Any type of research where behaviour is systematically observed and recorded. Difficult to deal with; data must be de-coded. Allows you to find things you otherwise wouldn"t have. Example: boesch (1991) on the hammer/anvil technique - tool use in chimpanzees - attempting to crack open nut; use hammer-like thing like rock to hit nut against anvil like trunk. Watched for specific qualitative behaviours (and reported specific descriptions as well as examples); came up with some operational definitions for things to observe. Coded all the times he saw the certain types of activities he observed. Stimulation present before they are 1 - passive behaviours. Facilitation moe likely by age: active teaching even less likely.