Stimulus intensity in sensory preconditioning of rats.

Examined the sensory preconditioning (SPC) analogs to UCS and CS intensity in 2 experiments with male hooded rats (N= 144). In Exp. I, Ss received S1-S2 (light and tone, counterbalanced) pairings with 1 of 3 different intensities of S2, followed by conditioned emotional response (CER) training to S2. Suppression of drinking by S1 (SPC groups) and S2 (CER groups) was tested. Amount of SPC was not significantly affected by S2 intensity, but the strength of the CER was an increasing function of S2 (CS) intensity. In Exp. II, amount of SPC was a monotonically increasing function of S1 intensity. Results are interpreted in terms of the similarities and differences between SPC and classical conditioning. (French summary) (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

UCS intensity and instructional set in classical eyelid conditioning: Discrimination conditioning and signal-detection analysis.

Conducted discrimination eyelid conditioning at 2 UCS intensities under inhibitory, neutral, and facilitatory instructional sets, in a experiment involving 144 undergraduates in 6 groups. Instructional set yielded receiver operating characteristic curves that were reasonably straight lines on a normal deviate plot. The tentative conclusion from signal-detection theory of an equal discriminability function across instructional sets was contrasted with 4 indices of discrimination, indicating significant but mutually contradictory changes in discrimination as a function of instructional set. Discrimination differences were produced by UCS intensity, particularly under the neutral instructions. (French summary) (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The acquisition of stimulus control over released pecking by hatchling chicks (Gallus gallus).

Analyzed the spatial and dynamic stimulus characteristics of the pecking arrow display that control simple release and/or learned release of pecking by 254 hatchling chicks in 5 experiments. Findings show (1) a pronounced preference by Ss to peck at red rather than green illuminated lamps, (2) significantly greater pecking by Ss to lamps attached to, and on the floor beneath, the pecking arrow during the display, and (3) little evidence that placement of a stimulus on the arrow, on the floor beneath the arrow, or in both locations differentially affected frequency of pecking to matching stimulus colors. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alarm reaction in acquisition and social transmission of simulated-predator recognition by zebra danio fish (Brachydanio rerio).

Alarm reactions occur in response to alarm substance passively released by injury to skin of zebra danio fish (Brachydanio rerio). Visual observation of alarmed conspecifics yields socially facilitated alarm by observers. Concurrent exposure of fish to alarm substance and a novel odorant (morpholine) later produced learned alarm to morpholine alone. Fish trained with morpholine plus alarm substance were mixed in with naive fish for a test with morpholine alone. The naive fish, separated out from the mixed groups, then demonstrated not only an acquired alarm reaction to morpholine but also an ability to communicate the acquired recognition of a simulated predator to a new group of naive observers. The results suggest the operation of a sophisticated antipredator defensive system in zebra danios that involves unlearned releasing stimuli, social facilitation, visual communication, learned predator recognition, and social communication of predator recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discriminative sensory preconditioning.

Describes an experiment in which 32 male hooded rats received either 7, 14, 28, or 56 pairings of a tone with a light and an equal number of unpaired tones of a different frequency. After then pairing the light with footshock in CER training, the ability of each tone to suppress drinking was tested. The paired tone yielded significantly more suppression than the unpaired tone. Suppression was an increasing function of number of presentations for the paired tone and a decreasing function for the unpaired tone. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Shock intensity and the Kamin effect in one- and two-way avoidance.

Describes 2 experiments with 144 and 162 male hooded rats. Response decrements as a function of the intersession interval occurred in both 1- and 2-way active avoidance conditioning. Percentage avoidances were a positive function of shock intensity in 1-way avoidance and a negative function of intensity in 2-way avoidance. The magnitude of the performance decrement was a function of shock intensity in 1-way avoidance, with the largest decrement at the lowest shock intensity. The magnitude of the performance decrement was unaffected by shock intensity in 2-way avoidance. The shape of the intersession-interval function was apparently unaffected by shock intensity in both types of active avoidance. (French summary) (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Classical discrimination eyelid conditioning in primary psychopaths.

Compared conditioning rates of 29 psychopaths and 24 nonpsychopaths on classical eyelid discrimination. Psychopaths produced fewer CRs to both CS+ and CS- over 3 instructional sets. Although less responsive, psychopaths were not poorer discrimination learners according to a signal detection analysis of the data. Psychopaths' CR latency, amplitude, and slope were similar to those of nonpsychopaths. Results suggest that psychopaths are not inferior conditioners to negative reinforcement, but rather that they employ different response sets than nonpsychopaths. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of shock intensity and food deprivation on one-trial discriminated avoidance.

Describes 2 experiments with experimentally naive hooded rats. In Exp. I with 45 Ss, a single shock followed food pellet retrieval following the transillumination of 1 wall of a conditioning chamber. Avoidance of the illuminated wall (discrimination) was an increasing function of shock intensity, with asymptotic performance at 1 ma. Measures presumed to reflect primarily a generalized emotional response conditioned to apparatus cues, however, were linearly increasing functions of shock intensity up to 4 ma. In Exp. II with 36 Ss, discrimination was a function of both shock intensity and level of food deprivation, with discrimination best under high shock intensity and low deprivation and poorest under low intensity and high deprivation. (French summary) (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanisms for social transmission of pecking preferences to neonatal chicks.

An arrow, motor driven to make "pecking" movements, released and directed pecking by 412 1-day-old domestic chickens. Stimuli (colored plastic pinheads) placed on or near the arrow tip resulted in pecking selectively directed to matching stimuli. Innate color and position preferences, a preference for stimuli with low environmental density, and a possible tendency of Ss to peck toward the center of a mass of peck-releasing stimuli were experimentally eliminated as explanations for the phenomenon. Other unsatisfactory explanations include reinforcement effects, social facilitation, and local enhancement. Arrow-directed pecking developed over trials, persisted after removal of arrow-operation and/or model stimuli, and required for acquisition only visual exposure to modeling conditions. Results demonstrate the operation of a mechanism for transmission of abstract information about the visual characteristics of food objects from hen to chicks. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)