Us vs. Them: Environmental Signals and Internal Biases Influence Group Inclusiveness

Guest post by Matthew Espinosa

Lady Gaga’s “little monsters”, Star Trek’s “Trekkies”, and Kansas City Chiefs’ super-fans that are really excited that “we just won the Super Bowl!”. There are many different social groups that help us label people that we are similar to (“us”) and different from (“them”) [1]. Oftentimes, these groups and the arguments that arise between them are lighthearted. In the world of American football, an Eagles fan may joke that rival Cowboys fans are all “overconfident, sore losers.” However, even arguments between relatively frivolous groups can sometimes rise to life-threatening levels, such as in 2018, where an altercation between Eagles and Cowboys fans led to one man being stabbed to death. Further, when group categories center around more meaningful and intrinsic qualities, such as political affiliation, race, or sexual orientation, conflict can be more frequent and have widespread consequences for the treatment of our most vulnerable members of society.

Why do we have such strong tendencies to categorize others into groups of “us” and “them”? Historically, identifiable traits, such as race, sex, or age, enabled our ancestors to quickly and accurately categorize others, helping them survive and reproduce in environments filled with competition, violence, and disease [2, 3, 4, 5]. However, in modern society, where groups are larger and more physically diverse, categorization can be more challenging. The resulting conflicts based on group categorization in modern society may then be due to cognitive tendencies that evolved to address historically relevant challenges.

Resource Scarcity

Historical competition between groups for scarce resources (i.e., food, shelter, etc.) presents one evolutionary threat that may contribute to modern group categorization biases [3]. More lenient group boundaries may be useful during times of abundance, but such a strategy is risky when resources are scarce (i.e., when there are too many mouths to feed). Therefore, we may become less willing to categorize others as one of “us” to maximize available resources during times of scarcity [6, 7].

Rodeheffer and colleagues [8] aimed to explore this possibility across two studies. In Study 1, White undergraduates were randomly assigned to view slideshows depicting captioned pictures of either economic hardship or prosperity. In Study 2, participants instead completed sets of analogy problems that contained words associated with scarcity (e.g., sweat: summer :: debt:__), abundance, or neutral words.

Modern Times of Economic Prosperity: More Than Enough to Go Around

Abundance: As the supply of consumer goods has increased, people are able to get groceries and other goods at low prices. As a result, many families have extra money to save, invest, or spend on first consumer products.

The New Economics of the 21st Century: A Harsh and Unpredictable World

Scarcity: As people are having a difficult time paying rent, worldwide food and water prices are also increasing. Experts agree that merely keeping food on the table will become a challenge in upcoming decades.

In both studies, group categorization was measured by having participants view artificially morphed photographs of Black-White biracial men and women’s faces. For each photograph, participants rated whether it would be more accurate to label the biracial individual as “Black” or “White”. They found that participants primed with resource scarcity cues, compared to those primed with abundance or neutral cues, categorized more faces as being “Black”, or part of their racial outgroup. Further, participants viewing abundance and neutral cues in Study 2 did not differ in the number of faces they categorized as “Black”, suggesting that group categorization biases were specific to cues of resource scarcity. These findings suggest that as you notice decreases in the availability and increases in the costs of housing and food, such as during the recent egg-tastrophe in the U.S., you might find yourself becoming more selective in who you consider one of “us” — or someone worth sharing your prized eggs with  — than you would in the past.

Disease Threat

Disease presents another threat that may have influenced our ancestors’ categorization tendencies. When the threat of disease was high, interacting with an outgroup member would historically increase one’s risk of contracting an infectious disease, and, without the wonders of Tamiflu®, survival was unlikely. Accordingly, our evolved disease-avoidance systems selectively focus on specific cues to disease, which may motivate more risk-averse categorization tendencies that are similar to what we saw in Rodeheffer and colleague’s research on resource scarcity.

To examine how disease threats influence group categorization, Makhanova and colleagues [9] assigned White participants to either a “green” or “orange” personality type, supposedly based on their results from a personality questionnaire. Participants then read an article about the rising threat of either a new Coronavirus (disease threat) or a severe winter storm (non-disease/weather threat). To assess group categorization tendencies, participants viewed photographs of men who were either (1) White or Black, and (2) younger or older in age (i.e., older adults are often associated with illness [4, 10]), then judged whether the men had the same or the opposite personality type as themselves. They found that people highly concerned with avoiding diseases were more likely than chance to label the photographed men as outgroup members, regardless of the article they read. Those without chronic disease avoidance concerns labelled older, White targets as outgroup members after reading the Coronavirus article, but not the winter storm article. Thus, the threat of disease motivates more restrictive group categorization, particularly towards those who possess physical qualities associated with disease.

Participants with chronic disease concerns (graph on the left) categorized all the faces as “them” more often than chance, whereas participants with low disease concerns (graph on the right) only categorized older White people as “them” more often than chance.
Adapted from Makhanova et al. (2021).

Social Biases

As we can see, evolutionarily relevant threats in our environment can influence how we label others. However, even when our environment is threat-free, people sometimes still exhibit restrictive categorization tendencies. For example, Black-White biracial individuals in the United States are often categorized as being only “Black” [11, 12], a phenomenon known as hypodescent. Hypodescent can occur due to socialized beliefs about equality and status hierarchies [13, 14], and raises questions about the intertwined nature of evolved cognitive processes and modern socio-cultural biases.

Ho and colleagues [15] sought to better understand how social biases influence hypodescent beliefs by looking at the roles of race essentialism, the belief that group members share essential or genetic characteristics [16], and negativity bias, the tendency to weigh negatively viewed concepts more strongly. In Study 1, the researchers measured White participants’ endorsement of race essentialism and negativity bias. The participants then rated the “whiteness or blackness” of three biracial targets who had: 1) one Black and three White grandparents, 2) three Black and one White grandparent, or 3) two Black and two White grandparents. In Study 2, the researchers manipulated essentialism beliefs by assigning participants to read a fictitious article that described race as either genetic (high essentialism) or non-genetic (low essentialism). Participants then labeled 20 biracial face morphs as being either “Black”, “Black-White biracial”, or “White”.

Example of morphed biracial faced used in Study 2 of Ho et al. (2015).

In both studies, participants with high race essentialism exhibited greater hypodescent when they also held a negativity bias towards Black people. That is, they labeled more biracial individuals as being only “black”, regardless of the actual degree to which they were genetically Black, when they believed race to be genetically determined. Participants who didn’t view Black people negatively or who viewed race as genetically determined did not exhibit hypodescent. These results suggest that race essentialism and negativity biases together can lead to more restrictive categorization tendencies, even when your environment tells you that everything is alright.

Why does this research matter, and what more can we learn?

Researchers have identified environmental threats and social biases that can lead us to be restrictive in who we consider “one of us.” Why does this matter? To illustrate, let’s move past our examples of sports fans and overpriced eggs, and take a quick dip into politics. For many voters, threats in their environment, such as economic recessions and pathogen outbreaks, and socialized beliefs often influence the candidates and policies they vote for. Further, political ideology itself represents a categorical group, and biases within this area could play a role in the development of extreme or radical voting practices that negatively impact vulnerable individuals that are deemed “them”. So, a better understanding of how our environment and social biases influence the way we categorize others can help us avoid the pitfalls associated with restrictive categorization tendencies, hopefully promoting more cooperative and inclusive social engagement — political or otherwise.

Nonetheless, critical questions remain to be explored about group categorization tendencies. Do these tendencies extend to people of different races (e.g., Asian-Latino biracial individuals), and do these categorization tendencies predict actual discriminatory behavior? Considering the lack of hypodescent expressed by children when categorizing biracial individuals [17], what are the developmental pathways through which restrictive group categorization arises? Fortunately, the findings of the studies discussed here provide an important foundation for future research to explore group categorization and the ways it influences our daily social interactions.

Matthew is an experimental psychology graduate student in the College of Science and Engineering at Texas Christian University. His areas of research interests include social ostracism, interpersonal relationships, and early life environment. When not in the lab, he enjoys cooking, watching scary movies, and reading about new research.


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