A selective effect of dopamine on information-seeking

  1. Valentina Vellani  Is a corresponding author
  2. Lianne P de Vries
  3. Anne Gaule
  4. Tali Sharot  Is a corresponding author
  1. Affective Brain Lab, Department of Experimental Psychology, University College London, United Kingdom
  2. The Max Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, United Kingdom
3 figures, 3 tables and 1 additional file


Stock market task.

(A) Participants observed the evolution of a financial market after investing in two of its five companies. They then indicated whether they believed their portfolio value likely went up or down relative to the previous trial and indicated their confidence in their answer. They then indicated how much they were willing to pay to receive or avoid information about their portfolio value. Next, their portfolio value in points was presented on screen or hidden (‘XX points’ was shown).

L-DOPA does not alter general aspects of information-seeking.

There were no differences in general information-seeking between those who received Placebo and those who were administered L-DOPA. In particular, there were no differences in the average number of trials on which the participants decided to receive or to avoid information or were indifferent (i.e. paid 0). Furthermore, there was no difference across groups in the number of trials participants missed (that is trials in which they were too slow in responding). Error bars SEM.

L-DOPA reduces the effect of valence on information-seeking.

(a) A mixed linear regression predicting Willingness To Pay (WTP) for information revealed an interaction between group (Placebo/L-DOPA) and valence (the amount by which the market went up or down), with no interaction between group and absolute market change. To tease apart the interaction, we ran linear mixed models separately for the L-DOPA and Placebo groups. Plotted are the fixed effects of those models. As observed, this revealed a significant effect of valence on information-seeking in the Placebo group but lack thereof in the L-DOPA group. Absolute change was a significant predictor in both groups. This indicates a reduction in the influence of valence on information-seeking under L-DOPA. (b) To further characterize the effect of valence and drug on information-seeking, we run separate mixed linear models for each group and polarity predicting WTP from market change, trial number and the interaction of the two. Plotted are the fixed effects of market change for each. As can be observed under L-DOPA market change was a significant predictor of information-seeking about potential losses and gains - the greater the expected gain/loss the more participants were willing to pay for information. In contrast, under Placebo market change was a significant predictor of information-seeking about potential gains, but not losses. These results show that L-DOPA selectively alters information-seeking about losses. (c) Plotted is the effect of market change on WTP for information controlling for any effects of trial number. As can be observed the slopes are significantly positive for all groups/conditions except for the Placebo group in the loss domain. Clouds are based on Standard Errors of the fixed effect. Error bars SEM, * p <0.05, ** p < 0.01, *** p < 0.001.


Table 1
DemographicsPlacebo mean (SD)L-DOPA mean (SD)p-Value
Age (years)24.36 (7.91)25.44 (7.92)0.301
GenderFemales N= 72
Females N= 71
Income (1-9)4.85 (2.38)4.61 (2.54)0.462
Education Level (1-10)7.09 (1.72)7.39 (1.50)0.157
  1. There were no differences between groups in terms of demographics. p-Value is of independent sample t-test , or in the case of gender of X2. Education was measured on a scale ranging from 1 (no formal education) to 10 (Doctoral degree ). Annual household income was measured on a scale from 1 (less than 10K) to 10 (more than 100K).

Table 2
Subjective State Questionnaire.

Subjective State Questionnaire (Joint Formulary Committee, 2009) revealed no differences in subjective state between groups. p-Value relates to independent sample t-test.

Subjective State QuestionnaireBefore the taskAfter the task
Placebo mean (SD)L-DOPA mean (SD)p-ValuePlacebo mean (SD)L-DOPA mean (SD)p-Value
Alert to drowsy2.68 (1.19)2.62 (1.08)0.6873.60 (1.41)3.85 (1.57)0.208
Calm to excited2.33 (1.11)2.29 (1.03)0.8082.34 (1.09)2.27 (1.22)0.632
Strong to feeble2.68 (1.01)2.63 (1.01)0.6992.97 (1.13)3.15 (1.35)0.264
Muzzy to clear headed4.47 (1.26)4.48 (1.11)0.9563.70 (1.23)3.41 (1.39)0.099
Coordinated to clumsy2.28 (1.14)2.22 (1.06)0.7222.80 (1.16)3.02 (1.31)0.187
Lethargic to energetic3.89 (1.14)3.94 (1.18)0.7363.20 (1.24)3.00 (1.43)0.263
Contented to discontented2.18 (1.01)2.12 (0.83)0.6202.58 (1.16)2.65 (1.19)0.644
Troubled to tranquil4.83 (1.02)4.66 (1.02)0.2014.52 (1.13)4.55 (1.13)0.858
Slow to quick witted4.32 (1.11)4.28 (1.04)0.7613.63 (1.30)3.31 (1.30)0.069
Tense to relaxed4.64 (1.11)4.67 (0.98)0.8034.47 (1.14)4.42 (1.23)0.733
Attentive to dreamy2.78 (1.26)2.73 (1.10)0.7403.47 (1.34)3.42 (1.38)0.804
Incompetent to proficient4.56 (0.98)4.70 (0.86)0.2604.14 (1.16)4.02 (1.26)0.450
Happy to sad2.43 (1.06)2.34 (0.84)0.4532.62 (1.12)2.57 (0.95)0.712
Antagonistic to friendly5.08 (0.97)5.07 (0.81)0.9424.65 (0.95)4.60 (1.04)0.703
Interested to bored2.35 (1.21)2.28 (1.02)0.6393.52 (1.45)3.63 (1.50)0.587
Withdrawn to sociable4.34 (1.17)4.36 (1.18)0.8683.90 (1.17)3.83 (1.39)0.672
Key resources table
Reagent type (species)
or resource
DesignationSource or referenceIdentifiersAdditional
Software, algorithmSPSSSPSSRRID:SCR 002865Version 25
Software, algorithmMATLABMATLABRRID:SCR_001622Version R2020a
Software, algorithmRRRRID:SCR_001905R-4.0.1
Chemical compound, druglevodopaOrion Pharma (UK) LimitedPubChem CID:6047150 mg
Chemical compound, drugcarbidopaOrion Pharma (UK) LimitedPubChem CID: 3435937.5 mg
Chemical compound, drugentacaponeOrion Pharma (UK) LimitedPubChem CID: 5281081200 mg

Additional files

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Valentina Vellani
  2. Lianne P de Vries
  3. Anne Gaule
  4. Tali Sharot
A selective effect of dopamine on information-seeking
eLife 9:e59152.