Straight‐alley escape behavior in infant mice: Effect of shock intensity

Separate groups of Swiss‐Webster mice between 5‐15 days of age received 25 training trials in a straight‐alley escape task at 1 of 4 shock intensities, ranging from .1‐.8 mA. An increase in shock level led to better escape performance at all ages, although the amount of improvement varied directly as a function of age. The results supported earlier work suggesting that the competing response measure was the most useful index of improved escape behavior at the early ages. Running speeds did not indicate improved within‐session escape performance at any age or shock level, although speeds clearly reflected maturational and motivational differences between groups.