Limitations of a bidirectional control procedure for the investigation of imitation in rats: Odour cues on the manipulandum

Magazine-trained observer rats confronted a conspecific demonstrator pushin g a joystick to the right or to the left for food reward before the observe rs were given access to the joystick from the position previously occupied by the demonstrator and rewarded for responses in both directions. For half of the observers (group 0), the joystick was in the same position when act ed upon by demonstrators and observers; for the other half(group 180) the m anipulandum was rotated 180 degrees within its mounting between observation and test. As in previous experiments using this bidirectional control proc edure, rats in group 0 showed demonstrator-consistent responding-that is, t hey pushed the joystick in the same direction, relative to the actor's body , as had their demonstrators. However, group 180 showed a reverse effect: r eliable demonstrator-inconsistent responding. These results suggest that at tractive odour or taste cues deposited by demonstrators on the side of the joystick contralateral to the direction of responding are sufficient to pro duce demonstrator-consistent responding in the bidirectional control proced ure.