A Centipede for Intransitive Preferrers

In the standard money pump, an agent with cyclical preferences can avoid exploitation if he shows foresight and solves his sequential decision problem using backward induction (BI). This way out is foreclosed in a modified money pump, which has been presented in Rabinowicz (2000). There, BI will lead the agent to behave in a self-defeating way. The present paper describes another sequential decision problem of this kind, the Centipede for an Intransitive Preferrer, which in some respects is even more striking than the modified pump. In the new problem, the BI reasoning that implies self-defeating behavior does not rest on the controversial robustness assumption concerning beliefs in one's future rationality. This strengthens the claim that foresight cannot save the intransitive preferrer from a self-defeating course of action.     

Response–reinforcer contiguity versus response-rate–reinforcer-rate covariance in rats' lever pressing: Support for a multiscale view

The multiscale molar view sees behavior as a flow, like a river, extended in time. Matching theory expresses the way activities compete for time. Relative time taken by any activity depends on relative induction. The present experiment tested matching theory applied to concurrent contingent and noncontingent food. As adjunctive activities that compete with operant activity, we recorded hopper head entries and presses on a lever near the food hopper that had no programmed consequences. Eight naïve rats were first exposed to a variable-time 60 s schedule, which across conditions was gradually transformed into a variable-interval 60 s schedule by increasing the proportion of food that was delivered contingent on pressing a lever far from the hopper. Another group of 4 rats that had been trained to press a lever near a food hopper were introduced in the second condition, in which one food delivery was contingent on far-lever pressing. We found induction following a power function to describe pressing on the far lever (operant activity). Matching theory combined with power-function induction also accounted for adjunctive activity. Results with single contingent food deliveries provided little support for the molecular view that behavior consists of discrete responses “strengthened” by immediately following reinforcers.     

Avoidance,induction, and the illusion of reinforcement

Environmental events that impact reproductive success may be called phylogenetically important events (PIEs). Some promote reproductive success, like mates and food; others threaten reproductive success, like predators and injury. Beneficial PIEs induce activities that enhance them, and detrimental PIEs induce activities that mitigate or avoid them. Free-operant avoidance relies on electric shock as a proxy for injury, a PIE. One theory takes avoidance behavior to be reinforced by its reducing shock rate. A more complete explanation is that avoidance both reduces shock rate and is induced by the PIEs it usually prevents. Shocks received act in concert with shock-rate reduction, in a feedback system. Four parametric data sets were analyzed to show that avoidance is induced by received shock rate according to power functions. Avoidance is not reinforced at all; avoidance is induced by its failures. Induction explains not only avoidance itself, but also phenomena unique to avoidance, like warmup and effects of unavoidable shock. Induction explains behavior more generally than reinforcement, because induction explains not only food-maintained operant and nonoperant behavior, but also shock-maintained behavior, including avoidance. Reinforcement fails to explain behavior when reinforcement is defined as strengthening by consequences. Induction erases the distinction between consequences and antecedents.     

P3b反映基于相似性的图形类别归纳决策过程(309)

先前关于归纳推理的研究没有探讨过图形类别归纳任务中决策过程的事件相关电位(ERPs)特征。该研究采用图形材料,通过记录和分析图形类别归纳推理任务的结论评估阶段的脑电信号,探讨了不同类别条件下图形归纳推理决策过程的ERP特征。实验结果显示,推理决策过程中,当前提为一些狗具有某种属性特征时,结论一致类别(狗类及马类)比结论不一致类别下(椅子类)的归纳推理诱发了更大的P3b的波幅; 而结论一致类别下,类别内(狗类)比类别外(马类)推理诱发更大的后部脑区的P3b的波幅,反映了相似性对类别归纳的贡献。该研究为理解类别归纳过程的决策阶段的动态加工过程提供了神经电生理学证据。研究结果进一步支持了类别归纳的相似性理论模型。     

Food rejection and the development of food category-based induction in 2–6 years old children

We studied children’s inductive inferences within the domain of food categories. There has so far been little research on inductive reasoning about food among children, despite the theoretical and practical importance of knowing what knowledge children bring to the table and how they use it. We tested the hypotheses that children’s food category-based induction performances and their food rejection are negatively correlated, and that these performances are influenced by the colour typicality of the food items. We recruited 126 children aged 2–6 years, and administered a category-based induction task. Participants were successively shown 8 sets of three pictures containing one target picture (a vegetable) and two test pictures (a vegetable dissimilar in colour to the target picture and a fruit similar in colour to the target picture). For each set, participants were told a novel property about the target picture and asked to generalise this property to one of the two test pictures. Additionally, the parents of each child filled out a questionnaire about his or her food rejection tendencies. Results on accuracy (i.e. if participants generalised the properties according to category membership, not perceptual similarity) provided the first empirical evidence in favour of a negative relationship between children’s food rejection and food category-based induction.     

Sad people are more accurate at face recognition than happy people

Mood has varied effects on cognitive performance including the accuracy of face recognition (Lundh & Ost, 1996). Three experiments are presented here that explored face recognition abilities in mood-induced participants. Experiment 1 demonstrated that happy-induced participants are less accurate and have a more conservative response bias than sad-induced participants in a face recognition task. Using a remember/know/guess procedure, Experiment 2 showed that sad-induced participants had more conscious recollections of faces than happy-induced participants. Additionally, sad-induced participants could recognise all faces accurately, whereas, happy- and neutral-induced participants recognised happy faces more accurately than sad faces. In Experiment 3, these effects were not observed when participants intentionally learnt the faces, rather than incidentally learnt the faces. It is suggested that happy-induced participants do not process faces as elaborately as sad-induced participants.     

类比迁移发生机制的研究

本研究包含两个实验,探讨类比迁移发生的机制。实验一主要探索类比迁移中的图式归纳是一种自动加工还是控制加工。实验二主要探索类比迁移中的图式归纳是保留性的还是排除性的。本实验结果表明,类比迁移中的图式归纳主要是控制加工,是一种保留性的归纳。     

Behavioral contrast and the automaintained key peck

In two experiments behavioral contrast was demonstrated during discrimination training in a positive automaintenance procedure. During the baseline condition in each experiment, a key was transilluminated for eight seconds by one of two colors (CS) following a variable intertrial interval signaled by a dark key. Keylight transillumination terminated with a response-independent food presentation. In the first experiment, food was eliminated during one CS for up to fifty sessions. After reinstatement of food following each CS, the discrimination was reversed. Six of the eight subjects showed positive behavioral contrast, i.e., response rates increased during the CS associated with food as they decreased during the CS associated with no food. The effect was replicated in Experiment II, but it did not occur when both the food and its associated CS were eliminated. These results were comparable to those obtained with operant discrimination training procedures (behavioral contrast) and with Pavlovian discrimination training. The results suggest that additivity theories of behavioral contrast may be insufficient to account for these data.     

A translational evaluation of potential iatrogenic effects of single and combined contingencies during functional analysis

Recent research suggests that combining putative reinforcers for problem behavior into a single, synthesized contingency may increase efficiency in identifying behavioral function relative to traditional functional analysis (FA). Other research suggests potential shortcomings of synthesized contingency analysis (SCA), such as the potential for false-positive outcomes. In prior comparisons of traditional FAs and SCAs, investigators could not ascertain with certainty the true function(s) of the participants' problem behavior for use as the criterion variable. We conducted a translational study to circumvent this limitation by training a specific function for a surrogate destructive behavior prior to conducting a traditional FA and SCA. The traditional FA correctly identified the previously established function of the target response in all six cases and produced no iatrogenic effects. The SCA produced differentiated results in all cases and iatrogenic effects (i.e., an additional function) in three of six cases. We discuss these findings in terms of the mechanisms that may promote iatrogenic effects.