Network theory
Network theory is a multidisciplinary framework used to analyze and interpret systems composed of interconnected entities, or nodes, which can represent individuals, organizations, or components in various contexts such as economics, social networks, ecosystems, and genetics. The ties, or edges, illustrate the relationships between these nodes, showcasing how they connect and interact with one another. This theory is closely linked to graph theory, where nodes are visually represented as points and ties as lines, offering a mathematical approach to understanding complex social dynamics.
Originating in the 1930s, network theory gained traction through the work of social scientists and mathematicians, notably in the 1950s when figures like Frank Harary and Dorwin Cartwright highlighted the effectiveness of mathematical models in predicting group behavior. Over the decades, the theory has expanded to address various applications, including environmental studies, where it helps illustrate resource flows and species interactions. A significant concept within network theory is the strength of ties, distinguishing between strong connections, like those with close friends, and weaker ties, which can often provide a broader range of information, as demonstrated by Mark Granovetter’s research in the 1970s.
The growth of the Internet and social media has further enriched the field, allowing for the exploration of new types of networks and the dynamics of online interactions. Overall, network theory serves as a powerful tool for understanding the intricate web of relationships that shape both individual and collective behaviors across diverse domains.
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Network theory
Network theory refers to a group of methods that help understand and interpret systems that consist of relationships between multiple subjects. It is used to help study economics, social networks, ecosystems, genetics, and the Internet, among other systems. Network theory is related closely to graph theory, and networks are often visually represented in the form of graphs.
The two most basic categories of a network are nodes or points and ties or edges. In a graph, the nodes are dots while the ties are the lines connecting them. Nodes represent the subjects or actors of a network. In many situations, the nodes are people. This is particularly true when studying social dynamics, such as in a school or workplace. However, nodes can also refer to organizations or groups. In an economic network, each business may be a node. Ties, meanwhile, represent the connections different nodes have to each other. For instance, two colleagues have their professional connection as a tie; other possibilities could be membership in a professional organization or accrediting board, or educational background.
Background
Network theory was first identified as a topic of study in the 1930s. Social scientists used it to attempt to gain a better grasp on human behavior within communities. In the 1950s, mathematician Frank Harary (1921–2005) and psychologist Dorwin Cartwright (1915—) approached network theory from a math-based perspective. Harary is considered one of the founders of graph theory, which uses math to observe different trends and patterns within graphs.
The duo popularized the connection between network and graph theory. The idea that social relationships and human behaviors could be studied and predicted with math was met with some skepticism among sociologists, but it soon proved effective at interpreting networks of large groups. It was difficult to apply math to an individual's behavior, but it could be used to help predict trends in a larger group dynamic. After the connection was made, network theory was often closely tied to mathematics.
In the same decade, ecologist Howard Odum (1924 – 2002) demonstrated that network theory had uses beyond sociology. He used networks as guides to highlight the flow of resources through ecosystems. Network theory became and continues to be a valuable part of environmental study, helping showcase the impact of loss of habitat or other environmental disasters or map how some species thrive in an ecosystem while others struggle.
Over the first few decades of network theory, one debate that arose was called the "small world" problem. Some theorists believed that any given person in a social network was at most only a handful of connections removed from any other given person in that same network. Sociology professor Stanley Milgram (1933 – 1984) conducted a notable experiment in the late 1960s, sending out dozens of letters to Americans. He requested that the letters be mailed to a particular person, but only if the recipient knew the identified person. If not, they were instructed to mail the letter to someone that they knew personally, who was more likely to know the target. Of the letters that were returned, the average number of connections was fewer than six. The concept of six degrees of separation became very common in network theory, and even expanded and became part of popular culture in, for example, John Guare's play of the same name.
Impact
Another aspect of network theory that arose over the years was the concept that ties may have different levels of strength. Among individuals, the strongest ties are between close friends and family members. They give each other large amounts of trust and typically show strong positive feelings toward each other. Weaker ties refer to casual acquaintances. It was not until 1973 that the value of weaker ties was made clear to network theorists. That year, Mark Granovetter (1943—) published findings from a study. He had interviewed people who had recently begun working new jobs. He asked the interviewees who had referred them to their jobs. The number of interviewees who were referred to their jobs by a weaker tie far outnumbered those who listed stronger ties. Network theorists began arguing that a large number of weaker ties could be more effective than fewer, stronger ties when it came to gaining a diverse amount of information of interest.
Researchers have identified several types of ties. Communication ties are exchanges of information or dialogue. Affective ties refer to positive feelings and trust between nodes. Material or work flow ties involve connections based on exchanging money or resources. Proximity ties are people who are simply physically near one another. Cognitive ties describes people who know of each other. Two nodes often have multiple ties. In addition to the number of ties between nodes, network theorists are interested in determining which way the ties are flowing. Between friends, affective and communication ties are likely to flow both ways. In different environments, however, ties are not always so balanced.
One particular type of network is the reaction network, which was developed for the field of chemistry. It uses symbols and visual representations of elements and compounds to demonstrate the effects of elements mixing and exposure to heat and pressure. The reaction network was later adapted for use in biology. It has been used to show how members of a species have adapted and responded to changes in their environment.
Network theory can also be used to study circuitry and power structures. It is a part of mapping power grids, service routes, plumbing systems, and many other public work structures. It has been used to help minimize the effects of power failures, since it can identify where too many nodes rely on ties to a single node.
The rapidly increasing popularity of the Internet in the late twentieth century and the advent of social media in the early twenty-first century provided new territory for network theory application and study. In many ways, the resulting networks are simply extensions of existing social networks, but the communication abilities that the Internet provides allow people to form ties that simply weren't possible for prior generations. Scientists studying social media through the lens of network theory tend to view social media users as nodes, positioning each node with regard to its access to information and resources.
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