  Another set of studies (Kuhlmeier et al. 2003; Hamlin et al. 2007) provide evidence that infants are not only sensitive to displays of agency, but also have a sense of (something like) cooperative behavior: they readily distinguish between helpers and hinderers. In the 2007 study, babies were shown animated displays that adults interpret as a red circle trying to climb a hill but having trouble making it all the way up  (Hamlin et al. 2007 video display on line). In half the trials, the babies see a yellow triangle gently ‘helping’ the circle up the hill; in the other half, they see a blue square gently pushing the triangle down to the bottom. Adults plainly see the yellow triangle as a helper, an agent whose goal is to assist the circle in getting up the hill; they see the blue square as a hinderer, an agent whose goal is to stop the triangle from getting up the hill. Babies make such a distinction as well. Six-months-olds showed surprise in test trials that came after the hindering and helping scenarios, in which the red circle is seen approaching its hinderer rather than its helper. Furthermore, in a live action version of the task, the 3-month-old babies themselves chose to touch the helper more than the hinderer when they were given both to  choose.[25] 