  The paper presents the results of a behavioral experiment conducted between
February 2020 and March 2021 at Universit\`a Cattolica del Sacro Cuore, Milan
Campus in which students were matched to either a human or a humanoid robotic
partner to play an iterated Prisoner's Dilemma. The results of a Logit
estimation procedure show that subjects are more likely to cooperate with human
rather robotic partners; that are more likely to cooperate after receiving a
dialogic verbal reaction following the realization of a sub-obtimal social
outcome; that the effect of the verbal reaction is independent on the nature of
the partner. Our findings provide new evidence on the effect of verbal
communication in strategic frameworks. Results are robust to the exclusion of
students of Economics related subjects, to the inclusion of a set of
psychological and behavioral controls, to the way subjects perceive robots'
behavior and to potential gender biases in human-human interactions.
