Ever wonder why you sleep poorly on your first night away from home? Neuroscience has the answer, and it has to do with ducks.
A mallard duck can rest one half of its brain at a time. According to an ornithological study, when a duck sleeps in a hostile environment, it keeps one eye open to stay alert to predators and one eye closed for a little shut-eye. When scientists examined the neurological behaviors of one of these half-sleeping ducks, they discovered that the side of the brain controlling the duck’s open eye had “activity levels of an awake bird,” while the other side had “brain waves characteristic of sleep.” Even with one half of the brain asleep, the duck was still alert, reacting to images of predators in less than a second. Other birds, such as the great frigatebird, use the same technique of resting one half of the brain at a time to “sleep on the wing” during their transoceanic flights. For our feathered friends, the ability to remain vigilant even during times of rest is crucial to their survival.
You can sleep with only half your brain, too. Odds are, you probably do it every time you sleep in a new place. It’s called “First-Night Effect.” The first night you sleep in unfamiliar or suspicious places (like a dingy motel or your great-aunt’s pull-out sofa), your brain goes into “duck-mode”: the left-side keeps watch while the right-side rests. Like the mallard, you have a biological instinct to keep vigil when you feel like you’re in an insecure environment.
Normally, we don’t have to worry about “keeping watch” when we sleep. For us, nighttime is not full of unbridled fear and bloodthirsty predation. But while our biological need for constant alertness has subsided, our need for spiritual vigilance is always pressing: Be sober and vigilant. Your opponent the devil is prowling around like a roaring lion looking for someone to devour. Resist him, steadfast in faith (1 Pt 5:8).
During the busyness of life’s daily tasks, we can doze off in the face of spiritual realities. On the one hand, this leaves us vulnerable to attack. We’re like (sitting) ducks in this regard. If we sleep with “both eyes closed” to the reality of the Devil, temptation, and sin, we are putting ourselves in danger. Every Christian needs to be constantly vigilant of the enemy and keep one eye open for the one prowling around looking to lead us into temptation.
But spiritual vigilance isn’t just about avoiding the enemy. It’s primarily about looking for Christ, keeping a part of your soul always on the lookout for his providential love, for Christ himself keeps vigil for you. Scripture highlights God as the prime sentinel, putting his protecting action as the sine qua non for productive vigilance: If the Lord does not watch over the city, in vain does its watchman keep vigil. In vain is your earlier rising, your going later to rest, you who toil for the bread you eat while he pours gifts upon his beloved while they slumber (Ps 127:1-2).
Our vocation as Christians is to keep watch with Christ. Unlike the duck-sleep vigilance that produces “First-Night Effect,” keeping watch for Christ won’t ultimately make you weary and craving charismatic coffee the next morning. Though the hustle and bustle of the work day might draw our thoughts away from God, we should strive—like pius mallards—to keep one half of our minds open to the presence of the divine. The more we live with an awareness of God’s love, the more we will be invigorated by the life of Christ. How do we do this? Through acts of faith. One simple practice is to make an act of faith in God’s intimate, providential guidance of all things: “I believe you are here in this moment, Lord. I believe you are in control.” By faith-filled recollection, we can stay alert to God’s love in any environment, keeping, in our hearts, one eye open to greet the Bridegroom when he comes.