Affect and emotions in placebo and nocebo effects: What do we know so far?

Once considered nuisance variance in clinical trials, placebo effects and nocebo effects are now widely recognized as important and mutable psychobiological contributors to mental and physical health. Psychological theory explaining these effects emphasizes associative learning and conscious expectations. It has long been suggested, however, that affective states such as moods, emotions, and distress could play a significant role. In this paper, we draw together and review the empirical data linking affective states to placebo and nocebo effects. To organize this disparate literature, three questions are addressed: (1) Does pre‐existing state and trait affect modulate placebo and nocebo effects? (2) Does administering placebo and nocebo treatments change affective states, and if so, does the resulting affect causally influence placebo and nocebo effects? Finally, (3) Can placebo treatments be successfully employed as a regulation strategy to modulate different affective states? In reviewing the evidence in relation to these three questions, it is clear that affect does play a key role in placebo and nocebo effects in many circumstances, and further, there may be a reciprocal dynamic at play between a treatment event, affect, and placebo/nocebo effects. The paper concludes by discussing implications for theory and intervention and recommends future research priorities.     

A Theoretical Framework for Analysing the Notion of Relative Importance of Criteria

Multiple-criteria decision aid almost always requires the use of weights, importance coefficients or even a hierarchy of criteria, veto thresholds, etc. These are importance parameters that are used to differentiate the role devoted to each criterion in the construction of comprehensive preferences. Many researchers have studied the problem of how to assign values to such parameters, but few of them have tried to analyse in detail what underlies the notion of importance of criteria and to give a clear formal definition of it. In this paper our purpose is to define a theoretical framework so as to analyse the notion of the importance of criteria under very general conditions. Within this framework it clearly appears that the importance of criteria is taken into account in very different ways in various aggregation procedures. This framework also allows us to shed new light on fundamental questions such as: Under what conditions is it possible to state that one criterion is more important than another? Are importance parameters of the various aggregation procedures dependent on or independent of the encoding of criteria? What are the links between the two concepts of the importance of criteria and the compensatoriness of preferences? This theoretical framework seems to us sufficiently general to ground further research in order to define theoretically valid elicitation methods for importance parameters.     

Evaluation of a finger prompt variation in the treatment of pediatric feeding disorders

Children with feeding disorders often engage in refusal behavior to escape or avoid eating. Escape extinction combined with reinforcement is a well-established intervention to treat food refusal. Physical guidance procedures (e.g., jaw prompt, finger prompt) have been shown to increase food acceptance and decrease inappropriate mealtime behavior when more commonly employed escape extinction (e.g., nonremoval of the spoon) procedures are ineffective. The finger prompt, however, has not been extensively evaluated as a treatment adjunct to target food refusal, thus necessitating further examination. The purpose of this prospective study was to assess a variation of a finger prompt procedure to treat food refusal and to assess caregivers' acceptability of the procedure. Three children age 1 to 4 years admitted to an intensive feeding disorders program and their caregivers participated. The finger prompt was effective in increasing bite acceptance across all participants and decreasing or maintaining low levels of inappropriate behavior for 2 participants. The procedure was also acceptable to all caregivers.     

An analysis of the value of token reinforcement using a multiple-schedule assessment

Token systems are widely used in clinical settings, necessitating the development of methods to evaluate the reinforcing value of these systems. In the current paper, we replicated the use of a multiple-schedule reinforcer assessment (MSA; Smaby, MacDonald, Ahearn, & Dube, 2007) to evaluate the components of a token economy system for 4 learners with autism. Token systems had reinforcing value similar to primary reinforcers for 2 of the 4 learners, but resulted in lower rates of responding than primary reinforcers for the other 2 learners. Differentiated responding across learners may warrant variation in clinical recommendations on the use of tokens. The results of this study support formal assessment of token system effectiveness, and the MSA procedure provides an efficient method by which to conduct such assessments.     

Re-exposure to reinforcement in Context A during treatment in Context B reduces ABC renewal

Previous work from our laboratory showed that intermittently re-exposing rats to reinforcement for lever pressing in a training (A) context, while eliminating lever pressing in a second (B) context, increased ABA renewal of lever pressing relative to rats that experienced only Context B during response elimination. In the current study, we replicated these procedures while assessing renewal in the presence of a novel context (i.e., ABC renewal). Unlike the findings described above, renewal was reduced in the group that experienced re-exposure to Context A during lever-press elimination relative to rats that experienced only Context B. These findings suggest that alternating between contexts associated with reinforcement and extinction during treatment reduces the probability that organisms will respond in novel contexts. These outcomes may be the result of discrimination and/or generalization processes. Moreover, this training procedure may offer a potential mitigation strategy for ABC renewal.     

How do horses (Equus caballus) learn from observing human action?

Animal Cognition - A previous study demonstrated that horses can learn socially from observing humans, but could not draw any conclusions about the social learning mechanisms. Here we develop this...