  Instructors and researchers think "thinking like a physicist" is important
for students' professional development. However, precise definitions and
observational markers remain elusive. We reinterpret popular beliefs
inventories in physics to indicate what physicists think "thinking like a
physicist" entails. Through discourse analysis of upper-division students'
speech in natural settings, we show that students may appropriate or resist
these elements. We identify a new element in the physicist speech genre: brief,
embedded, spontaneous metacognitive talk (BESM talk). BESM talk communicates
students' in-the-moment enacted expectations about physics as a technical field
and a cultural endeavor. Students use BESM talk to position themselves as
physicists or non-physicists. Students also use BESM talk to communicate their
expectations in four ways: understanding, confusion, spotting inconsistencies,
and generalized expectations.
