New research suggests babies are more likely to remember happy times than distressing ones.

The findings are good news for parents who worry their infants will have no memory of the happy playtime they spent together, Brigham Young University reported.

"People study memory in infants, they study discrimination in emotional affect, but we are the first ones to study how these emotions influence memory," said BYU psychology professor Ross Flom, lead author of the study.

To study infants' memory a team of researchers looked at their eye movements. The study subjects were set in front of a flat paneled monitor in a closed off partition and exposed to someone speaking to them in either a happy, neutral or angry voice. Directly after hearing the voice the infants were shown a geometric shape.

To test their memory of the shape the researchers did a follow-up test with the infants five minutes later and then a day later. In the follow-up the babies were shown the same geometric shape they had seen in the experiment and one they had not seen before. The mirrors allowed the study leaders to record how many times the baby looked from one image to the next and how long they spent looking at each shape. 

The babies who were introduced the shapes in a negative environment did not show an improvement in memory, but the babies who were introduced the image in the presence of a positive voice showed a significant improvement.

"We think what happens is that the positive affect heightens the babies' attentional system and arousal," Flom said. "By heightening those systems, we heighten their ability to process and perhaps remember this geometric pattern."

The findings were published in the journal Infant Behavior and Development.