Source: Teachers College Record, Volume 112 Number 4, 2010, p. 1163-1197.
Interest among social scientists in peer influences has grown with recent resegregation of the nation’s schools and court decisions that limit the ability of school districts to consider race in school assignment decisions. If having more advantaged peers is beneficial, then these trends may reduce educational equity. Previous studies have outlined individual or groups of theories about how peers influence one another, but these theories have rarely been subjected to empirical tests.
This study provides a description of a wide range of peer influence theories from psychologists, sociologists, and economists. A taxonomy is developed that distinguishes theories based primarily on whether students are hypothesized to change each other’s beliefs and values (direct influences) versus more indirect influences, such as the allocation of teachers and school resources.
Whether empirical evidence, including important new advancements by economists, informs the validity of the various theories is then considered. Although far from definitive, the study highlights the importance of carrying out empirical analysis that tests specific theories.
Quantitative researchers are increasingly aware of the great difficulty of determining whether correlations between individual and group outcomes reflect a causal effect of peers.
The review of empirical evidence focuses on experimental and quasi-experimental studies, which most plausibly reflect causal influences. These studies focus on student achievement as the outcome of interest.
The evidence is not completely consistent with any single theory, though it is more supportive of some over others. A new hybrid theory—group-based contagion—is proposed that is more consistent with the evidence.