文档介绍：A Bluffer’s Guide to Meta-Analysis1
By
Dr. Andy Field
University of Sussex

What Is The Point of a Meta-Analysis?
Psychologists are typically interested in finding general answers to questions. For example,
Lotze et al (2001) did a study to see what areas of the brain were activated during anal
stimulation: they inserted balloons (not party ones) into people’s rectums and inflated them
while the person was in an fMRI scanner. Then they sang happy birthday and … OK, they
didn’t, but they really did do the balloon thing. One of the areas of the brain in which they
were interested was the secondary somatosensory cortex (S2). Lotze et al. were probably
interested in what brain regions were activated in their sample as a means of extrapolating to
a wider population. However, what typically happens in science, is some other people then
come along, they think ‘hmm, shoving balloons up people’s arses looks like a fun way to spend
some research money’ and off they go with their fMRI scanner and balloons to traumatise the
local college populous. Of course, sooner or latter many more researchers will realise that this
whole bum balloon thing is much more fun than whatever it is they’re supposed to be doing,
and before you know it, the literature is riddled with research papers (and the world is riddled
with people who have conditioned surprised expressions on their face whenever they see an
fMRI scanner). Can we assimilate all of these studies to improve the accuracy of our
conclusions about which brain areas are activated by having crazy psychologists inflate
balloons up our back passages?
Until about 30 years ago, the answer was simply to do a subjective evaluation of the literature.
A typical review would entail the author collating articles on the give