D
uring an experiment in which people
played a game and won or lost money,
neuroscientist Robb Rutledge noticed
something strange. “Some people would be in
a really good mood, and it wouldn’t actually be
closely related to how much money they had,”
he says. “That seemed very surprising to me.”
Rutledge, then a grad student study-
ing the neuroscience of decision making at
New York University, wondered whether
it would be possible to figure out what
determines those moods—specifi cally, how
happy a person feels minute-to-minute. He
went on to do a postdoc at University Col-
lege London (UCL), where he ran similar
experiments in which volunteers played a
game for money, but this time he focused
on constructing a model for what fac-
tors determined the players’ emotional
responses to outcomes. Rather than the
amount of their winnings, what mattered
most to players’ moods was whether the
reward exceeded their expectations.^1
Based on previous work by other
researchers, Rutledge suspected the neu-
rotransmitter dopamine was involved in
the moods study participants reported.
So he and colleagues ran money-winning
experiments on people who’d been given
a drug that increases dopamine release.
Compared with people given a placebo,
people who got the drug reported feeling
better after small wins. But there was no
difference in how the two groups felt after
larger wins or losses.^2 Dopamine, while
important, isn’t the whole story, Rutledge
says. There must be other systems in the
brain that inform how we feel after these
types of events. He and his colleagues are
now searching for those systems.
Even if he finds them, Rutledge doesn’t
think his findings are likely to improve hap-
piness in healthy people. He’s more inter-
ested in helping people with depression.
A few years ago, he and colleagues did
fMRI scans of people with depression andhealthy controls as they performed a task
with associated rewards. The team also
built a smartphone app, The Great Brain
Experiment, and had 1,833 volunteers
rate their happiness levels as they played
games and earned or lost points. People
with depression and controls displayed
similar patterns of brain activation and
boosts in mood in response to unexpect-
edly large rewards, a finding that contrasts
with previous results.^3
Peter Dayan, a computational neu-
roscientist at UCL, says he was skepti-
cal about the app in the beginning and
thought it was unlikely to deliver interest-
ing data. But Rutledge, who started his
own lab at the university early last year,
was able to construct experiments that
surpassed Dayan’s expectations. Dayan
now thinks the use of The Great Brain
Experiment, which has topped 134,760
users as of October 1, and other apps will
turn out to be game changing because of
the large quantity of data they can deliver
to researchers.
“Robb has really pioneered the use of
smartphone technology to do large-scale
population studies of psychological pro-
cesses and link those processes to men-
tal health and mental illness,” says Molly
Crockett, a psychology researcher at Yale
University. She did a postdoc at UCL at the
same time as Rutledge and still collabo-
rates with him to investigate how people
form and change impressions of others.
“Robb has really inspired the rest of the
team in this research.”REFERENCES- R.B. Rutledge et al., “A computational and
neural model of momentary subjective
well-being,” PNAS, 111:12252–57, 2014.
(Cited 150 times) - R.B. Rutledge et al., “Dopaminergic modu-
lation of decision making and subjective
well-being,” J Neurosci, 35:9811–22, 2015.
(Cited 68 times) - R.B. Rutledge et al., “Association of neural
and emotional impacts of reward predic-
tion errors with major depression,” JAMA
Psychiat, 74:790–97, 2017. (Cited 18 times)
SCIENTIST TO WATC HRobb Rutledge: Happiness Hunter
© RICHARD BOLL
11.2018 |11.2018 | THE SCIENTIST THE SCIENTIST 57Principal Research Associate, University College London, Age: 37IBY SHAWNA WILLIAMS