Some parameters of behavioral contrast and allocation of interim behavior in rats

Two experiments examined the effects of baseline reinforcement rate and component duration on behavioral contrast and on re-allocation of interim behavior in rats. Positive behavioral contrast occurred during multiple variable-interval 10-second extinction (VI 10 EXT) after a multiple VI 10 VI 10 baseline condition, but not during multiple VI 60 EXT following multiple VI 60 VI 60 baseline. Component duration had no significant effect on contrast. These results differed from those found in studies of pigeons' key pecking. Contrast was accompanied by an increased rate of drinking in the changed component, but drinking in the constant component did not decrease. These results are not consistent with the competition theory of contrast, but are consistent with the predictions based on the matching law. However, no current theory seems to account for all instances of behavioral contrast.     

An eye‐tracking study on information processing in risky decisions: Evidence for compensatory strategies based on automatic processes

Many everyday decisions have to be made under risk and can be interpreted as choices between gambles with different outcomes that are realized with specific probabilities. The underlying cognitive processes were investigated by testing six sets of hypotheses concerning choices, decision times, and information search derived from cumulative prospect theory, decision field theory, priority heuristic and parallel constraint satisfaction models. Our participants completed 40 decision tasks of two gambles with two non‐negative outcomes each. Information search was recorded using eye‐tracking technology. Results for choices, decision time, the amount of information searched for, fixation durations, the direction of the information search, and the distribution of fixations conflict with the prediction of the non‐compensatory priority heuristic and indicate that individuals use compensatory strategies. Choice proportions are well in line with the predictions of cumulative prospect theory. Process measures indicate that individuals thereby do not rely on deliberate calculations of weighted sums. Information integration processes seem to be better explained by models that partially rely on automatic processes such as decision field theory or parallel constraint satisfaction models. Copyright © 2010 John Wiley & Sons, Ltd.     

母亲消极教养、同伴侵害与FKBP5基因对青少年抑郁的影响

累积压力假说与匹配-不匹配假说均可解释远端和近端逆境对个体抑郁的影响,但鲜有研究考察遗传基因在其中的调节作用。采用问卷法和DNA分型技术,对970名青少年进行间隔3年的追踪调查。分别以母亲消极教养、同伴侵害为远端和近端压力指标, FKBP5基因多位点累加得分为遗传指标,考察三者对青少年抑郁的交互作用及性别差异。结果发现,在男青少年中, E×E×G显著。当累加得分较高、同伴侵害水平较高时,母亲消极教养显著负向预测抑郁,符合匹配-不匹配假说;累加得分较低时, E×E不显著,但倾向于以累积压力假说的方式发挥作用。女青少年中, E×E×G不显著。研究结果提示,在男青少年中,累积压力假说与匹配-不匹配假说均可阐明抑郁的发生机制,分别适用于携带不同FKBP5基因多位点累加得分的个体。     

The relationship between differential stimulus relatedness and implicit measure effect sizes

Implicit measures have been hypothesized to allow researchers to ascertain the existence and strength of relations between stimuli, often in the context of research on attitudes. However, little controlled behavioral research has focused on whether stimulus relations, and the degree of relatedness within such relations, are indexed by implicit measures. The current study examined this issue using a behavior‐analytic implicit‐style stimulus relation indexing procedure known as the Function Acquisition Speed Test (FAST). Using a matching‐to‐sample (MTS) procedure to train stimulus equivalence relations between nonsense syllables, the number of iterations of the procedure was varied across groups of participants, hence controlling stimulus relatedness in the resulting equivalence relations. Following final exposure to the MTS procedure, participants completed a FAST. Another group of participants was exposed to a FAST procedure with word pairs of known relatedness. Results showed that increasing relatedness resulted in a linear increase in FAST effect size. These results provide the first direct empirical support for a key process‐level assumption of the implicit literature, and offer a behavior‐analytic paradigm within which to understand these effects. These results also suggest that the FAST may be a viable procedure for the quantification of emergent stimulus relations in stimulus equivalence training.     

Preference,resistance to change,and the cumulative decision model

According to behavioral momentum theory (Nevin & Grace, 2000a), preference in concurrent chains and resistance to change in multiple schedules are independent measures of a common construct representing reinforcement history. Here I review the original studies on preference and resistance to change in which reinforcement variables were manipulated parametrically, conducted by Nevin, Grace and colleagues between 1997 and 2002, as well as more recent research. The cumulative decision model proposed by Grace and colleagues for concurrent chains is shown to provide a good account of both preference and resistance to change, and is able to predict the increased sensitivity to reinforcer rate and magnitude observed with constant‐duration components. Residuals from fits of the cumulative decision model to preference and resistance to change data were positively correlated, supporting the prediction of behavioral momentum theory. Although some questions remain, the learning process assumed by the cumulative decision model, in which outcomes are compared against a criterion that represents the average outcome value in the current context, may provide a plausible model for the acquisition of differential resistance to change.     

The selective action of Cfunc control

According to relational frame theory Cfunc stimuli select which stimulus properties are transformed via derived stimulus relations. To date there has been no demonstration of the selective action of Cfunc control. We provide an analysis of the requirements for such a demonstration, and describe the results from four experiments employing a paradigm consistent with these requirements. We employed a paradigm based on virtual car races. The paradigm had two components: i) a sample racecar screen which showed the performance of a sample racecar, and used experimentally engineered symbols to communicate how the performance of each real racecar would compare with that of the sample racecar, and ii) a car race screen showing other racecars race. Two symbols were established as Crels for the relations of same and different, and two symbols were established as Cfuncs for the functional properties of speed and direction. The results from these experiments demonstrate Cfunc stimuli can select which functions transform via derived stimulus relations, a central component of relational frame theory. The study has implications for the study of relational responding in complex settings and for applied work aimed at refining repertoires of relational responding.     

Ratio responding as a function of concurrent avoidance schedules, yoked shocks, and ratio value

Fixed-ratio food-reinforced responding in rats was studied alone and with concurrent shock avoidance or with concurrent response-independent shocks matched to those that occurred in the avoidance condition. Under each condition, fixed-ratio size was increased over successive daily sessions. Fixed-ratio response rate generally passed through a maximum as a function of fixed-ratio size. Decreased fixed-ratio responding at values beyond the maximum occurred when (1) the time to complete a fixed ratio approximated the response-shock interval of the avoidance schedule, (2) the shock rate increased, and/or (3) the ratio requirements were so high that ratio strain occurred. Avoidance rates decreased slightly as fixed-ratio size increased.     

On the origin and preservation of cumulative record in its struggle for life as a favored term

This paper offers a case study of the origins, emergence, and evolution of the term cumulative record as the name for the means by which B. F. Skinner brought his behavior under the control of his subject matter. Our methods included on-line searches, reviews of Skinner's publications, and journal codings and counts. The results reveal that the term is not originally attributable to Skinner, but emerged earlier in ordinary language and in another discipline--education. It was not even original to Skinner in print in his own science. Still, the term was once original to him, which we address with additional analyses of his having originated and advanced it. We conclude with a discussion the constraints of our methods, suggestions for future research, and the variable appreciation of technology and terminology in science studies.     

Establishing Functional Classes In A Chimpanzee (Pan troglodytes) With A Two-item Sequential-Responding Procedure

A 9-year-old female chimpanzee was trained on a two-item sequential-responding task. Attempts were made with successive-reversal training to establish functional classes. In Experiment 1, the subject was exposed to between-session successive-reversal training in which one of two pairs of stimuli was reversed, and transfer of reversal responding to the other pair was tested with nonreinforcement probe trials. She did not show transfer during the course of reversals. Stimulus control established in the original training was maintained on nonreinforcement probe trials. In Experiment 2, within-session reversals were introduced. She showed transfer from the initially reversed pair to the other. The results were consistent with Vaughan's (1988) results with pigeons on successive discriminations, which indicated the formation of functional classes. In Experiment 3, crossover and wild-card tests were conducted to clarify the stimulus control of sequential responding. The results suggested that the sequential responding was controlled only by the first stimulus of each pair. To establish control by both first and second stimuli, trial-unique stimuli or wild cards were substituted for one of the items of the lists in Experiment 4. Further transfer tests, in which stimuli for the two new pairs appeared, were also given to the subject. She successfully responded to these two merged lists and reversed the order as the result of reversal training.     

THE CUMULATIVE QUALITY OF CULTURE EXPLAINS HUMAN UNIQUENESS

What explains the unique features of human culture? Culture is not uniquely human, but human culture is uniquely cumulative. Cumulative culture is a product of our collective intelligence and is supported by cognitive processes and learning strategies that enable people to acquire, transform, and transmit information and technologies within and across generations. Technological and social innovations are currently driving unprecedented changes in cultural complexity and diversity. Innovation is a cognitively and socially complex, multistep process that typically requires (cumulative) cultural learning to achieve. I argue that the technological solutions that characterize twenty-first-century innovation can only be explained by understanding both the capacity to learn from and build upon the insights of others and the transmission systems that store the knowledge and technologies of previous generations. Human uniqueness is a product of cumulative cultural learning, transmission, and innovation.