Table 1.
Participant Characteristics
| Characteristic | Altruists (n = 25) | Controls (n = 27) | p | Effect sizea |
|---|---|---|---|---|
| Male | n = 9 (36.0%) | n = 13 (48.2%) | .376 | 0.12 |
| White | n = 23 (92.0%) | n = 22 (81.5%) | .267 | 0.15 |
| Right-handed | n = 24 (96.0%) | n = 25 (92.6%) | .599 | 0.07 |
| Household income ≥ $60,000 | n = 19 (76.0%) | n = 24 (92.3%) | .109 | 0.22 |
| Education ≥ 4-year degree | n = 17 (68.0%) | n = 24 (88.9%) | .065 | 0.26 |
| Age (years) | M = 41.92 [38.04, 45.80] | M = 38.89 [35.38, 41.40] | .229 | 0.34 [–0.21, 0.88] |
| IQ | M = 108.28 [103.40, 113.16] | M = 111.22 [106.96, 115.48] | .375 | 0.25 [–0.30, 0.79] |
Note: One control subject did not report household income. For age and IQ, 95% confidence intervals are given in brackets.
a
Effect sizes for gender, race, handedness, income, and education are ϕs; effect sizes for age and IQ are ds.