Third, the varying intensity of emotional experience seen in greater and lesser bouts of happiness
can naturally be explained in terms of degree of activity in the relevant neural populations. There is
research showing that being more hateful involves more activity in areas such as the insula, and that
anticipation of greater rewards correlates with increased activity in the nucleus accumbens. It is
possible to test the hypothesis that increased degree of intensity of an emotional experience correlates
with increased rapidity of neural firing in the relevant brain areas as measured by brain scanners that
detect increased blood flow. For example, people's preference for Coke over Pepsi correlates with
increased activation in the ventromedial prefrontal cortex. The link between preference and
activation could be shown to be more than correlational, if some technique like electrostimulation of
neurons or transcranial magnetic stimulation could be used to send varying degrees of excitation or
inhibition to the appropriate brain areas.