  There is strong interest in the generation of synthetic video imagery of
people talking for various purposes, including entertainment, communication,
training, and advertisement. With the development of deep fake generation
models, synthetic video imagery will soon be visually indistinguishable to the
naked eye from a naturally capture video. In addition, many methods are
continuing to improve to avoid more careful, forensic visual analysis. Some
deep fake videos are produced through the use of facial puppetry, which
directly controls the head and face of the synthetic image through the
movements of the actor, allow the actor to 'puppet' the image of another. In
this paper, we address the question of whether one person's movements can be
distinguished from the original speaker by controlling the visual appearance of
the speaker but transferring the behavior signals from another source. We
conduct a study by comparing synthetic imagery that: 1) originates from a
different person speaking a different utterance, 2) originates from the same
person speaking a different utterance, and 3) originates from a different
person speaking the same utterance. Our study shows that synthetic videos in
all three cases are seen as less real and less engaging than the original
source video. Our results indicate that there could be a behavioral signature
that is detectable from a person's movements that is separate from their visual
appearance, and that this behavioral signature could be used to distinguish a
deep fake from a properly captured video.
