In the study, the spouses actually estimated their contributions by making a slash mark on a line segment which had endpoints labelled “primarily wife” and “primarily husband”. The experimenters set it up this way, rather than asking for numerical percentages, for ethical reasons. In pilot testing using percentages, they “found that subjects were able to remember the percentages they recorded and that postquestionnaire comparisons of percentages provided a strong source of conflict between the spouses.” (p. 325)
Ross & Sicoly (1979). Egocentric Biases in Availability and Attribution.
In the study, the spouses actually estimated their contributions by making a slash mark on a line segment which had endpoints labelled “primarily wife” and “primarily husband”. The experimenters set it up this way, rather than asking for numerical percentages, for ethical reasons. In pilot testing using percentages, they “found that subjects were able to remember the percentages they recorded and that postquestionnaire comparisons of percentages provided a strong source of conflict between the spouses.” (p. 325)