[1]
I am very thankful for Haug and Jung’s criticisms, from which I have learnt a great deal. Below I will use “the sense of self-as-subject” and “the sense of experiential ownership” interchangeably.
[2]
Note that, as I suggested in the target paper (Liang this collection, p. 6), the fact of experiential ownership and the sense of experiential ownership are not numerically different states or events that can be detached from a phenomenal state. Rather, they are two ways of characterizing the who-component of that state.
[3]
I discuss the Pre-reflective Account in “Body ownership and experiential ownership in the self-touching illusion” (Liang et al. 2015).
[4]
The experiments and data presented here are part of a bigger project; cf. “Body ownership and experiential ownership in the self-touching illusion” (Liang et al. 2015). Four students conducted the experiments under my supervision: Si-Yan Chang, Wen-Yeo Chen, Hsu-Chia Huang, Yen-Tung Lee.
[5]
The self-touching illusion was measured by two questionnaire statements: “It felt as if I was brushing my own hand” (S1), and “The one whom I brushed was me, not someone else” (S2). A Likert scale from “strongly disagree” (-3) to “strongly agree” (+3) was used for the questionnaires. In both Experiment 1 (sync. n=38, async. n=35) and Experiment 2 (sync. n=28, async. n=14), the statistics showed significant differences between the synchronous and asynchronous conditions (Exp. 1, S1: p<0.0010, S2: p<0.0010; Exp. 2, S1: p<0.0010, S2: p=0.0003; one-tailed t-test). The measurements of skin conductance responses (Exp. 1, sync. n=15, async. n=15; Exp. 2, sync. n=13; async. n=13) showed the same differences (Exp. 1, p=0.0080; Exp. 2, p=0.0473; one-tailed t-test). This provided objective support for the questionnaire data.
[6]
Cf. “Body ownership and experiential ownership in the self-touching illusion” (Liang et al. 2015). Briefly, (i) suppose for some reason that the participants understood WQ1 to be addressing someone else. That is, in their subjective experiences, it was not me who felt the brushing. Then, according to IEM, one would expect that most participants would answer “strongly disagree” (-3) or at least “disagree” (-2) on WQ1. But this is not the case either. This time, the average scores of WQ1 were too high to fit this interpretation. (ii) Suppose that the participants did not all understand WQ1 in the same way: some took it as addressing themselves, but others as addressing someone else. Then, assuming IEM holds, one would expect the participants to answer either +3 (or at least +2) or -3 (or at least -2). But, again, that is not the case. Many participants answered “slightly disagree” (-1), “not sure” (0), or “slightly agree” (+1). In fact, the standard deviation in each experiment is large (Exp. 1, SD=1.5001; Exp. 2, SD=1.5512), suggesting that the participants’ responses to WQ1 varied widely.
[7]
In addition to WQ1, we also presented WQ2 (“The one who felt being brushed was not me”) in the questionnaires. The direct contrast between WQ2 and WQ1 was so obvious that, even if the participants felt uncertain about WQ1, the contrast can still be easily recognized. So, if IEM holds, one could reasonably expect that participants’ responses would manifest a strong “negative correlation” between WQ1 and WQ2. For example, if a subject answers +3 to WQ1, then he/she would likely answer -3 (or at least -2) to WQ2, etc. However, we only observed a weak negative correlation between these two sets of results (coefficient R=-0.3278).