[MUSIC] In the previous section of this course, we considered the idea of familiarity and we discussed it within the room of non verbal processing. This, of course, is in the expertise literature. And within that literature, it's clear that experts differ from novices. We also consider the nature of familiarity, or proficiency, as it's discussed, in the language literature. And noted that monolinguals show differences in proficiency, and that those differences. End up mattering when we look at brain activity and at behavior. In this section we'll expand on this idea and consider it within the bilingual literature. And this is really seen very clearly within a case study that was presented in 1997. In this study Gomez Tortosa and colleagues interviewed and tested a bilingual who was about to go through neurosurgery. This person had lived in Bolivia until the age of 10 and moved to the US where she spoke primarily English. Here in the US. What they found was that after neurosurgery, it appeared that the first language, Spanish, had actually shown a larger reduction in proficiency than English. But let's think a little bit about their data, and talk about it in more detail. The first thing to consider is the test that was given to the patient. The Boston naming test has been used for many, many years to test aphasia. It's a picture vocabulary test, essentially, ranging from very simple things like bed, up to complex things, like trellis. Or an abacus. And the idea is that by varying the difficulty of these pictures investigators could look at whether there was a language impairment. Specifically tests on aphasics people who had had brain damage and were having language problems could be tested with this picture naming vocabulary test. So in general researchers consider that when there's a lower score there's a larger language impairment and when there's a higher score there's less of a language impairment. And there is, of course, variation within even the non-impaired population. Once scores start to drop under 50 it's considered this person may have a language impairment or some kind of problem with language. Comar Stutosa used the same battery to test the patient that I'd spoken about earlier who was a Spanish native speaker and had learned English at age ten. They administered half the battery before neurosurgery, and found that the patient scored 19 out of 30 in Spanish. Once the surgery was performed, they retested the patient using the full battery in Spanish and English. And there they found 32 out of 60 in Spanish, and 44 out of 60 in English. Based on these results, Gomez Tortosa, and colleagues conclude that there was more of an effect on Spanish after the neurosurgery than on English, and their argument is one that's been argued many, many times in the psychological literature. Basically that languages may be represented in different parts of the brain, and the damage to different parts of the brain can yield differential impairment. But here's the problem. First of all we don't know what the patient would have scored on the full battery before neurosurgery in both languages. So again Gomez Tortosa tested only Spanish, only half the battery, and found that there was a score of 19 out of 30 before surgery. After surgery, the score in Spanish went to 32 out of 60. So, if we doubled 19 and we figure, okay, it's about 38. Then there appears to be a decrement in Spanish. But we don't know anything about what English proficiency was like before surgery. The second thing we don't really know is, what's the variability within the normal bilingual population. So notice that the score of 32 in Spanish and 44 in English out of 60 would indicate some form of language impairment within the monolingual population. But here we have a bilingual. And we have what appears to be lower vocabulary. So shortly after that, Katherine Conner tested a group of bilinguals in San Diego and looked at what their performance on this boss naming test would be like without any kind of language impairment. And what she found was almost identical scores to the ones reported by Gomez Tortosa. Basically about 47 out of 60 in English and around 34 out of 60 in Spanish. And what that suggests is that in fact there may be a decrement in vocabulary in this particular group of bilinguals on this particular test. But in fact no language impairment. So I think it's important for us to consider the nature of proficiency and how it my play a role in what types of language scores we observe. And also I think it's crucial if we're ever going to consider whether someone has a language impairment to consider what's the variability within the normal population from which this. Patient comes from and then suggest or look at exactly what might be a range that's outside of what we would consider normal.
