Fig 8.

Cumulative record that Skinner (1948) presented as evidence of “reconditioning” of a response of hopping from side to side. Food was delivered once a minute independently of the pigeon's behavior. Food deliveries (labeled “reinforcements”) are indicated by arrows. No response immediately preceded the first and possibly the second food deliveries (circled), indicating that the result is actually an example of reinstatement. Copyright ©1948 by the American Psychological Association. Reprinted by permission.