Russel-Research-Method-in-Anthropology

Structured Interviewing II: Cultural Domain Analysis 309
terms was chosen as most alike among the 84 triads. (There are n(n 1)/2
pairs 9(8)/2 36 pairs.) They divided the total by seven (the maximum
number of times that any pair appears in the 84 triads). This produced a similarity
coefficient, varying between 0.0 and 1.0, for each possible pair of disease
terms. The larger the coefficient for a pair of terms, the closer in meaning
are the two terms. They were then able to analyze these data among Englishdominant,
Patois-dominant, and monolingual Patois speakers.
It turned out that when Patois-dominant and English-dominant informants
took the triad test in English, their cognitive models of similarities among diseases
was similar. When Patois-dominant speakers took the Patois-language
triad test, however, their cognitive model was similar to that of monolingual
Patois informants.
This is a very interesting finding. It means that Patois-dominant bilinguals
manage to hold on to two distinct psychological models about diseases and
that they switch back and forth between them, depending on what language
they are speaking. By contrast, the English-dominant group displayed a similar
cognitive model of disease terms, irrespective of the language in which
they are tested.
The Balanced Incomplete Block Design for Triad Tests
Typically, the terms that go into a triad test are generated by a free list, and
typically the list is much too long for a triad test. As you can see from Formula
11.1, with just nine terms, there are 84 stimuli in a triad test containing nine
items. But with 15 items, just 6 more, the number of decisions an informant
has to make jumps to 455. At 20 items, it’s a mind-numbing 1,140.
Free lists of illnesses, ways to prevent pregnancy, advantages of breast-feeding,
places to go on vacation, and so on easily produce 60 items or more. Even
a selected, abbreviated list may be 20 items.
This led Michael Burton and Sara Nerlove (1976) to develop the balanced
incomplete block design, or BIB, for the triad test. BIBs take advantage of
the fact that there is a lot of redundancy in a triad test. Suppose you have just
four items, 1, 2, 3, 4 and you ask informants to tell you something about pairs
of these items (e.g., if the items were vegetables, you might ask ‘‘Which of
these two is less expensive?’’ or ‘‘Which of these two is more nutritious?’’ or
‘‘Which of these two is easier to cook?’’) There are exactly six pairs of four
items (1–2, 1–3, 1–4, 2–3, 2–4, 3–4), and the informant sees each pair just
once.
But suppose that instead of pairs you show the informant triads and ask
which two out of each triple are most similar. There are just four triads in four
items (1–2–3, 1–2–4, 2–3–4, 1–3–4), but each item appears (n –1)(n –2)/2