The Bivalency effect in task switching: Event‐related potentials

Abstract

During task switching, if we occasionally encounter stimuli that cue more than one task (i.e., bivalent stimuli), response slowing is observed on all univalent trials within that block, even when no features overlap with the bivalent stimuli. This observation is known as the bivalency effect. Previous fMRI work (Woodward et al., 2008) clearly suggests a role for the dorsal anterior cingulate cortex (dACC) in the bivalency effect, but the time course remains uncertain. Here, we present the first high-temporal resolution account for the bivalency effect using stimulus-locked event-related potentials. Participants alternated among three simple tasks in six experimental blocks, with bivalent stimuli appearing occasionally in bivalent blocks (blocks 2, 4, and 6). The increased reaction times for univalent stimuli in bivalent blocks demonstrate that these stimuli are being processed differently from univalent stimuli in purely univalent blocks. Frontal electrode sites captured significant amplitude differences associated with the bivalency effect within time windows 100-120 ms, 375-450 ms, and 500-550 ms, which may reflect additional extraction of visual features present in bivalent stimuli (100-120 ms) and suppression of processing carried over from irrelevant cues (375-450 ms and 500-550 ms). Our results support the fMRI findings and provide additional evidence for involvement of the dACC. Furthermore, the bivalency effect dissipated with extended practice both behaviorally and electrophysiologically. These findings are discussed in relation to the differential processing involved in a controlled response style.

Age affects the adjustment of cognitive control after a conflict: evidence from the bivalency effect

“…Moreover, it is associated with activation in the dorsal anterior cingulate cortex, a brain area recruited for the adjustment of cognitive control (Grundy, Benarroch, Woodward, Metzak, Whitman, & Shedden, 2013;Woodward et al, 2008) and it draws on memory resources because amnesic patients fail to show the typical pattern of a long-lasting performance slowing (Meier, Rey-Mermet, Woodward, Müri, & Gutbrod, 2013). …”

Cognitive Control as a Function of Trait Mindfulness

“…The ACC is critically involved in post-conflict slowing (bivalency) effects (Grundy et al 2013;Grundy and Shedden 2014b;Woodward et al 2008). More ACC activity is required following high conflict than low conflict trials during the bivalency effect paradigm, and this may be a reflection of the ACC's role in predicting upcoming cognitive demand (Grundy and Shedden 2014b).…”

“…Before the experimental blocks, participants performed a practice block that was identical to pure univalent blocks 1 and 3 and lasted approximately 3-5 min. This was administered in order to ensure that participants were sufficiently practiced on all three tasks; lots of practice is standard for bivalency effect studies (Grundy et al 2013;Grundy and Shedden 2014a, b;Meier et al 2009;Woodward et al 2003).…”

“…Given an alpha level of 0.05, power of 0.80 and an effect size of η 2 = 0. 55 for the post-conflict slowing effect (from Grundy et al 2013) , the number of participants required to detect the post-conflict effect is 11. Thus, we had more than sufficient power to detect an effect.…”

“…Surprisingly, studies of mindfulness to date have mainly focused on the conflict trials themselves, rather than on how individuals adjust performance following conflict. Here we used the bivalency effect paradigm (Grundy et al 2013;Grundy and Shedden 2014a, b;Meier and Rey-Mermet 2012;Woodward et al 2003) to test the hypothesis that high mindful individuals are better able to recover from conflict than low mindful individuals.…”