The Neurobiology of Buying Behavior

The current knowledge about excessive buying is largely based on knowledge
obtained from interviews and survey studies. There is very little
neurobiological research on excessive buying. There are only two functional MRI
studies available, of which one study is based on only three excessive buyers.
More insight into the neurological basis of this common and dysfunctional kind
of consumer behavior is required.
Moreover, the currently available fRMI studies on excessive buyers focus on the
activation in the "reward center" of the brain. Differences between excessive
and non-excessive buyers regarding the inhibition system have not been studied
yet, while excessive buyers often experience a lack of control over their
buying behavior (Dittmar et al, 2007).
Through functional imaging we want to study (the difference in) the brain
activity of excessive and non-excessive buyers and the influence of friendship
on excessive buying. With excessive buyers we expect a lower activiation in the
brain areas involved in response inhibition than with non-excessive buyers,
while confronted with attractive products. We also expect that excessive buyers
are better at self-regulation (i.e. a relatively high activation in the brain
areas involved in response inhibition) when being reminded of a close
friendship.

The purpose of this study is to investigate whether excessive buyers are less
able to inhibit their response to attractive stimuli than non-excessive buyers.
Both because of a lower activation in the brain areas involved in response
inhibition and increased activation of the reward -related brain areas, when
confronted with attractive products. Secondary objective of this research is to
study the role of friendship in the capacity for inhibition.

Based on an existing paradigm we developed a Go / No-go task. Based on this
task, both the behavioral response and the neural response are measured.
Individual adjustments in the task will be made; for each subject, a photograph
of the subject with good friend to be inserted. Furthermore, the task will be
performed both by a group of excessive and a group of non-excessive buyers.
Subjects are classified as 'excessive' or 'non- excessive' buyer based on the
excessive buying scale (Ridgway et al, 2008). Before the scan will be
conducted, participants will be asked to fill in the Panas questionnaire, and
the Go / No-go task will be explained. The subsequent fMRI scan, in which
participants will do the Go / No-go task, will take around 60 minutes. Halfway
through the scan, participants will be asked to describe an experience in which
they have experienced close friendship. This will take 5 minutes. After this
description participants will continue with the Go / No-go task. After the
scan, participants are asked to complete a short questionnaire about their
buying urge and buying intentions. Also, the purpose of the study will be
explained and remaining questions will be answered. In total, the study will
last up to 2 hours.

There are no risks associated with this research.
Subjects will be exposed to a magnetic field of 3 Tesla and rapidly changing
magnetic gradients and radiofrequency fields. This field is used on a routine
basis in MRI and fMRI research. To date, no adverse effects have been
described. In rare cases, a peripheral nerve (abdomen) is stimulated by the
changing magnetic gradients. This causes a tickling sensation, but is harmless.