Does the Early Bird Really Catch the Worm? Or Could the Night Owl Get There First?
Early risers earning more is only a correlation — you can't tell whether the social structure favors early risers or whether early risers are simply different people; and chronotype is biological, not a choice of willpower.
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Chronotype is biological, not a choice of willpower
Angela and Stephen discuss the concept of chronotype — whether a person naturally becomes alert in the morning or the evening. Angela calls herself a lark, often waking before the alarm goes off. Stephen stresses that the 2017 Nobel Prize in Medicine went to circadian rhythm research, which shows this is biological — even plants have biological clocks, because the Earth rotates on its axis and there is day and night, so organisms must predict and adapt to that rotation. So the answer to "why don't you just be a morning person" is that this trait is extremely hardwired.
— Stephen DubnerTeenagers sleeping late has biological evidence, it isn't laziness
Angela cites a 2017 PLOS ONE paper that used 12 years of diary data from the American Time Use Survey and found that chronotype is near-normally distributed both overall and within every age group, with the mean shifting systematically with age: later through adolescence, peaking latest around age 19, then shifting earlier. In other words, teenagers' bodies tending toward late sleep has evidence behind it. The paper also found that before age 40 men are usually later chronotypes than women, and after 40 it reverses. This supports the recommendation to push back school start times.
— Angela DuckworthLater school start times have measurable benefits
In 2017 the Seattle school district pushed middle and high school start times from 7:50 to 8:45, nearly an hour later. Researchers from the University of Washington and the Salk Institute used this to measure sleep-wake cycles and found students' median sleep duration increased by 34 minutes, with measurable benefits. Based on these studies, the RAND think tank estimated that delaying middle and high school start times alone would generate 8.6 billion dollars in economic productivity gains. This shows sleep schedule isn't an individual problem but a system design problem.
— Angela DuckworthEarly risers earn more, but it's only a correlation
Danish economist Jens Banke published a 2012 paper, "Do Morning-type People Earn More Than Evening-type People? How Chronotypes Influence Income," whose analysis showed early risers earn significantly more than late sleepers, and that being a morning type especially benefits men. But Stephen stresses this is correlational data and cannot be called causal. Being an early riser correlates not only with income but also with happiness, productivity and health. So you can't distinguish: whether early risers are simply more productive people to begin with (a spurious correlation), or whether the social structure favors early risers.
— Stephen DubnerCOVID was a forced experiment, and people generally pushed back their wake times
Stephen says one thing learned from COVID is that many people are able to and prefer to work in very different ways. Angela adds that a big silver lining of COVID was a forced experiment, and research showed people really did change their sleep patterns: when they didn't have to be in the office at 9 and had more flexibility, people generally shifted their wake times later, more like weekends than weekdays. This proves the rigid nine-to-five system isn't immutable — it's just that before 2020 nobody was forced to test it.
— Angela DuckworthThe email signature solves an empathy problem, not an efficiency problem
Stephen says he's an early riser and often sends work emails at 5 a.m., and he thinks that's fine because email doesn't demand an instant reply. But some people who get an early-morning email think, "he sent it at 5, I only woke up at 7, I have to reply right away." So Angela added a line to the end of every email: "my work hours may not be your work hours, reply if you want, when you want." She says it's a tribute to her late friend Seagal Barsade, a scientist who studied emotion and empathy. Barsade was a famous night owl who wrote on every email, "my work hours may not be your work hours, please don't feel obligated to reply outside normal working hours."
— Angela DuckworthThe most effective lever for shifting your schedule is controlling light
Angela learned from Stanford neuroscientist Andrew Huberman's podcast that you can adjust your natural circadian rhythm by controlling light. Huberman recommends getting daylight within 15 minutes of waking, especially important in the low-sunlight winter months. Angela moved her laptop from her basement office to an upstairs spot by a window. Huberman also recommends minimizing light later in the day, i.e. dimming the lights at home after dark. Angela says she's also more careful about not playing on her phone, and instead reads on an old black-and-white-only Kindle, which she finds helps.
— Angela DuckworthFrom early bird to night owl is the body clock shifting with age
At 17, Angela wrote a college application essay titled "Confessions of a Teenage Owl," in which she called sleep a "needless waste of time," said she slept only four hours a night, and claimed she was "just as healthy and twice as happy for it." Stephen says anyone in medicine or science today would want to delete that sentence. Angela is now 52, says she tries to sleep more, and compares herself to "the wise owl is to the early morning lark" — she went from early bird to night owl. This confirms the paper's finding that chronotype shifts with age.
— Angela DuckworthIn their own words · checked verbatim
this is really a biological thing. This is not a decision that you make to be a morning person or an evening person. Even plants have biological clocks.
Angela Duckworth10:20
there is a tendency for early birds to get the worm, but we don't know whether it's because the worms are laid out for them on a buffet early or whether they tend to be different kinds of people.
Stephen Dubner12:23
one of the big silver linings of COVID is that we had a force experimentation. And this research shows that people did shift their sleeping patterns.
Angela Duckworth15:28
my work hours may not be your work hours, reply if you want, when you want.
Angela Duckworth21:00
My working hours may not be your working hours. Please do not feel obligated to reply outside of your normal work schedule.
Angela Duckworth22:00
what we're getting at is not only flexibility and experimentation, what we learned in COVID, we're getting at empathy. People really are different.
Angela Duckworth23:03
The 52-year-old Angela is to the 17-year-old Angela as the wise owl is to the early morning lark.
Angela Duckworth27:18
Figures
| Seattle school district middle and high school start time delay | from 7:50 to 8:45 | 9:17 |
| Increase in students' median sleep duration | 34 minutes | 10:20 |
| RAND estimate of economic productivity gains from delaying school start times | 8.6 billion dollars | 10:20 |
| Age of latest chronotype peak | about 19 | 8:12 |
| Age at which the male-female chronotype difference disappears | 79 | 29:23 |
| Earliest possible year of origin for "the second mouse gets the cheese" | 1994 | 28:22 |
| Earliest traceable publication year for "the early bird catches the worm" | 1636 | 27:18 |
Glossary
- chronotype
- A person's biological rhythm type — whether they naturally tend to sleep and wake early or late.
- lark
- A person who habitually rises early and is energetic in the morning.
- owl
- A person who habitually stays up late and is energetic at night.
- near-normal distribution
- A bell-curve-like distribution shape, high in the middle and low at both ends.
- crepuscular
- The habit of animals that are active at dusk and dawn.
How to listen
Founders and managers puzzled by the relationship between sleep schedule and work efficiency, especially those who need to design a team's collaboration rhythm or who have long been in conflict with the nine-to-five.
The listener mail segment from 16:56 to 19:00 is low on information; jump straight to the email signature discussion at 20:00.