 [P]articipants rated the extent of oneness they felt with the [person they might help] by responding to two items that were combined in all analyses to form a oneness index. The first item incorporated the Inclusion of Other in Self (IOS) Scale used by Aron et al. (1992) to measure self-other boundary overlap. It consisted of a set of seven pairs of increasingly overlapping circles. Participants selected the pair of circles that they believed best characterized their relationship with the [person they might help]. The second item asked participants to indicate on a 7-point scale the extent to which they would use the term we to describe their relationship with the [person they might help]. (1997: 484)