Figure 1

Behavioral protocol: The change detection task. Following the presentation of a red dot in the center of the screen the crows had to hold the head straight and centered to start the trial. They had to maintain this head-position until the choice period at the end of the trial. Each training session consisted of no-cue, pre-cue and retro-cue conditions. The overall duration of the conditions was matched. In all conditions the animals viewed an array of 2, 4 or 6 colored squares for 0.4 s. After a memory delay of 1.0 s the array re-appeared for 0.4 s. On 50% of the trials one color was exchanged and the animals had to indicate during the choice period if any color was changed in the new array. A peck to the center indicated no change while a peck on any of the peripheral stimuli indicated change. In the pre- and retro-cue conditions an additional stimulus was presented to cue the location at which the color-change would occur. If no change occurred the cue-location was chosen at random. On pre-cue trials the cue was presented before the sample-array while on retro-cue trials it was presented following the sample-array during the memory-delay.