Table 2.

Reliability and dependability of ERP response to monetary and social feedback

	Measure	Gain/like feedback	Loss/dislike feedback	RewP
Monetary Reward Task	Split–Half	0.91	0.89
	Cronbach’s α [95% CIs]	0.91 [0.88, 0.93]	0.88 [0.84, 0.90]
	Adjusted α			0.45
	Dependability [95% CIs]	0.91 [0.88, 0.93]	0.90 [0.87, 0.92]
Social Reward Task	Split–Half	0.81	0.84
	Cronbach’s α [95% CIs]	0.84 [0.80, 0.88]	0.84 [0.79, 0.88]
	Adjusted α			0.37
	Dependability [95% CIs]	0.84 [0.80, 0.88]	0.84 [0.80, 0.88]

Notes. The RewP indicates the relative difference between the gain and like feedback and the loss and dislike feedback. Generalizability (G) theory measures of overall dependability were computed in MATLAB using the ERP Reliability Analysis Toolbox (Clayson and Miller, 2017). Internal consistency of the ERP response to monetary and social feedback was examined using two approaches derived from classical test theory. First, split-half reliability was examined by calculating the correlation between averages based on odd- and even-numbered trials, corrected using the Spearman-Brown prophecy formula (Nunnally et al., 1967). Second, Cronbach’s α, which is roughly equivalent to the mean of all possible split-half correlations, was examined for all trials. The overall internal reliability of the RewP difference score (i.e. gain–loss, like–dislike) was estimated using an adjusted α formula (Furr and Bacharach, 2013).