-up to reach and estimate the characteristics of the nonrespondent population. Substantial differences favoring nonproprietary programs were found between proprietary and nonproprietary graduates in terms of economic gains following graduation and expressed satisfaction. Nevertheless, both types of programs were found to be generally effective in producing graduates with marketable skills; post-training salaries were high enough to indicate that the training was cost effective in all except proprietary computer training programs. The results supported several recommendations regarding the necessity for uniform standards of accountability in the regulation of vocational training programs, whether they are public or private.     

The “Black Sheep Effect”: Extremity of judgments towards ingroup members as a function of group identification

The present study proposes an extension to the phenomenon of ingroup favouritism, based on the hypothesis that judgments about ingroup members may be more positive or more negative than judgments about similar outgroup members. It contrasts predictions issued from the complexity-extremity hypothesis (Linville, 1982; Linville and Jones, 1980), from the ingroup favouritism hypothesis (Tajfel, 1982) and from Tesser's (1978; Millar and Tesser, 1986) attitude polarization model. Our main prediction, based on Social Identity Theory, is that judgments about both likeable and unlikeable ingroup members are more extreme than judgments about outgroup members. This phenomenon, coined the Black Sheep Effect, is viewed as due to the relevance that ingroup members'behaviour, as compared to that of outgroup members, has for the subjects' social identity. Three experiments supported our predictions. Experiment I additionally showed that inter-trait correlations were stronger for the ingroup than for the outgroup. Experiment 2 showed that the black sheep effect occurs only when the judgmental cues are relevant for the subjects' social identity, and Experiment 3 showed that levels of information about the target of the judgment were ineffective in generating judgmental extremity. Results are discussed in light of a cognitive-motivational alternative explanation to a purely cognitive interpretation of outgroup homogeneity.     

Coital behaviors, attitudes, and knowledge of students who experience early coitus

The purpose of this study was to investigate coital behavior, contraceptive practices, and attitudinal and knowledge differences between "early coital initiators" (subjects having initial coitus at 16 years or younger) and "late coital initiators" (subjects having initial coitus from 17 to 20 years of age). Data were compiled from the results of a questionnaire administered to 929 students enrolled in personal health courses at 14 colleges and universities. The sample used for analysis included only the never-married coitally experienced males and females aged 20 and older (N = 396). The results suggested that late coital initiators: were more effective contraceptors during initial coitus; had more committed relationships with their initial sex partners; engaged in more discussion about and planning for contraceptive use; and used more authoritative and reliable sources for contraceptive information than their younger counterparts. Both groups scored very low on basic knowledge questions concerning fertility, contraception, and sexually transmitted diseases. These results mandate greater public concern and involvement to delay early coital experiences and prevent unprotected sexual intercourse.