THE ACCURATE CALIBRATION OF INFANTS SCANNING RECORDS

The visual scanning characteristics of 10 infants were assessed repeatedly over the 2- to 14-week age period, using a bright-pupil/corneal reflection technique. The present report focuses on the calibration process-a procedure by which stimulus figures are mapped onto the raw scanning data. It is concluded that the major calibration parameters vary significantly among infants, and therefore separate calibration data must be collected on each infant if errors on the order of several degrees of visual angle are to be avoided. Moreover, it was found that infants' saccades often are not directed accurately toward the attracting stimulus, and hence repeated calibration trials are required for the precise determination of parameter values. After about 6 weeks of age, the parameter values established for a given infant remained largely invariant. During the initial weeks of life, however, parameter values occasionally changed, apparently because very young infants sometimes will center the image of an attracting stimulus about some extrafoveal location. This raises an additional complexity when interpreting the scanning records of very young infants. © 1990.