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Three shaved adult male albino rats were trained to press a lever to replace a hot air drive condition (50° C) with either a small reinforcer (32° C) or a large reinforcer (14° C). Following the 10-sec reinforcer, the drive condition was either reinstated immediately (no delay) or after a 15-sec exposure to the drive temperature, during which the bar was withdrawn (delay). Response rate during the no-delay procedure was faster for the small reinforcer than for the large. This relation reversed during the delay procedure. The former observation is similar to a satiation effect and the latter resembles an incentive effect.  相似文献   
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Three groups of rats underwent 24 days of training and 12 days of extinction (three trials per day) in a runway under conditions of increasing (I), decreasing (D), and random (R) sequences of reward magnitudes (0, 45, and 500 mg). The I Ss ran faster over the daily trials, the D Ss slowed down, and the R Ss ran at approximately equal speeds on each trial. The patterned running observed in training persisted in extinction, with the R Ss running fastest and the I Ss next. The results were discussed in terms of Capaldi’s sequential theory and Amsel’s frustration theory.  相似文献   
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Scott-jones D 《联谊会》1993,75(3):K1-12
There are a number of options that help adolescents make appropriate choices about sexual activity, pregnancy, and childbearing. Comprehensive sex education programs are a deterrent to unwanted pregnancy and early sexual activity. Educational attitudes must be changed to reflect a recognition that sexual behavior is not deviant, but a normal part of human development during the transition to adulthood. Programs to prevent unplanned pregnancies must focus on educational expectations, educational achievement, and career preparation. Provision of child care options will help adolescents stay in school. Program focus must be applicable to two groups: older and younger adolescents. Solutions offered by Claire Brindis, based on program evaluations, suggest broad guidelines and local community-specific prevention plans. The responsible expression of sexuality needs greater emphasis than has occurred in many programs, particularly those where sex education is controversial or is confined to a small amount of time. Schools have been the most responsible vehicle for provision of sex education. In addition to sexuality education and pregnancy prevention programs, programs which instill a desire for greater formal education have resulted in delayed sexual activity and childbearing. Schools can play an important role in socializing adolescents for the appropriate transition to adulthood. Schools have become less and less meaningful to adolescents. German apprenticeship programs have been successful in orienting students to jobs in real settings. The Public Service Academy in Washington, D.C., has provided similar opportunities for part-time work or internships in government. Abortion among adolescents is still a politically charged issue in the US. Many have recommended the Maryland example of designating the physician or mental health provider, instead of a judge, as the individual responsible for determining the maturity and best interests of the child in choosing abortion. Pliner and Yates have recommended parental notification laws only for adolescents aged under 15 years. Adoption, as a solution to an unwanted birth, has remained stable at about 1% among Black adolescents and has declined from 19% to 3% among White adolescents over the past 20 years. More research is needed on how to best handle the sense of abandonment and loss or feelings of irresponsibility due to the decision to put an unwanted baby up for adoption.  相似文献   
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