Temporal control by signals of interval duration within variable-interval schedules

Rats' lever pressing produced sucrose reinforcers on a variable-interval schedule where, in different conditions, the duration of a stimulus presented immediately after reinforcement was either correlated or uncorrelated with the duration of the current interreinforcement interval. Under the baseline schedule, in which no stimulus was presented, the minimum interreinforcement interval was 8 s and the mean postreinforcement pause of each subject approximated this value. Response rates increased slowly over the first 10 to 15 s and then remained roughly constant throughout the remainder of the interval. In both the correlated and uncorrelated conditions, the added stimulus resulted in the postreinforcement pauses lengthening to values in excess of the duration of the preceding stimulus. This resulted in a poststimulus pause which was, in most cases, roughly constant irrespective of the duration of the preceding stimulus, or of the reinforcement contingencies prevailing immediately after stimulus offset. Local response-rate patterns in the uncorrelated conditions were similar to those obtained under the baseline schedule in which no stimulus was presented. However, in the correlated condition local response rates increased across the remainder of the interreinforcer interval. Further, the rate of acceleration was inversely related to the duration of the preceding stimulus. These results show that a correlation between stimulus duration and the ensuing time to reinforcement can control behavior—a type of temporal control not previously reported.     

The timing of natural prehension movements

Prehension movements were studied by film in 7 adult subjects. Transportation of the hand to the target-object location had features very similar to any aiming arm movement, that is, it involved a fast-velocity initial phase and a low-velocity final phase. The peak velocity of the movement was highly correlated with its amplitude, although total movement duration tended to remain invariant when target distance was changed. The low-velocity phase consistently began after about 75% of movement time had elapsed. This ration was maintained for different movement amplitudes. Formation of the finger grip occurred during hand transportation. Fingers were first stretched and then began to close in anticipation to contact with the object. The onset of the closure phase was highly correlated to the beginning of the low velocity phase of transportation. This pattern for both transportation and finger grip formation was maintained in conditions whether visual feedback from the moving limb was present or not. Implications of these findings for the central programming of multisegmental movements are discussed.     

Job stress and job performance controversy: an empirical assessment

This study examined the relationship between job stress and employees' performance and withdrawal behavior among nurses (N = 440) in two hospitals in a metropolitan Canadian city on the east coast. Job stressors assessed included role ambiguity, role overload, role conflict, and resource inadequacy. Employees' performance was operationalized in terms of job performance, motivation, and patient care skill. Withdrawal behaviors assessed were absenteeism, tardiness, and anticipated turnover. Multiple regressions, curvilinear correlation coefficients, and canonical correlations were computed to test the nature of the relationship between stressors and the criterion variables of the study. In general, data were more supportive of the negative linear relationship between stress and performance than for positive linear or curvilinear relationship. However, the stressor role ambiguity did exhibit a monotonic nonlinear relationship with a number of criterion variables. Employees' professional and organizational commitment were proposed to moderate the stress-performance relationship. However, the data only partially supported the role of the moderators.     

Changing the response unit from a single peck to a fixed number of pecks in fixed-interval schedules

Each of three pigeons was studied first under a standard fixed-interval schedule. With the fixed interval held constant, the schedule was changed to a second-order schedule in which the response unit was the behavior on a small fixed-ratio schedule (first a fixed-ratio 10 and then a fixed-ratio 20 schedule). That is, every completion of the fixed-ratio schedule produced a 0.7-sec darkening of the key and reset the response count to zero for the next ratio. The first fixed-ratio completed after the fixed-interval schedule elapsed produced the 0.7-sec blackout followed immediately by food. These manipulations were carried out under two different fixed-interval durations for each bird ranging from 3 min to 12 min. The standard fixed-interval schedules produced the typical pause after reinforcement followed by responding at a moderate rate until the next reinforcement. The second-order schedules also engendered a pause after reinforcement, but responding occurred in bursts separated by brief pauses after each blackout. For a particular fixed-interval duration, post-reinforcement pauses increased slightly as the number of pecks in the response unit increased despite large differences in the rate and pattern of key pecking. Post-reinforcement pause increased with the fixed-interval duration under all response units. These data confirm that the allocation of time between pausing and responding is relatively independent of the rate and topography of responding after the pause.     

Good behavior game: effects of individual contingencies for group consequences on disruptive behavior in a classroom

Out-of-seat and talking-out behaviors were studied in a regular fourth-grade class that included several "problem children". After baseline rates of the inappropriate behaviors were obtained, the class was divided into two teams "to play a game". Each out-of-seat and talking-out response by an individual child resulted in a mark being placed on the chalkboard, which meant a possible loss of privileges by all members of the student's team. In this manner a contingency was arranged for the inappropriate behavior of each child while the consequence (possible loss of privileges) of the child's behavior was shared by all members of this team as a group. The privileges were events which are available in almost every classroom, such as extra recess, first to line up for lunch, time for special projects, stars and name tags, as well as winning the game. The individual contingencies for the group consequences were successfully applied first during math period and then during reading period. The experimental analysis involved elements of both reversal and multiple baseline designs.     

Stimulus control in the goldfish after massed extinction

Compared with the data of goldfish trained only with stimuli correlated with reinforcement, interspersed reinforcement-stimulus and extinction-stimulus trials resulted in sharper stimulus control and a marked reduction in the percentage of key-presses emitted in the presence of stimuli located near the extinction stimulus on the test dimension. If non-reinforced trials were not interspersed with reinforced trials, there was no sharpening of stimulus control and less reduction in key presses in the presence of stimuli near the extinction stimulus on the test dimension.     

西方关于青年马克思与异化的辯論

马克思早期著作的出版提供给我们一幅关于社会主义思想早期发展的图景,使人更清楚地看到它同哲学和社会学中现行讨论之间的联系。这一联系即早期马克思对此曾多所涉及的异化现象。在这篇论文里,作者指出对异化现象的现时流行的两种主要探索方法——本体论的和社会学的方法——的特征并提出这种看法:早期马克思对这一现象的分析中的黑格尔的本体论和经验社会学之间的紧张关系反映出这一分析——对理解人的地位的一种贡献——的优点而非弱点。     

伦理学的规范及其社会使命

苏联伦理学专业工作者在《高等学校马克思主义伦理学基础》教学大纲草案中,把马克思主义伦理学的规范问题作为一个专题进行了研究。可以说,它是当前苏联学术界对这一科学命题的各种看法的总结。马克思主义伦理学被理介为“关于道德发展的社会本质和规律性、关于共产主义道德形成的规律性、关于道德原别与道德规范和它在争取共产主义社会的斗争中的作用”的科学。对这一概念,肯定要做仔细的分析研究工作。这