Table 1.
Selected Sample Characteristics
| Characteristic | Overall Sample (N=114) | Volunteers (N=49) | Non-Volunteers (N=65) | p-valuea |
|---|---|---|---|---|
| Gender, N(%) | 0.025 | |||
| Male | 56(49.1) | 30(53.6) | 26(46.4) | |
| Female | 58(50.9) | 19(32.8) | 39(67.2) | |
| Race, N(%) | 0.072 | |||
| Asian | 36(31.6) | 10(27.8) | 26(72.2) | |
| Black | 38(33.3) | 16(42.1) | 22(57.9) | |
| White | 34(29.8) | 20(58.8) | 14(41.2) | |
| Other | 6(5.3) | 3(50.0) | 3(50.0) | |
| Age, years | 22.9(2.7) | 23.1(3.2) | 22.8(2.3) | 0.616 |
| Education, years | 15.4(2.0) | 15.1(2.4) | 15.6(1.7) | 0.178 |
| Drinks per week | 1.4(2.0) | 1.6(2.5) | 1.1(1.6) | 0.216 |
| NEO Neuroticism | 52.0(6.1) | 51.6(6.0) | 52.3(6.3) | 0.567 |
| NEO Extraversion | 42.6(5.8) | 43.3(5.7) | 42.1(5.9) | 0.273 |
| NEO Openness | 48.3(5.8) | 46.5(5.5) | 49.7(5.6) | 0.004 |
| NEO Agreeableness | 40.9(6.3) | 41.7(6.1) | 40.3(6.4) | 0.262 |
| NEO Conscientiousness | 44.4(4.4) | 44.7(4.76) | 44.1(4.1) | 0.456 |
| NEO Impulsiveness | 50.6(7.8) | 48.7(6.5) | 52.0(8.5) | 0.030 |
| NEO Values | 38.5(7.6) | 36.8(7.0) | 39.7(7.8) | 0.042 |
| NEO Competence | 40.7(6.7) | 42.3(7.6) | 39.5(5.6) | 0.027 |
| Impulsivity (BIS) | 56.7(9.8) | 57.5(10.6) | 56.1(9.1) | 0.434 |
| Sensation-Seeking (SSS) | 18.0(6.7) | 20.9(4.9) | 15.8(7.0) | <0.001 |
| SPSRQ Punishment | 7.0(4.6) | 6.4(4.1) | 7.4(4.9) | 0.229 |
| SPSRQ Reward | 9.4(4.1) | 9.7(4.3) | 9.2(4.1) | 0.583 |
| IMT Ratio | 0.30(0.2) | 0.33(0.2) | 0.28(0.2) | 0.074 |
| DMT Ratio | 0.33(0.2) | 0.37(0.2) | 0.30(0.2) | 0.058 |
| GoStop Ratio150msec | 0.3(0.3) | 0.3(0.3) | 0.3(0.3) | 0.991 |
| TCIP Immed. Choices | 12.8(13.4) | 13.4(12.8) | 12.4(13.9) | 0.693 |
| TCIP Delayed Choices | 24.1(16.6) | 22.1(15.7) | 25.6(17.2) | 0.270 |
| SKIP Longest Delay | 270.8(295.7) | 308.4(328.0) | 241.1(266.3) | 0.235 |
| SKIP Total Responses | 223.4(597.9) | 217.0(576.0) | 228.5(619.3) | 0.921 |
| IGT Net Total | 16.5(24.7) | 14.5(25.8) | 18.0(23.9) | 0.454 |
NOTE: Values represent means and standard deviations except where indicated otherwise.
a
Differences between volunteers and non-volunteers
p-values <0.05 are in bold.