Methods for Assessing Quality of Life and Well-Being in Frail Older People

The appropriateness, reliability and convergence of differing methods and associated instruments for the assessment of quality of life and well-being in frail older people was examined in 60 ( S 65 years of age) nursing home residents. The feasibility of measuring quality of life and well-being via a variety of instruments was explored through observation (an adaptation of Dementia Care Mapping), structured interview (Schedule for the Evaluation of Individual Quality of Life - Direct Weighting), and proxy questionnaire (Pleasant Events Schedule - Alzheimer Disease; Apparent Emotion Rating Scale). The observational assessment and Pleasant Events Schedule demonstrated good reliability. Significant associations were found between well-being as assessed by observation, and active social interaction and engagement in recreation as assessed by observation, quality of life as assessed by structured interview, and enjoyment of activities as assessed by proxy questionnaire. These findings indicate the importance of social activity in later life, and the potential of different approaches for the appropriate assessment of key aspects of quality of life in frail older people.     

COMPARING PLEASURE AND PAIN: THE FUNDAMENTAL MATHEMATICAL EQUIVALENCE OF REWARD GAIN AND SHOCK REDUCTION UNDER VARIABLE INTERVAL SCHEDULES

The relationship between positive and negative reinforcement and the symmetry of Thorndike's law of effect are unresolved issues in operant psychology. Here we show that, for a given pattern of responding on variable interval (VI) schedules with the same programmed rate of food rewards (positive reinforcement VI) or electric shocks (negative reinforcement VI), there is a fundamental mathematical equivalence between reward gain and shock reduction. We also provide the first normative account of how animals should respond on a negative VI schedule, showing that it is better to space responses evenly than to respond with a variable interresponse time (IRT). Published data from rats, however, indicate that these animals respond irregularly, often with a burst of activity immediately following a shock. While this is irrational in the experimental setting, it may represent an appropriate response to the heterogeneity of stimuli commonly encountered in natural environments. We discuss the broader implications of our analysis for understanding how animals evaluate appetitive and aversive stimuli.     

The ecological rationality of state-dependent valuation

Laboratory studies on a range of animals have identified a bias that seems to violate basic principles of rational behavior: a preference is shown for feeding options that previously provided food when reserves were low, even though another option had been found to give the same reward with less delay. The bias presents a challenge to normative models of decision making (which only take account of expected rewards and the state of the animal at the decision time). To understand the behavior, we take a broad ecological perspective and consider how valuation mechanisms evolve when the best action depends upon the environment being faced. We show that in a changing and uncertain environment, state-dependent valuation can be favored by natural selection: Individuals should allow their hunger to affect learning for future decisions. The valuation mechanism that typically evolves produces the kind of behavior seen in standard laboratory tests. By providing an insight into why learning should be affected by the state of an individual, we provide a basis for understanding psychological principles in terms of an animal's ecology.     

Memory for event frequency as a function of depression, age, intentionality, and level of processing

In two experiments, we examined memory for event frequency among depressed and/or elderly subjects (depression was either naturally occurring or induced by the Velten technique). We also manipulated level of processing and instructional set to test the notion that memory for event frequency is relatively invariant across a variety of tasks. Results supported the proposal that memory for frequency is robust in the face of depression and old age. Memory for frequency was enhanced, however, by semantic processing and by an intentional learning instructional set. Finally, the results suggest that the Velten technique not only induced variation in mood but also may have induced a semantic processing strategy in our depressed and elated subjects.     

The maximization of overall reinforcement rate on concurrent chains

We model behavioral allocation on concurrent chains in which the initial links are independent variable-interval schedules. We also quantify the relationship between behavior during the initial links and the probability of entering a terminal link. The behavior that maximizes overall reinforcement rate is then considered and compared with published experimental data. Although all the trends in the data are predicted by rate maximization, there are considerable deviations from the predictions of rate maximization when reward magnitudes are unequal. We argue from our results that optimal allocation on concurrent chains, and prey choice as used in the theory of optimal diets, are distinct concepts. We show that the maximization of overall rate can lead to apparent violations of stochastic transitivity.     

Evaluation of a sound-generator chip: The AY 3-8910

Despite the continuing decrease in computer prices, psychoacoustic research is still expensive because of the high cost of sound-generation equipment and software. A single-chip sound generator was evaluated as an inexpensive tone/noise generator, amplitude attenuator, envelope modulator, and sound mixer. Although the chip has some limitations, it offers important advantages for pilot research and laboratory demonstrations.