Werker – studying babies of depressed mothers

Typically one thinks about tuning to the properties of the native language as a kind of self-contained system, that the language input that the child receives or even the more active sort of interaction that the child has with other speakers of their language will provide the system with the information that’s required to tune the perceptual system to the properties of the native language and then set all the sequela in motion for language acquisition, so it seems to be in many respects the standard body of evidence would suggest that this is a perceptual tuning that is marching along according to maturation and then the input has an effect at the time that the system or the developing brain or the circuits in the brain are ready to become attuned to that particular input. But we know that in the visual system and other perceptual systems that more extreme environmental differences can change the timing of change so we know that enriched input, very enriched input or pharmacological, like drugs, can accelerate timing, and we know that dark rearing, so not getting enough visual input or not getting any input at all can sort of put critical periods or sensitive periods on hold and so delay timing until a later age. 

So in collaboration with Tekau Hinch and Tim Oberlander who studies maternal depression, and Whitney Wycomb, we asked whether exposure to certain pharmacological agents like anti-depressant medication and or exposure to maternal depression that isn’t treated with anti-depression medication might have an impact on the timing of developmental change. So we worked with a cohort of mothers who had been depressed throughout their pregnancy and had either been taking or not taking anti-depressant medication, serotonin reuptake inhibitors, and we compared them, We also had a control group, control cohort of mothers who were not depressed during pregnancy and we tested their babies on the timing of tuning to the properties of the native language and what we found is that exposure to maternal depression that had not been treated with SRIs seemed to be like dark rearing in visual development in that it seemed to put the whole developmental sort of trajectory on hold so that at ten months of age the babies were still discriminating the non-native consonant distinctions that are typically not discriminated at that age.  

So that seemed to be changing the course of development whether it’s for good or bad we don’t know yet; we need to test whether there’s a later outcome. But in the babies whose mothers had been depressed and had been taking SRIs throughout their pregnancy what we found is that they didn’t discriminate the consonant distinctions or the visual language change, I should say this holding pattern for the untreated maternal depression was there for visual language discrimination as well. These monolingual developing infants were still discriminating French from English at ten months so is that a delay, that’s a bad thing or is it just a different trajectory. But in the babies who’d been exposed to SRIs in utero, serotonin re-uptake inhibitor anti-depressants, what we found is that they weren’t discriminating the consonant change at either six or ten months, or the visual language change at either six or ten months.