Neuroscientists at the Ecole Normale Superieure in Paris say that by that age the internal brain architecture and connection seems to be in place to perceive objects in adult-like ways, the Los Angeles Times reported Friday.
"I think we have a pretty nice answer," researcher Sid Kouider said. "Babies as early as 5 months, and probably earlier, are displaying the same neural aspects of consciousness as adults."
Since infants of that age can't directly express what they're seeing or thinking, the researchers spent 5 years with babies at 5, 10 and 15 months of age who had to wear a cap with 128 electrodes and watch images of objects presented at eye-blink intervals.
"We had to be very patient," Kouider said.
The researchers compared the recorded brain waves of the infants with those of adults who were also presented with fleeting images and asked if they had "seen" anything, and found similar wave forms in infants as young as 5 months.
Some researchers cautioned the French scientists may be over-interpreting their data.
"The study is well done," said Charles Nelson, director of developmental medicine at Boston Children's Hospital, who wasn't involved in the French study but has done similar research. "They just take the inference too far."
Kouider has acknowledged the study describes brain function, not the content of the babies' thoughts, but said further research may unveil what babies actually know but can't tell us.