LOS ANGELES -- Americans who watch the most video online tend to watch less TV.
The finding released by The Nielsen Co. on Wednesday overturns a longstanding belief that people who watch more programming do so over all devices.
The ratings agency also found surprising differences based on the ethnicity of audiences.
African-Americans watched the most on TV and over mobile devices, while Asians watched the least TV and the most online video.
Hispanics were the most likely to have a smartphone, at 53 percent, followed by Asians at 48 percent, African-Americans at 39 percent and whites at 30 percent.
Overall, TV viewing crept up by 0.2 percent to 158 hours and 47 minutes a month, while video watching on the Internet jumped 35 percent to 4 hours and 33 minutes per month.