Introduction

Abstract

Most young adults are employed or enrolled in educational institutions to prepare for employment, whereas only a small percentage of older persons is working for pay. Not only are there distinct settings of daily activities in which there are age differences in the frequency of participants, but also in most significant aspects of life, we find major age-associated behavioral differentiation. Among the most striking overt behavioral differences between young and old persons, readily evident by gross observation, are decreases in vigor, speed of movement, motor coordination, and physical strength. All of these constructs denote an energetic component and they all exhibit a progressive decline with age. Similar types of changes are also apparent during aging in members of most lower species. These organismic decrements will lead to quantitative as well as qualitative changes in various gross behaviors. Younger persons are more likely to be found on tennis courts, ski slopes, and in many other leisure areas requiring sustained physical exertion, while older persons are more likely to sit on park benches and enjoy the tranquillity, or they tend to congregate in shopping malls.