Strange-face-in-the-mirror illusions: specific effects on derealization, depersonalization, and dissociative identity

Figures & data

Table 1. Items of SFQ-R and endorsements among participants (N = 21).

		MIRROR				PANEL				MIRROR vs. PANEL
	SFQ-R item	N(yes)	mean (SEM)	t	p	N(yes)	mean (SEM)	t	p	t	p
1	Did you see that some facial features were deformed?	20	3.00 (0.25)	12.06	0.000**	1	0.1 (0.1)	1.00	0.329	10.24	0.000**
2	Did you see a luminous face?	12	1.24 (0.31)	4.02	0.001*	4	0.48 (0.23)	2.12	0.047	2.17	0.042
3	Did you see a dark face with only a few facial features?	21	3.33 (0.17)	19.19	0.000**	5	0.52 (0.25)	2.14	0.045	8.97	0.000**
4	Did you see a monstrous face?	17	2.10 (0.27)	7.87	0.000**	3	0.24 (0.13)	1.75	0.096	6.88	0.000**
5	Did you see a face of a stranger or unknown person?	10	0.90 (0.27)	3.40	0.003	2	0.10 (0.07)	1.45	0.162	2.97	0.008
6	Did you see the face of a hero or a heroine or a warrior?	1	0.05 (0.05)	1.00	0.329	0	0.0 (0.0)	1.00	0.329	1.00	0.329
7	Did you see the face of a child?	0	0.0 (0.0)			0	0.0 (0.0)
8	Did you see the face of an old person?	6	0.76 (0.29)	2.61	0.017	1	0.05 (0.05)	1.00	0.329	2.37	0.028
9	Did you see the face of an adolescent?	7	0.67 (0.27)	2.47	0.023	0	0.0 (0.0)			2.47	0.023
10	Did you see a person of different gender or an androgyne?	6	0.67 (0.25)	2.65	0.016	1	0.10 (0.10)	1.00	0.329	2.55	0.019
11	Did you see the face of a domestic or wild animal?	5	0.38 (0.18)	2.17	0.042	4	0.33 (0.17)	1.92	0.069	0.18	0.858
12	Did you see the face of one of your parents or relatives?	4	0.33 (0.17)	1.92	0.069	0	0.0 (0.0)			1.92	0.069
13	Did you see the face of a person of another race?	2	0.19 (0.15)	1.28	0.214	0	0.0 (0.0)			1.28	0.214
14	Did you see the face of a spiritual or enlightened person?	11	1.19 (0.27)	4.37	0.000**	3	0.29 (0.17)	1.67	0.110	3.19	0.005
15	Did you get the feeling of being looked at through the mirror by another person?	13	1.62 (0.33)	4.84	0.000**	8	1.19 (0.36)	3.34	0.003	0.99	0.335
16	Did you see two or more faces at the same time?	20	3.14 (0.21)	14.95	0.000**	2	0.29 (0.21)	1.37	0.186	11.36	0.000**
17	Did you perceive a “presence” of something that physically did not exist?	14	1.38 (0.29)	4.79	0.000**	12	1.38 (0.33)	4.13	0.001*	0.00	1.000
18	Did you see a motionless face or an inanimate face?	15	1.57 (0.29)	5.43	0.000**	4	0.29 (0.14)	2.03	0.055	3.72	0.001*
19	Did you see a tree or a mountain?	0	0.0 (0.0)			5	0.48 (0.20)	2.35	0.029	−2.35	0.029
20	Did you see a detached face?	16	2.05 (0.32)	6.40	0.000**	2	0.10 (0.07)	1.45	0.162	5.50	0.000**
21	Did you see the face of a non-human being, like some kind of alien?	16	2.14 (0.31)	6.90	0.000**	4	0.43 (0.21)	2.01	0.058	4.95	0.000**
22	Did you perceive that you were looking at the face from outside the body?	15	1.71 (0.29)	5.83	0.000**	4	0.43 (0.22)	1.91	0.071	3.39	0.003
23	Did you see that the lips or the mouth moved in an unusual way?	8	0.76 (0.28)	2.77	0.012	3	0.19 (0.11)	1.71	0.104	1.98	0.062
24	Did you see that the face changed very quickly or the face transformed in an instant?	21	3.00 (0.21)	14.49	0.000**	3	0.38 (0.22)	1.71	0.104	9.08	0.000**
25	Did you see another personality that you would not have expected?	11	1.24 (0.30)	4.13	0.001*	1	0.10 (0.10)	1.00	0.329	3.77	0.001*
26	Did you see a person with a past life story different from yours, as if he/she were, for example, one of your “ancestors”?	6	0.52 (0.23)	2.33	0.030	3	0.29 (0.17)	1.67	0.110	1.42	0.171
27	Did you see a person that might communicate something new to you?	6	0.52 (0.24)	2.23	0.038	3	0.33 (0.20)	1.67	0.110	1.71	0.104
28	Did you see a cartoon-like face?	4	0.33 (0.16)	2.09	0.049	2	0.19 (0.13)	1.45	0.162	0.65	0.526
29	Did you see a face with transformed facial features?	20	3.10 (0.23)	13.58	0.000**	2	0.19 (0.15)	1.28	0.214	10.56	0.000**
30	Did you see that the eyes moved in an unusual way?	19	2.52 (0.29)	8.71	0.000**	4	0.62 (0.29)	2.15	0.044	5.53	0.000**
31	Did you see an unreal face, like in a dream?	19	2.86 (0.29)	9.96	0.000**	6	0.81 (0.30)	2.72	0.013	6.12	0.000**
32	Did you see that some facial features were in a different position than you would expect?	20	2.57 (0.24)	10.95	0.000**	3	0.43 (0.24)	1.83	0.083	7.07	0.000**
33	Did you see that the face changed without you wanting it?	21	3.14 (0.19)	16.87	0.000**	4	0.52 (0.26)	1.99	0.061	9.35	0.000**
34	Did you see the face as through a fog?	19	2.33 (0.30)	7.90	0.000**	3	0.38 (0.21)	1.79	0.088	5.84	0.000**
	Total SFQ-R score		51.33 (3.22)	15.95	0.000**		10.71 (3.31)	3.23	0.004	14.36	0.000**

Total SFQ-R score: sum of 34 items (item-19 excluded).

Reliability analysis of total SFQ-R score: alpha = 0.83.

Bonferroni-corrected (34 items) statistical significance level.

* p < .0015 ** p < .0005.

Figure 1. Set-up of mirror-fixation and panel-fixation. The 4-mm hole was used as fixation point for the participant’s task of staring at the hole. The square surface was either a glass mirror (in the mirror-fixation experimental condition) or a gray non-reflective panel (in the panel-fixation control condition). Behind the hole a micro-camera was mounted for monitoring the participant’s correct fixation and for measuring eye-blink rate (EBR).

Table 2. Subcales of SFQ-R.

		MIRROR			PANEL			MIRROR vs. PANEL
	SFQ-R subscale	mean (SEM)	t	p	mean (SEM)	t	p	t	p	effect size (d)
1	Facial feature visual deformation (FD)	15.05 (1.06)	14.24	0.000***	2.38 (0.88)	2.72	0.013*	12.67	0.000***	2.34
2	Bodily face detachment (BD)	14.14 (1.12)	12.61	0.000***	4.71 (1.24)	3.79	0.001***	9.43	0.000***	1.73
3	Dissociated self-identity (DI)	7.19 (1.37)	5.25	0.000***	1.62 (0.77)	2.10	0.049	5.57	0.000***	1.24

Subscales.

FD (derealization) sum of SFQ-R items: 1, 8, 11, 16, 31, 32, 34.

BD (depersonalization) sum of SFQ-R items: 15, 17, 22, 23, 24, 30, 33.

DI (dissociated self-identity) sum of SFQ-R items: 5, 10, 14, 21, 25, 26, 27.

Reliability analyses of subscales.

alpha (FD) = 0.78.

alpha (BD) = 0.80.

alpha (DI) = 0.90.

Bonferroni-corrected (3 subscales) significance level.

* p < .016 ** p < .003 *** p < .0016.

Figure 2. Individual scores on SFQ-R subscales. The horizontal axis identifies participants sorted by increasing scores in mirror-fixation (sum of FD, BD, and DI), which are represented in the vertical axis. (Top chart) mirror-fixation. (Bottom chart) panel-fixation. Participants were identified by numbers in the horizontal axis.

Table 3. Items of CADSS and endorsements among participants (N = 21).

		MIRROR				PANEL				MIRROR vs. PANEL
	CADSS item	N(yes)	Mean (SEM)	t	p	N(yes)	Mean (SE)	t	p	t	p
1	Do things seem to be moving in slow motion?	16	1.33 (0.20)	6.69	0.000**	16	1.86 (0.31)	5.98	0.000**	−1.44	0.165
2	Do things seem to be unreal to you, as if you are in a dream?	18	2.48 (0.28)	8.80	0.000**	17	2.43 (0.36)	6.70	0.000**	0.13	0.900
3	Do you have some experience that separates you from what is happening; for instance, do you feel as if you are in a movie or a play, or as if you are a robot?	12	1.10 (0.26)	4.26	0.000**	11	1.38 (0.33)	4.13	0.001*	−0.74	0.467
4	Do you feel as if you are looking at things from outside of your body?	15	1.52 (0.28)	5.42	0.000**	8	0.86 (0.30)	2.91	0.009	1.82	0.085
5	Do you feel as if you are watching the situation as an observer or spectator?	17	1.81 (0.29)	6.25	0.000**	11	1.29 (0.32)	4.05	0.001*	1.53	0.142
6	Do you feel disconnected from your own body?	18	1.76 (0.29)	6.03	0.000**	15	1.48 (0.28)	5.25	0.000**	0.84	0.409
7	Does your sense of your own body feel changed: for instance, does your own body feel unusually large or unusually small?	10	1.00 (0.29)	3.42	0.003	8	0.62 (0.22)	2.77	0.012	1.56	0.134
8	Would people seem motionless, dead, or mechanical?	15	1.71 ((0.32)	5.40	0.000**	3	0.38 (0.21)	1.79	0.088	4.09	0.001*
9	Do objects look different than you would expect?	15	1.71 (0.30)	5.68	0.000**	13	1.76 (0.34)	5.12	0.000**	−0.11	0.917
10	Do colors seem to be diminished in intensity?	18	2.90 (0.29)	9.95	0.000**	19	2.67 (0.31)	8.57	0.000**	0.84	0.411
11	Do you see things as if you were in a tunnel, or looking through a wide angle photographic lens?	15	2.00 (0.35)	5.68	0.000**	16	2.19 (0.32)	6.83	0.000**	−0.38	0.705
12	Does this experience seem to take much longer than you would have expected?	11	1.52 (0.38)	4.06	0.001*	19	2.10 (0.29)	7.18	0.000**	−1.37	0.186
13	Do things seem to be happening very quickly, as if there is a lifetime in a moment?	20	2.71 (0.26)	10.46	0.000**	13	1.19 (0.31)	3.90	0.001*	4.96	0.000**
14	Do things happen that you later cannot account for?	13	1.62 (0.35)	4.65	0.000**	16	1.67 (0.31)	5.36	0.000**	−0.15	0.880
15	Do you space out, or in some other way lose track of what is going on?	20	2.10 (0.24)	8.80	0.000**	15	2.19 (0.23)	9.74	0.000**	−0.32	0.754
16	Do sounds almost disappear or become much stronger than you would have expected?	14	1.90 (0.34)	5.65	0.000**	18	2.00 (0.27)	7.48	0.000**	−0.26	0.797
17	Do things seem to be very real, as if there is a special sense of clarity?	13	1.24 (0.28)	4.36	0.000**	10	0.71 (0.21)	3.42	0.003	2.06	0.053
18	Does it seem as if you are looking at the world through a fog, so that people or objects seem far away or unclear?	18	2.14 (0.30)	7.26	0.000**	17	2.38 (0.34)	6.97	0.000**	−0.60	0.554
19	Do colors seem much brighter than you would have expected?	8	0.76 (0.26)	2.96	0.008	9	0.81 (0.25)	3.30	0.004	−0.17	0.870
	Total CADSS score of dissociation		33.33 (2.51)	13.26	0.000**		29.95 (2.36)	12.71	0.000**	1.08	0.292

Total CADSS score: sum of 19 items.

Bonferroni-corrected (19 items) statistical significance level.

* p < .003 ** p < .0005.

Table 4. Scales of CADSS-Amnesia, CADSS-Depersonalization, and CADSS-Derealization. CADSS total score of dissociation is the algebraic sum of these three scales.

		MIRROR			PANEL			MIRROR vs. PANEL
		mean (SEM)	t	p	mean (SEM)	t	p	t	p
1	CADSS-Derealization	22.43 (1.42)	15.76	0.000***	20.48 (1.43)	14.30	0.000***	0.95	0.355
2	CADSS-Depersonalization	7.19 (1.07)	6.69	0.000***	5.62 (1.13)	4.97	0.000***	1.44	0.164
3	CADSS-Amnesia	3.71 (0.44)	8.39	0.000***	3.86 (0.30)	12.73	0.000***	−0.34	0.738

Bonferroni-corrected (3 subscales) significance level.

* p < .016 ** p < .003 *** p < .0016.

Figure 3. Individual scores on CADSS scales of Amnesia, Depersonalization, and Derealization. The participants were identified with the same numbers as in Figure 2.

Figure 4. Individual EBRs and scores on FD scale of SFQ-R in mirror-fixation.

Data availability statement

The data that support the findings of this study are openly available in figshare at (http://doi.org/10.6084/m9.figshare.22337242).