Words influence cognition well before infants know their specific meanings. For example, three-month-olds are more likelyto form visually-based categories when exemplars are paired with spoken words than with sine-wave tones. We testedwhether structure in infants environment can foster this effect. Caregivers often use exaggerated showing gestures whenlabeling objects, presenting words in synchrony with object motion, and creating amodal temporal structure in auditoryand visual modalities. Because attention to amodal structure attenuates encoding information specific to just one modality,we hypothesized that it can lead auditory signals to impact visually-based categorization. Indeed, when 3-month-olds arefamiliarized to videos in which tones occur in synchrony with object motion, tones subsequently facilitate categorization,just like words. Moreover, familiarizing infants to word-object synchrony enhances their subsequent categorization in thepresence of words. These results suggest that structure in infants environment may contribute to the special effects thatwords have on categorization.