The effect of dopamine on reading motivation and achievement.

Research showed a strong decreai in reading omtivation from fourth grade on
(Chall & Jacobs, 2003). On the age of fifteen, half of the Dutch students
indiciate that they never read for pleasure. At this moment it is still unclear
which biological processes underlie this decline in reading motivation.
Dopamine functioning influences motivation and reward-related behavior (Tripp &
Wickens, 2008). Reduced levels of dopamine are associated with less pleasure
feelings and an increase in dopamine levels causes people to perceive or
experience neutral events as more positive or rewarding (Berridge et al.,
1998). Additionally, subjects with higher levels of dopamine show improved
attentional functioning and learning (Breitenstein et al, 2006; Knecht et al.,
2004). Taking this into account, the efficiency of the dopamine system could
play an important role in the decline of reading motivation. This research may
contribute to the understanding of the influence of dopamine on reading
motivation and engagement.

The main goal of the study is to investigate if small amounts of dopamine could
influence engagement during reading, comprehension of the story and vocabulary
learning and to investigate if the effect of dopamine is different for carriers
of the long or short variant of the DRD4 gene. Additionally, the effect of
dopamine on how participants value reading is investigated.

The study will have a randomized, double-blind placebo-controlled experimental
design. A total of 80 participants, half of them carriers of the long variant
of DRD4 and the other half carriers of the short variant, will, after
genotyping, be selected from a group of about 120 students. All 80 participants
will be submitted to both experimental conditions (dopamine and placebo).

One hour after intake participants will read one of two passages from the novel
*A Clockwork Orange* by Anthony Burgess in Dutch translation, including about
30 non-words. During reading EEG is used to measure task engagement (Pope et
al., 1995). After reading the text, participants are asked questions about the
story and non-words in the text and complete two measures of reading
resistance.

Participants have to visit the university for a maximum of three times. Once
for DNA sampling and twice for the experimental sessions (1x Sinemet, 1x
placebo). Administration of a single dose of Sinemet is found to be safe and
without side effects.