Ángel Andrés Jiménez

Sensitivity, changeover responses, and choice in transition☆

Studies of choice in steady state have shown that sensitivity to reinforcement increases with increasing fixed-ratio changeover (FR CO) requirements. We assessed the generality of this finding with choice in transition. Food deliveries were programmed according to concurrent variable-interval (VI) schedules. Seven different VI pairs arranged ratios of food deliveries (left/right) of 27:1, 9:1, 3:1, 1:1, 1:3, 1:9, and 1:27 at a constant overall rate across components. Within sessions, all seven ratios were presented in random order. Each component lasted for 10 food deliveries; components were separated by 60-s blackouts. A changeover lever required 1, 2, 4, 8, 16, 32, and 64 responses to alternate between two main levers. Redeterminations to all FR COs, but 64 responses, were obtained in descending order. Choice adjusted rapidly to rapid changes in the reinforcer ratio, tracking the lever associated with the highest probability of reinforcer. Sensitivity to reinforcement increased with increasing FR CO, replicating the negatively accelerated function found in our earlier study. With successive reinforcers in components, however, sensitivity reached asymptote values sooner with the largest (8, 16, and 32 responses), than with the smallest (1, 2, and 4 responses), FR CO requirements.

Some Effects of Magnitude of Reinforcement on Persistence of Responding

The influence of magnitude of reinforcement was examined on both response rate and behavioral persistence. During Phase 1, a multiple schedule of concurrent reinforcement was implemented in which reinforcement for one response option was held constant at VI30 s across both components, while magnitude of reinforcement for the other response option was varied across the 2 components. In Phase 2, persistence was evaluated during extinction following steady-state responding. In Phase 1, responding of 3 of the 4 participants was greater on the option that produced the higher magnitude of reinforcement. Dwing Phase 2, 2 of these 3 participants’ response persistence under extinction was greater for the signal associated-with the greater magnitude of reinforcement. The influence of magnitude of reinforcement on behavioral persistence is discussed, as well as implications for studying behaioral maintenance.

The Ecological Revolution: The Senses Considered as Perceptual Systems, 50 Years Later - Part 2

ABSTRACT This editorial presents the second of a 2-part special issue honoring the publication of James J. Gibsons 1966 book, The Senses Considered as Perceptual Systems. As was pointed out by several reviews of this book written just after its publication (i.e., between 1967 and 1969), Gibsons 1966 book represents a revolution not only for the psychological science but also for domains beyond that of psychology. This second part of the special issue is composed of 5 theoretical contributions that represent, in addition to the 4 pieces previously published in the first part, the far-reaching influence of Gibsons ecological revolution.

The Senses Considered as Perceptual Systems: The Revolutionary Ideas of Gibson's 1966 Book, 50 Years Later - Part 1

ABSTRACT This editorial introduces the first part of a 2-part special issue of Ecological Psychology dedicated to James J. Gibsons 1966 book, The Senses Considered as Perceptual Systems, which presents many revolutionary ideas that are important not only for the study of perception but also for the science of psychology in general including the rejection of the mechanistic and dualistic stimulus-response formula (cf. Dewey, 1896), the rejection of sensation-based theories of perception, and the insistence that the unit of investigation and explanation is the mutual relation between people and other animals and their environments.

The effect of lever height on the microstructure of operant behavior

The effect of lever height on the temporal organization of reinforced lever pressing was examined. Lever pressing was reinforced on a variable-interval 30-s schedule in rats, with lever height manipulated across six successive conditions. Parameters of the organization of responses in bouts (bout length distribution, bout-initiation rate, within-bout rate, and sequential dependency) were estimated. These estimates revealed (1) a qualitative change in the distribution of IRTs and their sequential dependency when the lever was too high, (2) a mixture of geometrically-distributed bout lengths at all lever heights, and (3) longer bouts at lower and intermediate lever heights. In accordance with previous data, these findings suggest that lower and intermediate lever heights favored lever pressing with longer bout lengths, faster bout initiation, faster within-bout responding, and more sequentially dependent timing. These results underscore the disociability of motoric capacity in operant performance, and may reflect the influence of the body size on the temporal organization of the operant.

Invariants and Information Pickup in The Senses Considered as Perceptual Systems: Implications for the Experimental Analysis of Behavior

ABSTRACT Although Gibson focused his agenda on the study of perception and Skinner on learning as contingencies of reinforcement, they shared a nonrepresentational approach. We propose that the ecological concept of invariants developed in Gibsons book The Senses Considered as Perceptual Systems (1966) could underlie Skinners notion of contingencies of reinforcement as environmental opportunities for behaving. The proposal is divided in 3 parts: the concept of stimulus for perception, the role of the notion of invariants in the operant contingency, and the information for perception and behavior. We conclude that approximating contingencies of reinforcement as instances of environmental invariants can be fruitful for studying a number of phenomena within the context of operant conditioning.