An investigation of the dependency of subject-verb agreement on inhibitory control processes in sentence production

Agreement attraction, i.e., the production or acceptance of a verb that agrees with a noun other than the subject of the sentence, can be viewed as a process in which conflicting cues activate competing representations. The aftermath of such competition, in terms of cognitive processes, remains unclear. Using a novel referential communication task for eliciting agreement errors and both group-level manipulation of control demands and a detailed analysis of individual differences, we provide converging evidence for the role of monitoring and inhibitory control processes in agreement attraction for singular-subject sentences. We further demonstrate the dependence of producing plural verbs on such processes, suggesting the singular form is the prepotent default form. Collectively, these findings provide a clear demonstration for the role of monitoring and control processes in agreement computations, and more generally syntactic operations in sentence production.

Pronoun production remains stable over the adult lifespan for contexts with topic continuity

A prevalent finding in the referential communication literature is that older adults produce more ambiguous pronouns than younger adults, likely because they have difficulty determining the prominence of referents. This finding has been widely understood to reflect a general age-related deficit in communication. However, all studies from this line of work have used materials involving topic shifts (i.e. when the to-be-named referent shifts from one character to another, which requires perspective-taking and can be cognitively costly). To determine the extent to which younger and older adults’ pronominal use diverges, we investigated whether other aspects of the discourse context influence age-related differences in referential choice, apart from topic shifts. Here we tested a large sample of adults (N=496, ages 18-82) using narrative elicitation tasks across four experiments and nine contexts of topic continuity (i.e. contexts in which the to-be-named referent remained the same). In Experiments 1 and 2, we varied the number of characters in the scene while keeping the sex/gender of the characters distinct and found that pronominal use did not differ by age for scenes with 1, 2, and 3 characters. In Experiments 3 and 4, we varied the number of characters, the sex/gender of those characters (such that they were the same or different), and the linguistic emphasis placed on the main character. Again, we found no age differences across all conditions. Taken together, our findings suggest that older adults’ difficulty with prominence estimates is not all- encompassing, but rather appears to be confined to contexts involving topic shifts.

Over-Specification of Small Cardinalities in Referential Communication

The paper presents experimental evidence for the over-specification of small cardinalities in referential communication. The first experiment shows that when presented with a small set (2, 3, or 4) of unique objects, the speaker includes a numeral denoting a small cardinality into the description of given objects, although it is over-informative for the hearer (e.g., “three stars”). On the contrary, when presented with a large set of unique objects, the speaker does not include a numeral denoting a large cardinality into their description, so she produces a bare plural (e.g., “stars”). The effect of small cardinalities resembles the effect of over-specifying color in referential communication, which has been extensively studied in recent years (cf. Tarenskeen et al., 2015; Rubio-Fernández, 2016, among many others). This suggests that, like color, small cardinalities are absolute and salient. The second experiment demonstrates that when presented with an identical small set of monochrome objects, the speaker over-specifies a small cardinality to a much greater extent than a color. This suggests that small cardinalities are even more salient than color. The third experiment reveals that when slides are flashed on the screen one by one, highlighted objects of small cardinalities are still over-specified. We argue that a plausible explanation for the salience of small cardinalities is a subitizing effect, which is the human capacity to instantaneously grasp small cardinalities.

Multi-party referential communication in complex strategic games

Verbal communication is an ubiquitous aspect of human interaction occurring in many contexts; however, it is primarily studied in the limited context of two people communicating information. Understanding communication in complex, multi-party interactions is both a scientific challenge for psycholinguistics and an engineering challenge for creating artificial agents who can participate in these richer contexts. We adapted the reference game paradigm to an online 3-player game where players refer to objects in order to coordinate selections based on the available utilities. We ran games with shared or individual payoffs and with or without access to language. Our paradigm can also be used for artificial agents; we trained reinforcement learning-based agents on the same task as a comparison. Our dataset shows the same patterns found in simpler reference games and contains rich language of reference and negotiation.

Head turning is an effective cue for gaze following

In referential communication, gaze is often interpreted as a social cue that facilitates comprehension and enables word learning. Here we investigated the degree to which head turning facilitates gaze following. We presented participants with static pictures of a man looking at a target object in a first and third block of trials, while they saw short videos of the same man turning towards the target in the second block. In Experiment 1, newly sighted individuals (recently treated for congenital cataracts) benefited from the motion cues, both when comparing their initial performance with static gaze cues to their performance with head turning, and their performance with static cues before and after the videos. In Experiment 2, neurotypical school children (ages 5-10 years) and adults also revealed improved performance with motion cues, although most participants had started to follow the static gaze cues by the end of the first block. Our results confirm that head turning is an effective social cue when interpreting new words, offering new insights for a pathways approach to development.

ASL Production

Previous research has pointed at naturalness and communicative efficiency as possible constraints on language structure. Here, we investigated adjective position in American Sign Language (ASL), a language with relatively flexible word order, to test the incremental efficiency hypothesis, according to which both speakers and signers try to produce efficient referential expressions that are sensitive to the word order of their languages. The results of three experiments using a standard referential communication task confirmed that deaf ASL signers tend to produce absolute adjectives, such as color or material, in prenominal position, while scalar adjectives tend to be produced in prenominal position when expressed as lexical signs, but in postnominal position when expressed as classifiers. Age of ASL exposure also had an effect on referential choice, with early-exposed signers producing more classifiers than late-exposed signers. Overall, our results suggest that linguistic, pragmatic and developmental factors affect referential choice in ASL, supporting the hypothesis that communicative efficiency is an important factor in shaping language structure.