Early binding of feature pairs for visual perception

If features such as color and orientation are processed separately by the brain at early stages1,2, how does the brain subsequently match the correct color and orientation? We found that spatially superposed pairings of orientation with either color or luminance could be reported even for extremely high rates of presentation, which suggests that these features are coded in combination explicitly by early stages, thus eliminating the need for any subsequent binding of information. In contrast, reporting the pairing of spatially separated features required rates an order of magnitude slower, suggesting that perceiving these pairs requires binding at a slow, attentional stage.