A dilemma for subjective bayesians — And how to resolve it

Short though it is this paper has already undergone several revisions. My thanks to Graham Oddie for occasioning some of them.     

The role of sensorimotor impairments in dyslexia: a multiple case study of dyslexic children

This study attempts to investigate the role of sensorimotor impairments in the reading disability that characterizes dyslexia. Twenty-three children with dyslexia were compared to 22 control children, matched for age and non-verbal intelligence, on tasks assessing literacy as well as phonological, visual, auditory and motor abilities. The dyslexic group as a whole were significantly impaired on phonological, but not sensorimotor, tasks. Analysis of individual data suggests that the most common impairments were on phonological and visual stress tasks and the vast majority of dyslexics had one of these two impairments. Furthermore, phonological skill was able to account for variation in literacy skill, to the exclusion of all sensorimotor factors, while neither auditory nor motor skill predicted any variance in phonological skill. Visual stress seems to account for a small proportion of dyslexics, independently of the commonly reported phonological deficit. However, there is little evidence for a causal role of auditory, motor or other visual impairments.     

Verification, falsification, and the logic of enquiry

Our starting point is Michael Luntley's falsificationist semantics for the logical connectives and quantifiers: the details of his account are criticised but we provide an alternative falsificationist semantics that yields intuitionist logic, as Luntley surmises such a semantics ought. Next an account of the logical connectives and quantifiers that combines verificationist and falsificationist perspectives is proposed and evaluated. While the logic is again intuitionist there is, somewhat surprisingly, an unavoidable asymmetry between the verification and falsification conditions for negation, the conditional, and the universal quantifier. Lastly we are lead to a novel characterization of realism.     

Group play therapy and tangible reinforcers used to modify the behavior of 8-yr-old boys

Eleven third-grade boys were randomly assigned to three play therapy groups. The boys had been referred by their teachers because of shy, withdrawn behavior. The Token Group met in a play group (4 Ss), had a therapist, and received tangible reinforcements for social approach behavior. The Verbal Group (4 Ss) was treated similarly to the Token Group except that no tangible reinforcements were used. The Control Group (3 Ss) met in a play group without a therapist present. Fourteen play sessions were held for each group. The Token Group changed more than the Verbal Group; the Verbal Group changed more than the Control Group; the Control Group showed no change on the objective measures used. The Token Group exhibited an increase in social approach behavior and a decrease in discrete, problem behavior. The Verbal Group increased slightly in social approach behavior. All groups failed to demonstrate changes in “productivity”, “anxiety” and “general psychological adjustment”.     

The foundations of probability and quantum mechanics

Taking as starting point two familiar interpretations of probability, we develop these in a perhaps unfamiliar way to arrive ultimately at an improbable claim concerning the proper axiomatization of probability theory: the domain of definition of a point-valued probability distribution is an orthomodular partially ordered set. Similar claims have been made in the light of quantum mechanics but here the motivation is intrinsically probabilistic. This being so the main task is to investigate what light, if any, this sheds on quantum mechanics. In particular it is important to know under what conditions these point-valued distributions can be thought of as derived from distribution-pairs of upper and lower probabilities on boolean algebras. Generalising known results this investigation unsurprisingly proves unrewarding. In the light of this failure the next topic investigated is how these generalized probability distributions are to be interpreted.     

Reaching for the unknown: Multiple target encoding and real-time decision-making in a rapid reach task

Decision-making is central to human cognition. Fundamental to every decision is the ability to internally represent the available choices and their relative costs and benefits. The most basic and frequent decisions we make occur as our motor system chooses and executes only those actions that achieve our current goals. Although these interactions with the environment may appear effortless, this belies what must be incredibly sophisticated visuomotor decision-making processes. In order to measure how visuomotor decisions unfold in real-time, we used a unique reaching paradigm that forced participants to initiate rapid hand movements toward multiple potential targets, with only one being cued after reach onset. We show across three experiments that, in cases of target uncertainty, trajectories are spatially sensitive to the probabilistic distribution of targets within the display. Specifically, when presented with two or three target displays, subjects initiate their reaches toward an intermediary or ‘averaged’ location before correcting their trajectory in-flight to the cued target location. A control experiment suggests that our effect depends on the targets acting as potential reach locations and not as distractors. This study is the first to show that the ‘averaging’ of target-directed reaching movements depends not only on the spatial position of the targets in the display but also the probability of acting at each target location.     

Source Handler telephone interactions with covert human intelligence sources: An exploration of question types and intelligence yield

Law Enforcement Agencies gather intelligence in order to prevent criminal activity and pursue criminals. In the context of human intelligence collection, intelligence elicitation relies heavily upon the deployment of appropriate evidence-based interviewing techniques (a topic rarely covered in the extant research literature). The present research gained unprecedented access to audio recorded telephone interactions (N = 105) between Source Handlers and Covert Human Intelligence Sources (CHIS) from England and Wales. The research explored the mean use of various question types per interaction and across all questions asked in the sample, as well as comparing the intelligence yield for appropriate and inappropriate questions. Source Handlers were found to utilise vastly more appropriate questions than inappropriate questions, though they rarely used open-ended questions. Across the total interactions, appropriate questions (by far) were associated with the gathering of much of the total intelligence yield. Implications for practise are discussed.