Abstract
The integrated object account predicts that attention is spread
across all features that constitute one object, regardless of
their task relevance. We challenge that prediction with a novel
stimulation technique that allows for simultaneous
electrophysiological measurements of the allocation of attention
to two distinct features within one object. A rotating square
that flickers in different colors evoked two distinct
steady-state visual evoked potentials (SSVEPs) for rotation and
color, respectively. If the integrated object account were true,
we would expect identical SSVEP amplitudes regardless of what
feature participants attended. We found greater SSVEP amplitudes
for the to-be-attended feature compared with the to-be-ignored
feature. SSVEP amplitudes averaged across both features were
significantly reduced when participants attended to both
features, which was mirrored in behavioral costs, implying
competitive interactions or a division of attentional resources.
Surprisingly, this reduction in amplitude was mainly driven by
the SSVEP amplitude elicited by color changes. In conclusion, our
results challenge the integrated object account and highlight the
extent to which color is ``special'' within feature space.
