Philospohy - Presuppositions and perception
The Late Stephen Jay Gould said in "Ever Since Darwin: Reflections in Natural History" on the topic of Continental Drift

In short, we now accept continental drift because it is the expectation of a new orthodoxy. I regard this tale as typical of scientific progress. .... Facts do not `speak for themselves', they are read in the light of theory.

The concept that facts do not speak for themselves but are interpreted based on previously held beliefs (Be it a scientific theory or any other belief) should indicate that we need to be aware of our own presuppositions (beliefs we hold before we look at those facts) and how they effect our own interpretation as opposed to how other peoples presuppositions will effect theirs.

I recently commented on the poor reporting on a recent study on scent, pheromones and sexuality. An even more recent study has been reported by Opinion Journals Best of the Web. This new study, reported in the New Scientist links brain activity to negative perception of black americans in contrast to the brain activity when looking at white americans. The New Scientist explains

The new study showed that both white and black people had increased activity in an area of the brain called the amygdala--which responds to fearful or threatening situations--when completing a matching task with images of black faces....

"I think the results are very specific to being raised in this society where the portrayal of African Americans is not very positive, on average," says Matthew Lieberman at the University of California, Los Angeles, US, who led the study. "It suggests that those cultural messages are not harmless." . . .

Both black and white people showed increased amygdala activity on the visual matching task with black target photos. The same task with a white target face produced no such activity. Because black faces are presumed not to be "novel" to black subjects, Lieberman concluded they must have learned, through pervasive cultural cues, to associate black people with fear.

It seems pretty clear that the presupposition in interpreting this recent study was that the negative opinion of black americans was a learned behaviour (as best of the web observes), but more than that, the presupposition is also that this learned behaviour is learned due to racist messages that society is giving out. The options that this response is genetic, or due to observational experiences as opposed to cultural conditioning is ignored. (Note: I am not saying that either of these options is the case, I am just saying they are options, but they are ignored due to assumptions that are held, prior to the investigation)

Update: I have another post which also highlights the importance of presuppositions here.
- posted by Alan Grey @ Thursday, May 12, 2005