Folk taxonomies are systems of categorization created by non-scientists in order to organize, name, and understand the natural world. Folk taxonomies frequently diverge on some points from the phylogeny established by the scientific study of taxonomy but they also tend to align with scientific classifications on other points: sometimes folk taxonomies lump together many biological species under a single name or place species from several different biological orders in the same group, sometimes there is one-to-one correspondence, and sometimes folk taxonomies differentiate where scientific taxonomies do not. Differentiation between types in folk taxonomies is determined by a wide variety of attributes, some of which may not be immediately obvious to outsiders; morphology and behavior are important but so are the cultural significance and practical utility of the species constituting each group.
Psychological and cultural basis
It is an axiom of modern cognitive psychology, intellectually traceable to Gordon Allport, that humans are innately predisposed to prejudge. Allport believed that categories and "rubrics are essential to mental life" because they allow people to moderate their behavior based on previous experience. Quick responses to environmental stimuli are made possible by broad categories of similar stimuli based on their most pertinent aspects. Highly differentiated categories are less helpful in this respect because they require more effort when it may not be necessary in order to determine an appropriate response.
In a highly influential and oft cited chapter, Eleanor Rosch described the "principles of categorization" that govern the formation of "the categories found in a culture and coded by the language of that culture at a particular point in time." Her first principle followed in Allport's footsteps: organisms, humans included, seek to gain as much information from the environment as possible while exhausting as few cognitive resources as possible. LIke Allport, Rosch pointed out that "one purpose of categorization is to reduce the infinite differences among stimuli to behaviorally and cognitively usable proportions. It is to the organism's advantage not to differentiate one stimulus fromothers when that differentiation is irrelevant to the purposes at hand." She added a second principle that certain combinations of attributes occur together more often in the perceptual world than do others. This second principle identifies the reason categories work as well as they do: one may make inferences about an environmental stimulus based on its membership in a certain category of similar stimuli because other members of the category are very likely to share many of the same attributes.
Folk taxonomies behave in much the way that the Allport and Rosch models predict. Folk taxonomic systems from around the world are restricted to a memorizable number of between 250 and 800 general categories with relatively little differentiation at more specific levels except where the organisms being labeled are particularly culturally salient. People make inferences based on the relationships between species that are coded in their folk taxonomies and the inferences people from different cultures make will either converge or diverge depending on how their taxonomies converge or diverge.
The salient categories that appear within the taxonomies of different culture groups will differ. This results from the distinct set of cultural values each group embraces and the types of similarity that are judged to be relevant.
- Brent Berlin, Dennis E. Breedlove, Peter H. Raven. 1966. Folk Taxonomies and Biological Classification. Science 154(3746): 273-275.
- Alejandro López, Scott Atran, John D. Coley, Douglas L. Medin, and Edward E. Smith. 1997. The Tree of Life: Universal and Cultural Features of Folkbiological Taxonomies and Inductions. Cognitive Psychology 32: 251-295.
- Susan T. Fiske. 2005. "Social Cognition and the Normality of Prejudgment" In On the Nature of Prejudice: Fifty Years after Allport. John F. Dovidio, Peter Samuel Glick, Laurie A. Rudman, eds. Wiley, John & Sons, Inc.
- Eleanor Rosch. 1978. "Principles of Categorization." In Cognition and Categorization. Eleanor Rosch and Barbara Lloyd, eds. Hillsdale, N.J.: Erlbaumpp. 27-48.
- Rosch 1978: 29
- Peter H. Raven, Brent Berlin, Dennis E. Breedlove. 1971. The Origins of Taxonomy. Science 174(4015): 1210-1213.
- Lopez et al. 1997: 288