fill in the missing word

[Brian MacWhinney]

Dear Info-CHILDES,

  I was recently browsing through the interesting set of articles in the
recent issue of Language and Cognitive Processes devoted to language use in
children with language disorders.  Two of the studies there rely on the
classic "wug" test introduced in the late 1950s by Jean Berko Gleason at
Harvard and D. Bogoyvalenskiy in Moscow.  These were:

Thomas, M. S. C., Grant, J., Barham, Z., Gsödl, M., Laing, E., Lakusta, L.,
Tyler, L. K., Grice, S., Paterson, S., & Karmiloff-Smith, A. (2001). Past
tense formation in Williams syndrome. Language and Cognitive Processes, 16,
143-176.

van der Lely, H. K. J., & Ullman, M. T. (2001). Past tense morphology in
specifically language impaired and normally developing children. Language
and Cognitive Processes, 16, 177-217.

Both of these very interesting and carefully designed studies used the wug
test in the way it was originally formulated by Jean Berko.  To quote from
Thomas et al.

Task 1 was presented as a game called "Fill in the missing word."
The experimenter said:
I'm going to say something like: Every day I eat an
orange and you have to repeat that. Try that now.
Once the participant had successfully repeated the sentence the experimenter
went on: 
Then I¹ll say something like: "Just like every day, yesterday I ............
an orange" and you have to finish the sentence to fit in with what happened
yesterday. 
So after I say, "Just like every day, yesterday I ............ an orange"
you might say "Yesterday I (brief pause in case the participant was able to
complete the sentence spontaneously) I ATE an orange."

van der Lely and Ullman used essentially the same form of the task.  A quick
check of related literature shows that much of the recent work in this area
uses the task in this form.

However, when I was doing work in this area back in the late 1970s, I found
that this "fill in the blank" form of the task was very confusing for
children.  After using this form for about two days, I quickly shifted to a
form like this:

Look here is the fox.  He is niffing.  Watch him niff.  What did he do?

I found that very young children understood this version of the task much
more readily and that, as a result the production of either nouns or verbs
with zero marking was significantly reduced.  I believe that it is a lot
easier to understand that the totally natural question "What did he do?"
requires the past tense than to understand what the researcher is trying to
do with the rather unnatural "fill in the missing word" procedure.

It turns out that one of the major issues in the study of both SLI and
Williams syndrome is the tendency for these children to answer questions
with zero marking.  However, if the form of the test itself tends to
encourage zero marking, don't we have a measurement problem here?

I am wondering if other researchers have also noted a difference between the
two forms of the Berko test that I am mentioning.  I suppose that I should
have conducted a formal comparison of the two procedures back in the 1970s,
but it is never to late to get this issue clarified.

Many thanks.  Please feel free to post your comments on this directly to
info-childes.


--Brian MacWhinney