Primary objective is to examine the effect of tryptophan supplementation on the number of accepted unfair offers in the Ultimatum Game. Secondary objectives are to examine the effect of tryptophan supplementation on the response bias in a social…
ID
Source
Brief title
Condition
- Other condition
Synonym
Health condition
Gezonde proefpersonen
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Number of accepted unfair offers in the Ultimatum Game
Secondary outcome
1. Response bias in terms of the percentage positive expectations the social
evaluation task.
2. Remedial action in terms of adjustment of estimation time in the time
estimation paradigm.
3. Brain responses to offers in the Ultimatum Game, social evaluations in the
social evaluation task and performance feedback in the time estimation
paradigm.
Background summary
Serotonin is thought to play an important role in social interaction (Colzato
et al., 2013; Crockett et al., 2008). It has been found that experimentally
lowering the level of serotonin by tryptophan depletion modulates behavior in a
socio-economic task called the Ultimatum Game. The effect of increasing of
serotonin levels by means of tryptophan supplementation, however, is unknown.
Therefore we would like to replicate the study of Crockett et al., but instead
of decreasing serotonin levels we would like to examine the effect of
increasing serotonin levels.
Study objective
Primary objective is to examine the effect of tryptophan supplementation on the
number of accepted unfair offers in the Ultimatum Game. Secondary objectives
are to examine the effect of tryptophan supplementation on the response bias in
a social evaluation task and remedial action in a time estimation task. A final
secondary objective is to examine the effect of tryptophan supplementation
brain responses to important events in the three mentioned tasks.
Study design
Intervention study
Intervention
Supplementation of 0.8 grams tryptophan or placebo.
Study burden and risks
Participants have to ingest a drink containing a supplement of tryptophan (0.8
g) or placebo. After the drink they have to wait for an hour. In this hour
participants complete a number of questionnaires. Finally, after the 1 hour
waiting period participants perform a number of psychological tasks and
complete a second set of questionnaires. Tryptophan is an essential amino acid
that is present in almost every protein containing food. In this low dose there
are no risks associated with tryptophan supplementation and participants do not
benefit from participation in another way than receiving a small amount of
money for their voluntary participation.
Burg. Oudlaan 50
Rotterdam 3062PA
NL
Burg. Oudlaan 50
Rotterdam 3062PA
NL
Listed location countries
Age
Inclusion criteria
1. Age between 18 and 65
2. Sufficient understanding of Dutch
Exclusion criteria
1. Cardiac, hepatic, renal, neurological or psychiatric disorders
2. Personal or family history of depression
3. Migraine
4. Drug use and medication use
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL52484.078.15 |