Early and Late Selection in Young and Old Adults: An Event-Related Potential Study

The present experiment investigated differences in processing between young and old adults in a combined visual selection-memory search paradigm. No evidence was found for age-related differences in early visual selective attention. The elderly achieved relatively fast reaction times in the memory search task at the cost of a high error percentage. From these findings, and from the morphology of the event-related potential, it was concluded that old subjects perform controlled memory search more superficially than young subjects, In both old and young subjects high memory load was associated with decreased positivity in the P3 and Slow Wave area. This is interpreted in terms of Okita et al.'s(1985) concept of search negativity. N2 amplitude was found to be larger to non-target trials for both attended and unattended inputs. The latter result is discussed in relation to theories about N2 as an indicator of automatic mismatch detection.