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. Author manuscript; available in PMC: 2011 Dec 25.
Published in final edited form as: Behav Brain Res. 2010 Jun 19;214(2):402–408. doi: 10.1016/j.bbr.2010.06.020

Figure 4.

Figure 4

Mean (±SEM) escape rate (head entries during the light) across 5 experimental conditions. Filled and empty symbols help identify experimental conditions. In the Escape Only condition, responses during the light terminated the stimulus and produced a 15 s dark period. The addition of an avoidance contingency during the Unsignaled Avoidance + Escape condition allowed subjects to delay the light onset for 20 s by producing a head entry prior to light onset. A tone was added 5 s prior to the light onset during the Signaled Avoidance + Escape condition. A regular increase in response probability was observed across the Escape Only, and Unsignaled and Signaled Avoidance + Escape conditions. Using a pulse of bright light to signal the avoidance period during the Pre-pulse condition reduced escape probability. Removal of the escape contingency during the Avoidance Only condition quickly reduced head entries during the light to near zero levels. Results from the Mixed ANOVA are presented in the Experiment 3 results section.