Social categorizations are an important aspect of human society, dividing people into "us" and "them  " often along  attributes such as race or even political ideology . Social categorizations can, on the one hand, lead to a sense of belonging, and on the other hand, fuel conflicts. Thus, it is vital to understand where and how the boundaries for social categories form. We present a dynamical systems model for the formation of two social groups  on a continuous attribute. Our model makes the surprising prediction that individuals in the middle of the spectrum are seen as "them" by both social groups, and "us" by neither. We refer to these individuals as inbetweeners .  We test the model's prediction using US political survey data on how political independents are perceived by registered party members , as well as existing experiments on the perception of racially ambiguous faces, and find support . Our model suggests that inbetweeners can arise as the result of both groups drawing a more restrictive boundary than the middle of the spectrum, motivated by improving categorization accuracy alone. The model prediction is general and may be extended to social categorization along many other attributes .
Social categorizations divide people into "us" and "them , " often along continuous attributes such as political ideology or skin color. This division results in both positive consequences, such as a sense of community, and negative ones, such as group conflict. Further, individuals in the middle of the spectrum can fall through the cracks of this categorization process and are seen as out-group by individuals on either side of the spectrum, becoming inbetweeners. Here, we propose a quantitative, dynamical-system model that studies the joint influence of cognitive and social processes. We model where two social groups draw the boundaries between "us" and "them" on a continuous attribute. Our model predicts that both groups tend to draw a more restrictive boundary than the middle of the spectrum . As a result, each group sees the individuals in the middle of the attribute space as an out-group. We test this prediction using U.S. political survey data on how political independents are perceived by registered party members as well as existing experiments on the perception of racially ambiguous faces, and find support .
R
are an important aspect of human society, dividing
divide
A
,
A
continuous
R
race or even political ideology . Social categorizations can, on the one hand, lead to
political ideology or skin color. This division results in both positive consequences, such as
R
belonging, and on the other hand, fuel conflicts. Thus, it is vital to understand where and how the boundaries for social categories form. We present a dynamical systems model for the formation of
community, and negative ones, such as group conflict. Further, individuals in the middle of the spectrum can fall through the cracks of this categorization process and are seen as out-group by individuals on either side of the spectrum, becoming inbetweeners. Here, we propose a quantitative, dynamical-system model that studies the joint influence of cognitive and social processes. We model where
A
draw the boundaries between "us" and "them"
R
makes the surprising prediction that individuals in
predicts that both groups tend to draw a more restrictive boundary than
D
are seen as "them" by both social groups, and "us" by neither. We refer to these individuals as inbetweeners
A
As a result, each group sees the individuals in the middle of the attribute space as an out-group.
R
the model's prediction using US
this prediction using U.S.
D
,
D
. Our model suggests that inbetweeners can arise as the result of both groups drawing a more restrictive boundary than the middle of the spectrum, motivated by improving categorization accuracy alone. The model prediction is general and may be extended to social categorization along many other attributes