Choice in a successive-encounters procedure and hyperbolic decay of reinforcement

Pigeons responded in a successive-encounters procedure that consisted of a search state, a choice state, and a handling state. The search state was either a fixed-interval or mixed-interval schedule presented on the center key of a three-key chamber. Upon completion of the search state, the choice state was presented, in which the center key was off and the two side keys were lit. A pigeon could either accept a delay followed by food (by pecking the right key) or reject this option and return to the search state (by pecking the left key). During the choice state, a red right key represented the long alternative (a long handling delay followed by food), and a green right key represented the short alternative (a short handling delay followed by food). In some conditions, both the short and long alternatives were fixed-time schedules, and in other conditions both were mixed-time schedules. Contrary to the predictions of both optimal foraging theory and delay-reduction theory, the percentage of trials on which pigeons accepted the long alternative depended on whether the search and handling schedules were fixed or mixed. They were more likely to accept the long alternative when the search states were fixed-interval rather than mixed-interval schedules, and more likely to reject the long alternative when the handling states were fixed-time rather than mixed-time schedules. This pattern of results was in qualitative agreement with the predictions of the hyperbolic-decay model, which states that the value of a reinforcer is inversely related to the delay between a choice response and reinforcer delivery.     

个体与群体情境下3～5岁幼儿延迟满足的实验研究

采用实验法以90名3~5岁的儿童为被试,探讨其在个体和群体情境中延迟满足的特点。研究结果表明:3~5岁幼儿的延迟满足能力存在着显著的年龄差异,随着年龄的增长而不断提高;3岁幼儿延迟满足能力较弱,而4、5岁的幼儿在这种能力上有了较明显的发展,但从整体上来看,幼儿阶段的延迟满足能力仍然很低;3~5岁幼儿的延迟满足能力在不同的情境、不同性别中不存在显著的差异。     

胖负面身体自我女大学生对胖信息的注意偏好:注意警觉还是注意维持

本研究对已有负面身体自我个体注意偏好研究采用的实验范式的问题进行了分析,提出胖负面身体自我个体对胖相关信息的注意偏向存在的另一种可能,即胖负面身体自我个体对胖相关信息可能存在注意维持时间更长的假设。共设计了3个实验对假设进行验证。实验1a采用线索范式研究高胖负面身体自我个体对胖相关词语的注意警觉和注意维持,线索目标SOA为300ms,实验1b采用同样的实验范式,只是将实验材料变为更具直接意义的身体轮廓图。两个实验的结果均支持实验假设,但是未能排除反应准备和线索对目标产生掩蔽等因素的影响。因此,实验2在身体和花瓶轮廓图周围呈现字母,要求被试对字母进行辨认,对被试的注意维持成分进行直接的测量。结果验证了高胖负面身体自我女大学生对胖身体轮廓图注意维持时间更长。综合几个实验的结果,得到以下结论:在本实验条件下,胖负面身体自我女大学生对胖身体信息的注意偏差成分是注意维持时间更长。     

Acquisition and maintenance of trusting behavior

This study determined whether a two-person exchange situation contained natural contingencies for trusting behavior or whether external contingencies were necessary. Pairs of college students worked matching-to-sample problems for money. On each trial there was one problem and the subjects determined which of them would solve it. Trusting behavior was defined as an increase in the number of consecutive problems each subject allowed his partner to work during sessions that also ended with an equitable distribution. Simply, trust was a temporary deviation from equity. A subject could give the problem to the other person (cooperate), or not respond and let the other person take the problem (share). Other possibilities were for both subjects to try to take the problem (complete), or for neither subject to respond and thereby let the person who worked the last problem also work the next one (passive trust). When only four lever pulls were required to distribute a problem (no external contingencies to reach either equity or trust) subjects reached equity, but only minimal trust (strict alternation of single problems) developed in 18 sessions. When 30 or 60 lever pulls were required to distribute a problem (smaller response requirement for passive trust and therefore a contingency for trust), trusting behavior developed after a few sessions (fixed ratio 30) or after several trials of the first session (fixed ratio 60) and it ordinarily expanded gradually to 10 to 15 consecutive problems through passive trust. The aversiveness of the inequity involved in trusting appears to necessitate a contingency for acquisition. Once trust develops, however, this aversiveness is reduced as subjects learn the inequity is only temporary (e.g., once trust was acquired at fixed ratio 60 it was maintained at fixed ratio 4, which would not initially produce it), and the direction of the inequity appears to become of questionable importance (e.g., being behind was alternated over rather than within sessions and usually not in a systematic manner).     

Effects of Interspersing Briefer Mathematics Problems on Assignment Choice in Students with Learning Disabilities

Within- and between-series designs were combined and used to evaluate the effects of interspersing briefer math problems (i.e., one-digit by one-digit multiplication, 1 × 1) with more time-consuming problems (i.e., two-digit by one-digit multiplication, 2 × 1) on time allocation to one of two concurrent computer-delivered mathematics computation assignments in four high school students with specific learning disabilities in mathematics. The computer presented students with a choice of 2 × 1 problems with 1 × 1 problems interspersed every third problem (i.e., experimental assignment) or 2 × 1 problems without interspersal (i.e., control assignment). Visual and statistical analysis showed that students allocated a greater percentage of their time to the interspersal assignments. These results support previous research on the matching law and problem completion rates and suggest that students' preference for assignments can be improved through the interspersal technique. Discussion focuses on future research and applied educational implications for curricula construction and task sequencing.     

正负参照点下性别和损益情景对大学生延迟折扣的影响

大量研究表明,延迟折扣受到个体特质性和状态性因素的影响。本研究通过两个实验分别探究正参照点(实验1)和负参照点(实验2)下,特质性因素性别和状态性因素损益情景对大学生个体延迟折扣的影响。实验1研究发现,在正性参照点下,无论男女,收益情景的主观远期价值远高于损失情景。实验2研究发现,在负性参照点下,男女在损益情景的主观远期价值不同;与男性相比,女性的主观远期价值在损失情景中更高,而在收益情景中则无显著差异。本研究结果表明,在不同的参照点下,男女在损益情景中表现了不同的延迟折扣倾向;与男性相比,女性在负性参照点面对损失情景跨期选择时,更愿意选择延迟赔偿。     

DRA contingencies promote improved tolerance to delayed reinforcement during FCT compared to DRO and fixed-time schedules

Following Functional Communication Training (FCT), clinicians often gradually expose newly taught communicative responses to delayed reinforcement contingencies to prepare clients for the normative environment in which requests are frequently reinforced after a delay. The introduction of delays may result in the resurgence and maintenance of problem behavior and the weakening of the newly trained communicative response. The current study compared delay tolerance with three individuals diagnosed with intellectual and developmental disabilities when reinforcement for the functional communication response (FCR) was delivered following (a) the passage of time, (b) the omission of problem behavior, or (c) the occurrence of an alternative behavior. We measured delay tolerance in terms of minimizing problem behavior and maintaining efficient FCRs. Outcomes support requiring alternative responding during delays to attain optimal treatment results.     

Social discounting of pain

Impatience can be formalized as a delay discount rate, describing how the subjective value of reward decreases as it is delayed. By analogy, selfishness can be formalized as a social discount rate, representing how the subjective value of rewarding another person decreases with increasing social distance. Delay and social discount rates for reward are correlated across individuals. However no previous work has examined whether this relationship also holds for aversive outcomes. Neither has previous work described a functional form for social discounting of pain in humans. This is a pertinent question, since preferences over aversive outcomes formally diverge from those for reward. We addressed this issue in an experiment in which healthy adult participants (N = 67) chose the timing and intensity of hypothetical pain for themselves and others. In keeping with previous studies, participants showed a strong preference for immediate over delayed pain. Participants showed greater concern for pain in close others than for their own pain, though this hyperaltruism was steeply discounted with increasing social distance. Impatience for pain and social discounting of pain were weakly correlated across individuals. Our results extend a link between impatience and selfishness to the aversive domain.