Flexibility in conceptual combinations: A neural network model of gradable adjective modification.

Our ability to combine simple constituents into more complex conceptual combinations is a fundamental aspect of cognition. Gradable adjectives (e.g., 'tall' and 'light') are a critical example of this process, as their meanings vary depending on the noun with which they are combined. For example, a dark diamond is less dark than dark charcoal. Here, we investigate how a neural network encodes the flexible nature of gradable adjectives in adjective-noun pairs, using the perceptual feature of brightness as a test case. We trained a neural network to predict human brightness ratings for unmodified nouns and adjective-noun pairs and assessed its ability to generalize to untrained combinations (e.g., 'light paint' vs. 'dark paint'). We also explored how this information is encoded. We found that flexible learning of gradable adjectives was possible, with neural networks first making predictions based on the adjective alone, and then modulating these with information from the noun later in learning. We also found that model outputs mimicked the kind of non-additive feature modulation present in human data. Our results have implications for understanding how semantic composition occurs and generate testable predictions for future work.

Discourse coherence modulates use of predictive processing during sentence comprehension.

Context has been shown to be vitally important for comprehension. Lexical processing is facilitated when words are highly predictable given their local sentence context, suggesting that people pre-activate likely upcoming words to aid comprehension. However, this facilitation is affected by knowledge about the global context in which comprehension takes place: people predict less when in an environment where expectations are frequently violated. The current study investigated whether discourse coherence is an additional cue that comprehenders use to modulate lexical prediction. In a series of online, self-paced reading experiments, participants read target sentences preceded by short contextual preambles. Local facilitation effects were manipulated through the cloze probability of a critical word within the target sentence and discourse coherence was manipulated by varying the degree to which the target sentence was consistent with the information presented in the preamble. In the first two experiments, target sentences were read more slowly when they occurred in less coherent discourses, but no local facilitation effects were observed. In the third experiment, we strengthened the predictability manipulation by using semantically anomalous critical words. In this experiment, predictable words were processed more quickly and anomalous words more slowly when they occurred in highly coherent discourse. Our results suggest that comprehenders are sensitive to shifts in the topic of discourse and that they downregulate predictive processing when they encounter incoherence in the discourse. This is consistent with recent theoretical accounts suggesting that comprehenders flexibly engage in predictive processing, pre-activating semantic and lexical information less when their expectations are less likely to be reliable.

Predicting Definite and Indefinite Referents During Discourse Comprehension: Evidence from Event-Related Potentials.

Linguistic predictions may be generated from and evaluated against a representation of events and referents described in the discourse. Compatible with this idea, recent work shows that predictions about novel noun phrases include their definiteness. In the current follow-up study, we ask whether people engage similar prediction-related processes for definite and indefinite referents. This question is relevant for linguistic theories that imply a processing difference between definite and indefinite noun phrases, typically because definiteness is thought to require a uniquely identifiable referent in the discourse. We addressed this question in an event-related potential (ERP) study (N = 48) with preregistration of data acquisition, preprocessing, and Bayesian analysis. Participants read Dutch mini-stories with a definite or indefinite novel noun phrase (e.g., "het/een huis," the/a house), wherein (in)definiteness of the article was either expected or unexpected and the noun was always strongly expected. Unexpected articles elicited enhanced N400s, but unexpectedly indefinite articles also elicited a positive ERP effect at frontal channels compared to expectedly indefinite articles. We tentatively link this effect to an antiuniqueness violation, which may force people to introduce a new referent over and above the already anticipated one. Interestingly, expectedly definite nouns elicited larger N400s than unexpectedly definite nouns (replicating a previous surprising finding) and indefinite nouns. Although the exact nature of these noun effects remains unknown, expectedly definite nouns may have triggered the strongest semantic activation because they alone refer to specific and concrete referents. In sum, results from both the articles and nouns clearly demonstrate that definiteness marking has a rapid effect on processing, counter to recent claims regarding definiteness processing.

Clinical presentation of asymptomatic and symptomatic heterosexual men who tested positive for urethral gonorrhoea at a sexual health clinic in Melbourne, Australia.

BACKGROUND: Asymptomatic screening for gonorrhoea in heterosexual men is currently not recommended in many countries including Australia, given the prevalence is relatively low in the heterosexual population. We aimed to determine the proportion of urethral gonorrhoea cases among heterosexual men attending a sexual health clinic that was asymptomatic and symptomatic, the time since last sexual contact to the onset of symptoms and the time to clinic presentation following the onset of symptoms. METHODS: This was a cross-sectional study that included heterosexual men aged 16 years or above attending the Melbourne Sexual Health Centre (MSHC) in Australia between August 2017 and August 2018. Gonorrhoea cases were diagnosed by nucleic acid amplification testing (NAAT) and/or culture. Descriptive analyses were conducted for all gonorrhoea cases including demographic characteristics, recent sexual practices, reported urethral symptoms and duration, sexual contact with a person diagnosed with gonorrhoea, investigations performed and laboratory results. RESULTS: There were 116 confirmed cases of urethral gonorrhoea in heterosexual men over the study period of which 6.0% (95% CI: 2.7-12.1%) were asymptomatic. Typical urethral discharge was present in 80.2% (95% CI: 71.9-86.5%) of men. The mean time between last sexual contact and the onset of symptoms was 7.0 days, and between the onset of symptoms to presentation to the clinic was 5.6 days. CONCLUSIONS: A small proportion of heterosexual men with urethral gonorrhoea do not have any symptoms. Heterosexual men with urethral symptoms usually seek for healthcare within a week, prompting rapid healthcare-seeking behaviour.