Bias of thematic role assignment

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立 政 治 大 學

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N a tio na

l C h engchi U ni ve rs it y

Similar to Experiment 1, thematic role assignment is the key to comprehension in Experiment 2. Readers judge the thematic roles of the arguments based on both syntactic and semantic cues.

5.2 Bias of thematic role assignment

Our hypotheses for both experiments are based on some biases of interpreting semantic cues, which are based on real world and probabilistic information. In Experiment 1, there is a bias of thematic role assignment that assigns a certain kind of person to be the agent and another type of person to be the patient of an irreversible verb. This bias has its root in real life. Although both arguments of interest are animate, human common nouns, only one combination of the arguments and the verb looks plausible to readers. Therefore, while the arguments in the reversible relation suffer from the similarity-based interference (Gordon, et al., 2006), the ones in the irreversible relation suffer less from it. The bias motivates a rather precise thematic role assignment in the irreversible relation so the “similarity” of their lexical properties is decreased. So is the confusability of the two arguments. Though the arguments here are not from different noun categories as similarity-based interference was proposed, the bias of thematic role assignment in irreversible relation leads to a

‧ 國

立 政 治 大 學

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N a tio na

l C h engchi U ni ve rs it y

similar effect.

However, the similarity-based interference cannot explain the results in Experiment 2. Since the design of contrastive animacy makes the arguments dissimilar, the confusability should decrease for each condition regardless of the linear sequence of the animate / inanimate nouns. The results showed that there is a dynamic up-and-down alternation of the comprehension difficulty across conditions and that IA-ORCs and AI-SRCs are generally the most difficult while IA-SRCs the easiest. If the similarity-based interference works, all of the conditions in Experiment 2 should have reduced in difficulty or there is a steady modulation force of the contrastive animacy on RC difficulty as Experiment 1 showed. The fact is the modulation occurred out of the expectation of similarity-based interference. Animacy seems to have a rule of its own.

There is an animacy bias of thematic role assignment when contrastive animacy takes place. Our hypotheses for Experiment 2 were based on the bias: Animate nouns prefer to be agents, while inanimate nouns prefer to be patients; animate patients are salient enough (though not as salient as the previous two), but inanimate agents are not salient. Note that this bias works best when the verb can take both animate and inanimate nouns as both agents and patients. In Experiment 2, this kind of verb was

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立 政 治 大 學

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N a tio na

l C h engchi U ni ve rs it y

chosen and controlled across conditions. As a result, this hypothesis supports the findings observed at different positions. At the pre-relativizer, only one of the argument occurred with a verb. The sequence of the argument (N1) and the verb (V1) determines which thematic role the argument should be: If the argument follows the verb, it is in the object position and surfaces as a patient in the active voice sentence;

otherwise, it is in the subject position and surfaces as an agent. At this moment, the second argument is missing, so the animacy is not contrastive yet. Readers encounter difficulty when the inanimate noun in IA-ORCs serves as an agent but there is no such difficulty when the animate noun in AI-SRCs serves as a patient. Later when the head noun, the second argument, occurs, the animate head in IA-ORCs finds it against the bias to be a patient when an inanimate agent is in place. Similarly, the inanimate head of the AI-SRCs finds it difficult to fit into the agent role. Therefore, IA-ORCs and AI-SRCs are the most difficult among the four conditions for Chinese readers.

The AI-ORCs and IA-SRCs both have salient fit of animacy and thematic roles, so they are easier than the former two. IA-SRCs are the easiest since they do not suffer from perspective-shifting as AI-ORCs do.

Traxler et al. (2002) proposed that readers prefer to treat sentential subjects as the subject of relative clauses in the initial interpretation. The initial syntactic analysis

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立 政 治 大 學

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N a tio na

l C h engchi U ni ve rs it y

is correct for SRCs so processing proceeds smoothly. When readers read ORCs, the initial syntactic analysis is flawed and reanalysis is triggered. Moreover, semantic factors affected how much difficulty readers had when reanalyzing the sentence.

Readers can easily change perspective when that change is from a less preferred inanimate entity to a preferred animate entity; therefore, the ORCs with an inanimate head are reanalyzed faster than the SRCs with an animate head.

However, this proposal cannot explain the data in Chinese in which we found both ORCs with an inanimate head and SRCs with an animate head are difficult. It is possible that the design of Traxler et al.’s (2002) contrastive animacy experiment confounded the potential ease from irreversible argument-verb relation. In our experiment, the reversible argument-verb relation was adopted and the verb in the RC was controlled across conditions. On the contrary, both biases—the bias of thematic role assignment in terms of plausibility and the bias of thematic role assignment when contrastive animacy taking place—were compounded in Traxler et al.’s (2002) experiment (with example sentences shown in (29)).

(29) Contrastive animacy configuration in Experiment 3 (manipulation of animacy) (Traxler, et al., 2002)

a.

The director that watched the movie received a prize at the film festival.

b.

The director that the movie pleased received a prize at the film festival.

‧ 國

立 政 治 大 學

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N a tio na

l C h engchi U ni ve rs it y

c.

The movie that pleased the director received a prized the film festival.

d.

The movie that the director watched received a prized the film festival.

The thematic role assignment with animacy in the ORC with an animate head (b) and the SRC with an inanimate head (c) is against the bias for contrastive animacy role assignment. Therefore, these two conditions are more difficult than the other two.

However, since ORCs may be reduced in difficulty when the argument-verb relation is an irreversible one, the ORCs with an inanimate head (b) are further eased in difficulty. In sum, both biases took place in Traxler et al.’s (2002) experiment and the pure effect of animacy could not be established in their experiment.

In the present study, two experiments were designed to investigate these two biases separately. The bias of thematic role assignment that has effects when the argument-verb relation is irreversible can reduce the difficulty of syntactic complexity of both SRCs and ORCs, and the bias of thematic role assignment that exists when the arguments contrast in animacy strongly modulates syntactic ambiguities.