Effects of partial reinforcement on conditioning, conditional probabilities, asymptotic performance, and extinction of the rabbit's nictitating membrane response.

Classical conditioning and extinction of the rabbit nictitating membrane response was investigated under 100 per cent, and two 50 per cent reinforcement conditions (50% equated total trials, and 50% equated reinforced trials) at average intertrial intervals (ITIs) of 30 and 60 sec. It was found that: (1) partial reinforcement reduced the rate of conditioning, but all groups eventually attained asymptomatic performance levels near 100 per cent; (2) first-order and second-order conditional probabilities following reinforced and nonreinforced trials were virtually identical; and (3) no partial reinforcement extinction effect (PREE) was observed.