Probability effects tend to resemble ones obtained with traditional 'attentional' manipulations. Cued or probable objects are detected faster and more accurately. This goes beyond simple detection tasks. Even in perceptual estimation tasks, both spatial exogenous cuing Anderson & Druker (2013) and orientation probability (Anderson, 2014; Jabar & Anderson, 2015) improve precision.
However, are they both the same effect? Do they share the same mechanisms? We investigated this in a paper we recently submitted. By having both manipulations in one block, we could look at whether the effects interact or not.
Blue = High-Prob, Red = Low-Prob
While both orienation probability and spatial exogenous cuing led to changes in initiation time, the effects were very clearly additive. What about precision?
Still no interaction. While both orienation probability and exogenous cuing led to changes in angular precision, the effects were very clearly additive again (panel b). Curiously, while both manipulations affected angular precision, only orienation probability did this by changing the shape of the angular error distribution (panel a), as characterized by a kurtosis metric (panel c). This kurtosis finding matches what we reported in our previous papers (Anderson, 2014; Jabar & Anderson, 2015).
These results only seem to make sense if the effects work through different mechanisms. While both these effects seem 'attentional', surely it only leads to confusion to put them both under the same umbrella? Such studies highlight the importance of examining how seemingly similar effects might just differ when studied more closely.
The paper has been provisionally accepted at Frontiers in Psychology. Will update with a link once the paper is published online. Feel free to contact us if there are any queries. Update: Click here for the paper