| Approach |
|
| Move/stay toward |
Monkey moves from the back of the cage towards the stimulus inside the Perspex box or is standing/sitting in the front of the cage, close to the stimulus. |
| Touch |
Monkey touches, displaces or handles the Perspex box in which the stimulus is contained with hands and/or feet. |
| Defense |
|
| Freezing |
Monkey is sitting, standing or hanging motionless for at least 3 seconds. |
| Eye/head aversion |
Monkey avoids eye contact by glancing away from the stimulus or turns his whole face away from the stimulus. |
| Piloerection |
Monkey's hair stands on end in particular on the nape of the neck. |
| Move/stay away |
Monkey moves away from the stimulus inside the Perspex box or is standing/sitting at the back of the cage. The monkey may be climbing up in the back corner of the cage. |
| Visual Interest |
Monkey examines the stimulus in detail as if scanning or surveying the stimulus. He makes direct eye contact with the stimulus and stares at the stimulus for a variable length of time. This visual examination is accompanied by an abnormal crouch-like posture in which the head is close to, and lowered to the level of the stimulus with hindquarters raised up or down. The monkey may glance at the stimulus while assuming an abnormal crouch-like posture (minimum 0.5 sec). |
| No-look-at |
Monkey looks around aimlessly or is specifically directing its gaze towards something other than the stimulus. |
