Foundations of Probability

The foundations of probability are viewed through the lens of the subjectivist interpretation. This article surveys conditional probability, arguments for probabilism, probability dynamics, and the evidential and subjective interpretations of probability.     

Working with the complexities of adolescent mental health problems: applying time-limited adolescent psychodynamic psychotherapy (TAPP)

This article discusses the application in a CAMHS setting of a distinctive intervention for adolescent mental health difficulties, time-limited adolescent psychodynamic psychotherapy (TAPP). TAPP has been developed specifically for working with adolescents and the characteristic developmental and psychosocial complexities they present to mental health services. It is widely recognised that supporting the developmental process in adolescence is central to therapeutic interventions and the therapeutic aim of TAPP is to enable recovery of the capacity to meet developmental challenges. The key factors of TAPP are described, including the formulation and working with a developmental focus, the therapeutic stance, working with transference and counter-transference, working with time limits, and the emphasis is placed on engagement of adolescents in therapy in TAPP. The experiences of introducing and developing TAPP in the CAMHS service are discussed with two brief and one extended case examples and this leads to a discussion of the kinds of outcomes achieved. It is concluded that TAPP is a key and relevant intervention for adolescents in complex and vulnerable situations; further work will be undertaken to continue its application in these settings and to formally assess outcomes.     

Exercise dependence and the drive for muscularity in male bodybuilders,power lifters,and fitness lifters

Researchers have hypothesized differences in exercise dependence and drive for muscularity between bodybuilders and power lifters, while others have not found the predicted differences. This study assessed 146 weight lifters (bodybuilders, n = 59; power lifters, n = 47; fitness lifters, n = 40) on the Exercise Dependence Scale, Bodybuilding Dependence Scale, and the Drive for Muscularity Scale. Results showed that bodybuilders and power lifters were significantly higher than fitness lifters on EDS Total, 7 EDS scales, and the 3 BDS scales. In contrast, power lifters were found to be significantly higher on DMS Total and DMS Behavior scales than bodybuilders. The regression results suggest that exercise dependence may be directly related to the drive for muscularity.     

Mental models and omissive causation

Some causal relations refer to causation by commission (e.g., “A gunshot causes death”), and others refer to causation by omission (e.g., “Not breathing causes death”). We describe a theory of the representation of omissive causation based on the assumption that people mentally simulate sets of possibilities—mental models—that represent causes, enabling conditions, and preventions (Goldvarg & Johnson-Laird, 2001). The theory holds that omissive causes, enabling conditions, and preventions each refer to distinct sets of possibilities. For any such causal relation, reasoners typically simulate one initial possibility, but they are able to consider alternative possibilities through deliberation. These alternative possibilities allow them to deliberate over finer-grained distinctions when reasoning about causes and effects. Hence, reasoners should be able to distinguish between omissive causes and omissive enabling conditions. Four experiments corroborated the predictions of the theory. We describe them and contrast the results with the predictions of alternative accounts of causal representation and inference.     

Retracted: Unconscious arithmetic processing: A direct replication

Across two experiments involving four conditions, Sklar et al. (2012) found that complex subtraction equations can be solved without awareness of the equations. These findings challenge the current position that consciousness is necessary for performing abstract, rule‐following tasks. Given the important implications of their work, we directly replicate Sklar's findings using a larger sample (n = 94) from a different population. Using Continuous Flash Suppression, we investigated if people were able to solve an equation after subliminal (1300 ms) exposure to it. We found evidence for unconscious addition but not subtraction. The effect of unconscious addition was eliminated when participants reported subjective awareness of the primes. Critical review of our results and implications for further research are discussed.     

On the locus of the divided-attention effects

Reaction times in a choice reaction task were used to localize the livided-attention effect (less proficient performance under dual than under ingle-taks conditions) in a sequential-stage model of human information processing. Experiment 1 eliminated a central (memory-dependent) processing tage, while Experiment 2 suggested that a stimulus sampling process within the hitial encoding stage was the locus of the effect. Thus, the effect was localized in the input, not the central or an output stage of processing. A slower stimulus ampling rate was indicated under dual-than under single-task conditions.     

On the nature of central processing in choice reactions

A procedure for generating values of central processing uncertainty was developed from positive response data in a varied-set version of the Sternberg choice reaction task. This is a logical extension of a previously validated procedure for data from a fixed-set version of the same task. Both procedures provide information on the additive components of reaction time. It was concluded that S resolves more uncertainty in the varied-set than in the fixed-set situation. It was concluded also that S performs a rechecking operation prior to emitting a negative response, and this rechecking apparently involves less information than does the original testing for stimulus classification. This, in turn, suggests that rechecking is a self-terminating process with regard to display information. The results also imply that stimulus classification is partially serial and partially parallel, so a hybrid model may be appropriate for this task.