Overall, the percentage of Americans who take the “creationist” position is lower in the single-question format (when survey respondents are given an immediate option to express both acceptance of evolution and belief that God or a higher power had a role in such processes) than in the two-question format. When asked the single-question version, just 18 percent of U.S adults say humans have always existed in their present form, while 81 percent say humans have evolved over time. By contrast, in the two-question approach, nearly one third of respondents (31 percent) say humans have always existed in their present form, and 68 percent say they evolved over time. These results suggest that some Americans who do accept that humans have evolved are reluctant to say so in the two-question approach, perhaps because they are uncomfortable placing themselves on the secular side of a cultural divide.

The effect of the different question formats is especially pronounced among two of the most religious subsets of U.S. Christians: white evangelical Protestants and black Protestants. When asked using the two-question format, about two thirds of white evangelical Protestants (66 percent) take a “creationist” stance, saying that “humans have always existed in their present form since the beginning of time.” But when asked about human evolution in a single-question format, a 62 percent majority of white evangelical Protestants take the position that humans have evolved over time.