Table S1.

Separate distribution of behavioral types reported from 14 trials presented in eight studies (including this one) measuring conditional cooperation using the strategy method of ref. 1

TypeTrialSignificance
12345678910111213141–1213–14
Study codeF01FG10K08K08K08HT09HT09HT09HT09M09M09M13FV10BC16NANANA
GroupmatesHumanHumanHumanHumanHumanHumanHumanHumanHumanHumanHumanHumanComputerComputerHumanComputerNA
CountrySwitzerlandSwitzerlandAustriaJapanUnited StatesRussiaRussiaRussiaRussiaColombiaColombiaVietnamUnited StatesUnited KingdomNANANA
Conditional50%55%44%42%81%48%57%60%60%63%54%50%53%50%55%51%0.470*
Humped14%12%11%11%0%5%5%10%12%8%8%8%13%10%9%11%0.600*
Unclassified7%10%22%11%11%43%27%20%27%25%13%38%13%19%20%17%0.602*
Free rider30%23%22%36%8%5%11%10%2%4%25%4%23%21%16%21%0.168*
Study sample441403636364444205248484840725961120.458
  • Frequencies are presented as percentages; there may be some errors in totals due to rounding. For a summary statistics and comparisons of the distributions by studies using computers instead of humans, see the final three columns. F01, Fischbacher et al., 2001 (1); FG10, Fischbacher and Gachter 2010 (2); K08, Kocher et al., 2008 (3); HT09, Herrmann and Thoni 2009 (4); M09, Martinsson et al., 2009 (5); M13, Martinsson et al., 2013 (6); FV10, Ferraro and Vossler 2010 (50); BC14, this study. Trials 3–5 were one study investigating cross-cultural distributions. Trials 6–9 were one study, conducted in four Russian locations: two rural (6, 7) and two urban (8, 9). Trials 10 and 11 were one study, conducted in Colombia, with individuals of low-middle socioeconomic status (10) and high socioeconomic status (11). Trials 12 and 13 are separate studies, both conducted using computerized groupmates instead of humans. NA, not applicable.

  • * Fisher’s exact test of the corresponding absolute counts summed across all studies with either human or computer groupmates.

  • χ2 test of overall distributions. The absolute counts for each type were summed across all studies either with humans or with computers.