Table 3.

Quantitative evaluation of gorilla MSR studies

Study	Findings		Methodological criteria															Methods total	Overall total	Overall %
			1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Studies employing the Mark test	Self-directed responsesa (+5 points)	Mark test responses (+10 points)
Lethmate (1974)	5	10	1	–	0	1	0	0	–	–	–	–	–	–	–	–	–	2	17	57
Suarez and Gallup (1981)	0	0	1	1	0	1	0	0	–	1	1	1	1	1	1	0	1	10	10	33
Ledbetter and Basen (1982)	0	0	1	1	0	1	0	0	–	1	1	1	0	0	1	0	0	7	7	23
Parker (1994)	5	10	1	0	0	1	1	0	1	1	0	1	0	0	0	0	0	6	21	70
Patterson (1978); Patterson and Cohn (1994)b	5	10	0	1	0	0	0	1	0	1	1	1	1	0	0	0	1	7	22	73
Evans (cited in Swartz and Evans 1994)b	5	10	0	0	0	0	0	0	0	1	1	1	1	0	1	0	1	6	21	70
Swartz and Evans (1994)	5	0	0	1	0	1	0	0	1	1	1	1	1	1	1	0	0	9	14	47
Nicholson and Gould (1995)	5	10—but not clear	0	0	0	0	0	0	0	1	0	1	1	0	1	0	1	5	20	67
Shillito et al.—Expt 1 (1999)	0	0	1	0	1	1	0	0	0	1	1	1	1	0	1	0	1	9	9	30
Shillito et al.—Expt 2 (1999)	0	0	1	0	0	1	0	0	0	1	1	1	1	0	1	0	1	8	8	27
Shillito et al.—Expt 3 (1999)	0	0	1	0	0	1	1	–	0	1	1	1	1	0	1	1	1	10	10	33
Shillito et al.—Expt 4 (1999)	0	0	1	0	0	1	0	0	0	1	0	0	1	1	1	0	0	6	6	20
Shumaker and Swartz (2002)	0	10	0	0	0	0	0	0	0	1	1	1	1	0	0	0	0	4	14	47
Posada and Colell (2007)	5	10	0	0	0	0	1	0	1	1	0	1	1	1	1	0	1	8	23	77
Allen and Schwartz (2008)	5	10	0	0	0	0	1	1	0	1	1	1	1	0	1	1	1	9	24	80
Studies not employing the Mark test	Self-directed responses (+5 points)
Yerkes (1927)	0		0	0	0	0	0	0	–	1	0	0	0	0	0	0	0	1	1	8
Hoyt (1941)	5		0	1	0	0	0	0	0	1	0	0	0	0	0	0	0	2	7	54
Benchley (1944)	0		1	0	0	0	0	0	0	1	0	0	0	0	0	0	0	2	2	15
Riopelle (1970)	5		1	0	0	1	0	0	1	1	0	0	0	0	0	0	0	4	9	69
Law and Lock (1994) /Murray (2020)	5		1	0	1	1	1	0	1	1	0	0	0	0	0	0	0	6	11	85
Inoue-Nakamura (1997)	5		1	0	0	0	1	0	-	1	0	0	0	0	0	0	0	3	8	62

^aSelf-directed behavioural responses to mirrors outside of the mark test context

^bBoth Patterson and Swartz & Evans have refused to comply with reasonable requests from GG to examine their videotapes, so have not been assigned a score for this criterion