Connectionist Modeling of Experience-based Effects in Sentence ...

4.3 RC Extraction in Mandarin
The GPE score measured on a certain word only tells us how the predictions based
on previous words fit the probabilistic grammar. It does not include any effect of the
current word itself.
GPE
0.0 0.2 0.4 0.6 0.8 1.0
Mandarin SRC
N1 de N2 V2 N3
Region
epoch 1
epoch 2
epoch 3
GPE
0.0 0.2 0.4 0.6 0.8 1.0
Mandarin ORC
V1 de N2 V2 N3
Region
Figure 4.4: Simulation 1: Mandarin ORC regularity.
epoch 1
epoch 2
epoch 3
See figure 4.4 for GPE scores of SRCs and ORCs by training epochs. For means
and standard errors see table A.1 in the appendix. Collapsing over all regions and
epochs there was a significant advantage for object relatives. The difference shrank with
increasing epochs. For the ORC there was significant improvement on the main verb
over the three epochs. The SRC improved on the main verb and the relativizer. On
the first region (N1/V1) there was a marginal advantage for the ORC in the first epoch.
The second region (de) showed a significant object advantage in all epochs. There was
also an object advantage on region 4 (V2), which, however, disappeared after the second
epoch due to SRC improvement. Region three and five did not show any effect.
The results of experiment 1 showed the predicted frequency × regularity interaction.
In contrast to the English results by MC02 the regularity effect is seen in object relatives
in Mandarin. The effect, however, is is not located on the embedded RC but mainly on
the relativizer. It seems as the predictions for position 4 (here the relativizer) are easier
for the ORC because of the familiarity with the sequence ‘N V . . . ’ where the relativizer
should have a quite low continuation probability due to the small RC frequency in the
corpus. On the other hand, the SRC sequence ‘V N’ is very rarely occurring at the
sentence beginning, making more training necessary to learn the correct predictions.
Over training the network has to learn to assign a high activation to the relativizer after
an ‘V N’ and to exclude almost all other words as a continuation.
Experiment 1 superficially confirms the ORC regularity hypothesis. However, as the
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