Christopher G. Prince

Synching models with infants: a perceptual-level model of infant audio-visual synchrony detection

Synchrony detection between different sensory channels appears critically important for learning and cognitive development. In this paper we compare infant studies of audio-visual synchrony detection with a model of synchrony detection based on Gaussian mutual information [Hershey, J., & Movellan, J. (2000). Audio-vision: using audio-visual synchrony to locate sounds. In S. A. Solla, T. K. Leen, & K. R. Muller (Eds.), Advances in neural information processing systems (Vol. 12, pp. 813-819). Cambridge, MA: MIT Press], augmented with methods for quantitative synchrony estimation. Five infant-model comparisons are presented, using stimuli covering a broad range of audio-visual integration types. While infants and the model showed discrimination of each type of stimuli, the model was most successful with stimuli comprised of (a) synchronized punctuate motion and speech, (b) visually balanced left and right instances of the same person talking but speech synchronized with only one side, and (c) two speech audio sources and a dynamic-face motion source. More difficult for the model were stimuli conditions with (d) left and right instances of two different people talking but speech synchronized with only one side, and (e) two speech audio sources and more abstract visual dynamics - an oscilloscope instead of a face. As a first approximation, this model of synchrony detection using low-level sensory features (e.g., RMS audio, grayscale pixels) is a candidate for a mechanism used by infants in detecting audio-visual synchrony.

Editorial: Introduction to the Special Issue on Epigenetic Robotics:

This special issue of Adaptive Behavior stems from the 2002 Workshop on Epigenetic Robotics (Prince, Demiris, Marom, Kozima, & Balkenius, 2002). Authors of selected papers from that workshop were invited to extend their papers into journal-length treatments. These workshops (see also Balkenius, Zlatev, Kozima, Dautenhahn, & Breazeal, 2001; Prince, Berthouze, Kozima, Bullock, Stojanov, & Balkenius, in press) on epigenetic robotics (EpiRob) represent current contributions to developmental cognitive science. The focus of EpiRob is to bring together developmental psychology and robotics, to create robots that develop their behaviors and internal representations on the basis of long-term learning and sensorimotor environmental interactions. Developmental Psychology focusses on the psychological development of children, including their acquisition of object knowledge (e.g., Baillargeon, 1986; Spelke, 1998) and social skills (e.g., Carpenter, Nagell, & Tomasello, 1998). EpiRob research builds models of the psychological development of children. For example, EpiRob creates robots that exhibit object-knowledge development (e.g., Coelho, Piater, & Grupen, 2000; Metta & Fitzpatrick, this issue), and social skills (e.g., Breazeal & Scassellati, 2000; Kozima & Yano, 2001; Nagai, Hosoda, & Asada, in press). Epigenetic robotics may lead to better (e.g., more task-general) robotic systems (Huber & Grupen, 1997; Weng et al., 2001). Additionally, in good cognitive science tradition, by proposing concrete mechanisms for developmental processes EpiRob promises to add to our understanding of developmental psychology. For this special issue we selected three papers, spanning views in epigenetic robotics, incorporating theoretical, computational, and robotic investigations. EpiRob is integrative and broadly interdisciplinary (see also Kitano, 2002) and research is needed in several areas. First, we should develop a methodological approach to drawing from psychology in our modeling work. Since the areas of literature involved (e.g., developmental psychology and robotics) are vast, and since the conceptual perspectives are widely different in these disciplines, we need theoretical research that bridges the areas. Next, we need research showing how formal (e.g., computational) models can work together with developmental psychology to provide useful models of developmental mechanisms. Finally, we need research that shows how robotics can model developmental processes. The three papers selected for this issue reflect these three general areas. The work of Lindblom and Ziemke provides a theoretical treatment of how social development can contribute to epigenetic robotics; Schlesinger’s contribution brings together both developmental psychology and computational modeling; and finally, Metta and Fitzpatrick present an experimental robotic investigation. Jessica Lindblom and Tom Ziemke open this issue by discussing the concept of “social situatedness,” the idea that an agent’s intelligence develops in and requires a social context. In their paper, they relate epigenetic robotics and the developmental psychology tradition of Lev Vygotsky. In particular they consider the importance of social situatedness for the development of robot–robot interactions as well as more recent approaches to robot–human interactions, such as the Kismet (Breazeal & Scassellati, 2000) and Infanoid projects (Kozima & Yano, 2001). Additionally, the authors consider current research in primatol-

Comparing infants’ preference for correlated audiovisual speech with signal‐level computational models

How much of infant behaviour can be accounted for by signal-level analyses of stimuli? The current paper directly compares the moment-by-moment behaviour of 8-month-old infants in an audiovisual preferential looking task with that of several computational models that use the same video stimuli as presented to the infants. One type of model utilizes only signal-level properties of visual motion whereas the other adds audiovisual integration (either through correlation or instantaneous addition of audio and visual signals). Together these models account for a significant portion of the variance in infant looking.

Epigenetic robotics : Behavioral treatments and potential new models for developmental pediatrics

Epigenetic Robotics: Behavioral Treatments and Potential New Models for Developmental Pediatrics

Rodney A. Brooks, Cambrian Intelligence: The Early History of the New AI , Cambridge, MA: MIT Press, 1999, xii + 199 pp.,

ions, think about the problem features that are not included in the heuristics, operators, etc. It does seem clear that solutions to the perception problem can constrain the design of an intelligent system. Take for example the mathematical investigation into active vision (systems that can alter the positions of their camera sensors—see for example Aloimonos et al., 1988). Active vision, a general solution strategy in robotic perception, reduces the complexity of the perception problem, and is likely to constrain the rest of the solution space for the artificially intelligent system. Brooks has voiced an important question: What kinds of artificial intelligences can be obtained from architectures that emphasize sensory and motor systems? Brooks’s physical grounding hypothesis is “that to build a system that is intelligent

21.56 (paper), ISBN 0-262-52263-2.

Computational Principles of Mobile Robotics comprises 10 chapters, spanning hardware, mathematical formalisms, algorithms, implemented software and systems, and terminology related to autonomous robots that are designed to solve problems in large-scale space, i.e. mobile robots. Large-scale space consists of “regions of space substantially larger than those that can be observed from a single vantage point” (p. 1). Robot mobility, large-scale space, and navigational skills go hand in hand. On the one hand, a robot that is mobile needs navigational skills to exploit its movement, and these skills are useful in large-scale space. On the other hand, large-scale space and local sensing imply a need for mobility and navigation to other vantage points. The book provides problems to be worked at the end of each chapter. Six of the chapters also cite further relevant readings. Most of the book concerns individual robots, but Chapters 1, 5, 6, and 8 include some consideration of multi-robot issues. I will summarize the contents of the chapters, and then move on to my specific comments about the book.