children. With this test, an experimenter presents the participant with a drawing of a maze with a picture of a man in the center. While the participant watches, the experimenter uses his or her finger to trace a pathway from the opening of the maze to the drawing of the man. The participant is then expected to replicate the demonstrated pathway through the maze to the drawing of the man. Mazes vary in complexity as difficulty increases. Radial arm maze First pioneered by Olton and Samuelson in 1976, the radial arm maze is designed to test the spatial memory capabilities of rats. Mazes are typically designed with a center platform and a varying number of arms branching off with food placed at the ends. The arms are usually shielded from each other in some way but not to the extent that external cues cannot be used as reference points. In most cases, the rat is placed in the center of the maze and needs to explore each arm individually to retrieve food while simultaneously remembering which arms it has already pursued. The maze is set up so the rat is forced to return to the center of the maze before pursuing another arm. Measures are usually taken to prevent the rat from using its olfactory senses to navigate such as placing extra food throughout the bottom of the maze. Morris water navigation task The Morris water navigation task is a classic test for studying spatial learning and memory in rats and was first developed in 1981 by Richard G. Morris for whom the test is named. The subject is placed in a round tank of translucent water with walls that are too high for it to climb out and water that is too deep for it to stand in. The walls of the tank are decorated with visual cues to serve as reference points. The rat must swim around the pool until by chance it discovers just below the surface the hidden platform onto which it can climb. Typically, rats swim around the edge of the pool first before venturing out into the center in a meandering pattern before stumbling upon the hidden platform. However, as time spent in the pool increases experience, the amount of time needed to locate the platform decreases, with veteran rats swimming directly to the platform almost immediately after being placed in the water. Physiology