What cognitive processes underlie event-related
brain potential (ERP) effects related to visual multidimensional
selective attention and how are these processes organized?
We recorded ERPs when participants attended to one conjunction
of color, global shape and local shape and ignored other
conjunctions of these attributes in three discriminability
conditions. Attending to color and shape produced three
ERP effects: frontal selection positivity (FSP), central
negativity (N2b), and posterior selection negativity (SN).
The results suggested that the processes underlying SN
and N2b perform independent within-dimension selections,
whereas the process underlying the FSP performs hierarchical
between-dimension selections. At posterior electrodes,
manipulation of discriminability changed the ERPs to the
relevant but not to the irrelevant stimuli, suggesting
that the SN does not concern the selection process itself
but rather a cognitive process initiated after selection
is finished. Other findings suggested that selection of
multiple visual attributes occurs in parallel.