Verbal instructions targeting valence alter negative conditional stimulus evaluations (but do not affect reinstatement rates)

Negative conditional stimulus (CS) valence acquired during fear conditioning may enhance fear relapse and is difficult to remove as it extinguishes slowly and does not respond to the instruction that unconditional stimulus (US) presentations will cease. We examined whether instructions targeting CS valence would be more effective. In Experiment 1, an image of one person (CS+) was paired with an aversive US, while another (CS?) was presented alone. After acquisition, participants were given positive information about the CS+ poser and negative information about the CS? poser. Instructions reversed the pattern of differential CS valence present during acquisition and eliminated differential electrodermal responding. In Experiment 2, we compared positive and negative CS revaluation by providing positive/negative information about the CS+ and neutral information about CS?. After positive revaluation, differential valence was removed and differential electrodermal responding remained intact. After negative revaluation, differential valence was strengthened and differential electrodermal responding was eliminated. Unexpectedly, the instructions did not affect the reinstatement of differential electrodermal responding.     

Subjective,physiological, and behavioural responses towards evaluatively conditioned stimuli

Evaluative Conditioning (EC) is commonly defined as the change in liking of a stimulus (conditioned stimulus, CS) due to its pairings with an affective unconditioned stimulus (US). In Experiment 1, we investigated effects of repeated stimulus pairings on affective responses, i.e. valence and arousal ratings, pupil size, and duration estimation. After repeatedly pairing the CSs with affective USs, a consistent pattern of affective responses emerged: The CS_negative was rated as being more negative and more arousing, resulted in larger pupils, and was temporally overestimated compared to the CS_neutral. In Experiment 2, the influence of a mere instruction about the contingency between a CS and US on affective responses was examined. After mere instruction about upcoming pairings between the CS and US, subjective ratings also changed, but there was neither evidence for differential pupillary responses nor for differential temporal processing. The results indicate that EC via pairings or instructions can change the affective responses towards formerly neutral stimuli and introduce pupil size as a physiological measure in EC research. However, Experiment 2 suggests that there might be moderating factors based on the type of EC procedure involved.     

Autonomic conditioning to monetary and social stimuli and aggression in children

Poor conditioning to punishment, such as loud tones or electric shock, has been proposed as an important factor involved in the etiology of aggressive and psychopathic behavior. However, it is not known whether the association holds when monetary or social stimulus is used as the unconditioned stimulus, and if aggressive individuals also have impaired conditioning to rewards. In this study, skin conductance responses in a conditioning task involving both monetary/social reward and punishment as unconditioned stimuli were assessed in 340 male and female 8‐ to 9‐year‐old children from the community. Children reported their reactive and proactive aggression using the Reactive and Proactive Aggression Questionnaire (RPQ; Raine et al., 2006). Results showed that monetary/social reward and punishment were effective in eliciting physiological classical conditioning in children, and that reduced reward conditioning was associated with high levels of proactive aggression in particular. Findings highlight the importance of distinguishing between reactive and proactive aggression when examining antisocial behavior in children, and suggest that reward‐oriented treatment programs may not be effective for children with more proactive, instrumental aggressive behavior.

     

An Analysis of Feedback from a Behavior Analytic Perspective

The present paper presents a systematic analysis from a behavior analytic perspective of procedures termed feedback. Although feedback procedures are widely reported in the discipline of psychology, including in the field of behavior analysis, feedback is neither consistently defined nor analyzed. Feedback is frequently treated as a principle of behavior; however, its effects are rarely analyzed in terms of well-established principles of learning and behavior analysis. On the assumption that effectiveness of feedback procedures would be enhanced when their use is informed by these principles, we sought to provide a conceptually systematic account of feedback effects in terms of operant conditioning principles. In the first comprehensive review of this type, we compare feedback procedures with those of well-defined operant procedures. We also compare the functional relations that have been observed between parameters of consequence delivery and behavior under both feedback and operant procedures. The similarities observed in the preceding analyses suggest that processes revealed in operant conditioning procedures are sufficient to explain the phenomena observed in studies on feedback.     

Not so Sweet Revenge: Unanticipated Consequences of High-Intensity Sweeteners

While no single factor accounts for the significant increases in overweight and obesity that have emerged during the past several decades, evidence now suggests that sugars, in general, and sugar-sweetened beverages, in particular, may be especially problematic. One response to this concern has been an explosion in the availability and use of noncaloric sweeteners as replacements for sugar. While consumers have been led to believe that such substitutes are healthy, long-term epidemiological data in a number of cohorts have documented increased risk for negative outcomes like type 2 diabetes, heart disease, and stroke among users of artificial sweeteners. Experimental data from animals has provided several plausible mechanisms that could explain this counterintuitive relationship. In particular, my research has demonstrated that artificial sweeteners appear to interfere with basic learned, predictive relations between sweet tastes and post-ingestive consequences such as the delivery of energy. By interfering with these relations, artificial sweeteners inhibit anticipatory responses that normally serve to maintain physiological homeostasis, and over the long term, this interference could result in negative health effects like those seen in the human cohort studies. These data suggest that reducing the consumption of all sweeteners is advisable to promote better health.     

Imitation: definitions, evidence, and mechanisms

Imitation can be defined as the copying of behavior. To a biologist, interest in imitation is focused on its adaptive value for the survival of the organism, but to a psychologist, the mechanisms responsible for imitation are the most interesting. For psychologists, the most important cases of imitation are those that involve demonstrated behavior that the imitator cannot see when it performs the behavior (e.g., scratching one's head). Such examples of imitation are sometimes referred to as opaque imitation because they are difficult to account for without positing cognitive mechanisms, such as perspective taking, that most animals have not been acknowledged to have. The present review first identifies various forms of social influence and social learning that do not qualify as opaque imitation, including species-typical mechanisms (e.g., mimicry and contagion), motivational mechanisms (e.g., social facilitation, incentive motivation, transfer of fear), attentional mechanisms (e.g., local enhancement, stimulus enhancement), imprinting, following, observational conditioning, and learning how the environment works (affordance learning). It then presents evidence for different forms of opaque imitation in animals, and identifies characteristics of human imitation that have been proposed to distinguish it from animal imitation. Finally, it examines the role played in opaque imitation by demonstrator reinforcement and observer motivation. Although accounts of imitation have been proposed that vary in their level of analysis from neural to cognitive, at present no theory of imitation appears to be adequate to account for the varied results that have been found.     

I don't like it because it eats sprouts: conditioning preferences in children

Although little is known about how preferences develop in childhood, work in adults suggests that evaluative responses to stimuli can be acquired through classical conditioning. In two experiments children were exposed to novel cartoon characters, that were either consistently paired with a picture of a disliked food (Brussels sprouts) or a liked food (ice cream). Relative preferences for these stimuli (and others) were measured before and after these paired presentations (Experiment 1): preferences for the cartoon character paired with Brussels sprouts decreased, whereas preferences for the character paired with ice cream increased. These preferences persisted after 10 un-reinforced trials. Experiment 2 replicated this finding using affective priming as an index of preference for the cartoon characters. These findings demonstrate that preferences to novel stimuli can be conditioned in children and result from associations formed between the stimulus and a stimulus possessing positive or negative valence.     

Fear generalization in humans: Impact of verbal instructions

Fear generalization lies at the heart of many anxiety problems, but little is known about the factors that can influence this phenomenon. The present study investigated whether verbal instructions about specific stimulus features can influence conditioned fear generalization. All participants were fear conditioned to a yellow triangle, using an electric shock. Participants had received pre-experimental instructions saying that the shapes (or colours) of the stimuli were informative for the occurrence of shock (group Shape and group Colour, respectively). Next, generalization was tested to presentations of a blue triangle (same shape) as well as a yellow square (same colour). Fear reactions were measured through skin conductance and online ratings of shock-expectancy. The results showed strongest generalization to the same shape stimulus in group Shape, versus the same colour stimulus in group Colour. Hence, the same learning experience can have opposite effects in terms of fear generalization, depending on verbally transmitted information about the relative importance of individual stimulus features.