Processing Underpinnings of Chronotype x Time-of-Day Interactions: A Study of a Conditional Automaticity Account of (A)synchrony Effects

Abstract

Chronotype and time-of-day interactions are often manifest in differences between performance at times-of-day matching the individual's chronotype (on-peak) and off-peak performance. However, it is not clear which processing variables determine whether on- or off-peak benefits/costs will occur. We hypothesized that only processes entangled by conditional automaticity (CA) would manifest (a)synchrony effects: on-peak enhancement of core voluntary top-down control and off-peak augmentation of conditioned automatic processes. CA is an unconscious processing bias that reflects the enhancement of pathways linked, but not directly relevant, to the control structure of an ongoing, or recently completed, explicit task. Participants were 34 evening-types performing on-peak and 31 off-peak, and 30 morning-types on-peak and 29 off-peak. We used a spatial Stroop task to probe (i) top-down voluntary executive control, (ii) bottom-up CA (facilitation of the response opposite to the one currently under controlled inhibition), and (iii) an unconscious/automatic top-down control process autonomous wrt (i) and (ii), namely, a bias favoring response alternations over repetitions. Expected results were derived from a detailed processing model based on the CA hypothesis and supported by our results, namely, wrt to off-peak enhancements being restricted to conditional-automatic processes, coupled with off-peak impediment of the controlled process that conditioned that automaticity, and wrt to the absence of (a)synchrony for processes not bound by conditional automaticity, irrespective of either their top-down or involuntary character.