Felipe Cabrera

Early-session increases in responding during extinction

After training under a variable-interval 60-s schedule of reinforcement, four rats were exposed to 30-min extinction tests, which occurred either at the start or at the end of the session (each session being 50-min long). Response rate in extinction decreased when the extinction test occurred at the end of the session, but first increased and then decreased when the extinction test occurred at the start of the session. Consistent with other recent results, this finding suggests that some variable, other than reinforcement, contributes to early-session increases in responding.

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.