Cue duration determines response rate but not rate of acquisition of Pavlovian conditioning in mice

The duration of a conditioned stimulus (CS) is a key determinant of Pavlovian conditioning. Rate estimation theory (RET) proposes that reinforcement rate is calculated over cumulative exposure to a cue and the reinforcement rate of a cue, relative to the background reinforcement rate, determines the speed of acquisition of conditioned responding. Consequently, RET predicts that shorter-duration cues require fewer trials to acquisition than longer-duration cues due to the difference in reinforcement rates. We tested this prediction by reanalysing the results of a previously published experiment. Mice received appetitive Pavlovian conditioning of magazine approach behaviour with a 10-s CS and a 40-s CS. Cue duration did not affect the rate at which responding emerged or the rate at which it peaked. The 10-s CS did elicit higher levels of responding than the 40-s CS. These results are not consistent with rate estimation theory. Instead, they are consistent with an associative analysis that assumes that asymptotic levels of responding reflect the balance between increments and decrements in associative strength across cumulative exposure to a cue.

Response and Reinforcement in Operant Audiometry

Variable success in audiometric assessment of young children with operant conditioning indicates the need for systematic examination of commonly employed techniques. The current study investigated response and reinforcement features of two operant discrimination paradigms with normal I7-month-old children. Findings indicated more responses prior to the onset of habituation when the response task was based on complex central processing skills (localization and coordination of auditory/visual space) versus simple detection. Use of animation in toy reinforcers resulted in more than a twofold increase in the number of subject responses. Results showed no significant difference in response conditioning rate or consistency for the response tasks and forms of reinforcement examined.

Response Strength of Young Children in Operant Audiometry

An operant conditioning discrimination paradigm was evaluated in terms of relationships between response behavior of young children and two stimulus components of the paradigm, the discriminative stimulus (DS) and the reinforcing stimulus (RS). Experiment I measured response performance in normal 1-year-old subjects as a function of differences in intensity and/or complexity among three DSs. Results showed no significant differences in conditioning rate, habituation, or consistency of the conditioned response relative to variable properties of the DS. Experiment II examined response performance of normal 2-year-old children as a function of two modifications in the RS, reinforcement schedule and reinforcement novelty. Subjects reinforced on a variable-ratio schedule of intermittent reinforcement and subjects reinforced on a 100% schedule demonstrated equivalent response habituation and consistency. In the second part of the experiment, subjects receiving novel RSs showed significantly greater response recovery than subjects reinforced with familiar RSs. Comparison of normal 1- and 2-year-old children revealed similar rates of conditioning and response consistency. However, 2-year-olds habituated more rapidly than 1-year-olds.