Before starting to train chicks to associate a colour with a reward it is crucial to get them accustomed to spending time alone in the arena where the training takes place. This was done by gradually reducing the group size until all chicks had spent some time alone in the arena. 

When the training started chicks received help to learn to go to the rewarded bowl, which was either black or white depending on which colour the chick had been randomly assigned to. Thereafter they had to move on their own and choose one of the bowls.  As a reward the chicks received a small piece of a meal worm.   Each choice was noted in a test protocol as correct (the chick went to the rewarded bowl), incorrect (the chick walked to the unrewarded bowl) or help if they received help in making the correct decision. If the chick went to the incorrect bowl they were immediately picked up and therefore did not receive a reward. 

Upon making five six correct choices in a row the association was considered to be learned and the chick moved on to the cognitive judgment bias test. This test procedure you can learn more about under "cognitive judgment bias test" in the menu to the left.