Benoit Riou

Act-In: An integrated view of memory mechanisms

The present article proposes a new memory model called Act-In (Activation-Integration). Act-In extends the multiple trace memory models by placing them within the situated cognition perspective. Act-In considers that the activation and integration mechanisms play a key role in memory processes. These mechanisms are involved in both the construction of memory traces and the emergence of knowledge. The model is based on four main assumptions: (1) Memory traces reflect all the components of past experiences and, in particular, their sensory properties, actions performed on the objects in the environment and the emotional states of individuals. Memory traces are therefore distributed across multiple neuronal systems which code the multiple components of the experiences. (2) Knowledge is emergent and is the product of the coupling of the present experience with past experiences. (3) The brain is a categorisation system which develops by accumulating experiences and which, by default, produces categorical knowledge. (4) The emergence of specific knowledge (memories or episodic knowledge) requires very simple mechanisms which occur during learning and/or during retrieval. These assumptions are defended and discussed in the light of the work reported in the literature.

Visual memory and visual perception: when memory improves visual search

This study examined the relationship between memory and perception in order to identify the influence of a memory dimension in perceptual processing. Our aim was to determine whether the variation of typical size between items (i.e., the size in real life) affects visual search. In two experiments, the congruency between typical size difference and perceptual size difference was manipulated in a visual search task. We observed that congruency between the typical and perceptual size differences decreased reaction times in the visual search (Exp. 1), and noncongruency between these two differences increased reaction times in the visual search (Exp. 2). We argue that these results highlight that memory and perception share some resources and reveal the intervention of typical size difference on the computation of the perceptual size difference.

Demonstration of an Ebbinghaus Illusion at a Memory Level Manipulation of the Memory Size and not the Perceptual Size

Based on recent behavioral and neuroimaging data suggesting that memory and perception are partially based on the same sensorimotor system, the theoretical aim of the present study was to show that it is difficult to dissociate memory mechanisms from perceptual mechanisms other than on the basis of the presence (perceptual processing) or absence (memory processing) of the characteristics of the objects involved in the processing. In line with this assumption, two experiments using an adaptation of the Ebbinghaus illusion paradigm revealed similar effects irrespective of whether the size difference between the inner circles and the surrounding circles was manipulated perceptually (the size difference was perceptually present, Experiment 1) or merely reactivated in memory (the difference was perceptually absent, Experiment 2).

When seeing a dog activates the bark: multisensory generalization and distinctiveness effects.

The goal of the present study was to find evidence for a multisensory generalization effect (i.e., generalization from one sensory modality to another sensory modality). The authors used an innovative paradigm (adapted from Brunel, Labeye, Lesourd, & Versace, 2009) involving three phases: a learning phase, consisting in the categorization of geometrical shapes, which manipulated the rules of association between shapes and a sound feature, and two test phases. The first of these was designed to examine the priming effect of the geometrical shapes seen in the learning phase on target tones (i.e., priming task), while the aim of the second was to examine the probability of recognizing the previously learned geometrical shapes (i.e., recognition task). When a shape category was mostly presented with a sound during learning, all of the primes (including those not presented with a sound in the learning phase) enhanced target processing compared to a condition in which the primes were mostly seen without a sound during learning. A pattern of results consistent with this initial finding was also observed during recognition, with the participants being unable to pick out the shape seen without a sound during the learning phase. Experiment 1 revealed a multisensory generalization effect across the members of a category when the objects belonging to the same category share the same value on the shape dimension. However, a distinctiveness effect was observed when a salient feature distinguished the objects within the category (Experiment 2a vs. 2b).

Memory and consciousness: trace distinctiveness in memory retrievals.

The aim of this article was to provide experimental evidence that classical dissociation between levels of consciousness associated with memory retrieval (i.e., implicit or explicit) can be explained in terms of task dependency and distinctiveness of traces. In our study phase, we manipulated the level of isolation (partial vs. global) of the memory trace by means of an isolation paradigm (isolated words among non-isolated words). We then tested these two types of isolation in a series of tasks of increasing complexity: a lexical decision task, a recognition task, and a free recall task. The main result of this study was that distinctiveness effects were observed as a function of the type of isolation (level of isolation) and the nature of the task. We concluded that trace distinctiveness improves subsequent access to the trace, while the level of trace distinctiveness also appears to determine the possibility of conscious or explicit retrieval.

The Mask Who Wasn't There: Visual Masking Effect With the Perceptual Absence of the Mask

Does a visual mask need to be perceptually present to disrupt processing? In the present research, we proposed to explore the link between perceptual and memory mechanisms by demonstrating that a typical sensory phenomenon (visual masking) can be replicated at a memory level. Experiment 1 highlighted an interference effect of a visual mask on the categorization of auditory targets and confirmed the multimodal nature of knowledge. In Experiment 2, we proposed to reactivate this mask in a categorization task on visual targets. Results showed that the sensory mask has disrupted (slower reaction times) the processing of the targets whether the mask was perceptually present or reactivated in memory. These results support a sensory-based conception of memory processing and suggest that the difference between perceptual processes and memory processes is characterized by the presence (perception) or the absence (memory) of the sensory properties involved in the activity.

When memory components act as perceptual components: Facilitatory and interference effects in a visual categorisation task

When they live through an experience, individuals both perceive sensorimotor components in the environment (perception) and reactivate properties associated with the experience that are not perceptually present (memory). According to embodiment theory, memory consists of sensorimotor traces that are reactivated during the experience. The aim of this study was to demonstrate that a reactivated property in memory can influence the processing of a stimulus that shares this property even if the property itself is not perceptually present. In two experiments, participants had to categorise pictures of products which were typically sweet or unsweetened (they were asked if the products were edible or inedible). These pictures were preceded by (Experiment 1) or presented simultaneously with (Experiment 2) either a visual pattern that had been associated with the property of sweetness during a first phase or a visual pattern which was not associated with this property. The results revealed that the presentation of the pattern previously associated with the property of sweetness had a facilitatory effect (Experiment 1) or an interference effect (Experiment 2) on the categorisation of the pictures of sweet products. We propose an interpretation in terms of reciprocal influences between memory and perceptual mechanisms that involve the same sensorimotor properties.

Perceptual processing affects the reactivation of a sensory dimension during a categorization task.

According to grounded theories of cognition, knowledge is grounded in its sensory-motor features. Therefore, perceptual and conceptual processing should be based on the same distributed system so that conceptual and perceptual processes should interact. The present study assesses whether gustatory stimulation (participants tasted a sweet or a nonsweet yoghurt) could influence performance on a categorization task that involves the reactivation of the same sensory dimension. The results indicate that participants were slower (Experiment 1) or faster (Experiment 2), respectively, at categorizing pictures as representing edible sweet stimuli when they either simultaneously or had previously tasted a sweet yoghurt as compared to a nonsweet yoghurt. These results confirm the significant overlap between perceptual and memory mechanisms and suggest the functional equivalence between perceptually present and perceptually absent (memory reactivated) dimensions.

Editorial: Dynamics of Sensorimotor Interactions in Embodied Cognition.

The concept of incorporating the current situation and the body state within cognitive processes, referred to as embodiment, has revolutionized cognitive research (Glenberg et al., 2013). Interest in this approach has grown substantially in the last few decades. Embodied cognition has now been demonstrated across a wide range of topics, from babies (e.g., Smith and Gasser, 2005) to elderly adults (e.g., Vallet et al., 2013a), from normal cognition to neuropsychology (e.g., Vallet et al., 2013b) as well as in emotion (e.g., Vermeulen et al., 2007), and in neuroscience as a whole (e.g., Pulvermuller, 2013). Nevertheless, there is yet much to discover in order to better understand embodiment. One of the striking arguments of embodiment is that sensori-motor features are at the core of mental processes (Pecher and Zwaan, 2005; Barsalou, 2010). Their relationship should also be considered to be dynamic. In the embodied cognition approaches, perception, memory, and action are no longer regarded as (relatively) independent functions, but rather as closely interacting components. Some authors even argue for an overlap within these processes (Brunel et al., 2009, 2015; Vermeulen et al., 2009) that would rely on the same neural code (e.g., Hommel). One key direction in embodiment that needs to be further explored is the dynamic interaction between the sensory and motor components across the different cognitive functions. The present Research Topic aims to shed new light on this issue. The importance of studying this problematic is well presented in Dijkstra and Posts critical review. Their article highlights the crucial role of sensorimotor simulation across several cognitive activities (e.g., reasoning, evaluating) and how the interaction between the current situation and the simulation of past sensorimotor states mediates the emergence of adaptive behavior. This is possible since perception and memory interact closely and share processes and resources (e.g., Vermeulen et al., 2008; Riou et al., 2011; Rey et al., 2014). In other words, “direct” perception of an object and the mental simulation of this object involve common sensorimotor units. Heurley and Ferrier argue in their perspective that these interactions serve to plan and control actions to interact with well-known objects in non-optimal perceptual conditions, thus producing adaptive behavior. The idea that cognitive activities are strongly influenced by the given social and physical environment is referred to as situated cognition. Rey et al. demonstrate that motor simulation relies on the relevance of the object as a function of the task. Further evidence also supports the hypothesis that sensorimotor simulation is heavily influenced by situational aspects (Kapoula et al.). For instance, Amorim et al. have demonstrated that the visual angle and screen orientation along with contextual information modulates the resulting movement. The reverse is also applicable, since sensorimotor simulation shapes our perception of, as well as our interaction with, our environment. Grade et al. found that similar action simulation underlies both reachability and egocentric distance perception. This effect can be generalized across individuals and possibly incorporate the role of social environment in cognition. In accordance, Quesque and Coello show that during reach-to-grasp actions, participants unconsciously modify their trajectory curvature based on their partners eye level. This adaptation to biological motion is one the key component of social interaction, but human movements are so complex that they might be described as mathematically chaotic. Nonetheless, children quickly develop the ability to coordinate gaze, and in some respect posture, in response to complex chaotic motion structures (Haworth et al.). The dynamics of sensorimotor interactions allows for situational behavioral adaptation in reaching and grasping, but also in more complex evaluative processes. For instance, associations between handedness and valence have previously been found (e.g., Casasanto, 2011). de la Vega et al. extend this finding by showing that strong right-footers respond to positive words faster with the dominant foot. The association between valence and laterality, however, becomes less clear when motor fluency is taken into account. Brouillet et al. observe that most participants prefer choosing stable supports for “good” items, regardless of side and handedness. The space-valence association could also be reported for the vertical axis. Xie et al. demonstrate that the processing of affective valence concepts activated the vertical spatial axis (positive in the up position). The association between cognition and space in the context of emotion is well documented, but it is not restricted to this cognitive domain. Hartmann et al. report that simple arithmetics are associated with gaze shifting along the vertical axis. Interestingly, operand magnitude partly modulated horizontal gaze position as well. The reciprocal influence of motor components on numerical cognition may also provide the opportunity to assess numerical cognition with methods such as mouse tracking. In their perspective, Fischer and Hartmann point out important insight and methodological considerations on conceptual aspects related to numeric cognition. This perspective has been further elaborated by Faulkenberry and Rey. These recent reports offer a new perspective on cognitive functioning, one that combines sensorimotor dynamics with contextual and body information. These new concepts provide new opportunities to explore related domains such as motivation (Shalev) and anticipation (Raab) and offer a new framework to interpret well-known and sometimes contradictory results in fields such as short-term memory (Macken et al.) or healthy cognitive aging (Vallet).

The automatic visual simulation of words: A memory reactivated mask slows down conceptual access.

How do we represent the meaning of words? The present study assesses whether access to conceptual knowledge requires the reenactment of the sensory components of a concept. The reenactment—that is, simulation—was tested in a word categorisation task using an innovative masking paradigm. We hypothesised that a meaningless reactivated visual mask should interfere with the simulation of the visual dimension of concrete words. This assumption was tested in a paradigm in which participants were not aware of the link between the visual mask and the words to be processed. In the first phase, participants created a tone–visual mask or tone–control stimulus association. In the test phase, they categorised words that were presented with 1 of the tones. Results showed that words were processed more slowly when they were presented with the reactivated mask. This interference effect was only correlated with and explained by the value of the visual perceptual strength of the words (i.e., our experience with the visual dimensions associated with concepts) and not with other characteristics. We interpret these findings in terms of word access, which may involve the simulation of sensory features associated with the concept, even if participants were not explicitly required to access visual properties. Comment nous représentons-nous le sens des mots? La présente étude évalue si l’accès aux connaissances conceptuelles requiert la reconstitution des éléments sensoriels d’un concept. La reconstitution, c’est-à-dire la simulation, a été testée dans le cadre d’une tâche de catégorisation des mots au moyen d’un paradigme de masquage novateur. Nous avons émis l’hypothèse qu’un masque visuel réactivé superflu pourrait interférer avec la simulation de la dimension visuelle de mots concrets. Cette hypothèse a été vérifiée au moyen d’un paradigme dans le cadre duquel les participants n’étaient pas conscients du lien qui existait entre le masque visuel et les mots à traiter. Lors de la première phase, les participaient faisaient une association ton - masque visuel ou ton - contrôle du stimulus. Lors de la phase-test, ils ont catégorisé des mots qui étaient présentés avec l’un des deux tons. Les résultats ont montré que les mots étaient traités plus lentement lorsqu’ils étaient présentés avec le masque réactivé. Cet effet d’interférence a uniquement pu être corrélé avec et expliqué par la valeur de la force de perception visuelle des mots (c’est-à-dire notre expérience avec les dimensions visuelles associées aux concepts) et non avec les autres caractéristiques. Nous interprétons ces résultats en termes d’accès aux mots, lesquels peuvent impliquer la simulation de fonctions sensorielles associées au concept, même si les participants n’étaient pas tenus d’accéder aux propriétés visuelles.