Language input, poverty and SLP practice

Recent media attention to the Thirty Million Words Program has lead Dorothy Bishop to criticize “professionals in the field of language development” for being so naïve as to believe that “parent linguistic input lies at the heart of the problem” of the gap in language outcomes observed between children growing up in low versus high SES homes, citing Leffel and Suskind.  The blog post consists largely of what the author herself describes as a Psychology 101 description of the different ways in which parental language input and children’s language outcomes might be related. One cannot find any fault with the colourful diagrams illustrating alternatives to a direct causal relation from parental input to child language output; the possibility that children themselves may influence parental inputs is well known by SLPs who work with at-risk infants; the relation between these variables that is associated with the shared genetic heritage of the child and its parents has certainly not gone without notice-appeal to genetic causation, especially in the case of poverty-is so common now as to be banal. However, the assumptions that motivate the blog entry as a whole are simply wrong and must not pass without comment.

The first assumption, quite baldly stated, is that “professionals in the field of language development” are not aware that the relationship between language input and children’s language outcomes is complex when of course it is precisely those professionals who are responsible for revealing the many layers of that complexity. Erika Hoff for example goes to some lengths to describe the role of language input over and above the effects of shared genetic effects in her writing and research. Bernstein Ratner considers carefully the role of the child in shaping the nature of the interaction with the parent.  Rowe reveals how different types of input (over and above quantity) are optimum at different stages of language development. Breitmayer & Ramey, using a transactional model, describes how biological and environmental risk factors interact to explain varying responses to early versus late onset of an intervention.

The second assumption is that these different models require different policy responses whereas it should be clear that while the details differ, “parent linguistic input lies at the heart of the problem” in each case. There are some cases of heritable communication deficits where parent and child may have a similar language learning problem (SLI, SSD, dyslexia) but in these cases a greater quantity of more focused input will be a key part of the intervention – much of the research with this population suggests that these children learn language much like other children once given greater intensity of “normal” inputs. The involvement of at least one parent (often only one of the parents will share the child’s deficit) will be essential since starting early and maximizing input throughout the day is important. In those cases in which the child’s disability hampers the parent’s efforts to provide appropriate input, the child has the same need to receive language input none-the-less and SLPs are gifted at helping parent’s to adapt to their child’s particular needs. In m lab, we have been successful with a model in which we teach children to listen in individual therapy sessions while teaching parents to provide optimum inputs in group sessions. There is no reason to assume that programs to teach parents language stimulation techniques are “blaming the parents”, regardless of whether the assumed cause is biological or social disadvantage. And on the topic of social disadvantage specifically, many studies have demonstrated the effectiveness of teaching parents and teachers to provide the appropriate quantity and quality of input to low SES children. The point of the Thirty Million Words Project is to develop procedures that are appropriate for this specific population and that can be “scaled up” efficiently.

The third assumption is that language impairments will predominate among poor families and therefore the children who are the target of the Thirty Million Words project experience delayed language development due to their genetic heritage rather than poor language inputs. Careful reading of the literature on the relationship between SES and language skills does not support this assumption however. A recent large sample report by Letts et al for example reports that among their lowest SES quintile, they observed a larger than expected number of children with language delay; at the same time the proportion of children with language impairment (more than two standard deviations from the mean) was approximately 2% as expected with respect to the normal curve (see Table 4). Furthermore, discrepancies with respect to comprehension versus production, vocabulary versus grammar, and language versus global or verbal intelligence scores in these studies  further support the impression that the complicated relationship between SES and language skills that is observed cannot be explained by individuals with language impairment naturally falling into the lower social classes.

Now I am going to get personal. I am a first generation Canadian. My mother was born in London “within the sound of Bow Bells” into a desperately poor family, shared shoes, moon-light flits to avoid the landlord, alcoholism, domestic violence, the full catastrophe. Lucky for me she immigrated to Canada where she met my father. My father’s mother was an unmarried Croatian, thrown out by her goat farming family. He arrived in Canada as a teenager from a displaced persons (refugee) camp with as little education as you can get growing up in such camps during the second world war. After arrival in Canada he essentially educated himself via correspondence courses and then managed to enter and graduate top of his class from a technical college. My siblings and I are all well-educated and (upper) middle class due to public policies that do not assume the poor are responsible for their own circumstances – universal public education, public health care and direct transfers to families. My parents’ hard work, devotion to education and indeed their intelligence certainly played key roles but we couldn’t have achieved this in the UK, probably not even in the United States. This is not to say it was easy – my parents and I suffered from ongoing discrimination from Canadians who to this day view every wave of immigrants and refugees with suspicion if not outright hostility. When I achieved the highest kindergarten aptitude test scores in my school district my teacher told my parents it was a fluke and grouped me with the “dummies” until another fluke revealed that I was gifted (further testing conducted  to prove to my parents just how retarded I was!) I tell this story to contrast it with outcomes for my UK relatives several of whom are in jail. The most poignant story involves my exceptionally brilliant uncle who died absolutely poor (in the UK) living in a caravan no bigger than my on-suite bathroom. Public policy makes a difference and public policies are determined by the attitudes and choices of a nation’s people. Leffel and Suskind stress that an important part of their intervention is teaching parents that “intelligence is malleable and therefore can be increased with effort”. The public information campaign that emphasizes the Hart and Risley findings
does not reflect ignorance by language researchers about the complexity of the problem. It reflects our knowledge that the public and the policy makers they elect are very often convinced that the poor are not worth the effort. So let us congratulate the Thirty Million Words Project for making that effort and conducting exactly the kind of research that Bishop says we need.