Table 1.

Baseline (cm) and change over time (cm/min) in physical distance estimations within stranger and friend dyads assigned to receive alcohol and control beverages

Strangers					Friends
	b		95% CI	P		b	95% CI	P
Change over time in distance (minutes 6–36)
Alcohol	−0.29		−0.43, −0.16	<0.001		−0.19	−0.41, 0.02	0.078
Control	−0.06		−0.23, 0.10	0.458		−0.27	−0.55, 0.01	0.059
Baseline distance* (minutes 0–6)
Alcohol	142.86		136.19, 149.52	<0.001		134.43	125.53, 143.33	<0.001
Control	137.19		128.86, 145.52	<0.001		139.34	130.95, 147.73	<0.001

Alcohol/Friends (N = 52), Alcohol/Strangers (N = 56), Control/Friends (N = 48), and Control/Strangers (N = 56). Change over time values are derived from mixed models capturing linear slopes (cm/min) in physical distance from >6 min to the end of the interaction—the time period during which pharmacological alcohol effects were expected to emerge. Baseline values refer to the average estimated physical distance (centimeters) minutes ≤6 of the interaction.

^*For both Friend and Stranger dyads there were nonsignificant baseline group differences in physical distance between alcohol and control conditions: Strangers, b = −5.67, P = 0.292; Friends, b = 4.91, P = 0.424. In contrast to within-dyad effects, which hold constant many sources of noise, direct between-group comparisons in the current study are more likely to be impacted by variability associated with extraneous factors—e.g., precise angle of participants’ chairs and large height differentials. Thus, primary analyses focus on within-dyad change over time. See SI Appendix, Supplementary Information Text for details of physical distance approximations.