  Pupillary responses (PR) change differently for different types of stimuli.
This study aims to check whether observers PR can recognise real and posed
smiles from a set of smile images and videos. We showed the smile images and
smile videos stimuli to observers, and recorded their pupillary responses
considering four different situations, namely paired videos, paired images,
single videos, and single images. When the same smiler was viewed by observers
in both real and posed smile forms, we refer them as paired; otherwise we use
the term single. The primary analysis on pupil data revealed that the
differences of pupillary response between real and posed smiles are more
significant in case of paired videos compared to others. This result is found
from timeline analysis, KS-test, and ANOVA test. Overall, our model can
recognise real and posed smiles from observers pupillary responses instead of
smilers responses. Our research will be applicable in affective computing and
computer-human interaction for measuring emotional authenticity.
