New research suggests that children under two years old can learn certain communication skills from a video, such as how to use signs in sign language, and perform similarly in tests when compared to babies taught by their parents.

Researchers at Emory University found that babies were consistently able to understand the signs and pick out a photo of the corresponding object after watching an instructional video for 15 minutes, four times a week for three weeks. Babies who watched the video performed just as well in tests as babies who had been taught signs by their parents under similar conditions (15 minutes of instruction, four times per week for three weeks) but without a video.

"This is the first controlled study to show that babies as young as 15 months can learn communicative skills from commercial videos just as well as from parents," Shoshana Dayanim, lead author of the study, said in a statement. "They could recognize a novel photo of an object and label it using signs that they had only been exposed to from the video."

Four groups of parents and children participated in the study: (video with parent, video only, parent instruction only, control). Parents were instructed not to sign to their children or provide sign instruction of any kind outside of the video or parent instruction learning session.

The study included a group of and lasted for four weeks. Babies, many who could not yet speak, were shown an infant signing instructional video pieced together from several different commercially available videos.

When the babies were tested after a week without parent instruction or video watching, the infants not only recognized which photos went with which signs, but also were able to produce the signs themselves from memory. Infants who had been taught by their parents retained more of the signs during testing than babies who had watched the video.

The researchers caution that the results should not be seen as an endorsement of video watching for children under two, which has been recommended against by the American Academy of Pediatrics.

"We can't speak to the short-term or long-term cognitive effects of video exposure for infants overall -- only the potential for instruction," researcher Laura Namy said. "There are many caveats to our research: the nature of the learning material matters and a lot may depend on the learning context and the formal features of the video."

The research does, however, demonstrate that video can be an effective teaching tool for children under two under the right circumstances.

The findings are detailed in the journal Child Development.