Previous studies have shown that the processing stage of the spatial-numerical association of response codes (SNARC) effect was flexible. Two recent studies by Nan et al. (2021) and Yan et al. (2021) used the same experimental paradigm to check whether the SNARC effect occurred in the semantic-representation stage but reached contradictory conclusions, showing that the SNARC effect was influenced by a magnitude Stroop effect in a magnitude comparison task but not by a parity Stroop effect in a parity judgment task. The two studies had two distinct operational factors: the task type (magnitude comparison task or parity judgment task, with the numerical magnitude information task-relevant or task-irrelevant) and the semantic representation stage-related interference information (magnitude or parity Stroop effect, with the interference information magnitude-relevant or magnitude-irrelevant). To determine which factor influenced the SNARC effect, in the present study, the Stroop effect was switched in the two tasks based on the previous studies. The findings of four experiments consistently showed that the SNARC effect was not influenced by the parity Stroop effect in the magnitude comparison task but was influenced by the magnitude Stroop effect in the parity judgment task. Combined with the results of Nan et al. (2021) and Yan et al. (2021), the findings indicated that regardless of the task type or the task-relevance of numerical magnitude information, magnitude-relevant interference information was the primary factor to affect the SNARC effect. Furthermore, a two-stage processing model that explained the observed flexibility of the SNARC effect was proposed and discussed.

Sleep–wake rhythm disturbances have a negative impact on attention. However, how it affects attention and whether the restoration of regular rhythms can restore attention are unclear. This study aims to explore the effects of sleep–wake rhythm disturbances on three subfunctions of attention (alertness, orientation, and executive control) and the restoration of regular rhythms on these functions. Twenty-one participants in the experimental group (who experienced sleep–wake rhythm disturbances for at least one month; aged 18–26) were required to sleep regularly following a sleep schedule, whereas 20 participants in the control group (who maintained regular sleep for at least three months; aged 19–22) received no manipulation of their sleep. All participants were assessed using the attention network test three times in six days. All of them wore spectrum activity monitors and kept sleep diaries every day. The results showed that the effects of alertness and executive control in the experimental group were significantly lower than those in the control group. After five days of regular sleep, the difference in the alertness effect between the two groups significantly decreased. These results suggested that under natural conditions, sleep–wake rhythm disturbances could negatively influence alertness and executive control, and a short period of restoring a regular rhythm has a recovery effect on alertness.