Degree of incrementality is modulated by experimental context – ERP evidence from German quantifier restriction

ABSTRACT

The current ERP study investigates the role of non-linguistic context in incremental semantic comprehension. Using picture-sentence verification, we examined the neurophysiological correlates of contextual adaptation effects. We manipulated experiment-inherent frequency and tested whether a relatively high ratio of experimental to filler sentences constrains the contextual restriction of the German quantifier alle (“all”). While previous results indicate that the truth evaluation may be postponed when the experimental setting is completely ambiguous with respect to a potentially following restriction, the current study used a higher ratio of non-restricted vs. restricted sentences than the previous one (4:1 vs. 1:1) and thereby tested whether a low restriction probability increases the likelihood of an immediate truth evaluation. Our results show that experiment-inherent frequency distributions immediately modulate the N400 amplitude, analogous to previous studies on speaker reliability.

KEYWORDS:

• Language comprehension
• compositional-semantic processing
• event-related potentials
• adaptation effects
• N400

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The data that support the findings of this study are openly available in the Tübingen Archive of Language Resources at https://hdl.handle.net/11022/0000-0007-EC4A-D.

Notes

1 Augurzky et al. (2017) had labelled the longer sentences with restrictive cues as “experimental items”, whereas their “filler items” did not contain restrictive relatives. The reason was that Augurzky et al. (2017) were also interested in effects on the prepositions later in the sentence in addition to effects on the colour adjectives. In the present study, an analysis of the prepositions was, however, not feasible due to the lower number of sentences with restrictive relative clauses. For the analysis of ERPs on the colour adjectives, it does not make any difference whether short or long sentences are analysed because sentences did not differ up to the adjectives and the RSVP made any kind of preview of upcoming segments impossible.

2 Note that strictly speaking, and based on formal-semantic theory, the denotations of questions are more complex than those of declarative sentences. In fact, questions are often treated as sets of possible answers, which are “yes” and “no” for the simple polar questions used in the current experiment. We are aware of that fact, and we will use the expressions “true” and “false” throughout the manuscript as a cover term for “questions involving “yes” answers” and “questions involving “no” answers”.

3 An alternative explanation to the observed N400 pattern would be expectation-based. According to such a view, the simple, unicoloured contexts elicit a strong expectancy of a particular target word that is compatible with a “yes” answer. By contrast, predictions are weaker in the case of complex, bicoloured pictures. We will discuss this approach under the notion of “frequency-driven adaptivity in expectations” in the hypotheses and discussion sections below.

4 One motivation for this assumption is that listeners may try to prepare or anticipate their answers, e.g. yes, all triangles outside the circle are blue (cf. Bott et al., 2017) and that there are virtually no constraints on possible “no”-answers, rendering continuations leading to a “yes”-answer more expected than any individual continuation leading to a “no”-answer.

5 Including random slopes for participants led to “singular fit” (i.e. the estimated variances were close to zero) and did not improve model fit.

6 We would like to thank an anonymous reviewer for suggesting this post-hoc analysis to us.

7 We also carried out an additional analysis in a late time window (450–800 ms), analogous to the original study by Augurzky et al. (2017). As amplitude differences in the later time window are likely to be task-related effects (see the discussion in Augurzky et al., 2017), we refrain from interpreting these results in the current study but provide them in the following footnote and Appendix A for the sake of comparison.

8 In the late time window, an effect of context ($F(3,63)=20.70p<.001$) was found as well. Complex conditions did not differ from each other (p = 1), and neither did the simple, true condition B differ from condition D (complex, match outside; p = 1), or condition A (complex, match inside) from B (simple, true; p = .1). Each of the conditions, however, differed from condition C (simple, false; all: p<.001). Again, effect sizes differed in the single rois (roi× context interaction: $F(9,189)=5.74p<.001$). In the posterior rois, the difference between condition A (complex, match inside) and B (simple, true) approached significance (p = .06 in Roi 3 and p<.05 in Roi 4).

9 Note that contrary to Augurzky et al. (2017), where a high-pass filter was applied to the raw data without baseline correction, we used a $-\mathrm{200..0}$ ms baseline in the current study to correct for pre-stimulus activity. For the sake of a better comparison across studies, we re-analysed the data of Augurzky et al.. with the same pre-stimulus baseline as in the current experiment. Due to this process, we excluded four participants from the original Augurzky et al. study, as we had to manually re-analyse the data to exclude trials with extreme slow drifts. ERPs yielded by that analysis led to the same effects as in the results reported in Augurzky et al. (2017) (see Figure 3).

10 We would like to thank an anonymous reviewer for pointing out to us that the absence of a significant effect in the present study is by itself hard to interpret. It does not imply the non-existence of the effect but could, instead, also be due to a lack of statistical power. We would like to add to this that Frequency-Driven Adaptivity actually does not predict the absence but rather a decreased magnitude of the effect in the present as compared to the previous experiment. This is one reason, besides others that are discussed in Froman and Shneyderman (2004), Levine and Ensom (2001) and Miller (2009), we refrain from computing a power analysis but decided to carry out a direct statistical test, instead.

11 Asymmetries in processing true vs. false sentences could be explained based on fundamental ideas in logic, in particular computational logic, distinguishing between positive and negative judgments. Such asymmetries can be linked to the closed world assumption (see e.g. Lifschitz, 1985, 1996), which equates the negation of a proposition with the failure to derive that proposition from a given knowledge base. Interpreting negation in this way is central to efficient logic programming and has also been used successfully in modelling human reasoning and language understanding (Stenning & van Lambalgen, 2008; van Lambalgen & Hamm, 2005; and see also Baggio, 2018 for related research). It leads to an asymmetry between positive and negative judgments absent from classical logic and may thus provide a theoretical explanation for difficulties in processing false sentences that is based on the negative judgments themselves.

Additional information

Funding

This research was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project ID 75650358. Fabian Schlotterbeck also received funding from the Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg (MWK-BW, Baden-Württemberg Ministry of Science) and the Bundesministerium für Bildung und Forschung (BMBF, Federal Ministry of Education and Research) as part of the Excellence Strategy of the German Federal and State Governments.