Decision theory,reinforcement learning,and the brain

Decision making is a core competence for animals and humans acting and surviving in environments they only partially comprehend, gaining rewards and punishments for their troubles. Decision-theoretic concepts permeate experiments and computational models in ethology, psychology, and neuroscience. Here, we review a well-known, coherent Bayesian approach to decision making, showing how it unifies issues in Markovian decision problems, signal detection psychophysics, sequential sampling, and optimal exploration and discuss paradigmatic psychological and neural examples of each problem. We discuss computational issues concerning what subjects know about their task and how ambitious they are in seeking optimal solutions; we address algorithmic topics concerning model-based and model-free methods for making choices; and we highlight key aspects of the neural implementation of decision making.     

Psychological mindedness and therapist attributes

Background to study: Psychological Mindedness (PM) involves an interest in and ability to extract and make sense of psychological information (thoughts, feelings and behaviours) from a situation. The nature of the psychotherapeutic role and training demands therapists think about motives, distortions and inner experiences of others. Aims: This study empirically examined the association between PM and adaptive therapist attributes, clinician empathy, self understanding and the therapeutic relationship in practitioners. Method: Forty eight therapists responded to a postal questionnaire. Results: Statistically significant correlations were found between adaptive therapist attributes; empathy, the therapeutic relationship and level of self-understanding and PM.     

Bayesian theories of conditioning in a changing world

The recent flowering of Bayesian approaches invites the re-examination of classic issues in behavior, even in areas as venerable as Pavlovian conditioning. A statistical account can offer a new, principled interpretation of behavior, and previous experiments and theories can inform many unexplored aspects of the Bayesian enterprise. Here we consider one such issue: the finding that surprising events provoke animals to learn faster. We suggest that, in a statistical account of conditioning, surprise signals change and therefore uncertainty and the need for new learning. We discuss inference in a world that changes and show how experimental results involving surprise can be interpreted from this perspective, and also how, thus understood, these phenomena help constrain statistical theories of animal and human learning.     

Increased locus coeruleus tonic activity causes disengagement from a patch-foraging task

High levels of locus coeruleus (LC) tonic activity are associated with distraction and poor performance within a task. Adaptive gain theory (AGT; Aston-Jones & Cohen, 2005) suggests that this may reflect an adaptive function of the LC, encouraging search for more remunerative opportunities in times of low utility. Here, we examine whether stimulating LC tonic activity using designer receptors (DREADDs) promotes searching for better opportunities in a patch-foraging task as the value of a patch diminishes. The task required rats to decide repeatedly whether to exploit an immediate but depleting reward within a patch or to incur the cost of a time delay to travel to a new, fuller patch. Similar to behavior associated with high LC tonic activity in other tasks, we found that stimulating LC tonic activity impaired task performance, resulting in reduced task participation and increased response times and omission rates. However, this was accompanied by a more specific, predicted effect: a significant tendency to leave patches earlier, which was best explained by an increase in decision noise rather than a systematic bias to leave earlier (i.e., at higher values). This effect is consistent with the hypothesis that high LC tonic activity favors disengagement from current behavior, and the pursuit of alternatives, by augmenting processing noise. These results provide direct causal evidence for the relationship between LC tonic activity and flexible task switching proposed by AGT.     

Free Acts and Robot Cats

Philosophical Studies -     

Elasticity theory of topological defects in carbon nanotubes and graphene

We develop elasticity theory to predict the energies of topological defects in carbon nanostructures. The theory is a simple, quantitatively accurate and transferable continuum approach to predicting defect formation energies that obviates the need for computationally expensive quantum mechanical methods. Thus the theory has the potential to serve as the basis for thermodynamic and multi-scale modelling of the structural properties of carbon nanostructures.     

Qualified therapists’ experience of personal therapy

Recent work shows that the majority of therapists strongly value personal therapy for what it can bring to their professional practice, and for personal development. The aim of this study was to explore qualified therapists’ experiences of personal therapy. Of the 220 qualified therapists who were contacted via post and asked to take part in a questionnaire study, 48 returned the completed questionnaire, which consisted of a series of closed and open questions. Two‐thirds of respondents had engaged in personal therapy. The two most frequently cited reasons for engaging in personal therapy were personal growth and personal distress. Interpretative phenomenological analysis (IPA) identified two broad domains: impact on the person and impact on the professional. Results show that those surveyed recognised the value of personal therapy to themselves as a form of self‐care and personal development. Personal therapy was valued in professional practice as a form of experiential learning from being in the client role. The limitations of this research included a relatively low response rate, raising the question of whether those most likely to have had positive experiences of personal therapy were more likely to participate. Future research might deliberately seek to understand negative experiences of personal therapy. Other avenues for future research include the need to understand how experiences of therapy relate to gender, profession, and therapeutic orientation.