Abstract
Seeing adults use cellphones is a common daily experience for infants, yet little is known about how infants think about others' cellphone use. Do infants recognize that phone usage can affect the user's behavior? Here we asked whether infants expect a person's task performance to be impaired by phone use. Twenty-month-old infants watched adults building block towers. One adult did this while also using a phone, either looking at the screen and scrolling (Experiment 1; N = 24) or simply talking (Experiment 2; N = 24). Across both experiments, infants looked longer when the person who had been using the phone built a taller tower than the person who had not been using the phone, compared to the reverse. This suggests that infants expected phone usage to negatively impact performance. Thus, early in development, children recognize that cell phone use can affect people's goal-directed actions; this may be one example of a broader understanding of the impact of multitasking on performance.