Stimulus functions within a fixed-interval clock schedule: Reinforcement, punishment, and discriminative stimulus control

Abstract

Pigeons received food for responding on a fixed-interval 32-sec schedule divided into three equal parts, each correlated with a distinctive, response-independent, visual stimulus. Response rate was very low during the first two thirds of the interval but high during the terminal third. When a response-dependent brief stimulus correlated with the terminal third was arranged for each response in the presence of the stimuli correlated with the first two thirds, response rate was enhanced, especially in the middle third. However, response rate was suppressed when each response in the presence of the stimulus correlated with the final third produced a brief stimulus correlated with the initial third. A similar suppressive effect occurred when each response produced a brief stimulus correlated with the middle third. Response suppression decreased over successive responsedependent brief-initial-stimulus manipulations. The results were interpreted in terms of reinforcement, punishment, and discriminative stimulus control by visual stimuli correlated with parts of a fixed-interval schedule.Control of fixed-interval (FI) behavior by exteroceptive, discriminative stimuli can be demonstrated with either a continuous or discontinuous visual clock which demarcates the passage of time during an interval. For example, in experiments by Ferster and Skinner (1957), a small slit of light grew continuously and linearly throughout a lO-min interval, reaching its maximum size at reinforcement. FolIowing reinforcement, the clock reset to an initial value and started recycling. Ferster and Skinner showed that the pause after reinforcement lengthened and the terminal response rate increased as control by the clock developed.More recent studies of Fl clock schedules (Farmer

Turning Back the Clock on Serial‐stimulus Sign Tracking

“…The first responses, however, result in a disturbance of the ramp stimulus sequence and a lengthening of the IFI. These disturbances occur at a point in the conditioning process at which the incremental stimuli are just beginning to functionally elicit responding and, presumably, at a time when putative conditioned reinforcing and/or conditioned punishing properties of the stimuli may be developing (Auge, 1977). Response-produced degradation of the signal will, in turn, reduce the conditioned reinforcing or punishing capability of stimulus intensity changes.…”

Escape From Serial Stimuli Leading to Food

“…Similarly, in another variation on the standard observing procedure, Auge (1977) began with a sequence of three stimuli that accompanied successive thirds of the interval between food deliveries on a 32-s fixed-interval schedule of reinforcement. When he allowed his birds to produce one-second or half-second displays of the third stimulus in the presence of the first stimulus, pecking increased on the observing key, indicating that the third stimulus was a conditioned reinforcer; but when he allowed the same birds to produce the first stimulus in the presence of the third stimulus, the rate of pecking decreased, indicating that the first stimulus in the series functioned as a conditioned punisher.…”

Real-time factors in the rabbit’s nictitating membrane response to pulsed and serial conditioned stimuli

“…In particular, serial stimuli can gain control over response timing during CS-US intervals that stretch over several seconds or minutes (Boyd & Levis, 1976;Dubin & Levis, 1973;Gaioni, 1982;Holland & Ross, 1981;Matthews & Lerer, 1987;Newlin & LoLordo, 1976;Palya, 1985). Likewise, in operant conditioning, the fixedinterval-with-clock schedule also reveals the ability of serial stimuli to control response timing in the range of seconds to minutes (Auge, 1977;Ferster & Skinner, 1957).…”