Value-based decision-making battery: A Bayesian adaptive approach to assess impulsive and risky behavior

Using simple mathematical models of choice behavior, we present a Bayesian adaptive algorithm to assess measures of impulsive and risky decision making. Practically, these measures are characterized by discounting rates and are used to classify individuals or population groups, to distinguish unhealthy behavior, and to predict developmental courses. However, a constant demand for improved tools to assess these constructs remains unanswered. The algorithm is based on trial-by-trial observations. At each step, a choice is made between immediate (certain) and delayed (risky) options. Then the current parameter estimates are updated by the likelihood of observing the choice, and the next offers are provided from the indifference point, so that they will acquire the most informative data based on the current parameter estimates. The procedure continues for a certain number of trials in order to reach a stable estimation. The algorithm is discussed in detail for the delay discounting case, and results from decision making under risk for gains, losses, and mixed prospects are also provided. Simulated experiments using prescribed parameter values were performed to justify the algorithm in terms of the reproducibility of its parameters for individual assessments, and to test the reliability of the estimation procedure in a group-level analysis. The algorithm was implemented as an experimental battery to measure temporal and probability discounting rates together with loss aversion, and was tested on a healthy participant sample.     

The right to refuse treatment in Oregon: A two-year statewide experience

The right to refuse treatment seems well established for psychiatric patients. Individual states, however, have very different procedures for managing this right and for overriding the refusal. Oregon's administrative procedure for override depends on an evaluation by an independent examining psychiatrist. This article empirically examines the 432 refusals leading to override requests in three Oregon psychiatric institutions in 1983 and 1984. Treatment refusal was found to be a common occurrence in all age groups. Those who refused treatment were seriously ill, unemployed, single individuals with previous psychiatric hospitalizations. Most refused treatment because of denial of their illness or delusional thinking about medication. Most refusals were overridden following the independent psychiatrist's examination. Because of the significant cost of the override procedure to the patient and the mental health system, the authors propose a new procedure which combines parts of the current procedure with a requirement that, at the time of the civil commitment hearing, the judge makes a separate decision as to the patient's competency to make treatment decisions.     

Audiovisual presentation demonstrates that selective adaptation in speech perception is purely auditory

MRC Institute of Hearing Research, University of Nottingham, Nottingham NG72RD, England Both auditory and phonetic processes have been implicated by previous results from selective adaptation experiments using speech stimuli. It has proved difficult to dissociate their individual contributions because the auditory and phonetic structure of conventional acoustical stimuli are mutually predictive. In the present experiment, the necessary dissociation was achieved by using an audiovisual adaptor consisting of an acoustical [b?] synchronized to a video recording of a talker uttering the syllable [g?]. This stimulus was generally identified as one of the dentals [d?] or [??]. It produced an adaptation effect, measured with an acoustical [b?-d?] test continuum, identical in size and direction to that produced by an acoustical [b?]—an adaptor sharing its acoustical structure—and opposite in direction to that produced by an acoustical [d?]—an adaptor sharing its perceived phonetic identity. Thus, the result strongly suggests that auditory rather than phonetic levels of processing are influenced in selective adaptation.     

A Bayesian formulation of behavioral control

Helplessness, a belief that the world is not subject to behavioral control, has long been central to our understanding of depression, and has influenced cognitive theories, animal models and behavioral treatments. However, despite its importance, there is no fully accepted definition of helplessness or behavioral control in psychology or psychiatry, and the formal treatments in engineering appear to capture only limited aspects of the intuitive concepts. Here, we formalize controllability in terms of characteristics of prior distributions over affectively charged environments. We explore the relevance of this notion of control to reinforcement learning methods of optimising behavior in such environments and consider how apparently maladaptive beliefs can result from normative inference processes. These results are discussed with reference to depression and animal models thereof.     

Political Philosophy: The View from Cambridge

This article reports on a conversation convened by Quentin Skinner at the invitation of the Editors of The Journal of Political Philosophy and held in Cambridge on 13 February 2001.     

The value of RCT evidence depends on the quality of statistical analysis

The authors examined statistical practices in 193 randomized controlled trials (RCTs) of psychological therapies published in prominent psychology and psychiatry journals during 1999-2003. Statistical significance tests were used in 99% of RCTs, 84% discussed clinical significance, but only 46% considered-even minimally-statistical power, 31% interpreted effect size and only 2% interpreted confidence intervals. In a second study, 42 respondents to an email survey of the authors of RCTs analyzed in the first study indicated they consider it very important to know the magnitude and clinical importance of the effect, in addition to whether a treatment effect exists. The present authors conclude that published RCTs focus on statistical significance tests ("Is there an effect or difference?"), and neglect other important questions: "How large is the effect?" and "Is the effect clinically important?" They advocate improved statistical reporting of RCTs especially by reporting and interpreting clinical significance, effect sizes and confidence intervals.     

Sex Role Ideology, Relationship Context, and Response to Sexual Coercion in College Females

This study examined the impacts of traditional sex role orientation and relationship context upon women’s responses to sexual coercion in a sample of 114 female undergraduates in the northwestern USA. We examined differences in the amount of time participants allowed a simulated sexually coercive situation to continue, comparing groups based upon the extent to which participants endorsed traditional feminine sex roles on the Sex Role Ideology Scale, as well as the context of the relationship in which such behaviors occurred, which was manipulated as an independent variable. Results indicated that individuals in the long-term relationship condition took significantly longer to terminate the vignette than did their peers. However, no significant effect of traditionality upon response latency was observed.