  Estimating the engagement is critical for human - robot interaction.
Engagement measures typically rely on the dynamics of the social signals
exchanged by the partners, especially speech and gaze. However, the dynamics of
these signals is likely to be influenced by individual and social factors, such
as personality traits, as it is well documented that they critically influence
how two humans interact with each other. Here, we assess the influence of two
factors, namely extroversion and negative attitude toward robots, on speech and
gaze during a cooperative task, where a human must physically manipulate a
robot to assemble an object. We evaluate if the scores of extroversion and
negative attitude towards robots co-variate with the duration and frequency of
gaze and speech cues. The experiments were carried out with the humanoid robot
iCub and N=56 adult participants. We found that the more people are extrovert,
the more and longer they tend to talk with the robot; and the more people have
a negative attitude towards robots, the less they will look at the robot face
and the more they will look at the robot hands where the assembly and the
contacts occur. Our results confirm and provide evidence that the engagement
models classically used in human-robot interaction should take into account
attitudes and personality traits.
