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Discrete versus dimensional models of emotion?

Eliza Bliss-Moreau
Eliza Bliss-Moreau

Over the last number of months as an Associate Editor at Emotion, as well as a reader of the literature, I have seen an increasing number of scholars refer to “discrete emotion models” and pit them against “dimensional emotion models” in order to set up a primary hypothesis and its alternative.  This is a false dichotomy.  My challenge as an editor is that I have not been able to find a singular “quick read” piece of writing in the literature articulating why a discrete versus dimensional contrast doesn’t make sense (although there are longer papers on this that do make this point such as this, this, this, and this – if you know of others that are near and dear to you, send them my way).  I did a quick – entirely nonscientific – review of papers with the keyword “emotion” and “discrete or dimension or dimensional” published in 2017 and 2018 and there is some evidence that this is a problem in the published literature as well.  My first take was “I should write a manuscript about this”, and I may, ultimately. My goal here, however, is not to call people out for this analytical problem per se but to provide an explanation as to why pitting discrete emotion models against dimensional emotion models is logically problematic, so that folks can fix it if it is in their writing (or thinking) or not make it in the first place. I don’t see any way around that goal if I were to undertake writing a manuscript which would require appropriate scholarly referencing.  So, writing a blog post seemed like a good option.

The problem
There are lots of theories and models of emotion that focus on discrete emotions – how they come to be, their outputs, their functions, and so on.   They vary widely in their hypotheses about all of those features of emotion. But there is no dimensional theory of emotion.  Dimensions  – typically valence and arousal –  are characteristic of affect [i], not emotion.  According to a number of the major theories in our field, affect is thought either to be the causal foundation of emotion or one of the most important components of emotion.  Saying that affect is a causal foundation or critical component of emotion is very different, however, from saying that affect is emotion – and so, theories of emotions which recognize differences between affect and emotion are not reductionist about emotions.  According to these theories, whatever else emotion is, it is something “more” than just affect. It is therefore a mistake to talk about theories of emotions as if they are dimensional.  As a result, there is no way to pit “discrete emotion models” against “dimensional emotion models” because a) there is no dimensional emotion model, only dimensional affect models and b) emotion theories that hypothesize that multiple dimensions of affect underlie emotions in some way or another frequently hold that these emotions can be separated into distinct types and kinds, and therefore are, metaphysically speaking, discrete entities.

The background
It goes without saying that there are many different theoretical and methodological approaches to the study of emotion. Over the last decade or so, two types of theories have dominated discussion and study (despite both being around for much longer) – what we call the Classic View of Emotion (CVE) [ii] and Theories of Constructed Emotion (TCEs).  I use this terminology with very specific intentions, not just as shorthand labeling to differentiate my writing from that of other scholars.

The CVE says that emotions are precipitated by events and then produce a stereotypical set of outputs in the face, voice, autonomic/peripheral nervous system, behavior, and, or brain.  There is a predictable mapping between the types of events that cause emotions and specific emotions. Further, each emotion is thought to have some sort of specific pattern of physiological and behavioral outputs. Because of this, to understand the emotion state of another individual, an observer (who could be the self) can “read” the outputs and, because the relationship between the outputs at the emotion causing them is mapped, infer the identity of the emotion causes the relevant outputs.

The interesting unit of analysis from the CVE can be at any step of the process – the event that causes the emotions, the process by which the effects of the event are translated into the emotion, the phenomenological experience of the emotion, the process by which the emotion generates to the outputs, the type of outputs generated by the emotions.  CVEs stipulate that some special set of, or number of, emotions cannot be reduced to more fundamental or basic parts. This belief is reflected in the moniker of one type of CVE – “basic” emotion theory.

“Basic” emotion theories typically stipulate that a small set of emotions (e.g., 5 or 6) are unique kinds.  This means that they are held by the theory to be fundamental or basic [iii], irreducible, and have a modular neurobiological architecture [iv].  These theories sometimes stipulate that more “complex” emotions (e.g., guilt) may be built via combinations of basic emotions, but even those more emotions must follow the event–>emotion–>output schema according to this theory (a view articulated here, for example). Basic emotion theories argue that relationships between events, emotions, and outputs is biologically hardwired and evolutionarily conserved; these assumptions have guided investigation into the neurobiological basis of emotion (e.g., in nonhuman animals, and in humans) and evolutionary emergence of emotion (for example).

Basic emotion theory is arguably the dominant theory that embodies a CVE, but it is not the only theory, hence my use of “CVE” and not “Basic Emotion Theory” (or something similar) to name this perspective.  For example, most appraisal theories embrace a CVE insofar as they evaluate the specific pattern of cognition (called appraisals) that people make following events that lead to emotion – that is the process by which the event translates to emotions.

CVEs do say there are discrete emotions, whether they stipulate that a small set of emotions is biologically basic and hardwired or focus on the process by which an event precipitates an emotion or even the numbers of discrete emotions that exist.  The unit of analysis is typically specific, discrete emotions and these emotions are thought to be the source of the lion’s share of variance in outputs.  These are the theories, I believe, that scholars think they are referring to when they discuss “discrete emotion models” because of their emphasis on specific emotions (like happiness, sadness, fear, disgust, elation, and so on). Further, CVEs do not typically discuss or evaluate the importance of valence and arousal – the dimensions of affect.

Valence and arousal are the dimensions of affect, which, according to TCEs forms the basis of discrete emotions.  TCEs stipulate that emotions are not hardwired modules. Instead, TCEs say that each emotion is a causal by-product of a complex interaction of more basic parts, and that these parts can vary dramatically depending on age, behavioral context, cultural context, conceptual knowledge, and any number of other important physiological and cognitive factors [v].  Nevertheless, TCEs still recognize that emotions are discrete things. TCEs differ to some degree in the ingredients that they think are critical for the emergence of discrete emotions – hence Theories of Constructed Emotion and not Theory of Constructed Emotion.  But all TCEs hold that affect is a critical ingredient.

Affect is a state that is characterized by some degree of valence (hedonics, pleasantness to unpleasantness) and arousal (physiological activation) and can, but need not be, felt consciously.  People can report on their affect (“I feel good” or “I feel bad”) or, people can report on their emotions and affective information can be extracted from those reports (e.g., one characteristic of happiness is a good or pleasant feeling). That is, affect can be organized according to dimensions (valence and arousal). That is the case because discrete emotions are organized in a systematic way with regards to valence and arousal.  Happiness?  Positive valence, just slightly activated/aroused.  Depression?  Negative valence, very deactivated.  Fear, anger, disgust?  Very negative, very activated/aroused, and so on.

TCEs say that affect is an essential component of emotion, but they do not say that affect is emotion – and so they do not reduce emotion to affect. According to TCEs, a discrete emotion has affective components, but the affective states that are components of emotions are not alone sufficient to determine the identity of the emotion of which they are part. For example, there are a slew of negative, high arousal emotions which share a negative, high arousal affective state but are not the same emotion – think anxiety, disgust, anger, and fear.  The same affective state can thus be part of a number of discrete emotions depending on the context, what the person knows about emotion, past experiences, the language the person speaks, social norms, and so on.  As a result, it does not follow to say that emotions, according to TCEs, are (or can be described by) dimensions. Scholars guided by TCEs, just like those guided by CVEs, study discrete emotions – but they may be equally likely to study the various other ingredients that go into cooking up emotions, including affect.

Why does the distinction between discrete emotions and the dimensions of affect matter?
It is important to be clear about whether we are testing hypotheses about emotions (which nearly everyone agrees are discrete entities) or testing hypotheses about affect (which everyone agrees can be analyzed as falling into at least two continuous but bounded dimensions), or testing hypotheses about some combination of the two–for example, when we ask whether (discrete) emotions or (degrees of the dimensions of) affect capture more of the variance in a given situation. Keeping this distinction in mind can help us develop strong, testable hypotheses about the nature of emotion.

For example, the goal of my lab is to understand some of the biological mechanisms that generate the emotions – and we do that work largely in nonhuman animals.  While there is huge debate about the nature of nonhuman animal emotions, I have argued that affect is species nomothetic – at least in mammals who share a similar central-to-peripheral nervous system structure.  If this is the case, and if a given behavioral or physiological phenomenon is driven by affect and not discrete emotions, then we can hypothesize that it has a homolog in nonhuman animals.

Another issue in the nonhuman animal literature that appears regularly is that scientists will make strong claims about animals’ abilities to perceive emotion stimuli when they are actually testing an affect hypothesis.  For example, in a recent study, when goats were shown pictures of human faces generating behaviors typically associated with anger and those typically associated with happiness, goats spent more time investigating the “happy faces”.   The take home message, amplified by the media, was that a) goats understand human emotions or “goats can read human emotions” and b) “goats prefer happy people”.  That may very well be true, but given the experiment as conducted, there’s actually no way to determine whether goats prefer happy people or simply pleasant, neutral arousal people compared to negative, high arousal people.   It’s entirely possible that when a happy face was compared to a serene face, goats might opt for serenity.  If this was the case, one starts to build an argument that their choice has nothing to do with valence at all (let alone emotion), but rather arousal – lower arousal faces might be favored.

The hope
What CVE and TCE theorists, as well as scientists studying discrete emotions and the dimensions of affect, all have in common is the goal of understanding the mechanisms that generate and subserve emotions. My hope is that remaining clear about the difference between a hypothesis that is about discrete emotions versus a hypothesis that is about the dimensions of affect will speed those discoveries.

 

 

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[i] Thus, there is a dimensional theory of affect.  Valence and arousal aren’t the only dimensions that have been proposed to organize affect, but they are the dimensions that consistently appear in analyses of self-reports of emotion experience and judgements of emotion stimuli.  Jim Russell’s 1980 paper is a classic on this .  Here’s a resource of a broader discussion of affect.  And here’s a recent paper which proposed additional dimensions of affect.

[ii] As far as I know this labeling originated with Lisa Barrett and a version of it (the Classical View) is used throughout her book, How Emotions Are Made.

[iii] For examples of modern articulations of basic emotion theory see: here, here, here, here, and here.

[iv] There are lots of ways that a phenomenon can be modular, for example if the same stimulus or event produces a single emotion, then that Stimulus-Response link is modular.  When framed as a neuroscience argument, modularity has typically been interpreted as their being discrete neural and biological circuity for each emotions – such that emotions have, as Lisa Barrett calls them in here book, “fingerprints” in the brain (as well as voice, face, etc.).

[v] For a historical review of Theories of Constructed Emotion.  For an edited volume on Theories of Constructed Emotion (note that many of the chapters appear to be accessible on the authors’ websites).

We Are Not Born Alone

Tom Hollenstein
Tom Hollenstein

Relationships are good for us. For years, correlational study after correlational study has reported better health and mental health, longer life, less stress and negative emotions, and more happiness and positive emotions for those with good relationships compared to those with poor and/or few relationships.

As an example, consider an upcoming deadline at work that you worry you will not be able to meet, potentially resulting in dire consequences for your company and/or your job. Anxiety. Stress. The better you are able to manage that anxiety, the more likely you are to be able to focus and complete the task. If you are alone, both at home and at work, then the regulation of this stress is all on you. If you have good relationships both at work and at home, there are people to support you, encourage you, and help you feel less anxious.

How does this work?

The prevailing explanation is that relationships add benefits to individuals. Our default, or baseline, is as a solitary individual. This solitary baseline can then be enhanced by close relationships. Have one good relationship? That’s great. Have two? That’s even better. Have great relationships at home, work, and in the community? That’s the best. Let’s call this the Law of Added Positives: psychologically and biologically, good relationships provide extra positives to minimize individuals’ negatives.

However, according to Social Baseline Theory, based on evolution, neuroscience, and emotion advanced by James Coan and colleagues, the Law of Added Positives is not the way things work. In fact, they seem to work in reverse.

For millions of years, humans have been born into environments that included other people. Life begins with strong physical attachments to a mother that become5621007786_aa441a3deb_o strong emotional attachments to her and a group of (often related) others. Those that bonded and worked together for common solutions thrived; those that fought and worked against each other did not. An isolated individual was and remains an anomaly, someone unlikely to have the resources – resources that are as much psychological (e.g., emotional) and biological (e.g., neurological) as material. (e.g., food) – to survive and reproduce.

That is, our baseline or default circumstance is social.

Human biological systems evolved for – and now expect – a social environment where existential risk is distributed (i.e., safety in numbers) and survival efforts are shared. Fight the bear by yourself and you will expend a lot of energy and are less likely to survive; be one of a group fighting off the attacking bear, each individual using less energy with a greater likelihood that you survive. Less energy and greater chance of survival – that is what evolution is all about.

So how does this translate to modern day humans and the relationships-health connection? First consider some preliminary evidence provided by Proffitt and colleagues.

  1. Perception of effort is biased by energy cost/benefit. People perceive hills as steeper and distances as farther away when they are wearing a heavy backpack compared to when they are not. This is taken as evidence that neurobiological systems automatically adjust the perception of difficulty based on the energy required.
  2. Social proximity reduces perception of energy costs. If your friend is standing next to you with a heavy backpack, you will perceive the hill as less steep and the distance as not as far. Just being near someone else lightens the load.
  3. The closer the relationship, the greater the effect. It is not merely the presence of any other human being that indicates load sharing. Your best friend has a bigger effect on your perception of incline and distance than a new acquaintance.

So, if you’re facing that deadline at work alone, it may make the task seem more difficult and less possible.

Coan and colleagues developed Social Baseline Theory based on this and other evidence but tested it more directly, by looking at threat processing in the brain. They conducted a hand-holding fMRI study with three conditions: no hand holding, holding the hand of a stranger, and holding the hand of their partner. Participants received a mild ankle shock on 20% of trials in which they saw a threat cue on a screen. Threat-related brain activity was greatest in the alone condition, less in the stranger condition, and the least in the partner condition. Like the backpack studies, those with the least amount of threat-related brain activity had the highest quality relationships with their hand-holder. Other studies have shown this effect as well.

Instead of relationships adding some extra positives, as the Law of Added Positives would assume, those with the most load sharing were the most efficient at processing threat, requiring the least energy. As social connection and therefore load sharing, diminished, more energy for neural activation was required to deal with the threat. Maybe the law is one of Added Negatives.

Perhaps the greatest implication of Social Baseline Theory is the way that we conduct psychological, especially emotional, research. In an effort to minimize extraneous variables, much of what we have come to understand about human thoughts and feelings and behavior has come from experimental isolation – a single human alone in a room in front of a computer. The assumption has been that the individual is the fundamental unit of analysis and when we include other people it is to enhance or diminish whatever capacities were witnessed in isolation. Perhaps what we have revealed is human functioning at its least efficient, most taxing, and least natural.

Photo credit: https://flic.kr/p/9yH8Mm Shared via a Creative Commons license.

Narrowing the Achievement Gap with Social-Emotional Skills

Sherri Widen
Sherri Widen

By the time of kindergarten entry there is an achievement gap between children from low income families and those from higher income families. This gap continues to grow as children progress through school – low income children are less likely to complete high school, attend college, or find well-paying jobs. An important component of school-readiness is how well children are able to successfully navigate social and emotional situations. Social-emotional skills, for example, help children (and adults) get along with others and focus on tasks. The question is: How can we narrow the achievement gap between low- and higher-income children?

One factor that influences educational disparities is differences in family income level and children’s early learning opportunities at home. Indeed, by four years of age, children in low-income families have heard about 30 million fewer words than wealthier children. Such gaps are troubling given the strong links between early home environments and children’s development of social, emotional, literacy, and numeracy skills, which are critical for later academic success.

The story is not just about how economic resources shape cognitive learning – children’s early acquisition of social and emotional skills also creates meaningful differences in long-term success. Children who enter kindergarten with poor social-emotional skills have more difficulty forming and maintaining friendships, more behavior problems, and lower levels of academic achievement. Emotion regulation and self-regulation skills contribute to a variety of other skills that help children succeed in school including following directions, maintaining focus on a task, engaging in classroom activities, and working independently – skills that affect self-confidence, peer relationships, and coping with stress, which in turn affect academic success. But there is hope. Social-emotional skills can be developed via strategic interventions, and children who start out at a disadvantage may be able to overcome learning gaps.

One promising parenting intervention is Ready4K. Ready4K leverages the power of text messaging – texting is nearly ubiquitous (especially among traditionally texting at breakfastunderserved families) and extremely inexpensive and easy to scale – to support parents and enhance the home learning environment. Each week, Ready4k sends text messages with information and activities related to school-readiness skills to parents of preschoolers. So as not to overwhelm parents, and in an effort to help them build new parenting “muscles,” the information is provided in bite-sized pieces and recommended activities take only a few minutes a day and build on existing family routines. Ready4K has already used text-messages to improve preschoolers’ early literacy skills. This year, for the first time, the program will include text messages to support preschoolers’ social-emotional skills. For instance, it encourages parents to increase their children’s self-confidence by letting their children make choices. As another example, the new messages promote perseverance in children by praising their efforts on a difficult task. The hope is that stronger social-emotional skills will provide a solid foundation for children’s future success in school. By harnessing the power of text messaging (which most people have already) to deliver useful information to parents, we hope to help parents to raise the next generation of socio-emotionally competent children and narrow the achievement gap.

Emotion News is back after summer hiatus

Kristen Lindquist
Kristen Lindquist

Emotion News took a bit of a summer vacation this year as our contributors submitted grants, wrote papers, collected new data, and availed themselves of some much needed R&R. Fortunately, while we were offline, emotions were still very much in the news. With the release of the Pixar movie Inside Out,  kids and parents everywhere were learning just how important understanding our emotions is to day to day life. Scientists also weighed in, both applauding and criticizing the movie for what they thought it got right and what it didn’t get right about emotions. We’re currently cultivating a series of future blog posts outlining how scientists differ in what they think emotions are, and why this matters. Stay tuned!

In the near term, we’re excited to bring you a whole new year’s worth of posts on the science of emotion. We look forward to hearing again from Daryl Cameron, Piercarlo Valdesolo, Lisa Williams, and Sherri Widen, as well as a new group of contributors who study the impact of emotions on decision making, in business, in health, and beyond. For instance, up next we will hear from Alex Shackman, who will share his research on the neurobiology of anxiety.

Readers, if you’d like to see a particular topic covered this year, please leave us a note in the comment section below.  Scientists, if you’d like to join us as a contributor, please email us and pitch a piece.  You can reach us at kristen.lindquist [at] unc [dot] edu and eblissmoreau [at] ucdavis [dot] edu.

Happy reading!

Kristen Lindquist & Eliza Bliss-Moreau