Will something appear and if so, what will it be? Perceptual expectations can concern both the presence and content of a stimulus. However, it is unclear how these different types of expectations interact with each other in biasing perception. Here, we tested how expectations about stimulus presence and content differently affect perceptual inference. Across separate online discovery (N = 110) and replication samples (N = 218), participants were asked to judge both the presence and content (orientation) of noisy grating stimuli. Crucially, preceding compound cues simultaneously and orthogonally predicted both whether a grating was likely to appear as well as what its orientation would be. Across both samples we found that content cues affected both discrimination and presence judgements directly, namely by biasing the orientation judgements in the expected direction and enhancing confidence in stimulus presence on congruent trials. In contrast, presence cues did not affect discrimination judgements directly. Instead, presence cues influenced discrimination judgements indirectly by enhancing the effect of the orientation cues when expecting a stimulus to be present. This was the case on trials where a stimulus was present, as well as on grating-absent trials. Further, presence cues directly affected confidence in stimulus presence. This suggests that presence expectations may act as a regulatory volume knob for the influence of content expectations. Further, modelling revealed higher sensitivity in distinguishing between grating presence and absence following absence cues than presence cues, demonstrating an asymmetry between gathering evidence in favour of stimulus presence and absence. Finally, evidence for overweighted expectations being associated with hallucination-like perception was inconclusive. In sum, our results provide nuance to popular predictive processing accounts of perception by showing that expectations of presence and content have distinct but interacting roles in shaping conscious perception.
Reading research has long been concerned with the question of whether the reading brain accesses lexical representations via absolute or relative letter position information. In recent years, important results have been obtained with the flanker lexical decision task. Studies have shown faster decisions about target words (e.g., ‘rock’) when flanked by related letters (‘ro rock ck’) than unrelated letters (‘st rock ep')—and crucially, equal facilitation upon switching flanker positions (‘ck rock ro'), pointing to relative rather than absolute letter position coding. Yet, a later study employing longer targets and flankers yielded detrimental effects of switching flanker positions. In order to get a better grasp on the equivocal evidence thus far, here we carried out an extensive test of flanker relatedness and position effects, using various target and flanker lengths, all within a single experiment. We observed a clear reduction of flanker relatedness effects upon switching flanker positions, and this held true across target and flanker lengths. The present results unambiguously suggest that lexical access is driven by absolute letter position information, and furthermore, are accurately predicted by the recent PONG model (Snell, 2024b).
Young children acquire an amazing knowledge base, rapidly learning from, and even going beyond the observable evidence. They arrive at forming abstract concepts and generalizations and recruit logical operations. The question whether young infants can already rely on abstract logical operations, such as disjunction or negation, or whether these operations emerge gradually over development has recently become a central topic of interest. Here we target this question by focusing on infants' early understanding of negation. According to one view, negation comprehension is initially restricted to a narrow range of meanings (such as rejection or non-existence) and only much later infants develop a broader understanding that maps onto a fully-fledged negation concept. Alternatively, however, infants may rely on a fully-fledged negation concept from early on, but some forms of negation may pose more mapping and processing difficulties than others.
Here we tested infants' understanding of two syntactically and semantically different forms of negation, existential negation and propositional denial in a language (Hungarian) that has a separate negative particle for each, and thus the two negation forms can be directly compared. We engaged 15- and 18-month-old infants in a search task where they had to find a toy in one out of two locations based on verbal utterances referring to the object at one of the locations involving existential negation (Nincsen - not.be.3SG) or propositional denial (Nem itt van - not here be.3SG). In Experiments 1–3 we found a parallel development for these two kinds of negation. 18-month-olds successfully comprehended both, while 15-month-olds were at chance for both. In Experiment 4 we excluded the possibility that 15-month-olds' chance performance is explained by task-related difficulties, as they succeeded in a similar, but nonverbal task. Thus, 15-month-olds likely still have not solved the mapping for the two negation forms. The parallel performance of the two age groups with the two negation types (failing or succeeding on both) is consistent with the hypothesis that different forms of negation rely on similar conceptual underpinnings already in early development.
Different organizational structures have been argued to underlie semantic knowledge about concepts; taxonomic organization, based on shared features, and thematic organization based on co-occurrence in common scenes and scenarios. The goal of the current study is to examine which of the two organizational systems are more engaged in the semantic context of a picture naming task. To address this question, we examined the representational structure underlying the semantic space in different picture naming tasks by applying representational similarity analysis (RSA) to electroencephalography (EEG) datasets. In a series of experiments, EEG signals were collected while participants named pictures under different semantic contexts. Study 1 reanalyzes existing data from semantic contexts directing attention to taxonomic organization and semantic contexts that are not biased towards either taxonomic or thematic organization. In Study 2 we keep the stimuli the same and vary semantic contexts to draw attention to either taxonomic or thematic organization. The RSA approach allows us to examine the pairwise similarity in scalp-recorded amplitude patterns at each time point following the onset of the picture and relate it to theoretical taxonomic and thematic measures derived from computational models of semantics. Across all tasks, the similarity structure of scalp-recorded neural activity correlated better with taxonomic than thematic measures, in time windows associated with semantic processing. Most strikingly, we found that the scalp-recorded patterns of neural activity between taxonomically related items were more similar to each other than the scalp-recorded patterns of neural activity for thematically related or unrelated items, even in tasks that makes thematic information more salient. These results suggest that the principle semantic organization of these concepts during picture naming is taxonomic, at least in the context of picture naming.
The speech-to-song transformation is an illusion in which certain spoken phrases are perceived as more song-like after being repeated several times. The present study addresses whether this perceptual transformation leads to a corresponding change in how accurately participants imitate pitch/time patterns in speech. We used illusion-inducing (illusion stimuli) and non-inducing (control stimuli) spoken phrases as stimuli. In each trial, one stimulus was presented eight times in succession. Participants were asked to reproduce the phrase and rate how music-like the phrase sounded after the first and final (eighth) repetitions. The ratings of illusion stimuli reflected more song-like perception after the final repetition than the first repetition, but the ratings of control stimuli did not change over repetitions. The results from imitative production mirrored the perceptual effects: pitch matching of illusion stimuli improved from the first to the final repetition, but pitch matching of control stimuli did not improve. These findings suggest a consistent pattern of speech-to-song transformation in both perception and production, suggesting that distinctions between music and language may be more malleable than originally thought both in perception and production.
Understanding information processing biases is critical for improving scientific literacy. Research suggests that people rate scientific explanations with reductive jargon (e.g., irrelevant chemistry jargon in the explanation of a biological phenomenon) as better than those without – a phenomenon known as the reductive allure (RA) effect. Here, however, in three preregistered online experiments, we were unable to replicate this reductive allure effect using similar (and in some cases identical) materials and procedures to the original demonstration of the phenomena. Our results suggest that text-based RA effects may not be as strong as previously thought and are possibly changing over time.