What Is It Like to Be an Emotion Researcher? Tahn´eeEngelen1, Rocco Mennella1,2 July 2021 1 Cognitive and Computational Neuroscience Laboratory (LNC2), Inserm U960, Department of Cogni- tive Studies, Ecole´ Normale Sup´erieure,PSL University, 29 rue d'Ulm, 75005, Paris, France 2 Laboratory on the Interactions between Cognition, Action, and Emotion (LICAE) { Paris Nanterre University, 200 avenue de La R´epublique,92001 Nanterre Cedex, France. Corresponding authors: Tahn´eeEngelen & Rocco Mennella Corresponding authors e-mails: [email protected] & [email protected] Corresponding authors telephone: +33144322638 Corresponding authors fax number: +33144322642 Abstract. The field of emotion has a rich history, yet given the amount of time researchers have been bending over critical questions such as 'what is an emotion', the field has little consensus to show. The current paper focuses on one of the main topics of disagreement, namely the role of conscious feelings in emotion and their neural correlates. We argue that contemporary theories of emotional consciousness often rely on preliminary findings, stemming from both theoretical and methodological limitations. By drawing parallels with the field of perceptual consciousness, we highlight the unique methodological challenges of research on emotional consciousness. Finally, we make concrete propositions with the aim of moving the field forward. Keywords: Emotion, Consciousness, Theories of Emotion, Affective Neuroscience Background and scopes lution and development in virtue of their adaptive value". You should have seen the faces of the peo- ple from the world of cinema. What is it like to be an emotion researcher (Nagel, Both popular and scientific discord around the no- 1974)? Most differently from bats, emotion re- tion of emotion is not something new. Nonethe- searchers do not rely on echolocation to navigate less, a particularly intense debate is now ongoing their environment. In fact, one might guess that among renowned authors in the field of affective being an emotion researcher must feel, in many as- (neuro)science, about what emotions are and how pects, like being any other researcher. Against this to study them (Adolphs et al., 2019; D. J. An- fallacious intuition, we argue that it involves the derson Adolphs, 2014; Barrett, 2017; Berridge, unique quale of having no idea of what your own 2018; Fanselow Pennington, 2018; LeDoux, 2012, object of study is. 2021; Ledoux & Brown, 2017; Mobbs et al., 2019; Ironically, for an emotion researcher preparing a Panksepp et al., 2017). What seems to be the presentation, the most challenging slide is the first leading source for this impasse is that the con- one. As a real-life example, in a recent general cept of emotion still does not have a commonly public conference about emotions in science and accepted definition and is vague at the point of cinema, soon the time came for one of the authors not meeting the standards for a scientific construct to give a concise definition of human emotions. It (Izard, 2010; Russell, 2003, 2015). In this con- sounded like: \Well, it has to be highlighted that text of uncertainty, authors are nonetheless bring- several theories exist. I would say that, despite ing forward holistic theories of emotion, which are this diversity, most authors would agree that an in contradiction with one another on several lev- emotion is a set of behavioral, physiological, cog- els. Although such theories are typically successful nitive and subjective responses to environmental in wrapping up each author's own discoveries in a stimuli, which have been selected throughout evo- 1 coherent framework, they risk creating a scenario and psychophysiological reactions (Darwin, 1872; in which it becomes impossible comparing these James, 1891) (but see Fridlund & Russell, 2021 same theories and definitions to one another. As for an interesting and radically different interpreta- clearly explained in a recent paper (Pessoa, 2019), tion of Darwin's original perspective). This notion tight definitions can sometimes slow down scien- implied that emotional states, and correspond- tific progress by discouraging novel research ideas ing feelings, can be inferred from behavioral and which violate theoretical boundaries, rather than physiological responses and led to the development pushing them forward. In this context, we agree of modern behavioral paradigms for the study of that all of us should refrain from overtheorizing, emotional responses in animals and humans, ulti- taking a step back to the stage of testing specific mately opening the way to the birth of the mod- hypotheses, to accumulate knowledge that could ern affective (neuro)science (Panksepp, 2004). Af- be useful to explain humans' and animals' com- ter some decades of quiescence, today the debate plex behaviors (Adolphs & Anderson, 2018; Pes- around the role of conscious feelings in defining soa, 2019). emotions has risen again. For simplicity, we will Here, we write to push the debate forward, try- group theories into two global approaches (A1 and ing to cast two pairs of fresh eyes on one of the A2) and compare their arguments. Cited authors most strongly divisive topics, namely, the role of will excuse us for relying on this heuristic; we will conscious feelings in defining emotion. First, we try to highlight important differences where nec- will highlight how the contemporary discussion on essary, but the full complexity of each theory will emotion under many aspects is organized around not be covered. this main question. Second, we will suggest that On the one hand, some authors (A1) re-proposed existing theories of emotional consciousness rely on the idea that emotions equate to conscious feelings, insufficient evidence or overgeneralizations, stem- which can only be accessed through introspection ming from both theoretical ambiguity and method- (LeDoux, 2012; LeDoux & Hofmann, 2018). As ological pitfalls. Finally, we will end with practical a logical consequence, the core property of emo- suggestions for moving the debate forward. tion, the conscious feeling, can only be studied in humans, through subjective reports (LeDoux, 2021; Ledoux & Brown, 2017). For instance, the A broad view on the contemporary concept of \fear" ought to be attributed only to debate on emotion each human's unique conscious experience when facing threat and not to the behavioral, physiolog- We identified what we think is the topic of debate ical and cognitive reactions to threat. The under- from which stem most of the controversies around lying idea is that, while humans and other animals the foundations of emotion as a scientific concept, share the neural circuits to respond to threat, face namely the conscious versus unconscious nature of aggression or seek rewards (LeDoux & Daw, 2018), emotion. In other words, the question is whether none of these circuits determines the precise con- an emotion is essentially a reportable conscious ex- tent of the accompanying subjective emotional ex- perience, or whether it can be inaccessible to in- periences present in humans. In fact, although ba- trospective scrutiny or even unconscious. sic forms of bodily awareness and simple valenced The debate around the conscious versus uncon- states (positive/negative) probably exist in both scious nature of emotion has a long history, which humans and other animals, they are omnipresent we will not fully summarize here. However, it is in our cognitive life and not specific to emotional important to keep in mind that until relatively episodes (Barrett, 2017; Barrett et al., 2007). A1 recently, emotions were not considered a suitable authors do not deny the existence of behavioral phenomenon for experimental investigation. This and visceral reactions, but do not support a reli- was partly because emotions were viewed as in- able and specific causal relationship between these timate subjective experiences that could only be reactions and an instance of what we call emotion accessed through introspection. The equation be- (Barrett, 2017; Ledoux & Brown, 2017). Emo- tween emotion and conscious feelings was chal- tional consciousness, i.e., what emotion really is, lenged at the end of the XIX century by the idea is hierarchical: it is determined by a cognitive pro- that emotions are innate and universal functional cess which helps categorizing a range of somatic responses to environmental stimuli, selected by and visceral reactions into meaningful concepts. evolution, which map onto measurable behaviors 2 These concepts can then become conscious, when have proven useful to adapt to environmental chal- top-down modulatory effects bring them into work- lenges. This set of physiological and behavioral ing memory (Lane et al., 2015). This implies that responses is therefore a measurable and objective emotional feelings are \higher order" representa- indicator of the activation of the central emotion tions of both bodily states and low level cogni- generator. It is also highlighted that direct stimu- tive (e.g., perceptual) processes (Lane et al., 2015; lation of dedicated emotional neural circuits has Ledoux & Brown, 2017), conceivable as instances reinforcing effects on behavior (i.e., animals ac- of reportable access consciousness (Block, 1995). tively try to prolong or terminate the stimula- These emotional concepts are learned progressively tion) (Panksepp, 1998b, 1998a). This is some- through each individual's development, ultimately times taken as evidence for these circuits being allowing for the attribution of meaning