Effects on Contingent Negative Variation of Set Created by Anticipating Variable Foreperiods

Abstract

The influence of set on a simple reaction time task was examined by comparing the differences of psychological factors between a group of subjects who expected and experienced a fixed foreperiod Control condition: 12 subjects) and another group of subjects who were instructed to expect variable foreperiods but experienced the same fixed foreperiod (Instruction condition: 11 subjects), using the index of contingent negative variation (CNV). The foreperiod of simple reaction time task in each condition was fixed at 3 sec. Subjects were required to respond to 2 blocks of 24 trials, and each instruction was presented between blocks. On the second block CNV amplitudes were higher in the instruction condition as was every CNV component (early late, and whole component). The set created by anticipating variable foreperiods seems to increase cerebral activity, arousal, and attention during simple reaction time tasks.

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“…In addition, electroencephalographic (EEG) activity was recorded throughout the time estimation interval to provide a measure of covert preparation: a slowly developing, frontally dominant (Gomez, Flores, & Ledesma, 2007; Rosahl & Knight, 1995) negative voltage known as the Contingent Negative Variation (CNV). The CNV emerges during periods of time in which subjects are anticipating future events of personal or instructed significance (Brunia & van Boxtel, 2001; Elbert, Ulrich, Rockstroh, & Lutzenberger, 1991; Hiraku & Sakuma, 1996; Ruchkin, McCalley, & Glaser, 1977; Timsit-Berthier, 1984). Healthy subjects with accurate time estimation ability have been shown to exhibit CNVs of a smaller amplitude and slower rise time than healthy subjects with poor time estimation ability (Brown, Fenwick, & Howard, 1989; Ladanyi & Dubrovsky, 1985).…”