Interaction Studies - Volume 7, Issue 2, 2006

This article discusses the concept of joint attention and the different skills underlying its development. Research in developmental psychology clearly states that the development of skills to understand, manipulate and coordinate attentional behavior plays a pivotal role for imitation, social cognition and the development of language. However, beside the fact that joint attention has recently received an increasing interest in the robotics community, existing models concentrate only on partial and isolated elements of these phenomena. In the line of Tomasello’s research, we argue that joint attention is much more than simultaneous looking because it implies a shared intentional relation to the world. This requires skills for attention detection, attention manipulation, social coordination and, most importantly, intentional understanding. After defining joint attention and its challenges, the current state-of-the-art of robotic and computational models relevant for this issue is discussed in relation to a developmental timeline drawn from results in child studies. From this survey, we identify open issues and challenges that still need to be addressed to understand the development of the various aspects of joint attention and conclude with the potential contribution of robotic models.

For a robot to be capable of development it must be able to explore its environment and learn from its experiences. It must find (or create) opportunities to experience the unfamiliar in ways that reveal properties valid beyond the immediate context. In this paper, we develop a novel method for using the rhythm of everyday actions as a basis for identifying the characteristic appearance and sounds associated with objects, people, and the robot itself. Our approach is to identify and segment groups of signals in individual modalities (sight, hearing, and proprioception) based on their rhythmic variation, then to identify and bind causally-related groups of signals across different modalities. By including proprioception as a modality, this cross-modal binding method applies to the robot itself, and we report a series of experiments in which the robot learns about the characteristics of its own body.

This paper reports about our investigation on action understanding in the brain. We review recent results of the neurophysiology of the mirror system in the monkey. Based on these observations we propose a model of this brain system which is responsible for action recognition. The link between object affordances and action understanding is considered. To support our hypothesis we describe two experiments where some aspects of the model have been implemented. In the first experiment an action recognition system is trained by using data recorded from human movements. In the second experiment, the model is partially implemented on a humanoid robot which learns to mimic simple actions performed by a human subject on different objects. These experiments show that motor information can have a significant role in action interpretation and that a mirror-like representation can be developed autonomously as a result of the interaction between an individual and the environment.

Twelve-month-old infants interacted with two strangers in a free-play context. In the Experimental condition (n = 17), one stranger (Contingent partner) vocally responded immediately to infants’ looks towards her, whereas the other (Non-contingent partner) was yoked to the Contingent partner with a 1-, 2-, or 3-s delay. In the Control condition (n = 17), the Non-Contingent partner emitted the first vocalization and other non-contingent vocalizations during the free play session. The Contingent partner acted the same as in the Experimental condition. When a novel event occurred after the free-play session, infants looked significantly more to the Contingent partner regardless of condition. The study highlights infants’ selective looking to temporally contingent partners in novel situations.

Sensitivity to interpersonal timing was assessed in mother–infant interaction. In Study 1, 3-month-old infants interacted with their mothers over television and the mothers’ audio-visual presentation was either live or temporally delayed by 1 second. Infants gazed longer when the mother was presented live compared to delayed by 1 second, indicating that they detected the temporal delay. In Study 2, mothers interacted with their 3-month-old infants over television and the infants’ audio-visual presentation was either live or temporally delayed by 1 second. Mothers’ behavior was not altered by a 1-second delay in their infants’ behavior compared to a live presentation. In Study 3 and 4, the results were replicated with 6-month-old infants. Whereas infants detected the temporal delay in maternal responses, mothers likely adjusted to the delay in infant behavior. The discussion focuses on the role of interpersonal timing for detecting social contingency in dyadic and triadic communication.