[not in handout, see intranet]

Farroni, T., Mansfield, E. M., Lai, C., & Johnson, M. H. (2003). Infants perceiving and acting on the eyes: Tests of an evolutionary hypothesis.gif Journal of Experimental Child Psychology, 85(3), 199-212.

NB. the infants (4-5 months olds) did not respond to the motion of pupils in an inverted face (expt1), and they did not differentially respond to an upright face if there was no eye contact phase before the adult face pupils moved to one side (expt 2), but the infants moved their own eyes faster to the position of a target at the end of the sequence if it was on the side indicated by the direction of the last movement that the adult eyes made in a sequenc beginning with a period of eye contact (expt3) [the expt 3 sequence]

It has been hypothesized that an evolutionarily ancient mechanism underlies the ability of human infants to detect and act upon the direction of eye gaze of another human face. However, the evidence from behavioral studies with infants is also consistent with a more domain-general system responsive to the lateral motion of stimuli regardless of whether or not eyes are involved. To address this issue three experiments with 4- month-old infants are reported that utilize a standard face- cueing paradigm. In the first experiment an inverted face was used to investigate whether the motion of the pupils elicits the cueing effect regardless of the surrounding face context. In the second experiment pupil motion and eye gaze direction were opposed, allowing us to assess their relative importance. In a third experiment, a more complex gaze shift sequence allowed us to analyse the importance of beginning with a period of mutual gaze. Overall, the results were consistent with the importance of the perceived direction of motion of pupils. However, to be effective in cueing spatial locations this motion needs to be preceded by a period of direct mutual gaze (eye contact). We suggest that evolution results in information-processing biases that shape and constrain the outcome of individual development to eventually result in adult adaptive specializations. (C) 2003 Elsevier Science (USA). All rights reserved.

Farroni, T., Johnson, M. H., & Csibra, G. (2004). Mechanisms of eye gaze perception during infancy. Journal of Cognitive Neuroscience, 16(8), 1320-1326.

Previous work has shown that infants are sensitive to the direction of gaze of another's face, and that gaze direction can cue attention. The present study replicates and extends results on the ERP correlates of gaze processing in 4-month- olds. In two experiments, we recorded ERPs while 4-month-olds viewed direct and averted gaze within the context of averted and inverted heads. Our results support the previous finding that cortical processing of faces in infants is enhanced when accompanied by direct gaze. However, this effect is only found when eyes are presented within the context of an upright face.

Farroni, T., Johnson, M. H., Menon, E., Zulian, L., Faraguna, D., & Csibra, G. (2005). Newborns' preference for face-relevant stimuli: Effects of contrast polarity. Proceedings of the National Academy of Sciences of the United States of America, 102(47), 17245-17250.

There is currently no agreement as to how specific or general are the mechanisms underlying newborns' face preferences. We address this issue by manipulating the contrast polarity of schematic and naturalistic face-related images and assessing the preferences of newborns. We find that for both schematic and naturalistic face images, the contrast polarity is important. Newborns did not show a preference for an upright face-related image unless it was composed of darker areas around the eyes and mouth. This result is consistent with either sensitivity to the shadowed areas of a face with overhead (natural) illumination and/or to the detection of eye contact.