Treatments (groups) 
T1. High Growth (H1–H6) 
T2. Low growth (L1–L4) 
T3. High growth – Low growth (HL1–HL6) 
T4. Mixed growth (M1–M6) 

Resource dynamics 
High growth P = 0.02 and an initial amount of 50% of the tokens on
the screen. 
Low growth: P = 0.01 and an initial amount of 25% of the tokens on
the screen. 
Low growth for rounds 1–3 and high growth for rounds 4 and 5 
Mixed growth: Top half of the screen: high growth; bottom half of
the screen: low growth 
Practice 
14x14 individual resource 
Round 1 
14x14 individual resource 
Round 2 
28x28 grid shared by four people 
Round 3–5 
Each round starts with 5 min of text chat. Then 4 min of collecting
tokens in the 28x28 grid resources shared by four people. After the round, there
is a chance to subtract others’ tokens. 
Earnings—Nash solution 
$20.2 
$12.1 
$16.3 
$18.4 
Maximum earnings—cooperative solution 
$41 
$20.5 
$30.7 
$32.8 