Conclusions
The present study shows that memorizing (grouping-relevant and
-irrelevant) features in grouped objects involves multiple, sequential
stages of processing that can be traced using lateralized ERPs and alpha
activity. When multiple features of an object need to be encoded, the
observed benefit of grouping arises already at an early, perceptual
level, influencing subsequent processes of attentional selection, with
attention conferring an advantage to grouped items during the encoding
of the stimulus configurations into VWM and reinforcing the
representations of individual features during the retention stage. The
results provide support for a hierarchical model of memory
representation, with the grouping-relevant feature establishing a
superordinate object representation, which in turn enhances the
representation of the basic-level grouping-relevant and -irrelevant
features.