In the years before World War Two,
a pair of brothers worked together
as shoemakers
in the German town of Herzogenaurach.
But during the war, the siblings
had a terrible argument—
a fight so explosive it split
the family business in two.
At first, the feud only infected
their newly competing personnel.
But over the coming years,
this disagreement divided
all of Herzogenaurach.
Residents became fiercely
loyal to one brand of shoe.
Local businesses chose sides and
marriage across lines was discouraged.
Herzogenaurach eventually became
known as “the town of bent necks”
because its residents looked down
to ensure they were interacting
with members of their group.
But could such a serious divide
really be about shoes?
Doesn’t it take more significant
cultural differences
to produce this degree of conflict?
To answer this question, we can turn
to social psychologist Henri Tajfel
and his collaborators
at the University of Bristol.
This team developed
the minimal group paradigm,
a methodology designed to investigate
the minimal conditions required
to turn people against each other.
Their plan was to gather participants
without the usual factors
that lead to hostility,
such as religious, ethnic,
gender, or other cultural differences.
Then, they would split into groups,
and run them through scenarios
that added one variable at a time
to see what stirred up conflict.
But first, they needed
a control condition—
a pair of groups without any group bias.
The researchers told participants
they were being grouped
based on their ability to estimate things
correctly or incorrectly;
but in reality,
the groups were totally random.
Since the researchers ensured none
of the participants interacted,
no one could form any judgments
or personal bonds.
Then everyone was given resources
to distribute.
Each participant was free to give
resources to members of either group,
and importantly, everything was anonymous.
So whatever a participant decided,
it had no impact on how many resources
they personally would receive.
With all the ingredients
for discrimination removed
and no reason for competition
over resources,
the scientists assumed this would
make a conflict-free baseline
for further research.
But even in these groups,
where membership was only defined
by a perceived similarity
in possessing an arbitrary skill,
individuals still showed in-group bias.
They consistently gave more to members
of their own group than the out-group.
Later, research went even further,
informing participants that the only thing
determining their group membership
was a coin flip.
But group bias still occurred.
The minimal groups of “us” and “them”
were enough.
So, in the absence of stereotypes,
resource conflicts and status differences,
what was left?
What could possibly account for people
showing clear preferences
for the most temporary and meaningless
of groups?
The answer that came to Tajfel
and his colleagues was social identity.
People regularly use group membership
to help determine their sense of identity.
And these minimal group experiments
suggested that simply being categorized
as part of a group is enough to link
that group to a person’s sense of self.
Then, in an effort to create
a meaningful identity,
participants allocated more resources
to their in-group than the out-group—
pursuing their group's interests despite
no clear benefit to themselves
as individuals.
Variants of these experiments have
been conducted around the globe,
examining how a shared sense
of “us” can affect our attention,
perception, memory, and emotions.
The mental processes
behind minimal group distinctions
appear to be the same as many of those
that underlie real group identities.
So it is possible that these seemingly
insignificant differences can harden
into much more serious divides.
That said, minimal groups don't
always drive people apart.
Bringing individuals together
in a new group
can temporarily help people
overcome entrenched biases.
However, these positive effects are easily
negated by external factors
that reinforce existing group identities.
Ultimately, the psychology of groups
is part of the human condition,
and our tendency towards in-group bias
is an undeniable part of that.
So it's up to all of us to make
our groups and ourselves
as inclusive of others as possible.