A crucial step in language evolution was likely joint attention with alternating gaze between vocalizing individualsand an object. This triadic interaction likely formed a foundation for labeling of objects. We have argued that vocalizationsused for “social glue” – flexible low intensity and low arousal vocalizations given during e.g. grooming, keeping in contact withthe group, etc. – are a probable source of raw material for first labels. It is critical that these vocalizations be socially directed,by gaze contact. We longitudinally investigated directed gaze during vocalizations in low arousal interactions during the firstyear in three bonobo mother-infant pairs and compared them with 9 human mother-infant pairs. We found that bonobo infantsdirected their gaze to a conspecific during vocalizations only 8% of the time while human infants directed it 44% of the time.

Differential privacy concepts have been successfully used to protect anonymity of individuals in population-scale analysis. Sharing of mobile sensor data, especially physiological data, raise different privacy challenges, that of protecting private behaviors that can be revealed from time series of sensor data. Existing privacy mechanisms rely on noise addition and data perturbation. But the accuracy requirement on inferences drawn from physiological data, together with well-established limits within which these data values occur, render traditional privacy mechanisms inapplicable. In this work, we define a new behavioral privacy metric based on differential privacy and propose a novel data substitution mechanism to protect behavioral privacy. We evaluate the efficacy of our scheme using 660 hours of ECG, respiration, and activity data collected from 43 participants and demonstrate that it is possible to retain meaningful utility, in terms of inference accuracy (90%), while simultaneously preserving the privacy of sensitive behaviors.