Avoidance and Escape Responses in the Larval Leopard Frog

To investigate the ability of larval Rana pipiens to respond to a discriminated avoidance situation light was used as the conditioned stimulus (CS), while the two unconditioned stimuli (UCS) consisted of scrambled electric shock and being chased. An avoidance response occurred when the tadpole crossed the goal line prior to the onset of the shock. An escape response occurred when the subject crossed the goal line after the onset of the shock but prior to being chased. A chase response occurred when the subject had to be chased across the goal line. A subject was considered to have learned the avoidance response when it made 7 avoidance responses during any 10 consecutive trials. The number of subjects reaching this criterion went from 0% on Day 1 to 100% on Day 12.