Researchers involved: Sebastian Walter (Visual and Non-visual Means of Perspective Taking in Language, Goethe University Frankfurt) and Lennart Fritzsche (external partner, Goethe University Frankfurt)
Within our ViCom short-term collaboration, we conducted a single-trial forced choice study investigating the interpretation of gestural response elements as response to negative polar questions. The results for headshakes suggest that they are interpreted similarly to the German counterparts of yes and no. For headnods, by contrast, the results indicate that they can also receive an interpretation of the German response particle doch, which is specifically used to reject negative antecedents.
For the German answering system, Claus et al. (2017) found that in affirmations of negative antecedents both ja and nein may be used, but with different preferences. In order to reject negative antecedents, German speakers have to use the specialized particle doch (Blühdorn, 2012). In our ViCom short-term collaboration, we have taken a fresh look at pro-speech, i.e., speech-replacing, response elements in the visual domain, that is headnods and headshakes in German. Pivotal work by Loos and Repp (2024) showed that in affirmations of negative antecedents, speakers of German produce slightly more headnods than headshakes. In rejections they find more headnods than headshakes. However, the power of their data is limited, as pro-speech gestures are generally produced very sparsely (also in their data set), even though head gestures are quite common. Thus, as it stands there is an incomplete picture of the use of head gestures functioning as response elements.
Within the scope of a single-trial experimental rating study, we picked up on this and investigated whether pro-speech head gestures behave differently from verbal response elements in negative contexts for German. Participants (n = 592) were presented a negative polar question as in (1-a) and subsequently with one of the responses B1-B4 (cf. (1-b)-(1-d)).
- A: Sind die Schuhe nicht im Kleiderschrank? (‘Are the shoes not in the closet?’)
- B1: Ja. (‘Yes.’)
- B2: Nein. (‘No.’)
- B3: HEADNOD
- B4: HEADSHAKE
Afterwards, participants were shown two pictures: one that matched the content of (1-a) or not (i.e., a picture of a closet with shoes and a picture of a closet without shoes). They had to choose the picture that best matches B’s response to A’s utterance. The study was thus of a single-factor design with four levels (reponse element: ja vs. nein vs. headnod vs. headshake).
A logistic regression model with random slopes and intercepts for subjects was fitted onto the data and yielded a main effect for reponse element. Pairwise comparisons neither show a significant difference between ja and nein nor between nein and headshake. The headnod condition, however, diverged from ja and hence all other conditions. Choice proportions suggest a twofold function of headnods in negative contexts: i) they can be used to affirm negative antecedents (preferred) and ii) they display a doch-like function in that they can be used to reject negative antecedents. Thus, headnods in German are to some extent ambiguous in response to negative antecedents in German.
In follow-up experiments, we plan to investigate whether the preference for the doch-like function of headnod can be boosted by means of manipulating eyebrow movement and nod amplitude.