The Faces in Infant-Perspective Scenes Change over the First Year of Life

Mature face perception has its origins in the face experiences of infants. However, little is known about the basic statistics of faces in early visual environments. We used head cameras to capture and analyze over 72,000 infant-perspective scenes from 22 infants aged 1-11 months as they engaged in daily activities. The frequency of faces in these scenes declined markedly with age: for the youngest infants, faces were present 15 minutes in every waking hour but only 5 minutes for the oldest infants. In general, the available faces were well characterized by three properties: (1) they belonged to relatively few individuals; (2) they were close and visually large; and (3) they presented views showing both eyes. These three properties most strongly characterized the face corpora of our youngest infants and constitute environmental constraints on the early development of the visual system

Effect of partial occlusion on newborns' face preference and recognition

Many studies have shown that newborns prefer (e.g. Goren, Sarty & Wu, 1975; Valenza, Simion, Macchi Cassia & Umilt\ue0, 1996) and recognize (e.g. Bushnell, Say & Mullin, 1989; Pascalis & de Schonen, 1994) faces. However, it is not known whether, at birth, faces are still preferred and recognized when some of their parts are not visible because hindered by other configurations, that is when faces are partly occluded. Also, it is not known whether newborns\u2019 preference for an upright over an inverted face and newborns\u2019 face recognition are differentially affected depending on the salience of the occluded face features. Seventy-seven newborns (mean age of 43.5 hrs) were tested using the preferential looking (Experiment 1) and the habituation techniques (Experiment 2). Results demonstrated that newborns prefer and recognize occluded faces even if some portions of them are not available, at least when the hindered features are not salient. On the contrary, these abilities are affected by obscuring high salience facial features (i.e. eyes). However, while in the case of face detection, eyes occlusion completely prevented newborns\u2019 face detection, in the case of face recognition an analogous stimulus manipulation heavily impaired, but did not totally preclude, newborns\u2019 recognition performance. The data collected improve our comprehension of newborns\u2019 way of processing and encoding information to detect and recognize faces

Infants\u27 discrimination of faces by using biological motion cues

We report two experiments in which we used animated averaged faces to examine infants\u27 ability to perceive and discriminate facial motion. The faces were generated by using the motion recorded from the faces of volunteers while they spoke. We tested infants aged 4 ^ 8 months to assess their ability to discriminate facial motion sequences (condition 1) and discrim- inate the faces of individuals (condition 2). Infants were habituated to one sequence with the motion of one actor speaking one phrase. Following habituation, infants were presented with the same sequence together with motion from a different actor (condition 1), or a new sequence from the same actor coupled with a new sequence from a new actor (condition 2). Infants demon- strated a significant preference for the novel actor in both experiments. These findings suggest that infants can not only discriminate complex and subtle biological motion cues but also detect invariants in such displays

Classical conditioning of breathing pattern after two acquisition trials in 2-day-old mice

The aim of the present study was to test whether breathing pattern conditioning may occur just after birth. We hypothesized that sensory stimuli signaling the resumption of maternal care after separation may trigger an arousal and/or orienting response accompanied with concomitant respiratory changes. We performed a conditioning experiment in 2-day-old mice by using an odor (lemon) as the conditioned stimulus (CS) and maternal care after 1 h without the mother as the unconditioned stimulus (US). Each pup underwent two acquisition trials, in which the CS was presented immediately before (experimental paired group, n = 30) or 30 min before (control unpaired group, n = 30) contact with the mother. Conditioning was tested by using noninvasive whole body plethysmography to measure the respiratory response to the CS for 1 min. We found significantly stronger respiratory responses to the CS in the experimental group than in the control group. In contrast, somatomotor activity did not differ significantly between groups. Our results confirm the sensitivity of breathing to conditioning and indirectly support the hypothesis that learned feedforward processes may complement feedback pathways during postnatal maturation of respiratory control.</jats:p