For sure you know how difficult it is to track the correct shell in a shell game (German: “Hütchenspiel”). We have to fully attend to the correct object to not lose track of it. Selective attention is a crucial component of all sensory processing. Biopsychologists from Bochum tested the role of dopamine in attentional selection and in the maintenance of attention in pigeons. The birds were trained on a moving-dot paradigm comparable to the shell game and had to select a target among distractors and maintain attention to the target. Target and distractors consisted of white dots, moving at random on a touch-screen. Here you see a historic picture of the shell game along with a cartoon of three sequences of the experiment conducted with pigeons. In the pigeon-version of the shell game, the demand on attention was modulated by varying the number of distractors and the duration of motion. Both manipulations affected performance equally. In the next step, the contribution of dopamine to attention was investigated. Intracranial injections of D1-antagonist before testing led to decrements in performance that equally affected trials with different attentional demand. This drop in performance could not be attributed to altered motivation or motor performance. The conclusion was that dopamine has a critical role in attention. It is involved in the selection of targets for attention and in the stabilization of attention against interference. This is comparable to the role dopamine plays in working memory and argues for similar mechanisms underlying selective attention and working memory. For a video of the experiment, see below:

Rose, J., Schiffer, A.-M., Dittrich, L. and Güntürkün, O., The role of dopamine in maintenance and distractability of attention in the 'prefrontal cortex' of pigeons, Neurosci., 2010, 167: 232-237.