Publications of Kaufman, J.

Distinct processing of objects and faces in the infant brain

Previous work has shown that gamma-band electroencephalogram oscillations recorded over the posterior cortex of infants play a role in maintaining object representations during occlusion. Although it is not yet known what kind of representations are reflected in these oscillations, behavioral data suggest that young infants maintain spatiotemporal (but not featural) information during the occlusion of graspable objects, and surface feature (but not spatiotemporal) information during the occlusion of faces. To further explore this question, we presented infants with an occlusion paradigm in which they would, on half of the trials, see surface feature violations of either a face or an object. Based on previous studies, we predicted higher gamma-band activation when infants were presented with a surface feature violation of a face, but not of an object. These results were confirmed. A further analysis revealed that whereas infants exhibited a significant increase in gamma during the occlusion of an object (as reported in previous studies), no such increase was evident during the occlusion of a face. These data suggest markedly different processing of objects and faces in the infant brain and, furthermore, indicate that the representation underpinned by the posterior gamma increase may contain only spatiotemporal information.

Kaufman J, Csibra G, Johnson MH. Oscillatory activity in the infant brain reflects object maintenance. Proceedings of the National Academy of Sciences of the United States of America. 2005;102(42):15271-4.

Oscillatory activity in the infant brain reflects object maintenance

The apparent failure of infants to understand "object permanence" by reaching for hidden objects is perhaps the most striking and debated phenomenon in cognitive development. Of particular interest is the extent to which infants perceive and remember objects in a similar way to that of adults. Here we report two findings that clarify infant object processing. The first is that 6-mo-old infants are sensitive to visual cues to occlusion, particularly gradual deletion. The second finding is that oscillatory electroencephalogram activity recorded over right temporal channels is involved in object maintenance. This effect occurs only after disappearance in a manner consistent with occlusion and the object's continued existence.

Kaufman J, Csibra G, Johnson MH. Representing occluded objects in the human infant brain. Proceedings of the Royal Society of London Series B-Biological Sciences. 2003;270(Supplement):140-3.

Representing occluded objects in the human infant brain

One of the most striking phenomena in cognitive development has been the apparent failure of infants to show 'object permanence' in manual reaching tasks although they show evidence for representing hidden objects in studies measuring looking times. We report a neural correlate of object permanence in six-month-old infants: a burst of gamma-band EEG activity over the temporal lobe that occurs during an occlusion event and when an object is expected to appear from behind an occluder. We interpret this burst as being related to the infants' mental representation of the occluded object.