The results of this experiment appear in [this thesis.][2] Preregistration of this experiment is [here.][3] When subjects attend to vertically-oriented rectangles, contrary to what a similarity-based account might predict, subjects notice an unexpected horizontal (and thus slightly different from the attended set) rectangle _more_ often than they notice an unexpected vertical rectangle (a perfect match to the attended set). This unusual pattern of results may arise from one of the unexpected objects being a perfect duplicate of the attended set. Rather than being inattentionally blind to the vertical rectangle at higher rates than the horizontal one, subjects may be counting it along with the other attended objects. To investigate this possibility, we are replicating the [previous experiment][1], but altering the unexpected object's color to make it unique in the display. It will still vary in similarity of shape to one set of objects and not the other, but it will differ from both sets on the color dimension. The unexpected object should no longer be confused with the objects in the display, and the results should provide a clearer indication of the effects of similarity along an orthogonal feature dimension. [1]: https://osf.io/7kuw2/ [2]: https://www.ideals.illinois.edu/items/105273 [3]: https://osf.io/ugzg9