continuously changing, including where someone is looking and parts of the body that signal power and sexual availability. The American neuroscientist Michael Platt carried out a clever series of experiments to understand how much male rhesus monkeys value different kinds of social information and how much they will pay to obtain it. As in our discussion of wanting and liking, Platt nghtly assumed that rhesus monkeys would value most what they like most, and that they would pay the highest price for what they are most motivated to acquire. Each monkey watched a slide show with viewing options akin to pay-per-view television. Ona given trial, they could watch one of two images for as long as they liked, each viewing option associated with a particular amount of juice. For each pair of images, one delivered more juice than the other. Given that these were thirsty monkeys , they should prefer more juice over less juice. If monkeys have no interest in the images per se — because they have no value — then their viewing preferences should be strictly determined by where they can get the most juice. If, on the other hand, the images have value, and some images are more valuable than others, then they may be willing to look at an image that delivers less juice over an image that delivers more. This is costly viewing. This is paying for watching. Evidence for such preferences would reveal that rhesus monkeys value the social information that comes from the image over the juice itself, a surprising result given that juice is a primary reward whereas the image is only a secondary reward, indicative of things to come. Consistently, these male monkeys had two favorite channels, preferring those showing pictures of high ranking individuals and close-ups of female hindquarters. They preferred these over images of low ranking individuals, despite the fact that this choice often cost them the opportunity to drink more juice. Platt's findings show that monkeys are motivated to ac