Estimating subjectivity of typologists and typological classification with fuzzy logic

It is well known that interpretation always conveys a certain degree of subjectivity, which disappears as soon as interpreted data are stored in a computer database. This may lead to dangerous approximation and possibly to fallacious conclusions. To avoid this oversimplification, it has been suggested to use fuzzy databases, in which attributes may have a fuzzy nature and be indexed by a numerical coefficient, the fuzzy coefficient, which can be interpreted as the degree of confidence the researcher has in each possible assigned value. This technique has been successfully applied to gender and age assignment for the deceased in a cemetery investigation: in this case anthropological data offered statistical parameters that could be used to compute the fuzzy coefficient. Lithics classification is another field in which fuzzy databases have a potential usefulness, but in this case, no previous statistics may help in determining the fuzzy coefficient. We decided to perform an experiment during a standard typological classification of a flint tool assemblage from Israel. It concerned the classification of 50 tools, by different researchers. Each one was asked to note, besides the typology of each item, an evaluation of the “degree of sureness”, or the “possibility” of an item to belong to a particular type, in other words his or her guessed estimate of the fuzzy coefficient. This paper reports the results of this experiment, in order to evaluate the difference between researchers when performing a classification of tools, to recognize problematic types or items (which mostly differed between the typological lists presented) and eventually to compute a fuzzy coefficient for each type assignment, balancing the different evaluations of experts.

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