Biology subjects

Schroeger, E.

Publications and source records attributed to Schroeger, E..

4 recordsLinked to original sources

bioRxiv2026

Repetition Coherence Reveals Computational Principles of Auditory Object Formation

A foundational task for perceptual systems is to identify objects. In hearing, repetition -- for example of a feature critical to object identity -- is a powerful cue for object formation. The principles governing how repetition may underpin this process are not well understood, particularly for the noisy, approximate repetition typical of biological environments. To characterize the perceptual organization of acoustic scenes into objects, we adapted the very successful motion-coherence paradigm from vision research, developing a repetition-coherence framework to investigate the evidence accumulation that yields auditory perceptual objects. Participants heard dense tone-cloud sequences in which subsets of tones repeated across cycles. The proportion of repeating tones defined coherence, and the length of the repeating unit was varied. They performed two tasks: repetition detection, which captures the endpoint of object formation, and sensorimotor synchronization, which provides a continuous readout of object formation as it unfolds. The convergence between the two tasks validates sensorimotor synchronization as an online behavioral probe of an otherwise covert process. We discovered that at high coherence both detection and stable tracking were achieved at the same number of cycles, independent of other factors. Yet within this fixed integration regime, longer repeated units were less likely to give rise to a perceptual object, dissociating the likelihood of object emergence from its timing. This scale-independent integration limit suggests that auditory object formation is governed by two interacting principles: extraction of statistical regularities and a fixed integration window. The behavioral signatures parallel known neurophysiological dynamics, providing a helpful link to interpret them.

neuroscience↗

bioRxiv2024

Perceived biodiversity: is what we measure also what we see and hear?

1. Biodiversity is crucial for human health and well-being. Perceived biodiversity - peoples subjective experience of biodiversity - seems to be particularly relevant for mental well-being. 2. Using photographs and audio recordings of forests that varied in levels of species richness, we conducted two sorting studies to assess how people perceive visual and acoustic diversity and whether their perceptions align with measured tree and bird species richness ( actual diversity). Per study, 48 participants were asked to sort the stimuli according to any similarity-based sorting criteria they liked ( open sorts) and perceived diversity ( closed sorts). 3. The main perceived visual forest characteristics identified by participants in the open visual sorts were vegetation density, light conditions, forest structural attributes and colours. The main perceived acoustic forest characteristics identified in the open acoustic sorts comprised bird song characteristics, physical properties such as volume, references to the time of day or seasonality and evoked emotions. 4. Perceived visual and acoustic diversity were significantly correlated with actual tree and bird species richness, respectively. Notably, the relationship was twice as strong for the acoustic sense. The acoustic sense may thus be crucial to obtain a more thorough understanding of perceived biodiversity. 5. We further computed several visual and acoustic diversity indices from the photos and audio recordings, e.g. colourfulness or acoustic complexity, and assessed their relevance for perceived and actual diversity. While all acoustic diversity indices were significantly associated with perceived acoustic diversity and bird richness, we could not identify a visual diversity index that captured perceived visual diversity and tree richness. 6. Our results suggest that people can perceive species richness. Our identified visual and acoustic forest characteristics may help to better understand perceived diversity and how it differs from actual diversity. We present acoustic diversity indices that quantify aspects of perceived and actual acoustic diversity. These indices may serve as cost-efficient tools to manage and plan greenspaces to promote biodiversity and mental well-being.

ecology↗

bioRxiv2023

Perceptual learning of random acoustic patterns: Impact of temporal regularity and attention

Perceptual learning is a powerful mechanism to enhance perceptual abilities and to form robust memory representations of previously unfamiliar sounds. Memory formation through repeated exposure takes place even for random and complex acoustic patterns devoid of semantic content. The current study sought to scrutinise how perceptual learning of random acoustic patterns is shaped by two potential modulators: temporal regularity of pattern repetition and listeners attention. To this end, we adapted an established implicit learning paradigm and presented short acoustic sequences that could contain embedded repetitions of a certain sound segment (i.e., pattern) or not. During each experimental block, one repeating pattern recurred across multiple trials, while the other patterns were presented in only one trial. During the presentation of sound sequences that contained either temporally regular or jittered within-trial pattern repetitions, participants attention was directed either towards or away from the auditory stimulation. Overall, we found a memory-related modulation of the event-related potential (ERP) and an increase in inter-trial phase coherence for patterns that recurred across multiple trials (compared to non- recurring patterns), accompanied by a performance increase in a (within-trial) repetition detection task when listeners attended the sounds. Remarkably, we show a memory-related ERP effect even for the first pattern occurrence per sequence when participants attended the sounds, but not when they were engaged in a visual distractor task. These findings suggest that learning of unfamiliar sound patterns is robust against temporal irregularity and inattention, but attention facilitates access to established memory representations upon first occurrence within a sequence.

neuroscience↗

bioRxiv2019

Auditory predictions and prediction errors in response to self-initiated vowels

It has been suggested that speech production is accomplished by an internal forward model, reducing processing activity directed to self-produced speech in the auditory cortex. The current study uses an established N1-suppression paradigm comparing self- and externally-initiated natural speech sounds to answer two questions:\n\nO_LIAre forward predictions generated to process complex speech sounds, such as vowels, initiated via a button press?\nC_LIO_LIAre prediction errors regarding self-initiated deviant vowels reflected in the corresponding ERP components?\nC_LI\n\nResults confirm an N1-suppression in response to self-initiated speech sounds. Furthermore, our results suggest that predictions leading to the N1-suppression effect are specific, as self-initiated deviant vowels do not elicit an N1-suppression effect. Rather, self-initiated deviant vowels elicit an enhanced N2b and P3a compared to externally-generated deviants, externally-generated standard, or self-initiated standards, again confirming prediction specificity.\n\nResults show that prediction errors are salient in self-initiated auditory speech sounds, which may lead to more efficient error correction in speech production.

neuroscience↗