Instruction Effects and Relation between Extraversion and the Spiral Aftereffect

Abstract

The relation between extraversion (EPI) and length of aftereffect was investigated when spiral aftereffect was measured on the same Ss under three instructions: (a) normal— S is told to report “When the aftereffect appears to stop” and after Ss had been informed of two phases in the decay of the aftereffect and told to (b) report the end of the first, faster, phase of decay, or (c) report when “they were absolutely sure that the second phase of decay had ended.” Near zero correlations were obtained between E and SAE under conditions (a) and (c) but E and SAE were negatively and significantly correlated under condition (b). It is suggested that failure to differentiate these instruction conditions could account for many of the previous contradictory findings on the relation between E and SAE duration.