Léo Dutriaux

Humans conceptualize time in terms of space, allowing flexible time construals from various perspectives. We can travel internally through a timeline to remember the past and imagine the future (i.e., mental time travel) or watch from an external standpoint to have a panoramic view of history (i.e., mental time watching). However, the neural mechanisms that support these flexible temporal construals remain unclear. To investigate this, we asked participants to learn a fictional religious ritual of 15 events. During fMRI scanning, they were guided to consider the event series from either an internal or external perspective in different tasks. Behavioral results confirmed the success of our manipulation, showing the expected symbolic distance effect in the internal-perspective task and the reverse effect in the external-perspective task. We found that the activation level in the posterior parietal cortex correlated positively with sequential distance in the external-perspective task but negatively in the internal-perspective task. In contrast, the activation level in the anterior hippocampus positively correlated with sequential distance regardless of the observer’s perspectives. These results suggest that the hippocampus stores the memory of the event sequences allocentrically in a perspective-agnostic manner. Conversely, the posterior parietal cortex retrieves event sequences egocentrically from the optimal perspective for the current task context. Such complementary allocentric and egocentric representations support both the stability of memory storage and the flexibility of time construals.

La cognition incarnée est un courant théorique qui considère que l'esprit doit être compris dans le contexte de son corps, et de l'interaction de ce dernier avec l'environnement. Elle s'est construite en réaction à l'approche cognitiviste classique qui voit la cognition dite « centrale » (mémoire, raisonnement, compréhension...) comme un système de traitement de l'information de symboles amodaux, indépendant des systèmes sensorimoteurs. S'opposant à cette vision, la cognition incarnée soutient notamment que 1/ la cognition aurait pour fonction de guider l'action 2/ elle serait ancrée dans les systèmes sensorimoteurs, c'est-à-dire qu'elle aurait des ressources de traitement en commun avec eux plutôt que d'en être indépendante. Depuis les années 80, les travaux s'inscrivant dans cette approche sont chaque année plus nombreux. Pourtant, la cognition spatiale envisagée selon cette perspective reste encore un domaine peu exploré. L'objectif de la revue de littérature présentée dans cette thèse est de montrer que différentes sources d'informations des représentations spatiales, la perception, la mémoire, et le langage, sont incarnées. Si leurs sources sont incarnées, alors il y a de bonnes raisons de penser que les représentations spatiales le sont aussi. Nous rapportons ensuite quelques éléments suggérant que les représentations spatiales pourraient être incarnées. Notre travail expérimental a eu pour objectif de montrer que la mémoire d'objets pouvant constituer une base à la formation d'une représentation spatiale est incarnée, dans le sens où elle aurait pour fonction de guider l'action, et qu'elle est ancrée dans les systèmes sensorimoteurs. A cette fin, nous avons réalisé plusieurs études explorant, au travers de postures réduisant les possibilités d'action, le rôle du système moteur dans la mémoire (Expériences 1 à 11), le langage (Expériences 9a à 10), et les représentations spatiales (Expériences 10 et 11). Les Expériences 1 à 8 ont montré dans l'ensemble qu'une posture contraignante a un effet négatif sur la mémoire d'images ou de noms d'objets manipulables, mais pas sur la mémoire des objets-non-manipulables (effet PI). Les Expériences 9a et 9b ont utilisé des phrases et ont montré que l'effet de la posture sur la mémoire de noms d'objets manipulables est présent lorsqu'il est associé à un verbe impliquant une action, mais pas lorsqu'il est associé à un verbe n'impliquant pas d'action. Les Expériences 10 et 11 ont utilisé respectivement des descriptions spatiales et des environnements virtuels, et ont montré nouvellement que des objets décrits ou présentés à une distance ne permettant par leur atteinte manuelle sont moins bien mémorisés que ceux situés à une distance proche. Après avoir discuté de ces résultats, nous proposerons notre conception des modèles de situations spatiaux incarnés.

Theories of Embodied and grounded cognition posit that knowledge retrieval is rooted in sensorimotor simulations of past experiences. Accordingly, individuals with diverse sensorimotor experiences may retrieve knowledge differently. Here, we asked whether and how congenital blind individuals remap the representation of vision-related verbs in the motor system. Participants memorized lists of phrases combining an object to an action-related (“to take a guitar”), vision-related (“to see a guitar”), or control verb (“to hear a guitar”). The lists were either learned with the hands at rest or behind their back. Results replicated previous findings showing that recall for action-related phrases was lower in both groups when they were learned with the hands behind the back. As expected, posture impacted the memory of vision-related phrases only in blind people, although in the opposite direction. These findings provide evidence for the sensorimotor grounding of knowledge and shed light on how blind individuals represent knowledge.

The neural system that encodes heading direction in humans can be found in the medial and superior parietal cortex and the entorhinal-retrosplenial circuit. However, it is still unclear whether heading direction in these different regions is represented within an allocentric or egocentric coordinate system. To investigate this problem, we first asked whether regions encoding (putatively) allocentric facing direction also encode (unambiguously) egocentric goal direction. Second, we assessed whether directional coding in these regions scaled with the preference for an allocentric perspective during everyday navigation. Before the experiment, participants learned different object maps in two geometrically similar rooms. In the MRI scanner, their task was to retrieve the egocentric position of a target object (e.g., Front, Left) relative to an imagined facing direction (e.g., North, West). Multivariate analyses showed, as predicted, that facing direction was encoded bilaterally in the superior parietal lobule (SPL), the retrosplenial complex (RSC), and the left entorhinal cortex (EC), a result that could be interpreted both allocentrically and egocentrically. Crucially, we found that the same voxels in the SPL and RSC also coded for egocentric goal direction but not for allocentric goal direction. Moreover, when facing directions were expressed as egocentric bearings relative to a reference vector, activities for facing direction and egocentric goal direction were correlated, suggesting a common reference frame. Besides, only the left EC coded allocentric goal direction as a function of the subject’s propensity to use allocentric strategies. Altogether, these results suggest that heading direction in the superior and medial parietal cortex is mediated by an egocentric code, whereas the entorhinal cortex encodes directions according to an allocentric reference frame.

Trichotillomania (hair pulling disorder) is characterized by the recurrent and repetitive pulling of one’s own hair, often resulting in distress for the individual. Being able to accurately measure trichotillomania is essential for understanding hair pulling and developing interventions to decrease pulling. Most current assessment measures are unsituated, asking an individual to assess their pulling by abstracting across unspecified life situations to construct overarching impressions. This abstraction process can potentially lead to inaccurate judgements that ignore important sources of situational variance. We used the Situated Assessment Method (SAM²) to develop a situated psychometric instrument for assessing trichotillomania: the SAM2 Trichotillomania Assessment Instrument (SAM2 TAI). Using the SAM2 TAI, participants in two studies (n = 117 and n = 99) evaluated 52 situations for pulling frequency and urge strength, along with a set of processes known to influence pulling (e.g., external triggers, reduction of negative emotion, situational control, emotion regulation). As expected, large reliable individual differences emerged across these measures of trichotillomania, together with substantial situational effects and situation by individual interactions. High levels of construct and content validity were also observed, demonstrating that the SAM2 TAI provides meaningful assessments of constructs associated with trichotillomania. Prediction of trichotillomania at both the group and individual levels supported theoretical models of trichotillomania in the literature, while establishing individual prediction profiles that varied widely. Interestingly, the SAM2 TAI was only moderately related to a well-established unsituated measure of trichotillomania, the MGH-HPS, indicating that situated and unsituated measures capture different information.

Summary: The neural system that encodes heading direction in humans is found consistently in the medial and superior parietal cortex and the entorhinal-retrosplenial circuit. However, it is still unclear whether heading direction in these different regions is represented within an allocentric or egocentric coordinate system. To investigate this problem, we first asked whether regions encoding (putatively) allocentric facing direction also encode (unambiguously) egocentric goal direction. Second, we assessed whether directional coding in these regions scaled with the preference for an allocentric perspective during everyday navigation. Before the experiment, participants learned different object maps in two geometrically similar rooms. In the MRI scanner, their task was to retrieve the egocentric position of a target object (e.g., Front, Left) relative to an imagined facing direction (e.g., North, West). Multivariate analyses showed, as predicted, that facing direction was encoded bilaterally in the superior parietal lobule (SPL), the retrosplenial complex (RSC), and the left entorhinal cortex (EC). Crucially, we found that the same voxels in the SPL and RSC also coded for egocentric goal direction. Moreover, when facing directions were expressed as egocentric bearings relative to a reference vector, activities for facing direction and egocentric direction were correlated, suggesting a common reference frame. Besides, only the left EC coded allocentric goal direction as a function of the subject’s propensity to use allocentric strategies. Altogether, these results suggest that heading direction in the superior and medial parietal cortex is mediated by an egocentric code, whereas the entorhinal cortex encodes directions according to an allocentric reference frame.

Memories acquired incidentally from exposure to food information in the environment may often become active to later affect food preferences. Because conscious use of these memories is not requested or required, these incidental learning effects constitute a form of indirect memory. In an experiment using a novel food preference paradigm (n = 617), we found that brief incidental exposure to hedonic versus healthy food features indirectly affected food preferences a day later, explaining approximately 10% of the variance in preferences for tasty versus healthy foods. It follows that brief incidental exposure to food information can affect food preferences indirectly for at least a day. When hedonic and health exposure were each compared to a no-exposure baseline, a general effect of hedonic exposure emerged across individuals, whereas health exposure only affected food preferences for high-BMI individuals. This pattern suggests that focusing attention on hedonic food features engages common affective processes across the general population, whereas focusing attention on healthy food features engages eating restraint goals associated with high BMI. Additionally, incidental exposure to food features primarily changed preferences for infrequently consumed foods, having less impact on habitually consumed foods. These findings offer insight into how hedonic information in the obesogenic food environment contributes to unhealthy eating behavior that leads to overweight and obesity. These findings further motivate the development of interventions that counteract the effects of exposure to hedonic food information and that broaden the effects of exposure to healthy food information.

From the perspectives of grounded, situated, and embodied cognition, we have developed a new approach for assessing individual differences. Because this approach is grounded in two dimensions of situatedness—situational experience and the Situated Action Cycle—we refer to it as the Situated Assessment Method (SAM2). Rather than abstracting over situations during assessment of a construct (as in traditional assessment instruments), SAM2 assesses a construct in situations where it occurs, simultaneously measuring factors from the Situated Action Cycle known to influence it. To demonstrate this framework, we developed the SAM2 Habitual Behavior Instrument (SAM2 HBI). Across three studies with a total of 442 participants, the SAM2 HBI produced a robust and replicable pattern of results at both the group and individual levels. Three trait-level measures of behavior regularity across 80 behaviors, 40 positive behaviors, and 40 negative behaviors exhibited large reliable individual differences. Several sources of evidence demonstrated the construct validity of these measures. At both the group and individual levels, the SAM2 measure of behavior regularity was associated with factors from the Situated Action Cycle known to influence habitual behavior in the literature (consistency, automaticity, immediate reward, long-term reward). Regressions explained approximately 65% of the variance at the group level and a median of approximately 75% at the individual level. The SAM2 measure of behavior regularity also exhibited well-established interactions with personality measures for self-control and neuroticism. Cognitive-affective processes from the Situated Action Cycle explained nearly all the variance in these interactions. Finally, a composite measure of habitualness established habitual behaviors at both the group and individual levels. Additionally, a composite measure of reward was strongly related to the composite measure of habitualness, increasing with self-control and decreasing with neuroticism.

The grounded cognition approach posits the involvement of sensory-motor processes in the representation of knowledge. However, the functional impact of these processes on cognition has been questioned, and some authors have explored the effect of motor interference on memory to test causally this hypothesis. In a seminal study, Dutriaux and Gyselinck (2016) showed that keeping the hands behind the back during learning decreases the memory of manipulable objects, but not the memory of nonmanipulable objects. The aim of this paper is to shed light on the mechanism behind the effect of posture in memory observed by Dutriaux and Gyselinck. The present experiment replicated the posture manipulation during learning but asked participants to keep their hands behind the back during recall. Results showed a similar detrimental effect of the hands behind the back specific to manipulable objects. This shows that the mechanism behind this effect arises from postural interference rather than from a compatibility between the posture during learning and the posture during recall and adds new evidence in favor of the sensory-motor grounding of knowledge.