Infinite Prospects*

People with the kind of preferences that give rise to the St. Petersburg paradox are problematic—but not because there is anything wrong with infinite utilities. Rather, such people cannot assign the St. Petersburg gamble any value that any kind of outcome could possibly have. Their preferences also violate an infinitary generalization of Savage's Sure Thing Principle, which we call the Countable Sure Thing Principle, as well as an infinitary generalization of von Neumann and Morgenstern's Independence axiom, which we call Countable Independence. In violating these principles, they display foibles like those of people who deviate from standard expected utility theory in more mundane cases: they choose dominated strategies, pay to avoid information, and reject expert advice. We precisely characterize the preference relations that satisfy Countable Independence in several equivalent ways: a structural constraint on preferences, a representation theorem, and the principle we began with, that every prospect has a value that some outcome could have.     

Luminance affects age-related deficits in object detection: implications for computerized psychological assessments

As psychological instruments are converted for administration on computers, differences in luminance and contrast of these displays may affect performance. Specifically, high-luminance assessments may mask age-group differences that are apparent under lower luminance conditions. We examined the effects of luminance and contrast on object detection using computerized and naturalistic assessments. Younger and older adults displayed more differences in performance across differing contrast levels in conditions that were matched for luminance, despite the conditions appearing perceptually different. These findings indicate that computerized assessments should be created with luminance levels that are similar to those of the tasks they purport to simulate in order to enhance their validity.     

Relationship between reaction time variability and motor skill development in ADHD

Slower and more variable reaction times to computerized tasks have been documented in children diagnosed with attention deficit/hyperactivity disorder (ADHD). Recent research supports a role for attentional lapses in generating abnormally variable and slow responses. However, given the association between ADHD and impairments in motor control, we hypothesized that slower or more variable reaction times might also correlate with motor development. The aim of this case-control study was to explore the relationship between motor function, reaction speed and variability, and ADHD. After comprehensive educational and clinical assessments, motor skill development was evaluated in 35 children ages 9 to 14 (19 with ADHD) using the Physical and Neurological Examination for Subtle Signs (PANESS) test battery. Finger-sequencing speed and variability were quantified with goniometers. Reaction times were measured with 20 trials each of computerized simple and choice (binary) tasks. Compared to healthy controls, children with ADHD had slower and more variable reaction times, and these findings correlated with impaired motor development (PANESS) and slow and variable finger sequencing (goniometers). Further studies of motor development in ADHD may identify factors influencing speed and variability of reaction times.     

The value of grandparents

This paper is a slightly revised version of a paper presented on 26 October 1989 as one of the Tavistock Open Lectures. The role of grandparents is discussed and the value of a supportive presence, both externally and internally, is emphasised, especially at birth and at times of mental illness. This concept is extended to the maternal or ‘grand’-maternal role adopted by agencies attempting to improve the quality of mental care, and its value is also visible in the transference in psychotherapeutic work.     

Toward a psychoeducational curriculum for training sport-injury rehabilitation personnel

Abstract

This paper addresses significant gaps in the wining programs of sport-injury rehabilitation personnel (SIRPs) in the psychology ma. The main aim of the article is to offer for consideration a psychoeducational curriculum that is specifically designed for the training of professionals who work with injured athletes. In addition to describing the applied implications of research on the psychological aspects of sport injuries for professional practitioners. reviews of what SIRPs consider is missing-but-desirable in their professional wining. and the effectiveness of certain psychological strategies, are presented. Finally. an overview of a prototypical three-year curriculum for professional training programs is outlined.     

Community Counselling in African Contexts

This article explores community counselling as a form of professional practice for psychologists, with a particular focus on practices that are relevant in African contexts. The discussion identifies and discusses various models of practice identified in community psychology, including an ecological perspective, a public health and community mental health framework, interventions that focus on promoting a sense of community, indigenous approaches to community counselling and a critical or social action framework. Examples relating to each of these models of practice are drawn from various African settings, providing practitioners with some insights into how theory can be operationalised into practices that are relevant to African contexts. The article concludes with a discussion on community research, with a particular focus on ethical considerations relevant to a community approach in African contexts. The latter discussion emphasises the importance of working with the community as partners, and suggests the possibility of developing a Code of Ethics aimed specifically at guiding community counselling practice in African contexts.     

“Mindless” Decision Making as a Failure of Contextual Reasoning

People often make decisions without reference to vital information, even when such information is readily available. In the present research, the authors addressed the possibility that this tendency may derive from failure to have pertinent information immediately available in the decision context. Participants rated the utility of decisions in either the presence or absence of simple pertinent information. The information provided required no training and was relatively obvious (e.g., if money is spent on a given item, that money will not be available for other expenditures). Presentation of such information in the immediate context of decisions significantly improved participants' abilities to understand their negative consequences. These results indicate that the presentation of pertinent information in immediate decision contexts, even information that is already available through participants' long-term memory, can improve the understanding of decision situations and reduce “mindlessness” in decision processes.     

A Note on the Natural Basis of Action Categories

What is the basis for the categorical distinctions evident in action? For some visually-guided activities it can be shown that categories of action are specified by criterial values of optical properties. In the more general case, the criterial optical properties should be scaled relative to dimensions of the acting animal. The analysis of the prey-catching behavior of praying mantids is used to exemplify the strategy for determining naturally defined boundaries on actions.