Russel-Research-Method-in-Anthropology

The Foundations of Social Research 31
Still, we know that there are gradations of skin color besides black and
white, so it’s reasonable to ask whether people who are more black are more
likely to be a victim of homicide, to die in infancy, to be poor, etc. Around
1970, medical researchers began to find a relation in the United States between
darkness of skin color and blood pressure among people labeled ‘‘Blacks’’
(see Boyle 1970; Harburg et al. 1978). The darker the skin, the higher blood
pressure was likely to be.
Later, researchers began to find that education and social class were more
important predictors of high blood pressure among Blacks than was darkness
of skin color (see Keil et al. 1977, 1981). This meant that darker-skinned people
were more likely to be the victims of discrimination and, as a consequence,
uneducated and poor. Poverty causes stress and poor diet, both of which are
direct causes of high blood pressure.
But suppose we treated skin color as the continuous variable it really is
rather than as a dichotomous variable? Clarence Gravlee (2002b) did this in
his study of race and blood pressure in Puerto Rico. He measured skin color
in two ways. First, he showed people a line with nine numbers on it and asked
them to rate themselves from light to dark by telling him which number best
described their skin color. Then he measured the color of people’s inner arm
with a photospectrometer. The first measure is emic (what people think, themselves,
about their color) and the second is etic (an objective, external measurement
that doesn’t depend on what people think).
Now, etic skin color—the amount of melanin that people have in their skin,
as measured by a photospectrometer—by itself doesn’t account for variation
in blood pressure. But the difference between etic skin color and what people
say their color is is strongly associated with people’s blood pressure (Gravlee
2002b:182). The relationship between these variables is anything but simple.
Poor people who rate themselves as having darker skin than they really have
are likely to have higher blood pressure. For middle-class people, it’s the other
way around: They are likely to have lower blood pressure when they rate their
skin color as darker than it really is. The puzzle requires a lot more work, but
this much is clear: Variation in blood pressure is not caused by melanin (Gravlee
and Dressler 2005).
It may not be possible for everyone who uses skin color as an independent
variable to measure it with a photospectrometer (the gadgets are very expensive),
but if we did this, we could assess whether white schoolteachers react
more negatively to darker-skinned black children than they do to lighterskinned
black children, and if so, by how much. This would help us account
for some of the variation in black children’s school scores as a function of
teacher reaction to skin color. This, in turn, would show how skin color leads