Erratum to: Atten Percept Psychophys

DOI 10.3758/s13414-014-0689-0

The publisher regrets having incorrectly edited the equation for the feature-cost index, after the final version had been approved. The equation should read:

$$ \frac{d{\prime}_{single- feature}-d{\prime}_{two- feature}}{d{\prime}_{single- feature}+d{\prime}_{two- feature}} $$