Humans stand alone as the sole extant species able to flexibly and effectively respond to virtually any environmental condition or threat, resulting in dominance over most environments on earth. While other animals may exceed human capabilities in some or many sensory modalities, human cognitive, affective and motivational systems integrate to promote unique capacities such as the ability to simulate possible experiences and imagine outcomes, and monitor changing environmental states in order to adapt dynamically in the service of goals. Our unreasonable effectiveness at navigating both our immediate and longer-term needs is facilitated by our motivational flexibility, which affords adaptive and context appropriate behaviors. Innate motivational drives, i.e. survival mechanisms (see Mobbs et al 2015), satiety, social bonding, along with evolutionarily endowed and culturally guided values, and orthogonal levers described by theories such as Regulatory Focus (promotion / prevention see (Higgins, E.T. 1997)), facilitate particular motivational states and shifts thereof (i.e. imperative or interrogative (see Murty & Adcock 2017) to guide ongoing behavior in order to satisfy our needs. These motivational factors interact with the various contexts we encounter to inform our exploration behaviors in our myriad physical and digital information environments. This thesis assesses the effects of motivation in its various manifestations on how we explore our myriad environments; how and when we sample specific kinds of information and what we prioritize; and the downstream effects on cognition, behavior and memory. Each study deploys a novel, custom platform and varying dynamic contexts designed to examine 1) decision-making under competition and threat in a virtual foraging task (Study 1); 2) navigational behavior under threat and subsequent spatial and item-based memory in virtual navigation task (Study 2); and 3) information foraging, and attitude change in the modern digital information environment (Study 3). Motivational factors are shown to affect exploratory behaviors in each of these domains. Threat often induces an imperative motivational state, influencing environmental selection in a two-patch foraging task, and access to or use of memory systems in the service of navigational goals. Finally, online contexts interact with motivational influences to determine how we search for, select, and consume competing information to form or update attitudes and make decisions.

Although a relative consensus exists about the contribution of post-learning sleep in the consolidation of novel information in long term memory, the definition of the respective contributions of sleep stages in memory consolidation processes remains a matter of debates. Scrima (1982) proposed the hypothesis that Slow Waves Sleep (SWS) contributes preventing retroactive interference on recently acquired information, whereas Rapid Eyes Movement sleep (REM) contributes consolidating this information. This interesting hypothesis was never validated by others studies and rapidly forgotten in the sleep literature. In this framework, our doctoral thesis explored the role of sleep stages in consolidation and protection of lexical and emotional retroactive interference. Regarding lexical interference, we use a classical interference paradigm in which participants learn a list of unrelated word pairs (A). After a retention interval varying according to the study, a novel list of word pairs (B) is learned just before delayed recall of list A. List B is composed of 50% word pairs in which the initial word of the pair is also presented in list A, hence creating interference. In a first study, we showed an interference effect after a retention interval containing 3 nights of sleep (sleep condition) but not after a first night of sleep deprivation and two recovery nights (sleep deprivation condition). Our findings may be in line with the reconsolidation theory in that after a night of sleep the reactivation of consolidated memory traces puts them back in a labile form, hence again sensitive to interference. By contrast, in the sleep deprivation condition, subjects would create a dual trace (A and B) allowing them to fend off the negative impact of interference: the second list does not modify the first but the two lists coexist. The same results were observed in a second study after a 45-min nap vs. a wake episode. In this study, the controlled morning nap paradigm aiming at producing predominant post-training SWS or REM sleep episodes, allows us to investigate whether a nap containing SWS or REM sleep increases nevertheless the protection against interference. Our results partially support Scrima’s hypothesis. Indeed, if SWS seems to have a protective effect against interference for novels memories, we failed to evidence REM sleep-related consolidation effects on word pairs not subjected to interference. <p>In a second section of my doctoral thesis, we investigated the protective role of sleep against emotional interference. Previous studies have showed that a change of mood from learning to recall induced a retroactive emotional interference and consequently impaired recall capacities, whereas a similar mood at both encoding and recall sessions facilitated retrieval (a phenomenon named ‘Mood-state Dependent Memory’, MDM). In a first study, we showed that sleep reduces the MDM effect by unbinding memories (i.e. word pairs) from their emotional context (i.e. the emotional mood context). In this study, subjects learned a list of word pairs after a mood induction procedure, then slept or stayed awake during the postlearning night. After two recovery nights, subjects recall 50% word pairs after the same mood induction procedure and 50% in a different mood state. MDM effect was observed in the sleep-deprived condition whereas it has disappeared in the sleep condition. This study validated the “Sleep to Forget and Sleep to Remember” model (van der Helm & Walker, 2010) stating that sleep (especially REM sleep) facilitates the decoupling of declarative memories from their emotional context, hence reducing the MDM phenomena. However, in a second study comparing the effects of "early" and "late" sleep periods (dominated by SWS and REM sleep, respectively) on resistance to emotional interference, we failed to evidence a specific role of REM sleep in this emotional unbinding process. We surmise that the demodulation process is initiated during the first post-learning night (potentially during REM sleep) but may need several nights or several successions of NREM-REM cycles across a whole night to be achieved. A third study evidenced that MDM is not reduced after one night of sleep. These results do not allow us to confirm that emotional unbinding process needs several successions of NREM-REM cycles across a whole night to be achieved but rather need several nights. <p>To sum up, sleep seems to protect memories against both lexical (especially SWS), and emotional interference; the latter being achieved by unbinding memories from their emotional context.<p> / Doctorat en Sciences Psychologiques et de l'éducation / info:eu-repo/semantics/nonPublished

Our decisions reflect who we are and shape who we become. The field of decision-making and learning has revealed how past outcomes guide our future choices by updating value representations. However, we often make choices among options we never experienced before, and therefore their value is not immediately accessible. How do we navigate these choices? This dissertation posits that such decisions rely on memory mechanisms that facilitate generalization and inferential reasoning. Through a combination of behavioral experiments, computational modeling and neuroimaging measures, I explore the diverse ways in which memory mechanisms influence value-based decisions between options for which value is unknown. In Chapter One, I investigate how individuals assign value to unchosen alternatives and propose that memory creates an associative link between choice options, with consequences for later updating of value. Through a series of five experiments, I demonstrate an inverse relationship between the valuation of unchosen options and the direct learning about chosen options, and show that this inverse inference of value is related to memory of the decision itself. In Chapter Two, I manipulate the associative link between choice options using a well-established memory manipulation technique and observe a reduction in the inverse inference of unchosen options. This provides further evidence for the causal role of associative memory in the inferential effect. Additionally, I introduce a novel policy-gradient model incorporating memory components that offers the best explanation for observed behaviors. Lastly, in Chapter Three, I present behavioral and neuroimaging evidence supporting the influence of conceptual knowledge in value-based decisions involving entirely new choice options. I show that people use existing category knowledge to group similar items together, enabling value extraction at a category level and generalization to novel items. Overall, this dissertation underscores the fundamental role of memory in shaping the construction and use of value to guide choice. It emphasizes the adaptive and flexible nature of memory, showing how it combines past experiences to guide future actions.

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