This study investigated the functional significance
of the N2 response to novel stimuli. In one condition,
background, target, and deviant stimuli were simple geometric
figures. In a second condition, all stimulus types were
unfamiliar/unusual figures. In a third condition, background
and target stimuli were unusual figures and deviant stimuli
were simple shapes. Unusual figures, whether they were
deviant, target, or background stimuli, evoked larger N2
responses than their simple, familiar counterparts. N2
elicited by an unusual background stimulus was larger than
that evoked by simple, deviant stimuli, a pattern opposite
that exhibited by the subsequent P3. Deviance from immediate
context had limited influence over N2 amplitude. The results
suggest that novelty N2 and novelty P3 reflect the processing
of different aspects of “novel” visual stimuli.
The novelty P3 is particularly sensitive to deviation from
immediate context. In contrast, the novelty N2 is sensitive
to deviation from long-term context that renders a stimulus
unfamiliar and difficult to encode.