Consumption-leisure tradeoffs in pigeons: Effects of changing marginal wage rates by varying amount of reinforcement

Pigeons' rates of responding and food reinforcement under simple random-ratio schedules were compared with those obtained under comparable ratio schedules in which free food deliveries were added, but the duration of each food delivery was halved. These ratio-with-free-food schedules were constructed so that, were the pigeon to maintain the same rate of responding as it had under the simple ratio schedule, total food obtained (earned plus free) would remain unchanged. However, any reduction in responding would reduce total food consumption below that under the simple ratio schedule. These “compensated wage decreases” led to decreases in responding and decreases in food consumption, as predicted by an economic model of labor supply. Moreover, the reductions in responding increased as the ratio value increased (i.e., as wage rates decreased). Pigeons, therefore, substituted leisure for consumption. The relationship between these procedures and negative-income-tax programs is noted.     

THE EFFECTS OF CONTINGENT AND NONCONTINGENT REWARDS ON THE I.Q. SCORES OF CHILDREN OF ABOVE-AVERAGE INTELLIGENCE1

This study investigated the effects of candy reinforcement on I.Q. test scores in first and second graders of above-average intelligence. Thirty-six subjects were randomly assigned to one of three groups and either given candy contingent on correct responses, noncontingently, or not given candy. After measuring all subjects on Form L of the revised Stanford Binet, each subject in the contingent group was given an M & M immediately following each correct answer on Form M, while a yoked-comparison subject received the same number of M & M's before responding to a question and therefore without regard to correctness of answers. It was expected that both types of candy administration would produce higher I.Q. change scores than the no-candy control group, but there were no statistically significant differences among the three treatments. The differences between the first and second test scores were 4.17 (contingent), 4.67 (noncontingent), and 1.00 (no reinforcement). Reasons for this failure to replicate previous findings were discussed.     

The effects of varying the distribution of generalization stimuli within a constant range upon the bisection of a sound-intensity interval by rats

Two male, albino rats were trained on a two-valued, self-paced, discrete-trials auditory discrimination. In the presence of a high-intensity stimulus (90 decibels SPL, 4 kiloHertz), response A was reinforced; in the presence of a low-intensity stimulus (50 decibels SPL, 4 kiloHertz), response B was reinforced. When discrimination performance was asymptotic, stimuli intermediate in intensity were presented with the training stimuli in a maintained generalization paradigm. Generalization gradients were derived from the relative frequencies of response A in the presence of each stimulus. A relative frequency of 0.50 was then determined and used as the bisection point of the intensity interval defined by the 90- and 50-decibel stimuli. The bisection point varied with the distribution of the stimuli presented in generalization. This effect was similar to context effects seen in human psychophysics.     

Conjunctive schedules of response-dependent and response-independent reinforcement

Pigeons received food when they emitted the number of responses specified by a fixed-ratio schedule, and the time specified by a fixed-time schedule had elapsed. The order of meeting the response and time requirements was irrelevant. In different conditions, stimuli signalled completion of one, both, or neither requirement. Ratio size interacted with stimulus condition to determine performance. When a stimulus signalled the end of the fixed-time period, under all ratios the birds tended to respond after the stimulus appeared. When stimuli followed both components, small ratios produced responding during the fixed-time period, and other ratios resulted in responses after the time period had elapsed. With either no stimulus changes, or with a stimulus correlated with completion of the ratio alone, responding first increased and then decreased as the ratio increased. Low and high ratios produced stable response frequencies and patterns in successive intervals. Intermediate ratios resulted in two types of performance. Intervals with long initial pauses and few responses during the fixed-time period were followed by intervals with short pauses and numerous responses and vice versa. The source of these dynamic effects was hypothesized to be number of responses per reinforcer in one condition and response-reinforcer contiguity in the other.     

Intervention effects and relative variation as dimensions in experts' use of visual inference

Recent research indicates that when analyzing graphically presented single-subject data, subjects trained in visual inference appear to attend to large changes between phases regardless of relative variation and do not differentiate among common intervention effect patterns. In this follow-up study, experts in applied behavior analysis completed a free-sort task designed to assess the effects of these dimensions on their use of visual inference. The results indicate that they tended to differentiate among common intervention effect patterns but did not attend to relative variation in the data.     

PILLS OR SKILLS FOR HYPERACTIVE CHILDREN

The controversial nature of drug treatment of hyperactivity, the incidence and sequelae of hyperactivity, and problems of differential diagnosis of hyperactivity versus aggression were discussed. The effects of psychostimulant medication and behavior therapy on hyperactive children were reviewed with regard to effects on their social and academic behavior. Both treatments have resulted in clear short-term changes in social behavior but neither long-term academic nor long-term social effects have been shown with either treatment. Short-term effects on academic behavior have resulted from behavioral interventions but not from psychostimulants. However, the interventions have been too brief to allow one to draw unequivocal conclusions about the clinical efficacy of behavioral treatments. Although there have been long-term evaluations of psychostimulant therapy, there have not been any evaluations of long-term behavioral treatment programs for hyperactive children. Given the salutary short-term effects of behavior therapy with hyperactive children, extended clinical trials of behavior therapy need to be conducted. Finally, specific directions are suggested for future research.     

Cry analysis detects subclinical effects of prenatal alcohol exposure in newborn infants

The threshold, latency, and peak fundamental frequency (basic pitch) of crying were sensitive to the subclinical effects of prenatal alcohol exposure through the first month of postnatal life. Whereas infants with prenatal alcohol exposure showed a lower cry pitch and higher cry threshold at 2 days of age, higher pitched cries, typical of nervous system insult, were evident at 14 and 28 days. A longer latency was also evident at 14 days.     

时序信息加工机制及其通道效应的实验研究

研究由两个实验组成,实验一采用纯粹的视听方式,以线段长度和声音频率为材料,对时序信息的加工方式（自动加工与控制加工）、编码特点（时序信息是何时编码的）以及通道效应进行了研究。实验二以汉字为材料重复实验一的过程;结果表明,时序信息的加工存在视听通道效应,其机制源于记忆,且与实验材料的加工深度以及加工方式有关;时序信息既包含有自动加工,又包含有控制加工。视觉刺激倾向于自动加工,而听觉则倾向于控制加工;时序信息是在项目学习时编码获得的,而不是在提取时建构的。     

字频在直接和间接记忆测验中的比较研究

本研究通过3×2×2混合设计实验,比较了字频在即刻和第5天两种施测时间下的两类记忆测验中的不同作用。本研究支持了词汇通达搜索模型对宇频作用机制的分析及传输适当认知程序观点对实验性分离现象的解释,并发现外显记忆与内隐记忆都会发生遗忘,但原因可能并不相同,而且字频影响两类记忆的遗忘进程。     

Ratio size and cocaine concentration effects on oral cocaine-reinforced behavior.

Monkeys were given a choice between cocaine solutions and water under concurrent fixed-ratio reinforcement schedules. The operant response was spout contact. Six rhesus monkeys served as subjects. The cocaine concentration was varied from 0.0125 to 0.8 mg/ml, and the fixed-ratio value was varied from 8 to 128. Cocaine maintained higher response rates than did water over a wide range of conditions. Response rate and number of cocaine deliveries per session were inverted U-shaped functions of concentration. These functions were shifted to the right as the fixed ratio was increased. The number of cocaine deliveries was more persistent as fixed-ratio value was increased when the unit dose was larger rather than smaller. Cocaine consumption was analyzed as a function of unit price (fixed-ratio value divided by cocaine concentration), and unit price accounted for between 77% and 92% of the variance in cocaine consumption for individual monkeys. The current data support the claim that a drug's reinforcing effects increase directly with dose and underscore the need to gather parametric data when examining the effects of experimental manipulations on a drug-reinforced baseline.