You probably recall little of your days in the womb, but a new study suggests that short-term memory may be present in fetuses at 30 weeks of age…

The new study tested how fetuses in nearly 100 pregnant women responded to a specific stimulus, in this case, a “vibroacoustic stimulation,” which is a very low sound that makes a vibration. The researchers observed the reaction using an ultrasound. When the fetus first receives the stimulation, it is startled. But after repeated trials of the same stimulation, 30 seconds apart, the fetus gets used to the sound and doesn’t react.

“A normal fetus, of about 30 or 32 or 34 weeks, would stop responding after [about] 13 or 14 stimuli,” said Nijhuis.