A series of three studies published in Evolutionary Psychological Science examined friendship preferences. Participants’ most desired traits in friends were honesty, ethicality, pleasantness and availability, while the most undesired traits were dishonesty, competitiveness and impatience.
Friendship is a universal and integral part of humanity, ranging across cultures and time; this raises the evolutionary question of why we even make friends. Two reasons have been proposed to explain our capacity to form friendships, including social support and social input (i.e., social interaction). Given the absence of state-based support and protection throughout our evolutionary history, it was necessary to rely on others (predominantly genetic relatives) for survival.
However, relying on family can have limitations. Despite shared genetic interests providing motivation to support relatives, family members could be geographically far, have poor health, or limited resources. Support from in-laws is another possibility, but conflict with in-laws is a common phenomenon which could affect the reliability of this source of support.
Menelaos Apostolou and Panagiota Vetsa write, “Accordingly, securing assistance from non-genetically related individuals or non-genetic relatives would make a considerable difference to one’s chances of survival, which in turn, would favor the evolution of behavioral mechanisms that would enable people to form relationships of cooperation and mutual help.”
The capacity to make friends could be exploited – for example, approaching someone in the guise of friendship when true interests lie in acquiring them or others in their social sphere as a mate. Another form of exploitation might be targeting individuals who may prove useful in advancing personal goals (e.g., career, social influence). The authors add, “Accordingly, the capacity to make friends would be further favored by selection forces, because friendships could provide individuals with mating and personal advancement benefits.”
Some traits would enable people to provide consistent support and input to friends (e.g., kindness), while other traits would make this unlikely (e.g., selfishness). Differences in friendship value would select for mechanisms that would enable humans to allocate resources toward maintaining high value friendships. In this work, Apostolou and Vetsa seek “to identify desirable and undesirable traits in friends, classify them into broader trait categories, and examine their importance.”
Study 1 recruited 236 individuals from Greece and the Republic of Cyprus. Participants wrote down traits they would want their friends to have and not to have. A total of 50 desirable traits and 43 undesirable traits emerged.
Study 2 included 706 Greek-speaking participants who were given the sentence “I would like a friend of mine to be:” followed by the 50 traits identified in Study 1, presented in random order. For each trait, participants gave a rating ranging from 1 (strongly disagree) to 5 (strongly agree).
Study 3 recruited 861 Greek-speaking individuals who were presented with the statement “I would like a friend of mine NOT to be:” followed by the 43 traits identified in Study 1. Once again, they provided ratings on a 5-point scale. In all three studies, participants provided demographic information, including age and sex.
In order of importance, desirable traits were classified into honest, ethical, pleasant, available, discreet, tolerant, empathetic, fun, smart, and alike, while undesirable traits were categorized into dishonest, competitive, and impatient. These findings support the framework that traits which would facilitate cooperation and mutual support would be preferred, while traits that would hinder this would be unwanted. For example, “high[ly] competitive and jealous individuals would prefer to see others, including their ‘friends,’ doing worse than them  and thus, they would be less likely to assist them in times of need.”
Further, the preference for friends who are smart, pleasant, and fun over those who are impassionate or pessimistic suggests people seek quality social input. In other words, people want friends they can have a good time with.
Compared to men, women provided higher ratings overall; this aligns with prior research indicating women have higher expectations for friends, and are more selective than men. As well, the researchers found an age effect for most traits, and suggest this may reflect increased selectivity for friends as people age.
A limitation to this research is that it did not distinguish between same- and opposite- sex friendships. It could be the case that people have different preferences for their same- and opposite- sex friends.
Apostolou and Vetsa conclude, “The complexity of the phenomenon mandates that considerable more work is necessary in order for friendship preferences to be understood, which is necessary for understanding human friendship.”
The research, “Friendship Preferences: Examining Desirable and Undesirable Traits in a Friend”, was authored by Menelaos Apostolou and Panagiota Vetsa.