Interaction Histories and Short-Term Memory: Enactive Development of Turn-Taking Behaviours in a Childlike Humanoid Robot

In this article, an enactive architecture is described that allows a humanoid robot to learn to compose simple actions into turn-taking behaviours while playing interaction games with a human partner. The robot’s action choices are reinforced by social feedback from the human in the form of visual attention and measures of behavioural synchronisation. We demonstrate that the system can acquire and switch between behaviours learned through interaction based on social feedback from the human partner. The role of reinforcement based on a short-term memory of the interaction was experimentally investigated. Results indicate that feedback based only on the immediate experience was insufficient to learn longer, more complex turn-taking behaviours. Therefore, some history of the interaction must be considered in the acquisition of turn-taking, which can be efficiently handled through the use of short-term memory.Peer reviewedFinal Published versio

Imitation recognition and its effect on subsequent interactions between pet dogs (Canis familiaris)

Tese de mestrado. Biologia (Biologia Evolutiva e do Desenvolvimento). Universidade de Lisboa, Faculdade de Ciências, 2012It has been argued that imitation might facilitate social interactions and may increase affiliating emotions between individuals. Hence imitation recognition can be considered as the recognition of matching actions performed by other individuals with those of the self and also importantly it is thought to foster sensitivity to social contingencies. Imitation recognition has mainly been associated only with humans. Although phylogenetically distant from humans, dogs might provide a useful model for understanding the evolution of imitation recognition and its effects on affect. It has already been previously demonstrated that though it is not their characteristic way of learning socially, dogs are capable of imitation. Therefore, imitation recognition may also play a role in the social interactions of dogs. In order to investigate this question, an experimental set up was designed so that two dogs (subject and partner) would work simultaneously on two identical apparatuses for which they had been previously trained to operate either using their paw or mouth. Subsequently, it was studied whether dogs could locate food more successfully in a cooperative task, based on gazing cues given by a partner who had performed a matching action rather than when the cues were given by a partner that used a non-matching action. The present study provides evidence that dogs are able to follow conspecific gaze in order to locate hidden food. Moreover, that it depends on the social context and previous interactions between dogs. Namely if both subject and partner had used the same action during the simultaneous working phase, it affected the dogs’ outcome in a subsequent two-way object choice task as subjects made a higher number of correct choices and also above chance levels and took less time to approach the bowls. Henceforth, this study contributes to better understand how dogs interact and cooperate.Tem-se argumentado que a imitação pode facilitar interacções sociais e pode aumentar emoções afiliativas entre indivíduos. Deste modo, o reconhecimento da imitação pode ser considerado como um indivíduo reconhecendo as suas próprias acções nas acções realizadas por outros indivíduos. Pensa-se ainda inclusivamente que promova uma maior sensibilidade às contingências sociais, no entanto o reconhecimento da imitação tem sido sobretudo apenas associado aos seres humanos. Embora filogeneticamente distante da espécie humana, o cão doméstico pode ser um modelo útil para a compreensão da evolução do reconhecimento de imitação e os seus efeitos sobre empatia. Já foi demonstrado anteriormente que embora não seja a sua forma característica de aprendizagem social, os cães são capazes de imitar. Assim, o reconhecimento da imitação pode desempenhar também um papel importante nas interacções sociais dos cães. Para investigar esta questão, concebeu-se uma experiência de modo a que dois cães (indivíduo focal e parceiro) trabalhassem simultaneamente em dois aparelhos idênticos para os quais tinham sido previamente treinados usando a pata ou a boca. Subsequentemente avaliou-se a hipótese dos cães numa tarefa cooperativa serem capazes de localizar alimento, com base no olhar do parceiro para um determinado local, com maior taxa de sucesso caso tivessem previamente realizado a mesma acção. O presente estudo demonstra que os cães são capazes de seguir o olhar de um conspecífico de forma a localizar alimento escondido. Além disso, demonstrou-se que esta capacidade depende do contexto social e interacções prévias entre estes. Deste modo, caso ambos, indivíduo focal e parceiro, tivessem usado a mesma acção durante a fase inicial, maior o número de escolhas correctas feitas pelo indivíduo focal não feitas ao acaso, bem como, este levava um menor tempo deste a aproximar-se das taças. Este estudo contribui para uma melhor compreensão da interacção e cooperação entre cães

Investigating the Effects of Robot Engagement Communication on Learning from Demonstration

Robot Learning from Demonstration (RLfD) is a technique for robots to derive policies from instructors' examples. Although the reciprocal effects of student engagement on teacher behavior are widely recognized in the educational community, it is unclear whether the same phenomenon holds true for RLfD. To fill this gap, we first design three types of robot engagement behavior (attention, imitation, and a hybrid of the two) based on the learning literature. We then conduct, in a simulation environment, a within-subject user study to investigate the impact of different robot engagement cues on humans compared to a "without-engagement" condition. Results suggest that engagement communication significantly changes the human's estimation of the robots' capability and significantly raises their expectation towards the learning outcomes, even though we do not run actual learning algorithms in the experiments. Moreover, imitation behavior affects humans more than attention does in all metrics, while their combination has the most profound influences on humans. We also find that communicating engagement via imitation or the combined behavior significantly improve humans' perception towards the quality of demonstrations, even if all demonstrations are of the same quality.Comment: Under revie

The regulatory function of social referencing in preschoolers with Down syndrome or Williams syndrome.

The present project examined the regulatory function of social referencing in two neurodevelopmental disorders that have been well defined genetically and are characterized by differing patterns of socio-cognitive development: Down syndrome (DS) and Williams syndrome (WS). In addition, since the social referencing process requires children to coordinate three fundamental abilities (initiation of joint attention, gaze following, emotional responsivity), the present project also included three follow-up studies which examined these abilities separately. Participants were 21 children with DS (M age = 4.97 years; SD = .74) and 21 children with WS (M age = 4.92 years; SD = .76) closely matched on age and gender. The results of the Social Referencing task indicated that the majority of children in both diagnostic groups formed positive opinions about the ambiguous stimulus when the adult communicated a joyful nonverbal message but had difficulty using the adult\u27s expression of fear to regulate their behavior in response to the ambiguous stimulus. Children with DS were more likely than were children with WS to shift gaze between the adult and the ambiguous stimulus. However, the children with DS frequently formed a positive opinion of the fearful stimulus and were more likely than were the children with WS to touch the stimulus. When the adult reacted fearfully to the ambiguous stimulus, the longest look directed to her by children with WS was significantly longer than the longest look directed by children with DS. In addition, children with WS were less likely to form an opinion of the fearful stimulus and more likely than children with DS to resort to superficially imitating the adult\u27s display as opposed to using the adult\u27s opinion of the stimulus to form their own. The results of the follow-up studies demonstrated that children with DS were more likely than were children with WS to initiate joint attention with the adult and to respond to joint attention in triadic situations. In addition, in a situation with a reduced attentional demand on the child than that used in the Social Referencing task, results indicated that the majority of children in both groups formed a positive opinion of the stimulus when the adult communicated a joyful message about it. However, when the adult communicated a fearful message, only one child in each group formed a negative opinion of the stimulus. In summary, the results indicate that there are both similarities and differences in the problems encountered by children with DS and children with WS in the social referencing process. Both groups had difficulty interpreting the communicative significance of fearful reactions. However, children with DS were more successful than children with WS both at coordinating attention in triadic interactions and at identifying the source of the adult\u27s interest. Furthermore, despite demonstrating poorer overall intellectual ability and more limited verbal ability, children with DS evidenced better executive functioning than did children with WS. This difference in executive functioning may contribute to some of the advantages shown by children with DS