Individual behavior under risk and under uncertainty: An experimental study

These experiments are concerned with individual behavior under risk and under uncertainty. By exploiting the isolation effect the experiments were able to offer to 134 subjects the possibility of actually gaining or losing an important sum of money.The experimental data show that under risk as well as under complete ignorance the subjects' attitudes towards prospects of gains and towards prospects of losses are totally unrelated.The data also show that when facing prospects of gains, the subjects generally take the exact probabilities of the events into account, whereas, when facing prospects of losses many of then have only recourse to coarser categories of plausibility, or even no longer use their information at all.     

Approximations of rational criteria under complete ignorance and the independence axiom

Rational decision making under complete ignorance, a limit case of uncertainty, is defined. Through a concept of approximation, a meaning is given to a criterion almost possessing a property. Rational criteria depend almost on the sole bounds of the outcome range of each decision, they are almost continuous, they can almost possess a transitive indifference relation; however, under Savage's Independence Axiom, this last property restricts possible criteria to those which can be approximated, at least partly, by either the Maximin or the Maximax criterion.     

Contents Volume 54

Volume Contents

Contents Volume 54     

Biomechanical analysis of older adults stepping up: a method of evaluating balance

The aim of this study was to analyze differences in biomechanical parameters between elderly and control participants when stepping up, to evaluate control of balance. Eleven control and 14 elderly participants performed a step from an initial static posture onto a 7-cm-high force plate. For the spontaneous-velocity condition, elderly participants performed a slower progression velocity than control participants. Elderly participants spent proportionally more time in stance phase, with a corresponding decrease in swing phase, than the control participants, irrespective of movement velocity. In contrast, at spontaneous velocity the parameters related to ground-reaction force (GRF) showed that anteroposterior and mediolateral forces at toe-off of the support limb and the slope of vertical force during weight transfer were significantly smaller for the elderly than for control participants. These GRF parameters depended on the stepping-up velocity. The elderly develop a spatiotemporal strategy and reduced movement velocity to control support balance.     

Intergenerational reliance on social assistance: Evidence from Canada

This paper provides the first analysis of the intergenerational transmission of participation in a Canadian social assistance program. Two sources of intergenerational transmission are taken into account: one that is due to a possible causal link between parents' and children's participation, and one that is due to a correlation between individual and environment specific characteristics across generations. The basic data come from the Québec government's administrative records and cover 17,203 young people who were 18 years old in 1990 and whose parents were recipients of social assistance during at least one month between 1979 and 1990. The results reveal that, on average, a one-percentage unit increase in parental participation during the youth's pre-adult years (age 7–17) raises the youth's participation rate by 0.29 percentage unit during early adulthood (age 18–21). This impact is stronger during the early stages of childhood (age 7–9) and during late adolescence (age 16–17).