Infants' visual following: Effects of size and sound

In Study 1, 22 infants were observed at 1 and 2 mo of age as they visually followed 4 possible combinations of a big or small doll's head accompanied by loud or soft speech. The targets moved on a horizontal track at the Ss' eye level. Ss followed the larger and louder targets, but there was no interaction between size and loudness. Study 2, with 47 Ss, indicated that the effect of size on following was apparently general at 1 mo; at 2 mo, it was specific to heads and did not extend to other 3-dimensional objects such as geometric or animal shapes. Studies 3 and 4, with 40 9-wk-old Ss, explored the nature of the effect of sound. Results indicate that 2-mo-olds followed a variety of objects more when they were accompanied by a variety of sounds than when they were silent; their following, however, was the same whether the sound source moved conjointly with the target or was in a clearly displaced stationary location. At this age, therefore, sound apparently exerts its influence through alterations in arousal rather than through facilitation of localization. (29 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).