The open field test is used to evaluate fear in rodents. Subjects are placed in the center of a box with a defined “center” region, and are free to explore the box for a set duration. During the open field test, rodents exhibit a behavior known as “thigmotaxis,” in which they initially hug the walls of the area and later venture out into the center. This behavior is attenuated via anxiolytic drugs and is intensified in rodent strains with high anxiety.