Thomas, H. (1965). Visual-fixation responses of infants to stimuli of varying complexity. Child Development, 36, 629-638.

Stimulus complexity as a mediator of the visual fixation responses of infants was investigated by testing two hypotheses: (1) The distribution of visual fixations among a set of differentially complex stimuli will impose an ordered relationship upon the stimuli. (2) The infants' visual fixations to the stimuli will change with increasing age. Older Ss are expected to fixate more complex stimuli, younger Ss less complex ones. Forty-nine infants were presented with all pairs of four differentially complex stimuli to which fixation times were recorded. Level of stimulus complexity was defined by the judgments of nine students. After parametric analysis for two age groups, Younger (25 Ss, 2-14 weeks old) and Older (24 Ss, 15-26 weeks old), it was concluded that the second hupothesis received partial support and the first hypothesis good support. The results were interpreted within complexity theory, after which comparisons were made with some of Fantz's findings.