More Than Words: Syntactic Packaging and Implicit Sentiment

1. More Than Words: Syntactic Packaging and Implicit Sentiment Greene & Resnik 2009

2. framing makes a difference… (a) On November 25, a soldier veered his jeep into a crowded market and killed three civilians. (b) On November 25, a soldier’s jeep veered into a crowded market, causing three civilian deaths.

3. associated with subject: • volitionality • causation • animacy • change of state • kinesis • independent existence from event associated with event or state: • telicity • punctuality associated with object: • affectedness (?) • change of state • kinesis • independent existence from event Greene & Resnik’ssummary of semantic properties associated with the things in a typical transitive ‘X verbs Y’ frame

4. Experiments were done • Greene & Resnikpropose (a) that syntactic framing involves manipulation of these semantic properties and so (b) there is a relation between syntactic choices and implicit sentiment • But the point is that sympathy towards the subject increases with (if variables are assumed independent) non-volitionality, non-animacy, non-kinesis or (if not) volition and telicity

5. Practical application • These properties are not directly observable for verbs and neither automatic annotation nor labeled training data exists (…but see last slide) • Therefore, use “observable proxies for underlying semantics” – use grammatical relations between domain-relevant terms as proxies for underlying semantic properties

6. Sample: Life Without Parole does not eliminate the risk that the prisoner will murder a guard, a visitor, or another inmate. Dependencies:nsubj(murder, prisoner); aux(murder, will); dobj(murder, guard) Features: TRANS:murder, murder:nsubj, nsubj:prisoner, murder:aux, aux:will, murder:dobj, dobj:guard

7. Featuresvs. baseline N = a+b frequent bigrams a) OPUS features for 14 selected kill-verbs b) OPUS features for 117 verbs of high relative frequency

8. Also did a comparison using OPUS features for the 14 most frequent verbs that were not in the kill-verb list, to check that it wasn’t just a larger feature set, particular syntactic relations, etc. that is improving performance – this fails to beat the baseline

9. Bitter Lemons • Israel vs. Palestine perspectives already annotated with previous classification attempt by Lin et al. • 297 documents of 700-800 words; chosen for a “topic area of … considerable controversy” but which “eschews an … extreme style of writing” and balanced sides

10. Tests • 423 experiments with variable threshold of domain-relevant terms • (barely) measurable improvement; note that guest-trained scenario does better than editor-trained scenario

11. stative: durative, no change of state, ?non-volitional activity: atelic, durative, no change of state, ?volitional accomplishment: telic, durative, ?volitional achievement: telic, non-durative, change of state, ?non-volitional semelfactive(‘blinked’): atelic, non-durative, no change of state  Smith 1991, Levins 2007