Structural priming is a tendency to use a syntactic structure in the current sentence (target) because of its structural similarity to a previously encountered (prime) sentence (Pickering & Ferreira, 2008). Early research suggested that structural priming requires only shared abstract syntax without a necessity to share any prosodic, semantic, or lexical similarities between the sentences (Bock, 1989; Bock & Loebell, 1990).
However, today's research shows that structural priming effects are often supported by non-structural aspects of language. For example, Ziegler and colleagues (2019) challenged Bock and Loebell research (1990) which provided evidence for abstract syntactic priming.
Ziegler et al.'s replication suggested that solely abstract structure is not sufficient to elicit syntactic priming and that other factors are usually needed, e.g. effects of animacy, semantic structure, information structure, shared phonology or others. Perhaps the best-known enhancing effect is a repetition of semantically related words (mostly verb) called lexical boost.
Similar effect was observed also for homophones (homophone boost) (Santesteban et al., 2010) or phonemes (Lee & Gibbons, 2007). These findings suggest that morphology could play some role as well.
However, to our knowledge, this issue has been addressed only in two studies, which yield contradictory results. Santesteban and colleagues (2015) did not find the evidence that case endings in ergative Basque language contribute to structural priming.
On the other hand, Chung and Lee (2017) successfully primed the use of case markers in Korean. In Czech the same case can be encoded with different endings in different nouns.
We can therefore address the question whether the repetition of the same morpheme used for marking a grammatical function can enhance the priming more than the using different morpheme coding the same case. We masked the experiment as memory test, where the participants (N = 59) read prime sentences and described following target pictures for later recall.
We modified two independent variables in primes - type of the sentence and noun case endings. Sentence type had three levels - double-object construction with dative-accusative order or with accusative-dative order, or a neutral intransitive prime sentence.
Case endings for nouns in accusative and dative had two conditions - in same-suffix condition the prime nouns had suffixes identical to suffixes used in the target nouns. In the different-suffix condition, the dative and accusative nouns in the target were inflected using different suffixes.
Prime: Same suffix: Kráva olizuje ovečc-e hlav-u/Cow licks sheep-DAT head-ACC Different suffix: Průvodce popisuje návštěvník-ovi ulic-i/Guide describes visitor-DAT street-ACC Target: Klaun nabízí baletc-e žvýkačk-u/Clown offers ballerina-DAT chewing _gum-ACC Data were analysed using generalized linear mixed-effect model with random intercepts for subjects and items. For different-suffix sentences, no significant effect of priming against the neutral condition, neither acc/dat (p=0.239) nor for dat/acc sentences (p=0.527).
In same-suffix sentences we found significant effect of acc/dat primes compared to dat/acc (p=0.005). The results also suggest that effect like lexical boost exist also on morphological level, and that the ordering of case forms is easier to prime if these forms share case-marking suffixes.
The experiment used two different sets of affixes in target sentences. Currently, we finished collecting data for an adjusted version of the experiment that only has one set in the targets with phonetically salient dative marking (ending -ovi).
The expectation is that the morphological boost effect will be stronger here. Results of this second experiment will be reported at the conference.