Attention sharing provides an important context for infant learning, but it is not fully understood how infants respond to parents' isolated or combined actions to shift from nonsharing to attention-sharing states. To investigate this, we recorded unscripted toy-play interactions of infants (3 to 11 months old, N = 35) and mothers at home, and coded attention-related behaviors. These included infants' and mothers' visual fixations, and mothers' attention-directing actions including gaze shifts, pointing gestures, object manipulations, verbalizations, and object sounds. In addition, dyadic attention was continuously classified into one of seven states of shared or nonshared attention. Results showed that mothers usually produced a combination of attention-directing cues within the 7 sec. before infants shifted their attention to match the mother's focus. Mothers' cue combinations usually included object manipulation and either a gaze shift or a verbalization. Infants seldom looked at mothers' faces and followed a very small proportion of isolated gaze shifts or pointing gestures. However, infants frequently shifted attention to watch mothers manipulate objects. The results indicate that during toy play, combinations of maternal attention-specifying actions selectively elicit infants' attention following.
Gaze following is the ability to redirect one's gaze to the location where another agent is looking. We present a computational model of how human infants or other agents may acquire gaze following by learning to predict the locations of interesting sights from the looking behavior of other agents through reinforcement learning. The model accounts for many findings about the development of gaze following in human infants. During learning, the model develops pre-motor representations that exhibit many properties characteristic of mirror neurons, but they are specific to looking behaviors. The existence of such a new class of mirror neurons is the main prediction of our model. The model also offers a parsimonious account of how these and possibly other mirror neurons may acquire their special response properties. In this account, visual representations of other agents' actions become associated with premotor neurons that represent the intention to perform corresponding actions. The model also demonstrates how this development may be obstructed in autism spectrum disorder, giving rise to specific physiological and anatomical differences in the mirror system.
These data suggest that decreases in plasma free-VEGF levels are greater after treatment with aflibercept or bevacizumab compared with ranibizumab at 4 weeks. At 52 and 104 weeks, a greater decrease was observed in bevacizumab versus ranibizumab. Results from 2 subgroups of participants who did not receive injections within at least 1 month and 2 months before collection suggest similar changes in VEGF levels after stopping injections. It is unknown whether VEGF levels return to normal as the drug is cleared from the system or whether the presence of the drug affects the assay's ability to accurately measure free VEGF. No significant associations between VEGF concentration and systemic factors were noted.
Abstract-Gaze following, the ability to redirect one's visual attention to look at what another person is seeing, is foundational for imitation, word learning, and theory-of-mind. Previous theories have suggested that the development of gaze following in human infants is the product of a basic gaze following mechanism, plus the gradual incorporation of several distinct new mechanisms that improve the skill, such as spatial inference, and the ability to use eye direction information as well as head direction. In this paper, we offer an alternative explanation based on a single learning mechanism. From a starting state with no knowledge of the implications of another organism's gaze direction, our model learns to follow gaze by being placed in a simulated environment where an adult caregiver looks around at objects. Our infant model matches the development of gaze following in human infants as measured in key experiments that we replicate and analyze in detail.Index Terms-Adaptive systems, artificial intelligence, autonomous mental development, behavioral science, cognition, cognitive science, computational and artificial intelligence, cybernetics, emergent phenomena, intelligent systems, learning systems, multiagent systems, systems, man, and cybernetics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.