Our ability to remember things can limit social capital in several different ways. Two main features of memory are relevant, 1) long-term memory maintaining mental models of social details, and 2) working memory to develop coherent mental models required for effective listening and comprehension (Cowan 2014). Long-term memory is required to remember names, faces, and other details of individuals, but more importantly, it is required to remember social relationships and their qualities. Simply recognising someone can be easy; however, remembering how you know them, where they work, whom they are connected to, their past actions (similar to reputation), and many other details can be much more difficult and requires good long-term memory.
Working memory is also important since, without sufficient working memory, information would be lost before you could combine it into a coherent, complete thought (Cowan 2014). Working memory could be limited in terms of how many items can be held at once, and it could be limited in the amount of time for which an item remains in working memory (ibid). It is not clear to what extent an individual can improve their working memory; however, there is clearly a limit.
We are limited by the ability to manage our social relations at the cognitive level (Barrett, Henzi, and Dunbar 2003). In order to maintain social relationships, we need to remember much more than names and faces; we need to integrate and maintain a mental model of the social relationships among the members of a network (Stiller and Dunbar 2007). We need to remember personal details and the nature of these relationships, such as trustworthiness, reliability, goodwill, and numerous other characteristics. Dunbar explained it as “the number of people you would not feel embarrassed about joining uninvited for a drink if you happened to bump into them in a bar” (Dunbar 1996, p. 77).
There is considerable individual variation in social network size for various reasons; however, cognitive capacity appears to be a limiting factor (Stiller and Dunbar 2007). Hill and Dunbar (2003) found that, on average, humans tend to have a social network (people who are known individually and with whom one has a personal relationship) of approximately 150 people. Other research found an average social network size of 611 people with a significant variance – 90 percent of people had between approximately 150 and 1500 (McCormick, Salganik, and Zheng 2010). The substantial differences in results seem to stem from the way in which a social network is defined and the methods used to quantify them.
These numbers do not attempt to qualify the nature of social relationships. Research by Dunbar and others postulated that an individual sits in the centre of a personal social network with social contacts located at varying distances based on emotional closeness and frequency of contact. The “inner circle” may include just a handful of people with whom there is a deep personal connection and frequent contact, while the outer circle of acquaintances may include up to 1500 or more people (Dunbar and Spoors 1995; Hill and Dunbar 2003).
The size of one’s social network is not just a function of cognitive ability since it also relates to one’s inclination and motivation for social interaction. For example, someone whose career success is related to developing and maintaining a large social network would likely have a large network. A realtor would have a large social network because of the amount of time they invest in social activities and the skills and strategies they utilise to build and maintain relationships effectively. While cognitive abilities clearly play an important role, they can be supported or supplemented by non-cognitive systems and tools. Even something as simple as handwritten records can complement memory. Technology can extend this much further and even bolster reputation and facilitate low-cost connection and communication. Regardless, there is a maximum associated with the trade-off between network size and relationship quality and space-time constraints.
Another factor in social network size is the role of power and status, which are often neglected in social capital literature (notable exceptions being Bourdieu 1984, 1986, 1992). Power and status carry obvious reputational advantages and can intrinsically enhance network size. Power and status effectively shift the onus of relationship establishment and maintenance to others since others are likely to pursue the benefits of ties with powerful individuals. This allows privileged individuals to have a larger network size for the same investment of time and cognitive effort. They also have more to offer by virtue of their position and status in instrumental and non-instrumental trade. For example, many people would want to have a relationship with the local city mayor, placing a greater onus of building and maintaining relationships on others rather than on the mayor.
The role of power and status has the most significance at the individual level since it relates to the uneven distribution of social capital. It does not necessarily aggregate to the social capital of larger social groupings, except where many individuals in the group have power and status relative to other individuals outside the grouping. For example, status would be an important factor in the social capital of a group of politicians (since they have status relative to others in society). However, it would not be an important factor in the social capital of the entire society since the inequity of high and low-status individuals would effectively neutralise net benefit. It could be argued that societies with low levels of social stratification have less social capital because of the lack of high-status individuals who enable the activation of social capital benefits. The counterargument is that inequity typically creates more individuals with low status than individuals with high status, consequently the net social capital outcome is negative. Considering social capital is a highly complex multi-dimensional concept, it is difficult to investigate the legitimacy of these claims.