Bittersweet: The Neuroscience of Ambivalent Affect

Abstract

Ambivalent affective states, such as bittersweetness, nostalgia, and longing, which are felt as having both positive and negative aspects, are an important component of human experience but have received little attention. The most influential theoretical frameworks in affective neuroscience focus largely on univalenced states. As a result, it is not known whether ambivalent affect corresponds to a simultaneously positive and negative valenced state or whether it results from a rapid vacillation between positive and negative states. Here we hypothesize that ambivalent affect involves both mechanisms, that is, rapid vacillation and simultaneity of positive and negative affect, albeit at different neurobiological levels. Rapidly vacillating univalent emotions could give rise to an ambivalent feeling, a mechanism that depends on brainstem nuclei that facilitate rapid action programs of emotional behavior while inhibiting opposing behaviors. This reciprocal inhibition prevents organisms from simultaneously implementing responses to conflicting emotions but also allows for rapid switching between emotions triggered by counterfactual thinking and rapid reappraisal of situations. We propose that as these transitions occur and respective interoceptive information reaches the insular cortex, further processing of this “emotional moment” would allow separate emotional events to be experienced as one “mixed” and integrated feeling.

Keywords

ambivalence affective neuroscience emotion feelings

Think back to when you graduated from school. There was probably a sense of excitement for finally reaching that point, perhaps an enthusiasm for wherever you would be heading next. But at this same moment and in moments leading up to it, there may well have been a reflective feeling, lining the edges of this enthusiasm with an uncertainty. Things would never be the same—the ordinary moments of your current life were about to change. Although you wanted to graduate and seemed to be moving on to something you wished for, there was also a shadow around the places, things, and people you were leaving and were fond of. There was joy and laughter but also enough sadness to bring some tears. You were feeling bittersweet.

Most research on affective experience addresses states of positive or negative valence, such as fear, joy, sadness, disgust, or anger (Celeghin, Diano, Bagnis, Viola, & Tamietto, 2017; Critchley & Garfinkel, 2017; Croy, Olgun, & Joraschky, 2011; Ekman, 1992; Russell, 2003). Yet human affect also includes less frequent states that appear to have both positive and negative valences. These ambivalent states remain understudied, and the mechanisms behind their appearance have not been elucidated.

Examples of ambivalent states include sentiments such as bittersweetness and longing (also referred to by the German term Sehnsucht) and nostalgia. The feeling that occurs during cue-induced craving in addiction has also been viewed by some as a mixed positive and negative state (Cartwright & Stritzke, 2008; Veilleux, Conrad, & Kassel, 2013). Such feelings may be described and experienced somewhat differently across individuals, cultures, and contexts, but the fundamental condition of feeling simultaneously positive and negative appears to be universal (Lomas, 2017; Miyamoto, Uchida, & Ellsworth, 2010; Rafaeli, Rogers, & Revelle, 2007; Scheibe, Blanchard-Fields, Wiest, & Freund, 2011). Note that ambivalent affective states appear to have less clear neural correlates than their univalent counterparts, and experiments in psychology have yielded varied and conflicting interpretations as to how they may be constructed. This should not be surprising given that the most influential theoretical frameworks in affective neuroscience have focused largely on univalenced states. As a consequence, we do not know whether ambivalent states result from a rapid sequence of two different emotions or from an actual mixture of the two (Kreibig & Gross, 2017; Larsen, 2017; Norris, Gollan, Berntson, & Cacioppo, 2010; Young, 1918). Here we rely on current work in psychology and neuroscience to discuss the potential psychological and neural foundations of ambivalent affective states and consider how they may be investigated.

Emotion, Feeling, and Valence in the Homeostatic View of Affect

Before we proceed, it is important to establish the meaning of three terms within our framework: emotion, valence, and feeling. Definitions of emotion differ according to whether emotions are viewed, for example, as innate or acquired, as states described as categorical or in terms of dimension, and according to whether they necessarily include the conscious experience associated with them (Adolphs, 2016; L. F. Barrett, 2017; LeDoux & Brown, 2017; Vandekerckhove & Panksepp, 2011). In our view, an emotion is a set of physiological changes produced by a largely innate “action program” (Damasio, 2018; Damasio & Carvalho, 2013). The changes are triggered by stimuli, simple as well as complex, that directly or indirectly threaten or strengthen homeostasis and thus threaten or favor the integrity of the organism. The physiological changes are largely carried out by subcortical structures that act to alter the chemical and visceral parameters of the interior. From our perspective, emotions do not include the conscious experience that co-occurs and follows them. For conscious experience accompanying emotion, we prefer the specific term emotional feelings, which are supported by processes of interoception and also require cortical processes.

All affective states can be classified in terms of valence, which corresponds to positive or negative affective valuation of any experience. Emotions can be said to have valence in the sense that they relate to events that take the organism toward or away from homeostasis, but valence truly blossoms in the realm of feeling. Conscious experiences of emotive states tend to be clearly evaluated as positive or negative. Feelings elicited by a specific emotion tend to have a specific valence.

Ambivalent Affect May Result From Both Vacillation and Mixing but at Different Physiological Levels

The main question concerning ambivalent affect concerns whether it is best viewed as a genuinely mixed, simultaneously positive and negative experience or as a rapid vacillation between two distinctively valenced processes that occur so rapidly that the distinct components cannot be experienced separately (Larsen, 2017; Young, 1918). One way to address this question is to consider the construct of valence, specifically how positive and negative valence relate to each other. If valence is a unidimensional construct in which an affect’s valence lies somewhere on a single positive-negative spectrum, ambivalent affect must be a rapid vacillation, as the two ends cannot coexist (L. F. Barrett & Russell, 1998; Larsen, 2017; Russell & Carroll, 1999). If positive and negative valence instead exist independently as separate constructs, ambivalent feelings can involve feeling positivity and negativity concurrently (Cacioppo & Berntson, 1994; Larsen & McGraw, 2014; Schimmack, 2001).

Psychological research on ambivalent affect has used the valence issue as a way of investigating simultaneity versus vacillation. Studies using postexperience rating scales as well as in-the-moment button presses to signify the presence of positive and negative feelings support the position that subjects do experience these sentiments simultaneously in certain kinds of situations (Larsen & Green, 2013; Larsen & McGraw, 2011; Larsen, McGraw, & Cacioppo, 2001; Larsen, McGraw, Mellers, & Cacioppo, 2004; Moeller, Ivcevic, Brackett, & White, 2018; Schimmack & Hemenover, 2007; Schneider & Schwarz, 2017). Several psychometric studies have suggested that separate positivity and negativity dimensions have stronger explanatory power than a unidimensional model of valence and that positivity and negativity are not inversely correlated with each other, as they would have to be as part of a unidimensional construct (An, Ji, Marks, & Zhang, 2017; Briesemeister, Kuchinke, & Jacobs, 2012; Cacioppo & Berntson, 1994; Colombetti, 2005; Moeller et al., 2018). Nonetheless, some have contradicted this position by pointing out that the rapid alternation between opposite valences may be too fast to be subjectively detected. If that is the case, self-report would reflect both emotional feelings that occurred during the narrow time frame, and accounting for this rapid vacillation can lead to similar predicted data for a unidimensional model of valence (L. F. Barrett & Bliss-Moreau, 2009; Russell, 2017; Russell & Carroll, 1999). The idea that simultaneous contradicting feelings is an illusion of consciousness has been around since the early 1900s, when researchers concluded that while people certainly believed they were experiencing mixed feelings, the nature of affect meant that the feelings would not be simultaneous (Johnston, 1908; Young, 1918).

Research on the neural substrates of valence provides evidence that positive and negative valence are physiologically separate states. Several studies using neuroimaging data suggest that rather than a single locus of changing activity, both independent regions and overlapping regions of the brain are responsible for the representation of positivity and negativity (Berridge, 2019; Lane, Reiman, Ahern, Schwartz, & Davidson, 1997; Lindquist, Satpute, Wager, Weber, & Barrett, 2015). Although unidimensional models can account for much variance in the data, they are not as satisfactory as models that separate positive and negative constructs (Colibazzi et al., 2010; Lewis, Critchley, Rotshtein, & Dolan, 2006; Viinikainen et al., 2010; Viinikainen, Kätsyri, & Sams, 2012).

An important possibility this debate has failed to consider is that both concurrence and vacillation may be involved, albeit at different physiological levels. A complete affective experience comprises multiple levels of processing related to different systems of the brain hierarchy (Berridge, 2019; Immordino-Yang, 2010; Man, Nohlen, Melo, & Cunningham, 2017; Norris et al., 2010; Tye, 2018). In our view, it is critical to distinguish between the largely subcortical level, at which emotional action programs are triggered, and the cortical level, at which the experience of emotional feelings largely depend. These distinct yet integrated components of the affective process may contribute different experiential contents concerning the same situation. Whereas the neural substrates for feelings would accommodate bivalent representations, the neural substrates for emotions would not. Ambivalent affect may not be reducible to the simple alternatives of vacillation or simultaneity. Instead, the vacillation of opposite action programs and the simultaneity of experience might coexist, albeit at different hierarchical levels of neural structure and affective process: emotion and feeling (Fig. 1).

Fig. 1.

An initial stimulus triggers not only the first emotion action program but also the recall of facts and ideas associated with the stimulus. Recalled material, in turn, can trigger a second emotion of a different valence. As a result of the reciprocal inhibitory innervation in brainstem nuclei, the initial action program is inhibited, after which the two emotions relevant to the situation rapidly alternate. While this plays out as a sequence of events at the level of emotion action programs, at the subjective level, the sequence is experienced as a single integrated feeling.

Drawing on Child Development Data to Describe the Cognitive Processes Behind Ambivalent Affect

Stages of child development provide a window into the discrete functions that are necessary for ambivalent affect. At 4 to 5 years of age, children generally report experiencing only one feeling at a time relative to a situation (Larsen, To, & Fireman, 2007; Smith, Glass, & Fireman, 2015). Four- to five-year-old children also show limited ability to perceive ambivalent affect in situational stimuli and cannot be trained to do so (Holm, Greaker, & Strömberg, 2002; Kestenbaum & Gelman, 1995; Peng, Johnson, Pollock, Glasspool, & Hams, 1992; Wintre & Vallance, 1994). By approximately 7 to 8 years of age, children report feeling opposite valences simultaneously; this is shown through self-report and through tasks that require the prediction of feelings that may occur in different hypothetical situations (Harter & Buddin, 1987; Wintre & Vallance, 1994). Children do not begin to report a subjective sense of conflict concerning these opposing feelings until approximately the age of 10 to 11 years old (Choe, Keil, & Bloom, 2005; Donaldson & Westerman, 1986; Whitesell & Harter, 1989; Zajdel, Bloom, Fireman, & Larsen, 2013). This trajectory aligns with the development of affective processes, during which subcortical-prefrontal and prefrontal-associative cortical pathways develop to support more complex utilization, representation, and control of affect and emotion (Casey, Heller, Gee, & Cohen, 2019; Goldsmith & Davidson, 2004; Tottenham, 2014). The frontal lobe transitions from operating in a localized manner to operating within distributed functional networks such as the broader central executive and salience networks (Fair et al., 2009). Moreover, there is evidence that the insula’s effective connectivity to these networks increases with maturation (Uddin, Supekar, Ryali, & Menon, 2011).

These developmental facts support our hypothesis that ambivalent affect is a complex phenomenon that requires multiple levels of processing, where different types of information of potentially different valence are produced and eventually integrated (Filippetti, Kirsch, Crucianelli, & Fotopoulou, 2019; Fischer & Bidell, 2006; Immordino-Yang, 2010; Kuhlmann, Hofmann, Briesemeister, & Jacobs, 2016). Moreover, the fact that ambivalent and univalent feelings emerge at different stages of development is consistent with the idea that simultaneity and vacillation of valences would depend on different neural substrates.

Reciprocal Inhibition in Brainstem Nuclei Prevents Simultaneously Opposite Emotions While Also Allowing Rapid Switches Between Them

From our perspective, emotions arise in part from distinct action programs that are largely coordinated by brainstem nuclei, in what has been characterized as the “lateral emotional motor system” (Bandler & Shipley, 1994; Denton, McKinley, Farrell, & Egan, 2009; Venkatraman, Edlow, & Immordino-Yang, 2017). Through descending pathways of the brainstem, distinct emotional action programs are executed in response to homeostatic needs (Ekman, Levenson, & Friesen, 1983; Panksepp, 1998; Rainville, Bechara, Naqvi, & Damasio, 2006; Venkatraman et al., 2017). Action programs can be adjusted when the influence of the cerebral cortex as a consequence, for example, of interoceptive feedback, cognitive regulation, or endocrine changes from the medial emotional motor system. These action programs are not identical with their corresponding conscious feelings and in fact may even be misinterpreted in introspection (Brewer, Cook, & Bird, 2016; Critchley, 2009; Critchley, Eccles, & Garfinkel, 2013; Davidson, 1993; Jung, Ryu, Lee, Wallraven, & Chae, 2017; Venkatraman et al., 2017). Emotional action programs are responses to something specific that calls for a primarily consistent and coordinated response across various bodily systems. Although the exact patterns of autonomic response may be hard to categorize universally, psychophysiological research has revealed supportive evidence that the autonomic nervous system produces distinguishable patterns for distinct emotional states across individuals, genders, and cultures, although more work is needed on this topic (Levenson, Ekman, & Friesen, 1990; Levenson, Ekman, Heider, & Friesen, 1992; Scherer & Wallbott, 1994; Tsai, Chentsova-Dutton, Freire-Bebeau, & Przymus, 2002).

A fact of major relevance for a discussion of ambivalent affect concerns the neural substrates for conflicting emotional action programs. These programs are innervated through a system of reciprocal inhibition. Examples of this are seen for maternal versus predatory behavior and fight/flight versus freeze responses in functional and lesion studies focused on the periaqueductal gray (Bandler & Shipley, 1994; De Oca, DeCola, Maren, & Fanselow, 1998; Fanselow, 1994; Sukikara, Mota-Ortiz, Baldo, Felício, & Canteras, 2006). Reciprocal inhibition allows for rapid behavioral switches as circumstances change, and this flexibility is impaired by lesions to the relevant brainstem nuclei (Bandler & Shipley, 1994; Strigo & Craig, 2016; Sukikara et al., 2006). This suggests that opposite emotions at the level of the brainstem rapidly vacillate rather than mix, just as the fixed-action patterns of rats do in response to simultaneous palatable and aversive tastes (Berridge, 2019; Berridge & Grill, 1983, 1984).

We acknowledge that there is some uncertainty regarding whether the above findings truly rule out all possible overlap between basic positive and negative reactions at the level of the viscera. Changes to physiological states are not instantaneously resolved once the emotional action program is discontinued, and so it is possible that some of these features may overlap temporally even if they are not being enacted at the same time (e.g., increased heart rate resulting from one emotion could remain while breathing has already slowed as a result of another emotion). This could create an emergent distinct physiological profile for a mixed emotion in the moment (Kreibig, Samson, & Gross, 2013). However, we doubt that an emergent unique pattern is a satisfactory explanation for mixed feelings. Mixes of truly opposite affective states (such as happiness and sadness) would likely be physiologically neutral in this circumstance, as the switch between opposite action programs would lead to largely cancelled-out autonomic changes.

Interoceptive Signals Resulting From Rapid Action Program Switches Produce a Unified Feeling Moment

The processes discussed so far have concerned ambivalent affect as a sequence of vacillating events across time. But the stark contrast between ambivalent affect and a typical instance of one affective state following another comes from the sense of simultaneity. The subjective experience of co-occurring emotions is a defining element of mixed feelings, regardless of the extent to which they are truly simultaneous. For ambivalence to be experienced, there must be representations of both emotions at some level of the nervous system, even though the respective emotional action programs may not be executed at the same time.

A region well situated to play a role in this process is the anterior insula. The insula receives information about the homeostatic state of the body from the brainstem nuclei, including the nucleus of the solitary track, and is known to be involved in conscious interoception (Critchley, Wiens, Rotshtein, Ohman, & Dolan, 2004). According to Craig (2009), the anterior insula assembles experiences of discrete moments in time to form a series of “global emotional experiences,” each of which integrates information from somatic states across a period of time (Wittmann, 2013). Although on average these moments represent ~125 ms of somatic states (Picard & Craig, 2009), the true length of each individual moment is variable in temporal length but limited by the amount of salient information it gathers. In other words, each discrete “global emotional moment” collects information from the body and “fills up” when its capacity has been reached. This can make time appear to go by faster or slower depending on how quickly these moments fill up. This phenomenon is observable in instances of emotional time dilation, in which affective experiences alter the subjective perception of time (Droit-Volet & Gil, 2009; Stetson, Fiesta, & Eagleman, 2007).

There is additional and more impressive evidence that the insula is important for the sense of time from the study of seizures with ecstatic auras, which in lesions of the anterior insula induce euphoria, a feeling of timelessness, and a feeling of heightened or “overloaded” consciousness (Gschwind & Picard, 2016; Picard & Craig, 2009; Picard & Kurth, 2014). Thus, the anterior insula’s buffered representation of states allows for the integration and comparison of affective information across time. Indeed, insular activity connected with the integration of rapidly changing emotions appears to be associated with processing ambivalence (Critchley, Elliott, Mathias, & Dolan, 2000; Szabó et al., 2017; Wilson-Mendenhall, Barrett, & Barsalou, 2014). The emotional reappraisals involved in ambivalent affect may be in rapid enough succession to be integrated within the same emotional moment, and thus people experience both emotions as a unique and integrated emotional feeling (Fig. 1).

Further cognitive elaboration of this moment may occur outside the insula. Just as the posterior insula projects current information about bodily states to the anterior insula for processing into a summated moment, the anterior insula projects to other brain regions where the contextual relevance and the valences of these moments can be considered. With ambivalent affect, afferent pathways to the orbitofrontal cortex (OFC) and anterior cingulate cortex (ACC) possibly contribute to this process, and the summated moment may be evaluated as a source of conflicting affective information (Medford & Critchley, 2010; Roy, Shohamy, & Wager, 2012; Rushworth & Behrens, 2008; Seth, Suzuki, & Critchley, 2012; Sutherland, Carroll, Salmeron, Ross, & Stein, 2013; White, Joseph, Francis, & Liddle, 2010).

Ambivalent Affect Relies on Memory and Reappraisal Processes

It is no coincidence that many ambivalent affective states such as nostalgia, longing, and Sehnsucht are driven largely by memories and the feelings associated with them (Oba, Noriuchi, Atomi, Moriguchi, & Kikuchi, 2016; Scheibe & Freund, 2008; van Tilburg, Bruder, Wildschut, Sedikides, & Goritz, 2018). Many ambivalent affects such as nostalgia and longing involve the recall of specific memories of positive or negative valence followed by counterfactual thinking leading to reappraisal of the recalled contents (Epstude & Roese, 2008; van Tilburg et al., 2018). This is especially likely with the recall of events or individuals that currently are perceived as psychologically or temporally distant and, in many instances, permanently so (Farrell, 2006; Scheibe, Freund, & Baltes, 2007).

Evidence for the importance of memory’s active role in the affective experience of nostalgia has been demonstrated in research using functional MRI, in which nostalgic images, compared with visually and conceptually similar images, evoked increased and sustained coactivation of the hippocampus and ventral striatum (Oba et al., 2016). From this perspective, the memory first confers a primarily positive emotion, but a rapid reappraisal reveals that the topic should also trigger a negative emotion. Once this happens, the emotions begin to vacillate rapidly because of the presence of both the image of the initial stimuli and its reappraisal both being cortically present; one image does not “delete” the other—at this level, it just becomes more prominent in an ebb and flow. Possible evidence of this is seen in a study aiming to cluster various affective states by their subjective and neural similarities. Using hierarchical clustering analysis of whole-brain neural patterns and of experiential traits for 15 different categories of affect, it was found that longing was the only category of affect to be clustered with positive affect neurally but with negative affect in terms of experience (Saarimaki et al., 2018). Note that a multivariate pattern analysis of this same neural data was unable to distinguish longing from other affective states. Along with shame, longing was one of only two states—among 15—that could not be successfully distinguished from the others at an above-chance level. It is possible that the neural representations of this state may have an uncommonly high amount of temporal fluctuations because of the ebb and flow of continuous reappraisals. Accordingly, we could hypothesize that a construct such as regional homogeneity, which measures the similarity between the time series of voxels and their nearest neighbors, would be decreased during ambivalent states. Such evidence is in fact available for bittersweet feelings in a study of lovelorn individuals. The data reveal decreased regional homogeneity of the anterior cingulate cortex associated with the length of time spent in love (Song et al., 2015).

Conflict Is Critical to the Function of Ambivalent Affect

The perception of conflict may be a crucial element in the unique experience of ambivalent affective states, distinguishing them from a simple sum of two simultaneous experiences (Berrios, Totterdell, & Kellett, 2015; Mejia & Hooker, 2017; Schulte, Maderwald, Kraemer, & Brand, 2012). Insula and OFC projections to lateral prefrontal and anterior cingulate regions likely contribute to the experience of conflict. A unique subregion of the OFC, which is known for responding to affective conflict compared with either positivity or negativity (Becker et al., 2014; Schulte et al., 2012; Simmons, Stein, Matthews, Feinstein, & Paulus, 2006), has been found to be similarly responsive to bittersweetness (Schulte et al., 2012) and longing (Saarimaki et al., 2018; for t-map, see Saarimaki, 2018). This suggests that conflict turns these states into more than the positive and negative sums of their parts. Whereas the OFC is suited for representing multiple features of an affective state, the regions to which it projects are instead optimized for the more conclusive evaluations involved in carrying out decisions (Rolls & Grabenhorst, 2008). It is in these regions, the ACC, the dorsolateral prefrontal cortex (PFC), and the anterior PFC, that upcoming decisions are considered and the degree of uncertainty surrounding the action is weighed (Hsu, Bhatt, Adolphs, Tranel, & Camerer, 2005; Luttrell, Stillman, Hasinski, & Cunningham, 2016; Nohlen, van Harreveld, Rotteveel, Lelieveld, & Crone, 2014; Stolyarova, 2018; Vaccaro & Fleming, 2018). Activity in the ACC has been shown to relate to feelings of ambivalence and conflict (Cunningham, Raye, & Johnson, 2004; Nohlen et al., 2014; Preckel, Scheele, Eckstein, Maier, & Hurlemann, 2014; Saunders, Lin, Milyavskaya, & Inzlicht, 2017).

The conflict within ambivalent affect allows people to be motivated not only by what is present but also by representations of what could be (Fong, 2006; Rothman, 2011; Seth et al., 2012). As a result of counterfactual thinking or even mere recall, people often think of noncurrent scenarios about which they may feel different compared with the current scenario; this happens often with nostalgia, longing, and Sehnsucht. As this occurs, nostalgia, longing, and Sehnsucht lead people to adapt their decision-making in ways that they probably would not if they had solely experienced negative affect.

For example, ambivalent affect has been found to be beneficial in working toward social, economic, and health-related goals, in which the actions required for progress may cause negative feelings but in the long-term will lead to positive feelings (Fredrickson & Branigan, 2005; Garland et al., 2010; Hershfield, Scheibe, Sims, & Carstensen, 2013; Scheibe & Freund, 2008). Being able to represent such future positive feelings motivates people to continue with the actions that are necessary to obtain the goal despite their negative feeling. Along these lines, ambivalent affect can also provide a sense of comfort, promoting both psychological and physiological resilience in the face of negative mood or the traumatic elements of memories (Braniecka, Trzebinska, Dowgiert, & Wytykowska, 2014; Larsen, Hemenover, Norris, & Cacioppo, 2003). This effect that has been well documented for nostalgia (Matsunaga et al., 2013; Newman, Sachs, Stone, & Schwarz, 2020; Routledge, Wildschut, Sedikides, & Juhl, 2013; Zhou, Sedikides, Wildschut, & Gao, 2008; Zhou, Wildschut, Sedikides, Chen, & Vingerhoets, 2012). Interestingly and consistently, nostalgia and Sehnsucht/longing are elicited primarily during negative moods and as a response to negative emotional states (Kotter-Grühn, Wiest, Zurek, & Scheibe, 2009; Sedikides, Wildschut, Arndt, & Routledge, 2008; Wildschut, Sedikides, Arndt, & Routledge, 2006). Although only limited work has been done on these topics, the current research on nostalgia supports these interpretations, as it consistently shows links between trait-level susceptibility to negative affect, susceptibility to nostalgia, and the neurobiological correlates of affect representation and memory (F. S. Barrett & Janata, 2016; Luo et al., 2019; Oba et al., 2016; Trost, Ethofer, Zentner, & Vuilleumier, 2012).

The behavior-expanding nature of ambivalent affect is not always beneficial. In instances of longing and Sehnsucht in which the desire is definitively unobtainable, the feeling is more pervasive and associated with lowered perceived well-being (Kotter-Gruhn, Scheibe, Blanchard-Fields, & Baltes, 2009; Scheibe et al., 2011). This same effect can also occur in nostalgia when it represents a strong, undesired change in self-identity or the current state of being (Iyer & Jetten, 2011). Nostalgia itself was considered a serious psychiatric condition in centuries past—a malady bearing someone’s overattachment to what was once loved and an inability to adapt to a new environment, eventually leading to “catatonia” and sometimes death (Rosen, 2009; Roth, 1991). Although nostalgia is no longer classified as a psychiatric disorder, elements of prolonged ambivalent affect may also relate to varied psychopathologies such as posttraumatic stress disorder, obsessive-compulsion disorder, depression, and addiction (Bhar & Kyrios, 2007; Jerg-Bretzke, Walter, Limbrecht-Ecklundt, & Traue, 2013; Losada et al., 2018; Veilleux et al., 2013; Verplanken, 2012). Still, ambivalence is not purely negative in the clinical setting. There is some evidence that deficits related to affective intelligence, such as alexithymia and reduced perspective taking, are associated with less awareness of ambivalent feelings in the self and others for various populations (Albano, Piccardi, Pizzamiglio, Volpe, & D’Amico, 2013; Beck, Kumschick, Eid, & Klann-Delius, 2012; Bird & Cook, 2013; O’Kearney, Salmon, Liwag, Fortune, & Dawel, 2017; Schultz, Izard, & Abe, 2005).

Furthermore, whereas nondialectical thinkers tend to exhibit ambivalent affect during primarily positive life events compared with primarily negative ones, dialectical thinkers exhibit ambivalent affect equally during both positive and negative life events (Hui, Fok, & Bond, 2009; Miyamoto et al., 2010). These findings show that ambivalent affect represents a marker of complexity in affect representation and interpretation, especially when considered developmentally (Albanese, De Stasio, Di Chiacchio, Fiorilli, & Pons, 2010; Schultz et al., 2005; Steele, Steele, Croft, & Fonagy, 1999; Zajdel et al., 2013). Finally, increased experiences of ambivalent affective states are also associated with psychotherapy-induced improvements, demonstrating their complicated relationship with temporal change (Adler & Hershfield, 2012).

Future Directions

Ambivalent affective experiences may well remind people of why they have conscious affect in the first place. Standard affective experiences guide people’s decision-making in an advantageous manner, one likely reason why affect was selected in evolution (Damasio, 2018; Denton et al., 2009). But ambivalent affective experiences appear to have their own advantages. The bittersweet affects discussed earlier are valuable because they counter the disadvantages that standard affective experiences can produce in a complex social world. On occasion, it is advantageous to decide against or ignore immediate feelings. Given how important affect is in motivating decisions, the especially nuanced representations that ambivalent affect allow would be an asset.

Although ambivalent affective experiences appear to be universal, the culturally specific variants are evidence for conceptual fine tuning leading to divergent and culturally novel feelings (Lomas, 2017; Perlovsky, 2009). For example, evidence shows that semantic word categories influence the neural representation and experience of affect; the presence or existence of a word to label an affective experience shapes that experience as a more consistent entity within its category (Brooks et al., 2017). But there is no reason to assume that language is the only type of conceptual information that can contribute to the shaping of novel affective experiences. Sociocultural and technological shifts in how people interact with the world lead to new feelings that, once labeled, converge conceptually. Furthermore, the process by which people cognitively embody and integrate homeostatic signals into feelings is strongly influenced by psychosocial development during childhood and even infancy (Fotopoulou & Tsakiris, 2017; Seth & Friston, 2016). Given how dependent ambivalent affect is on the affective-interoceptive processes people develop during childhood, the experience of these states is likely to be highly influenced by upbringing (Lane & Schwartz, 1987).

Affective neuroscience has devoted well-deserved attention to how core affect manifests and influences people’s behavior. Nonetheless, in an ambiguous world, people also need to understand the more complex and nuanced feelings that are often at odds in situations that society paints as binary, such as the nostalgia for a relationship that has since finished or for certain political and moral issues. The cultural ideals of decisiveness and definitiveness should not force people to simplify feelings. When does having something to miss or to long for help people persevere or else compromise their functional capacity? How does a feeling of longing form when what people long for is unclear or abstract? When does the triggering of nostalgia help everyone cope with a changing unfamiliar world, and when does it bias the reconsolidation of memories and future decision-making in maladaptive ways? Affective neuroscience can help researchers explore these clinical and fundamental questions.

The study of ambivalent feelings can also answer important questions about the general science of affect, for example, whether positive and negative valence are represented neurally as part of a unidimensional construct or as two separate dimensions, how affective states should be contrasted or classified, whether there must be a distinct word for feeling distinct experiences, and whether some affects are more basic or complex than others. Ambivalent feelings are more difficult to characterize on an objective basis than the plain variety. Still, the fact that they constitute a significant aspect of people’s affective life warrants their investigation as affective neuroscience moves closer to being a science of the human experience.

Footnotes

Transparency

Action Editor: Aina Puce

Editor: Laura A. King

ORCID iD

Anthony G. Vaccaro

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