Variance and individual bias. One could, of course, amend the
conformity hypothesis so that it becomes a “conformity with a tendency toward positivity” hypothesis. But this would beg the question; it wouldn’t suggest any underlying mechanism for where the
favorable evaluation of positive reviews is coming from. Instead, to
look for such a mechanism, we consider versions of the individualbias hypothesis. Now, recall that it can be difficult to distinguish
conformity effects from individual-bias effects in a domain such as
ours: if people’s opinions (i.e., star ratings) for a product come from
a single-peaked distribution with a maximum near the average, then
the composite of their individual biases can produce overall helpfulness votes that look very much like the results of conformity. We
therefore seek out subsets of the products on which the two effects
might be distinguishable, and the argument above suggests starting
with products that exhibit high levels of individual variation in star
ratings.