Have you ever felt your brain sluggishly trudging through an early morning tasks? Or have you found yourself unexpectedly sharp and productive late in the afternoon? You’re not imagining it.
Our bodies are wired to perform differently throughout the day. The circadian rhythm influences everything from our energy levels to cognitive sharpness, including attention. 🧠
In a world of rigid work & school schedules, we’ll likely find ourselves at odds with our internal clocks. The effect of this is explored in today’s study of ‘science says.’
The review study analysed four components of attention:
Tonic alertness is like our internal “ready mode.” It is the baseline level of alertness that keeps us prepared to notice and react to what’s happening around us. It represents the overall state of arousal or mental activation that our body and mind maintain at any given moment.
Phasic alertness is our ability to quickly respond to something after a warning signal. It’s what helps us prepare and react swiftly to sudden changes in our surroundings.
Selective attention is the ability to focus on one stimulus and respond to it while ignoring others. It helps us filter out distractions and concentrate on what matters.
Sustained attention: is the ability to stay focused and respond over an extended period of time (minutes–hours).
The basic conclusion is as follows:
In the morning (7:00–10:00), attention is at its lowest due to the body’s natural rhythm and the lingering effects of sleep inertia. It improves by late morning (10:00–14:00) but tends to dip again after lunch (14:00–16:00). Performance picks up in the late afternoon and early evening (16:00–22:00), reaching a peak before declining again at night (22:00–4:00). The lowest levels occur in the early morning hours (4:00–7:00).
This pattern applies to people with a typical sleep schedule (23:00–7:00) and an intermediate chronotype. You can adjust the times above according to your chronotype by adding or subtracting the difference in sleep & waking time.
When we misalign our natural circadian rhythm with demanding tasks it can impact our performance. Eating snacks, taking short naps, or consuming caffeine may provide temporary boosts in alertness. However, the authors not that “[a]lthough these measures tend to offer a transitory increase in alertness, they may not be effective to improve phasic alertness, selective attention or sustained attention” (p. 87).
While some of us have the freedom to synchronise our cognitively demanding tasks with this circadian rhythm, kids at school are not. Consequently, the authors conclude with a critical note on school schedules (often starting from 07:00–08:00). Even for those with a ‘normal’ circadian rhythm, these times are severely misaligned. For the evening chronotype, this effect is exacerbated: school starts when their attention is lowest.
This ‘science says’-article is based on: Valdez, P. (2019). Circadian Rhythms in Attention. (link)
