The Automaticity of Social Behavior towards Robots: The Influence of Cognitive Load on Interpersonal Distance to Approachable versus Less Approachable Robots

Social robots are designed to promote social responses by human users. Based on the Media Equation theory, we argue that the way in which people interact with technology resembles the way in which humans interact with other humans, and, crucially, that these social responses are mainly of an automatic nature. To investigate the automaticity of social behavior towards robots, the current study assessed a well-studied (in human-human interaction) social behavior: interpersonal distance people keep, though not from other humans but from a robot. Earlier research suggested that the social behavior of distance keeping depends (amongst others) on the bodily posture of the interaction partner. Based on these earlier studies, we expected that participants would keep an interpersonal distance dependent on the posture of their robotic interaction partner especially if a participant was responding in more automatic ways. We manipulated robot posture (approachable versus less approachable) and the cognitive load of the participant (high versus low), and measured user-robot approach distance in ten short interaction tasks. In line with expectations, results suggested that especially participants under high cognitive load approached the robot closer when its posture communicated approachableness than when it communicated less approachableness. Thereby, the current results suggested that especially when people are cognitively distracted, their behavior towards robots is of a social nature and comparable to their behavior when responding to other humans. Implications for theory, research and design of social robots are discussed.