Listening and speaking strategies in face-to-face interactions

Understanding spoken language is a fundamental human ability, crucial for facilitating social interaction and enabling the exchange of information. While it may appear a simple process, speech comprehension is a constant challenge, particularly when communication occurs in acoustically complex environments such as a noisy room or a multitalker scene. The vast majority of research has focused on how listeners cope with these situations by adapting their internal mental resources, such as attention and memory. Yet, this conceptualization overlooks the fact that individuals regularly rely on overt behavioural strategies when managing listening demands. These include speech-reading on the lips of the talker or postural adjustments, such as turning one’s head to optimize the listening experience. In addition, listeners can also rely on social support from the speaker, as signalling their difficulty in understanding, can prompt clarifications and reformulations. In this thesis, I examine listening as a fundamentally embodied and interpersonal process. On the one hand, the goal is to clarify the mechanisms that regulate the spontaneous use of these behavioral adaptations during listening. On the other hand, the aim is to understand whether these behaviors can also serve as a social signal to trigger speech adjustments in the interlocutor. In the first part of the thesis, I show that the implementation of behavioral adaptations during listening reflects not only task difficulty. They also result from a cost-benefit evaluation where the listener weighs cognitive demands against their motivation to engage in the listening task. In older adults with typical hearing, I document reduced use of spontaneous behavioral adaptations during listening. I propose that age-related differences are associated with a shift in the cost-benefit evaluation, where the perceived costs of a strategic behavior (cognitive, motivational, and physical demands) outweigh its potential benefits. In the second part of the thesis, I provide experimental evidence that behavioral adaptations to listening challenges can also serve as a non-verbal cue that guides supportive speech adjustments from the interlocutor. This occurs even in the absence of semantic knowledge regarding the comprehension abilities of the listener. Interestingly, this socially adaptive ability appears to be preserved across the adult lifespan. Taken together, the findings of this thesis provide new evidence that understanding effortful listening is an embodied and interpersonal process. It also frames behavioral adaptations during listening as a powerful cognitive offloading strategy for the listener and a crucial social cue for the speaker.