One of the main focuses of my research lies in the development and implementation of a new psycholinguistic approach, purely behavioral in nature, known as Auditory Classification Images (ACI). This approach draws inspiration from reverse correlation studies in vision psychophysics, which aimed to link random fluctuations in a stimulus to the corresponding perceptual response of a participant in a task, on a trial-by-trial basis. The objective of this project is to adapt and operationalize the reverse correlation technique for the auditory modality, with the ultimate goal of applying it to the exploration of speech perception, particularly phoneme comprehension. Auditory Classification Images enable us to visualize the « listening strategy » of a participant, revealing the information they extract from the auditory stimulus to perform the task.

The Matlab toolbox that we develop is available as a Github repository : https://github.com/aosses-tue/fastACI. It can be used to replicate the previous auditory revcorr experiments or to design new ones.

With this toolbox you can run listening experiments as used in the studies Varnet et al. 2013, Varnet et al. 2015, Osses & Varnet 2021, Varnet & Lorenzi 2022, and Osses & Varnet 2022 (see section « References« ). You can also reproduce most of the figures contained in the mentioned references.

Citation key	fastACI experiment name	Type of background noise	Target sounds
Varnet et al. 2013	speechACI_varnet2013	white	/aba/-/ada/, female speaker
Varnet et al. 2015	speechACI_varnet2015	white	/alda/-/alga/-/arda/-/arga/, male speaker
Osses & Varnet 2021	speechACI_varnet2013	speech shaped noise (SSN)	/aba/-/ada/, female speaker
Varnet & Lorenzi 2022	modulationACI	white	modulated or unmodulated tones
Osses & Varnet subm	speechACI_Logatome	white, bump, MPS	/aba/-/ada/, male speker from the OLLO database

Administrative details

Collaborators: Alejandro Osses, Géraldine Carranante

Fundings:

NSCo Doctoral School, L. Varnet’s thesis scholarship (2012-2015)

Agence Nationale de la Recherche, projet ANR-20-CE28-0004 « Exploration des représentations phonétiques et de leur adaptabilité par la méthode des Images de Classification Auditive rapides » (2021-2023)

Selected publications and presentations:

English

Varnet, L., Knoblauch, K., Meunier, F., Hoen M. (2013). Using auditory classification images for the identification of fine acoustic cues used in speech perception. Frontiers in Human Neuroscience, 7:865. doi: 10.3389/fnhum.2013.00865. (article)

Varnet, L., Knoblauch, K., Serniclaes, W., Meunier, F., Hoen M. (2015). A Psychophysical Imaging Method Evidencing Auditory Cue Extraction during Speech Perception: A Group Analysis of Auditory Classification Images. PLoS ONE, 10(3):e0118009. doi:10.1371/journal.pone.011800. (article)

Osses Vecchi, A. & Varnet, L. (2021). Consonant-in-noise discrimination using an auditory model with different speech-based decision devices. DAGA proceedings (article)

Osses Vecchi, A. & Varnet, L. (subm). A microscopic investigation of the effect of random envelope fluctuations on phoneme-in-noise perception (preprint)

Varnet, L. Presentation to the Hearing Institute (2021, Paris): « New methodologies for studying listening strategies in phoneme categorization tasks » (slides)

Varnet, L. Presentation to the Laboratoire de Psychologie et NeuroCognition (2023, Grenoble):  » Using reverse correlation to study speech perception » (slides)

Varnet, L. Presentation to ARO 2022: « Auditory Classification Images: A Psychophysical Paradigm to Explore Listening Strategies in Phoneme Perception » (slides, video)

Français

Varnet, L. (2015). Identification des indices acoustiques utilisés dans la compréhension de la parole dégradée. Université Claude Bernard Lyon 1. (thèse)

Varnet, L. Présentation à la Fête de la Science (2020, ENS Paris): « Observer l’esprit humain sans neuroimagerie » (vidéo)

Sur ce blog :
– L’image de classification auditive, partie 1 : Le cerveau comme boîte noire
– L’Image de Classification Auditive, partie 2 : À la recherche des indices acoustiques de la parole
– A visual compendium of auditory revcorr studies