Abstract
While humans normally take suboptimal monetary decisions in cognitive tasks, there is growing evidence that they are nearly optimal when those decisions are based on perceptual judgments (see for example Maloney et al. 2006). One widely recognized departure from optimality is uncertainty aversion, a preference for gambles with known risks over gambles with unknown risks (Ellsberg 1961). Last year we showed that our subjects were uncertainty averse when choices involved abstract probabilities, but this attitude was eliminated when abstract probabilities were replaced by visual uncertainty, the uncertainty intrinsic to our visual system and visual stimuli (Pedersini 2011). This year we argue that the reason why visual stimuli eliminate and even reverse uncertainty aversion may be the perception of control over the task. In a series of experiments we compare the subjects’ choices in a cognitive task, in which they preferred drawing marbles from an urn with known probability of winning than from one with an unknown probability, and in a visual task, in which they clearly preferred a visual search task over its abstract equivalent. In the visual search, subjects had to look for Ts among Ls on a 1/f noisy background and were awarded 10 pts for correct answers. In the abstract search, subjects saw a 10x10 grid of boxes. They could open 10 boxes and finding at least one green chip would make them win 10 pts and the exact probability of finding a green chip was explicitly given. While subjects showed uncertainty aversion in the marble task, they were uncertainty loving in the search task. They also showed the ability to deploy different levels of effort in the visual search, depending on the possible control they had over the task in different experiments.
Meeting abstract presented at VSS 2012