  Pursuit of honest and truthful decision-making is crucial for governance and
accountability in democracies. However, people sometimes take different
perspectives of what it means to be honest and how to pursue truthfulness. Here
we explore a continuum of perspectives from evidence-based reasoning, rooted in
ascertainable facts and data, at one end, to intuitive decisions that are
driven by feelings and subjective interpretations, at the other. We analyze the
linguistic traces of those contrasting perspectives in Congressional speeches
from 1879 to 2022. We find that evidence-based language has continued to
decline since the mid-1970s, together with a decline in legislative
productivity. The decline was accompanied by increasing partisan polarization
in Congress and rising income inequality in society. Results highlight the
importance of evidence-based language in political decision-making.
