Data from: How scientists perceive the evolutionary origin of human traits: results of a survey study

Various hypotheses have been proposed for why the traits distinguishing
humans from other primates originally evolved, and any given trait may
have been explained both as an adaptation to different environments and as
a result of demands from social organization or sexual selection. To find
out how popular the different explanations are among scientists, we
carried out an online survey among authors of recent scientific papers in
journals covering relevant fields of science (palaeoanthropology,
palaeontology, ecology, evolution, human biology). Some of the hypotheses
were clearly more popular among the 1266 respondents than others, but none
was universally accepted or rejected. Even the most popular of the
hypotheses were assessed “very likely” by <50 % of the respondents,
but many traits had 1–3 hypotheses that were found at least moderately
likely by >70 % of the respondents. An ordination of the hypotheses
identified two strong gradients. Along one gradient, the hypotheses were
sorted by their popularity, measured by the average credibility score
given by the respondents. The second gradient separated all hypotheses
postulating adaptation to swimming or diving into their own group. The
average credibility scores given for different subgroups of the hypotheses
were not related to respondent’s age or number of publications authored.
However, (palaeo)anthropologists were more critical of all hypotheses, and
much more critical of the water-related ones, than were respondents
representing other fields of expertise. Although most respondents did not
find the water-related hypotheses likely, only a small minority found them
unscientific. The most popular hypotheses were based on inherent drivers,
i.e. they assumed the evolution of a trait to have been triggered by the
prior emergence of another human-specific behavioural or morphological
trait, but opinions differed as to which of the traits came first.