While superficially similiar, attending to features (color, orientation, etc.) is associated with distinct behavioural effects, as compared to attending to a location. In Jabar & Anderson (2017), we showed that a similiar distinction exists for probability. While orientation probability affected perceptual precision, spatial probabilty did not.
We wanted to extend that finding to a different task. 2-alternative forced choice (2AFC) tasks are much more common in the literature than estimation tasks, but they typically introduce possible alternate accounts, such as response biases. In a previous post, we outlined a novel method by which response preparation can be measured in a 2AFC task.
That procedure was implemented in a paper that was recently published at Attention, Perception, & Psychophysics. Collaborating our previous work, feature probability was indeed found to be distinct from spatial probability. Chiefly, the two probability types operate under different circumstances, and can affect RT and accuracy in different ways.