Queriquita brought to my attention
a very recent paper (published online before print @ Aug 26, 2013) that connects external stimuli to prenatal learning. This is the first paper that I know of that offer some substantive evidence of prenatal learning with a good experiment design, though the sample size is pretty small (17 treatment, 16 control).
What it is: Prenatal stimulation using audio (2 segments of ~4 min each) of pseudowords (tatata, ta^tata [pitch change], tatota [vowel change]) @ 167-177 Hz, each of which are played hundreds of times in each segment. The stimulation was done at 29 weeks old (which is good since the auditory organs are already well developed). Relatively good control, no aberration, health or hearing problems in mothers or babies.
Testing evidence: EEG signal in 9 channels measured at 1-27 days old while sleeping, on 4 categories: pitch changes, vowel changes, vowel duration, and vowel intensity. Note that only the first two were "taught" prenatally.
Result: Prenatally stimulated babies show greater spikes of signal for these 4 categories, indicative of "learning" since the last two categories were not "taught". Control experiment rules out auditory sensitivity factor.
Comment: The p-value (i.e., the probability that the occurrence is more than a random chance) for the "learning" part is still somewhat in a suggestive range (0.01-0.05), with some that are actually pretty good. So, I would consider that the evidence is substantive, but not definitive. It certainly needs a good follow up. For sure this is not some randomly-chosen rhythm like BabyPlus had suggested and definitely not done at 18 week gestational age!
What is very interesting to me is that the EEG channel that shows the most response is
C4, which is roughly on the right side of
precentral gyrus (which is traditionally linked to motoric ability). This is somewhat hard to interpret what the stimulation means to the brain. The precentral gyrus can be activated by passive listening of speech, which may be the case for this experiment. Had it been the
Pars opercularis part of the frontal lobe, which is responsible for speech-language development and the anomaly in which has been associated with autism, it would have been easier. Could it be that C4 is also picking up signals from Pars opercularis? Maybe. I need to consult with EEG experts on this.
This study simply shows that the neural connectivity of the brain is changed due to external vocal stimuli. Whether this changes are good or bad or are indicative of real learning is unknown.
Digg
