Think back to your high school days, and the social interactions that come to play in the high school arena (scary and traumatic, I know, but just humor me here). Who did you find yourself making friends with? Were there clubs or sports teams that structured your friend groups? On a group level, were there noticeable differences between how girls and boys would interact with one another? Could these differences in individual social interactions be an artifact of personality?
When scientists try to understand how individuals interact with each other, these are the types of questions that they tend to ask themselves. They try to answer these questions using a tool called social network analysis, which is a way to quantitatively assess both direct and indirect interactions amongst individuals within a system. One of the major advantages of social network analysis is that it allows us to understand interactions from the scale of individuals, dyads, all the way up to the group level. For example, we can ask questions about how the larger group can be broken down into sub-groupings such as “cliques” as well as how individuals within the network will associate themselves based on particular attributes such as gender or personality type. Although social network analysis has been around in sociology, psychology, and related disciplines since the 1950s, it has been adopted more recently by scientists studying animals and other biological systems in order to understand how these organisms arrange themselves (Farine et al., 2015).
Thinking back to our high school social arena, when you began high school, you probably hung out with people who were similar to you: in the same grade, on the same teams, or with similar extracurricular interests. Social networks in animals are often structured similarly. For example, yellow-bellied marmots tend to engage in more affiliative (i.e. friendly) interactions with similarly-aged animals (Wey, 2010). Just like 9th graders tend to interact with other 9th graders, the juvenile yellow-bellied marmots tend to affiliate with other juveniles, and adults with adults.
Social network studies can also comment on family dynamics playing out in a larger group. Have you ever heard the phrase “Blood is thicker than water?” If so, you know that this common analogy eludes to the fact that humans are more apt to help others when they are related to them, as opposed to having no relation (Eberhard, 1976). In returning to our high school example, let’s consider a scenario where your younger sister is being picked on by a bully. Now let’s consider another scenario where someone you’ve never met is being picked on by a bully. Who are more likely to help: your sister (a blood relative) or a stranger (a non-blood relative)? More often than not, you would choose to help your sister (not-withstanding the intricate complexities of sibling relationships). This means that you’d preferentially help your ‘kin’, or family, over others. These tendencies to interact preferentially with kin over non-kin can be identified and studied using social network methods. Interestingly, animals show the same tendencies to interact with and intervene for kin over un-related individuals. This is also true of many animal societies, from baboons (Silk et al., 2003) to killer whales (Williams, 2006).
As we have described thus far, social networks are tools that we can use to identify patterns for social interactions both in human and animal systems. Another interesting way social networks are used is to study the transmission of information or diseases through a population. In schools, a variety of information can be transmitted through social networks — such as rumors or answers to homework problems. In animal societies, the transmission of information can occur using similar mechanisms. For example, chimpanzees learn novel foraging techniques, such as moss-sponging, through their social network (Hobaiter et al., 2014). Animals that have close social relationships are more likely to pick up the skill from each other.
Additionally, pathways through social networks can serve as conduits for transmitting viruses and bacteria amongst individuals. In your high school (or in life in general), you are more likely to get the flu or a head cold from people you come in contact with regularly versus those whom you only see occasionally. This phenomenon is also seen in many wild animals. For example, the transmission of E. coli was more likely between giraffes that exhibited stronger social bonds (i.e. spent more time together; VanderWaal et al., 2013).
As you can see, social networks are useful tools for scientists of various fields to understand interactions between individuals. These social network tools developed for analyzing human social interactions can also be brought into the non-human world to help understand animal societies. Just like the multiple levels of social interactions in high school (i.e. among grades or friend groups), animal societies can also contain similar hierarchical structures or clustering of relationships. Using social network tools in both situations can help us better understand how these levels of complexity can contribute to individual social interactions.
Eberhard, M. J. W. (1976). The evolution of social behavior by kin selection. Quarterly Review of Biology, 50, 1-33.
Farine, D. R., & Whitehead, H. (2015). Constructing, conducting, and interpreting animal social network analysis. Journal of Animal Ecology, 84, 1144-1163.
Hobaiter, C., Poisot, T., Zuberbühler, K., Hoppitt, W., & Gruber, T. (2014). Social network analysis shows direct evidence for social transmission of tool use in wild chimpanzees. PLoS biology, 12, e1001960.
Silk, J. B., Alberts, S. C., & Altmann, J. (2003). Social bonds of female baboons enhance infant survival. Science, 302, 1231-1234.
VanderWaal, K. L., Atwill, E. R., Isbell, L., & McCowan, B. (2014). Linking social and pathogen transmission networks using microbial genetics in giraffe (Giraffa camelopardalis). Journal of Animal Ecology, 83, 406-414.
Wey, T. W., & Blumstein, D. T. (2010). Social cohesion in yellow-bellied marmots is established through age and kin structuring. Animal Behaviour, 79, 1343-1352.
Williams, R., & Lusseau, D. (2006). A killer whale social network is vulnerable to targeted removals. Biology Letters, 2, 497-500.B
Featured image: social network analysis [Source]