6 March 2021 | New Scientist | 39after a change in friendship, they were
almost identical. It seems that when we
replace someone in our social network,
we slot the new friend into exactly the same
position the old one previously occupied in
terms of the frequency with which we contact
them. Our study had revealed that people
have a characteristic social fingerprint.
How often you contact each of your friends
probably reflects aspects of your personality,
such as extraversion, neuroticism and
conscientiousness. Our analysis revealed
another factor influencing your social
fingerprint: whether you are male or female.
Over the course of the study, some friendships
held up better than others, and we wondered
why. The answer tended to differ between
the sexes. For the girls as a whole, the activity
most effective in preserving a pre-university
friendship was talking together, whether in
person or by phone. For the boys, talking had
absolutely no effect on how likely a friendship
was to survive. What made the difference
was doing stuff together more often than
they had before – going to the pub, playing
sports, climbing mountains or whatever. Such
activities also had a positive effect on the girls’
friendships, but it was nowhere near as great.Calling patterns
This could have implications for how well our
friendships are bearing up during the pandemic,
while face-to-face meetings are restricted. It
might also help explain a difference we found
in the amount of time girls and boys spent on
the phone. Of course, there were big individual
variations, but for girls, calls averaged 150
seconds in the morning, rising to 500 seconds
by the end of the day. Boys’ calls, by contrast,
averaged just 100 seconds throughout the day.
Further analysis, led by Talayeh Aledavood
at Aalto University, revealed another aspect
of our identity with an influence on our social
fingerprint. When we looked at the times at
which our students were calling and texting,
they found clear differences. Some were most
active on their phones during the day and
others used them mostly at night. We alsoCH
RIS
ST
EEL
E-P
ER
KIN
S/M
AG
NU
M^ P
HO
TO
S
“ Our study had
revealed that
people have a
unique social
fingerprint”
>students who sent an average of 100 texts a
day – and kept this up for the entire duration
of the study.) Luckily, I was collaborating at
the time with some physicists on a project
about online networks and persuaded a
couple of them to help with the complicated
task of analysing the data. We were amazed
by what we found.
We could see the layers of the students’
social circles very nicely. What we hadn’t
expected, however, was the fine detail
in how individuals allocated their social
effort. Each showed a distinct pattern in the
frequency with which they called friends.
One might call their best friend 30 times a
month and their second best friend 10 times,
while another would call their two top friends
20 times each, for example. But that wasn’t the
most surprising thing. There was an average
of around 40 per cent turnover in network
membership over the 18 months – which is
fairly normal for young adults – yet, when we
looked at the patterns of contact before andOur social circle
includes family, so
people with larger
families tend to
have fewer friends