Table 1. The four experimental treatments. Note: The label for the groups is given in parentheses.

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