NurtureShock (34 page)

Basis of “lost hour” of kids’ sleep:
There seems to be universal agreement as to the fact that kids are getting less sleep
today than in years past. However, there’s less agreement in just how much sleep kids have lost. We base our “one lost hour”
on research we did in sleep studies and general time use studies: our determination is probably a conservative assessment.

According to one report, in 1997, children age 3 to 5 were found to be getting just over 10.8 hours of sleep per night, while
children 6 to 8 years old were getting 10.1 hours of sleep. In 2004, the National Sleep Foundation found that the 3- to 5-year-olds
were down to 10.4 hours of sleep, and the 6- to 8-year-olds were down to 9.5 hours. (Compare Hofferth and Sandberg [2001]
to the National Sleep Foundation’s 2004 Sleep in America Poll.)

Over the same time period, Brown University found that, in 1997, nine- to twelve-year-olds were getting about 9.6 hours of
sleep, but in 2004, sixth graders were getting 8.3 of sleep—a difference of 1.3 hours. Carskadon (2004) and Sleep in America
poll (2006).

Further support for the hour loss of sleep can be found in an influential and widely cited study of Swiss children. In that
study, throughout the 1990s, sleep duration for children fell across all ages—meaning that a two-year-old slept less in 1986
than he would have in 1974, and a fourteen-year-old slept less in 1986 than he did in 1974. The youngest children actually
saw the most severe drop in sleep duration. Six-month-old infants born in 1993 were sleeping 2.5 hours less than those born
in 1978, while there was a 1.0 hour difference for sixteen-year-olds. Iglowstein et al. (2003).

In 2005, the American Academy of Pediatrics’ Working Group on Sleepiness in Adolescents/Young Adults and the AAP Committee
on Adolescence issued a technical report that opined that the Iglowstein study was an “impressive work” and a valuable guideline
as to trends in youth sleep in the United States; if anything, the American scholars believed that the US results would be
more “extreme” than the Swiss results. Millman et al. (2005). And Landhuis et al. believe that a two-hour drop in the past
two decades is also a supportable claim. Landhuis et al. (2008).

Other studies addressing the international downward trend in sleep duration include: Van Cauter et al. (2008) and Taheri (2006).

Rhode Island study on teens setting bedtimes:
Wolfson and Carskadon (1998).

Sleep deprivation and its effects on emotional stability and development:
For ADHD, authors’ interviews with Ronald Chervin
and Louise O’Brien; Chervin et al. (2005); Chervin et al. (2002); and Chervin et al. (1998). For emotional stability of adolescents,
authors’ interviews with Ronald Dahl, David Dinges, and Frederick Danner, as well as Dahl (1999); Danner and Phillips (2008).

Experimental manipulation of children’s sleep duration and test performance:
Since Sadeh’s experiment, Tzischinsky et al.
(2008) essentially replicated his findings—having eighth graders sleep an hour more than normal. The students who slept the
extra time scored significantly higher on math tests and attention measures.

Effects of sleep loss akin to lead exposure:
McKenna (2007).

Studies reporting a sleep/grade correlation:
See, e.g., Danner and Gilman (2008); Warner et al. (2008); Bachmann and Ax (2007);
and Fredriksen et al. (2004).

Sleep deprivation’s interference with brain mechanisms:
Durmer and Dinges (2005).

Slow-wave sleep and kids’ learning vocabulary:
Backhaus et al. (2008).

Edina, Minn. SAT scores:
The
New York Times
previously reported on Edina’s SAT gains; however, the article reported incorrect scores. The
Times
reported lower figures than the students had actually achieved. Wahlstrom had requested a correction at the time; however,
no one responded to her query. Per our request to Wahlstrom, Wahlstrom retrieved the information that she had previously provided
the
Times
, and then re-analyzed the data to confirm the accuracy of the increase.

O’Reilly of the College Board explained to us in an interview that the increase is even more extraordinary on two points.
First, the scores we include in the text were based on the 1600-point test: a 212-point increase would essentially account
for 14% of a total score. Second, most Minnesota students take the ACT: only the most competitive students take the SAT. Accordingly,
O’Reilly says that students in the top 10% of an Edina SAT class would be in the
top 1%
nationally. We also note that the increase in scores after the later start time is roughly equivalent to the increase promised
by professional SAT prep courses.

Later school start times result in improved quality of life:
Htwe et al. (2008); Danner and Phillips (2008) and Wahlstrom
interviews.

Prevalence of early morning high school start times:
Wolfson and Carskadon (2005).

McMaster review of obesity prevention programs:
Thomas (2006). British officials completed a similar large-scale review of
obesity prevention programs and also concluded that there was “scant” evidence that such programs were effective. See “Obesity
‘Not Individuals’ Fault” (2007). Stice et al. (2006) also considered the efficacy of most programs to be “trivial.”

Kids’ TV watching and other sedentary activity:
Vandewater isn’t the only scholar who disputes the premise that kids limit
their physical activity because they are watching television. Taveras et al. (2007) concluded that if a kid watched an hour
less of television each week, there would be no increase in his physical activity. And other researchers have measured the
time spent on homework, computer use, reading, hobbies, hanging out with friends, even sitting in a car on the way to school.
When those are considered, television is as little as one-third of a teen’s sedentary activity. Biddle et al. (2009); Biddle
(2007); and Utter et al. (2003).

Studies showing relationships between sleep deprivation and children’s obesity:
In addition to the American, Australian, Canadian,
and Japanese studies finding a connection between children’s shortened sleep and obesity, this same relationship has now also
been found by scholars in France, Germany, Portugal, Tunisia, China, Hong Kong, Taiwan, Brazil, and New Zealand—where scholars
found that shortened sleep in elementary school children predicted obesity at age 32. Studies reporting a connection include:
Landhuis et al. (2008); Nixon et al. (2008); Taveras et al. (2008); Lumeng et al. (2007); Eisenmann et al. (2006); Chaput
et al. (2006); Gupta et al. (2002); and Sekine et al. (2002).

Two meta-analyses also have found a relationship between children’s sleep and obesity: Cappuccio et al. (2008) and Chen et
al. (2008).

While some scholars—e.g., Hassan et al. (2008) and Horne (2008)—are still unsure about the relationship between sleep and
kids’ obesity,
Pediatrics
has determined that enough data supports short-sleep’s relationship to overweight in children, that sleep should be considered
in assessing an individual child’s weight issues. Krebs et al. (2007). And other scholars believe that the data is now persuasive
enough that kids’ sleep and obesity should be considered a public health issue. Young (2008).

CDC/USDA positions on kids and sleep:
Park (2008); Schoenborn and Adams (2008); Redding (2007); and Hensley (2007).

Chapter 3, Why White Parents Don’t Talk About Race

Infants’ perception of racial differences:
Kelly et al. (2007) have determined that infants begin to notice the visually apparent
aspects of racial differences somewhere between the third and sixth months.

Experiment with cross-race groups:
Rooney-Rebeck and Jason (1986).

Subgroupism in Japanese schools:
Based in part on authors’ interview and correspondence with David Crystal and Crystal et
al. (2000).

Shushing kids’ discussion of race:
In one case we learned about, a kindergarten teacher began her lecture on Martin Luther
King Jr. only to have one of the children cut her off with: “Mommy says we shouldn’t talk about color.” Polite and Saenger
(2003).

Study of Detroit high school students:
Oyserman et al. (2006).

Black Santa and White Santa:
Account is based on authors’ interviews, correspondence with Coperhaven-Johnson, and her report,
Coperhaven-Johnson (2007).

Chapter 4, Why Kids Lie

100,000 children testifying:
Following Talwar’s discoveries about children’s understanding of lying, and under what circumstance
they are more likely to lie, the Canadian legislature revised its procedure to determine if children should be allowed to
testify. Talwar et al. (2002) and Bill C-2 (2004).

Lie-detection systems:
In an extensive review of 150 studies on lie detection, University of Portsmouth professor Aldert Vrij
concluded: “[T]here is not a single verbal, nonverbal or physiological cue uniquely related to deception. In other words,
nothing similar to Pinocchio’s growing nose actually exists.” Vrij (2004). Perhaps the most common belief about lie detection
is that people avert their gaze when telling a lie. However, study after study show that gaze aversion has little if any relation
to a person’s lying. Gaze aversion is even less of a signal for children: they frequently look away from a conversation partner
when they are concentrating. See, e.g., Talwar and Lee (2002a) and Vrij et al. (2004).

Fascinatingly, in a 2006 study of over 11,000 survey responses from 57 countries, 64% of respondents said that gaze aversion
signaled lying. Scholars hypothesize that the myth of gaze aversion comes from a different emotional state altogether: around
the world, people look down at the ground as an indication of shame. Therefore, the scholars suggest there’s an (errant) assumption
that liars are ashamed of their falsehood and thus look away. Global Deception Research Team (2006).

Parents’ inability to detect children’s lies:
Talwar has been regularly studying parents’ failure to identify children’s lying,
first publishing results in 2002. She isn’t alone in her findings, either: scholars Angela M. Crossman and Michael Lewis found
similar results, with parents again performing at levels lower than chance in identifying children’s lying in their study.
Crossman and Lewis (2006).

In Talwar’s newest study, she’s been looking to see if some people are just better at lie detection than others. She’s found
that only 4% were repeatedly significantly better at lie detection. Leach et al. (2009).

Prevalence of children who peek and lie:
The percentages of children who will cheat and lie during the peeking game we’ve
reported come from Talwar’s first 2002 study. Talwar and Lee (2002a). However, Talwar has since replicated this pattern in
many subsequent studies: the percentage of children who peek and those who lie remain amazingly consistent. Additionally,
other scholars have since replicated her work in their own versions of the peeking game.

Lying’s connection with intelligence:
Talwar has found that children with more advanced executive functioning and working
memory are better liars. She’s also seen relationships between children’s lying and “theory of mind”—the ability to understand
and keep track of multiple people’s points of view.

Children’s lying to make a parent happy:
Along with Talwar’s research, Bussey’s work fleshes out this insight. When Bussey
has presented children with anecdotes, and asked them to predict if the protagonist would be truthful or not, the children’s
responses were in part determined by whether or not the story had said if the protagonist would be punished for a misdeed
or its admission. Bussey has also shown that it isn’t until children are eight years old that they begin to believe that truth
telling may make the truth teller himself feel better. Bussey (1999) and Wagland and Bussey (2005).

Additionally, a 2007 University of Texas, El Paso, study offers an intriguing twist for both Talwar’s conclusion that children
lie to make an adult happy and Dweck’s praise-addicted children. In the UT study, young children were asked if they’d seen
anyone take an examiner’s toy. Some children were told, “Thank you, you’ve been a big help,” every time they answered “Yes”
to
any
of the examiner’s questions. Within four minutes, half of the children who had heard that praise had begun making false confessions.
They actually lied about wrongs they weren’t a part of, so that the praise could continue. Billings et al. (2007).

Frequency of children’s lies:
Wilson et al. (2003) and Wilson et al. (2004).

Tattling:
The primary work on children’s tattling comes from den Bak and Ross (1996) and Ross and den Bak-Lammers (1998).
Friman et al. (2004) is also informative, particularly on his point that fourth-graders consider tattling an aggressive act
on par with stealing or destruction of another’s property.

Frequency of adult lies:
There are popularized claims that the average adult lies at least three times in a ten-minute conversation.
However, that statistic is based on an experiment in a highly manipulated situation—where two strangers were told to sit in
a room and at least one had been instructed to say things that would make the other like him. Even in that artificial environment,
40% of the test subjects never lied at all. The data from DePaulo and Hancock on the frequency of lies is based not on an
experimental manipulation, but on diary studies—where people kept track, on a daily basis, of every lie that they told. In
the DePaulo and Hancock studies, people in the general population lied only about once a day—college students twice a day.
DePaulo et al. (1996) and Hancock et al. (2004).