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The Surprising Effects of Parents' Sleep Deprivation

Being tired can interfere with parents' ability to express joy.

Parents deal with sleep deprivation all the time, but they may not be aware of the underlying channels through which their tiredness affects their children.

Many parents intuitively understand how sleep deprivation slows or inhibits their mental processes, reduces their ability to stay calm when confronted with negative stimuli, and interferes with their ability to manage their emotions. One study by Anderson and Platten (2011) showed that sleep deprived participants responded more quickly to negative stimuli. Another study by Gujar and colleagues (2011) found that when sleep-deprived research participants were shown others’ emotional expressions, they had increased reactivity to them. When they napped (and especially when they got REM sleep), their increased reactivity was reversed. It’s clear that sleep is an important contributor to calm and peaceful parenting.

However, research speaks to another important result of the "zombie effect": being tired can interfere with parents’ ability to express joy (both verbally and nonverbally).

Here are some surprising effects of sleep deprivation, and why they matter so much to parents:

When Tired, Your Face Has a Harder Time Forming Happy Expressions

Minkel and colleagues (2011) found that sleep deprived research participants were significantly less facially expressive. Although tired participants had trouble expressing both sadness and happiness, they had the hardest time forming happy facial expressions.

When Tired, Your Voice Has Less Positive Affect

McGlinchey and colleagues found that following a night of sleep deprivation, research participants used fewer words and expressed less positive affect and more negative affect via speech (McGlinchey et al., 2011). Another study found that sleep-deprived participants had voices that were more monotonic or flat (Harrison and Horne, 1997).

When Tired, You Appear Sadder

Sundelin and colleagues (2013) found that people who have been sleep deprived are perceived to be more sad and fatigued, often based on cues such as redder eyes, hanging eyelids, swollen eyes, darker circles under the eyes, pale skin, more wrinkles around the eyes, and droopy corners of the mouth.

Emotional contagion research suggests that emotions like enthusiasm and joy, as well as sadness, fear, and anger, can be passed from person to person, including from parent to child, within seconds (Hatfield cited in Colino, 2016; Goleman, 1991, Hatfield et al., 2014; Waters, West, and Mendes, 2014). When parents are joyful, kids often model off their joyful facial expressions, verbal expressions, markers, habits, responses, and behaviors. However, when parents are sad, angry, anxious, or just plain “flat,” kids pick up on and mimic those markers instead. This becomes particularly important during a child’s second year, when children gain the developmental ability to mimic adults using cues across a variety of contexts (Jones, 2009).

Remembering that getting enough sleep has the potential to help us spread joy may prevent us from watching that one extra not-great rerun on TV, scrolling aimlessly on social media, or reorganizing our medicine cabinet until way past our bedtime.

Due to work schedules, a child's reflux or health problems, or other factors, there may be no way to prevent lack of sleep. Parents can remember to give themselves extra compassion when they don't feel like their chipper selves.


Anderson, C. and Platten, C.R. Sleep deprivation lowers inhibition and enhances impulsivity to negative stimuli. Behav Brain Res. 2011; 217: 463–466

Colino, Stacey. 2016. “Are You Catching Other People’s Emotions?” U. S. News and World Report. Posted January 20.

Goleman, Daniel. 1991. “Happy or Sad, a Mood Can Prove Contagious.” The New York Times. Posted October 15.…

Gujar, N., McDonald, S.A., Nishida, M., and Walker, M.P. A role for REM sleep in recalibrating the sensitivity of the human brain to specific emotions. Cereb Cortex. 2011; 21: 115–123

Harrison, Y. and Horne, J.A. Sleep deprivation affects speech. Sleep. 1997; 20: 871–877

Hatfield, Elaine, Lisamarie Bensman, Paul Thornton, and Richard Rapson. (2014). “New Perspectives on Emotional Contagion: A Review of Classic and Recent Research on Facial Mimicry and Contagion.” Interpersona 8, no. 2: 159-179.

Jones SS. The development of imitation in infancy. Philosophical Transactions of the Royal Society B: Biological Sciences. 2009;364(1528):2325-2335. doi:10.1098/rstb.2009.0045.

McGlinchey, E.L., Talbot, L.S., Chang, K.-H., Kaplan, K.A., Dahl, R.E., and Harvey, A.G.The effect of sleep deprivation on vocal expression of emotion in adolescents and adults. Sleep. 2011; 34: 1233–1241

Minkel, J., Htaik, O., Banks, S., and Dinges, D. Emotional expressiveness in sleep-deprived healthy adults. Behav Sleep Med. 2011; 9: 5–14

Sundelin, T., Lekander, M., Kecklund, G., Van Someren, E.J., Olsson, A., and Axelsson, J. Cues of fatigue: effects of sleep deprivation on facial appearance. Sleep. 2013; 36: 1355–1360

Waters, Sara, Tessa West, Wendy Mendes. 2014. “Stress Contagion: Physiological Covariation Between Mothers and Infants.” Psychological Science 24, no. 4: 934-942.