Abstract
Purpose. Although the presence of a spontaneous preference in infants indicates visual discrimination, the absence of a spontaneous preference does not necessarily indicate non-discrimination. Novelty preference techniques can demonstrate discriminability in the absence of a spontaneous preference. In the context of infant color vision, we investigated the interaction between spontaneous preferences and novelty preferences.
Methods. Red and blue stimuli of varying purity were generated on a video monitor. Pairs of disks were identified that had equal or unequal spontaneous preferences. 16-week-old infants were studied with two measurements. Spontaneous preferences were measured using forced-choice preferential looking. Novelty preferences were measured using a forced-choice novelty preference technique. In the second technique, infants are familiarized to a pair of identical chromatic disks. A test phase follows in which the chromaticity of one of the disks is changed (novel). The infant's preference for the novel stimulus indicates discrimination.
Results. When spontaneous preferences were equal, the magnitude of novelty preferences increased with increasing purity difference. When spontaneous preferences were unequal, both spontaneous preferences and novelty preferences increased with increasing purity difference. Familiarization to the stimulus with higher spontaneous preference yielded an increase in preference for the previously non-preferred stimulus, whereas familiarization to the stimulus with lower spontaneous preference yielded no increase in preference for the previously preferred stimulus.
Conclusions. In the absence of spontaneous preference, novelty preference can be used to reveal discrimination among suprathreshold chromatic stimuli.