Two possible accounts for the attentional demand of statistical properties.

<p>Panel A illustrates the same-cost account of the encoding of statistical properties: Attention can be focused on a single object or distributed over a set, and it allows observers to perceive the attended information in essentially the same way, no matter whether this information is an object feature or statistical property. Panel B illustrates the cost-free account of the encoding of statistical properties: Attending to a single object allows observers to perceive its features, whereas the statistical properties of a set that is out of attentional focus can be simultaneously perceived for free without any additional cost.