A NOTE ON TRANSFER OF STIMULUS CONTROL IN THE DELAYED-CUE PROCEDURE: FACILITATION BY AN OVERT DIFFERENTIAL RESPONSE

This case study describes initially unsuccessful attempts to use the delayed-cue procedure to teach conditional discriminations to an individual with moderate mental retardation. The task was matching printed-word comparison stimuli to dictated-name sample stimuli. In three experiments, the subject typically waited for the delayed cue unless differential responses to the dictated samples (repeating the sample names) were required. Hence, the study provides an example of a way to make the delayed-cue method more effective. The stimulus control bases for the results are discussed.     

汉字内隐记忆的实验研究（Ⅱ）：任务分离和反应倾向

在实验Ｉ的基础上,操纵学习时的呈现时间（２５０ｍｓ,５００ｍｓ,７５０ｍｓ）和注意变量（目标和非目标字）,运用任务分离方法及间接证明逻辑,比较了再认测验和整字偏好测验在不同条件下的辨别力（Ａ′）和反应倾向（Ｂ″）。结果：（１）双向功能分离的出现表明再认测验和偏好测验存在本质差异。根据“过程纯净”假设,可以推证内隐记忆存在于偏好测验中。此时,匹配比较法的标准未满足。（２）偏好测验中,５００ｍｓ呈现目标字时,有显著正向启动效应：７５０ｍｓ呈现非目标字时,有显著负向启动效应。（３）内隐记忆和外显记忆发生时,都具有稳定的心理状态。但是前者的报告标准较松宽,而后者的较严格。     

Biasing the pacemaker in the behavioral theory of timing

In the behavioral theory of timing, pacemaker rate is determined by overall rate of reinforcement. A two-alternative free-operant psychophysical procedure was employed to investigate whether pacemaker period was also sensitive to the differential rate of reinforcement. Responding on a left key during the first 25 s and on a right key during the second 25 s of a 50-s trial was reinforced at variable intervals, and variable-interval schedule values during the two halves of the trials were varied systematically. Responding on the right key during the first 25 s and on the left key during the second 25 s was not reinforced. Estimates of pacemaker period were derived from fits of a function predicted by the behavioral theory of timing to right-key response proportions in consecutive 5-s bins of the 50-s trial. Estimates of pacemaker period were shortest when the differential reinforcer rate most strongly favored right-key responses, and were longest when the differential reinforcer rate most strongly favored left-key responses. The results were consistent with the conclusion that pacemaker rate is influenced by relative reinforcer rate.     

Risk perception and the location of a repository for spent nuclear fuel

This study investigates lay people's reactions to a repository for nuclear waste. Risk perception is seen as a complex concept, comprising both affective and cognitive components. Attitude towards nuclear power and trust in experts and authorities had a substantial impact on risk perception, while personal knowledge about nuclear waste disposal had no effect. Thus, the more positive one's attitude towards nuclear power is and the more trust one has in experts and authorities, the lower one's risk perception is. Also, reactions were expected to vary with distance between the home district and the location of a repository. These variations differed in nature for people with alternative levels of risk judgement. The distance between the home and a repository affected approval of the proposed site. Distance between home and repository also had an effect on risk feelings and somewhat less on beliefs about consequences. Estimated total risk was directly mediated by beliefs about consequences, but even more so by risk feelings. With regard to risk, one can conclude that it is important to make a distinction between an emotional and a cognitive component of risk perception.     

5-11岁儿童元知觉发展的实验研究

本项研究旨在探索 5 -1 1岁儿童元认知发展的规律 ,2 80名昆明市及路南县汉、撒尼族儿童参与了三项知觉实验 ,实验结果表明 :1儿童随年龄的增长 ,有关知觉组织策略的知识及自我监察的能力也逐渐发展 ,表现为系统观察、选取有效策略及计划性的增强。 2儿童对信息的加工不断深入 ,从表浅的加工过渡到详尽的加工 ,不仅要求补充必要的信息 ,而且主动搜索隐蔽的线索以促进识辨。3儿童自我评价从笼统、含糊逐渐向客观、全面发展。4路南儿童元知觉的发展晚于昆明儿童两年 ,但在路南的汉族儿童和撒尼族儿童之间不存在显著差异 ,说明文化教育对儿童元知觉发展的重要影响。     

Converging measures of speech segmentation in preverbal infants

Two studies using novel extensions of the conditioned head-turning method examined contributions of rhythmic and distributional properties of syllable strings to 8-month-old infants' speech segmentation. The two techniques introduced exploit fundamental, but complementary, properties of representational units. The first involved assessment of discriminative response maintenance when simple training stimuli were embedded in more complex speech contexts; the second involved measurement of infants' latencies in detecting extraneous signals superimposed on speech stimuli. A complex pattern of results is predicted if infants succeed in grouping syllables into higher-order units. Across the two studies, the predicted pattern of results emerged, indicating that rhythmic properties of speech play an important role in guiding infants toward potential linguistically relevant units and simultaneously demonstrating that the techniques proposed here provide valid, converging measures of infants' auditory representational units.     

Infants' sensitivity to arbitrary object-odor pairings

The ability of 4-month-old infants to learn the arbitrary relationship between an object and a distinctive odor was assessed. Infants were familiarized with two objects while one of them was paired with a cherry odor. Results indicated that only female subjects showed evidence of matching. They increased their looking to the target object in the presence of the odor but not in the absence of the odor, relative to baseline levels.     

Human d-amphetamine drug discrimination: methamphetamine and hydromorphone.

Standard measures of subjective and discriminative effects of drugs were compared in 5 human volunteers. Subjects responded on a second-order color-tracking procedure, where 30 mg of d-amphetamine served as a discriminative stimulus for one response and its absence as the discriminative stimulus for another response. Self-reported subjective effects were assessed concurrently using the single-dose questionnaire, subscales of the Addiction Research Center Inventory, and several analogue rating scales. On different days following discrimination acquisition, varying doses of d-amphetamine, methamphetamine, and hydromorphone were administered. In these test sessions, either response was reinforced. Methamphetamine and d-amphetamine occasioned dose-related increases in d-amphetamine appropriate responding; hydromorphone did not. Methamphetamine and d-amphetamine occasioned dose-related increases in reports of the drug received being most like "speed"; hydromorphone occasioned dose-related increases in reports of the drug received being most like "dope." All three drugs occasioned dose-related increases in reports of drug liking, and increases in the morphine-benzedrine group, amphetamine, and benzedrine group scales of the Addiction Research Center Inventory. This experiment demonstrated that although explicit discriminative control of behavior by a drug may covary with drug identification, it does not necessarily covary with other self-reported subjective effects. Thus, the complementary nature of the data provided by drug discrimination and standard subjective-effects measures provides quantitative and qualitative data useful in studying both relatively novel compounds and the behavioral biology of psychoactive drugs in general.     

Temporal discrimination learning of operant feeding in goldfish (Carassius auratus)

Operant temporal discrimination learning was investigated in goldfish. In the first experiment, there was a fixed daily change in illumination. Eight subjects were trained to operate a lever that reinforced each press with food. The period during which responses were reinforced was then progressively reduced until it was 1 hr in every 24. The final 1-hr feeding schedule was maintained over 4 weeks. The feeding period commenced at the same time each day throughout. The food dispensers were then made inactive, and a period of extinction ensued for 6 days. The pattern of responding suggested that the fish were able to exhibit temporal discrimination in anticipation of feeding time. This pattern of responding persisted for a limited number of days during the extinction procedure. The second experiment produced evidence that operant temporal discrimination could develop under continuous illumination.     

Discrimination of methadone and cocaine by pigeons without explicit discrimination training.

Pigeons were trained to peck a key on a variable-interval 2-min schedule of food reinforcement. Prior to each session, either 2.0 mg/kg methadone (n = 3), 3.0 mg/kg cocaine (n = 4), or 5.6 mg/kg cocaine (n = 2) was administered. When each pigeon's rate of pecking was stable, a range of doses of the training drug and saline were administered prior to 20-min extinction sessions separated by at least four training sessions. Rate of pecking during these extinction tests was generally an increasing function of dose, with the lowest rates obtained following saline and low doses and the highest rates obtained following doses near the training doses. Dose functions from pigeons trained with 5.6 mg/kg cocaine were steeper than those from pigeons trained with 3.0 mg/kg cocaine. Pigeons trained with methadone or 3.0 mg/kg cocaine were then given discrimination training, in which food reinforcement followed drug administration and 20-min extinction sessions followed saline administration. Rates of pecking under these conditions quickly diverged until near-zero rates were obtained following saline and high rates were obtained following drug. Discrimination training steepened dose functions for the training drugs, and the effects of several other substituted drugs depended on the pharmacology of the training drug. The pigeons trained with 5.6 mg/kg cocaine were tested with d-amphetamine, methadone, and morphine prior to discrimination training. d-Amphetamine increased rates dose dependently, and methadone and morphine did not. The results suggest that discriminative control by methadone and cocaine was established without explicit discrimination training.