Table 1.

R² of data fitting with logistic function

	Exp2. Horizontal Ponzo			Exp3. Vertical Ponzo			Exp1. Ebbinghaus
	Mono.	Dich.	Bino.	Mono.	Dich.	Bino.	Mono.	Dich.	Bino.
H.C.	0.9993	0.9980	0.9942	0.9881	0.9637	0.9705	0.9469	0.9901	0.9855
L.C.	0.9853	0.9848	0.9972	0.9616	0.9300	0.9943	0.9906	0.9945	0.9812
A.H.	0.9889	0.9840	0.9826	0.9988	0.9997	0.9987	0.9852	0.9539	0.9593
X.L.	0.9815	0.9704	0.9467	0.9983	0.9923	0.9826	0.9949	0.9778	0.9334
C.S.	0.9962	0.9962	0.9965	0.9900	0.9865	0.9966	0.9987	0.9952	0.9877
D.S.S.	0.9968	0.9933	0.9948				0.9879	0.9678	0.9860

R² value of logistic fitting in illusion magnitude measurement is listed for each participant in each condition (monocular, dichoptic, binocular) of each illusion (Ponzo illusion in horizontal design, Ponzo illusion in vertical design, Ebbinghaus illusion). The R² value reflects the goodness of the fit and justifies the use of logistic fitting to quantify the illusion magnitude.