last updated:

April 13, 2021

[Brain Image]    

PSY 340 Brain and Behavior

Class 27: What is an Emotion?


How would you answer the question below that psychologist Dacher Keltner (2019) poses to his classes?

“If you could flip a switch and shut off the experience of emotion,
all emotions, from that moment going forward, would you?”

                Models of Emotion

How can we define emotion? In the history of psychology, this has been a notoriously difficult concept to define. Consider how these three biological psychologists above each has a different approach.
  • Paul Ekman (University of California, San Francisco) claims emotions are basic innate biological states, universal across the human race, consisting of specific types (originally 6 in number, now 21) and displayed by facial expressions.
  • Joe LeDoux (NYU) differentiates between (1) unconscious biological circuits of the brain which are constantly monitoring the environment and warning when there may be some difficulty (e.g., there is a threat nearby) and (2) conscious processes of assessment of what those warnings may mean which leads to an actual emotion (e.g., fear)
  • Model of Constructed EmotionLisa Feldman Barrett (2017, Northeastern University) • Theory of Constructed Emotion
    • The brain's purpose = "to efficiently ensure resources for physiological systems within an animal's body (that is, its internal milieu) so that an animal can grow, survive, and reproduce" (p. 3)
    • How does the brain do this? "It runs an internal model of that body in the world" (p. 5) and doing so requires a great level of metabolic investment (20% of our total energy). It is costly to model the body in the world. That internal model of the body involves representations of and interpreting internal sensations (we call this our sense of "interoception").
    • The least costly way of modeling our world internally is to use predictive coding. Hence, the brain matches what it is experiencing to models it already has because of past experience of the world and is sensitive to any errors in what it predicts.
    • The brain "implements its internal model with 'concepts' that 'categorize' sensations to give them meaning. Predictions are concepts." (p. 7) "The brain continually constructs concepts and creates categories to identify what the sensory inputs are, infers a causal explanation for what caused them, and drives action plans for what to do about them. When the internal model creates an emotion concept, the eventual categorization results in an instance of emotion. (Barrett, 2017, p. 13)
    • Drawing a conclusion from these points, Barrett (2017) asserts that emotions are the concepts constructed by the brain as its best prediction about what is now happening to the person.

Despite their differences, most psychologists argue that an emotion comprises at least three different elements:

Walter B
              Cannon1. Emotions, Autonomic Nervous System Arousal, and the James-Lange Theory

So, how can we understand the ways in which the body and the emotions are connected?

Commonsense view:

[Emotions: Commonsense View]

James-Lange view:

[Emotions: James-Lange View]

Named for William James (1842-1910; American) & Carl Georg Lange (1834-1900; Danish)

A modern version of this theory says that emotions follow this pattern:

  • Event or stimulus which challenges you
  • Cognitive appraisal of the situation comes first
  • This leads to action (we including our bodies do something; the behavioral- response) and then
  • Emotional feeling follows after the action. Hence, an emotion is a kind of thought or conclusion.

BotoxA. Is physiological (ANS) arousal necessary for emotional feelings? The results are contradictory

B. Is physiological (ANS) arousal sufficient for emotions? Probably...in extreme cases

      [Facial Feedback
              Hypothesis Example]   Mobius syndrome

Bottom Line: The perception of the body's reactions may be somewhat important for us to interpret our feelings.

C. Is Emotion a Useful Concept?

Brain regions and emotions

2. Do People Have A Limited Number of Basic Emotions

Ekman emotions

Paul Ekman (see above) proposed that there are six basic, universal and distinct emotions: happiness, sadness, anger, fear, disgust, and surprise. His facial expression research showed that people worldwide would correctly identify one of these emotions when presented with a set of posed photographs about 58% of the time.

Other psychologists argue that Ekman's evidence is weak: what about the 42% incorrect responses? Or, people seeing more than one emotion in a single photograph? Or, the reality that we observe more of a person than their face alone?

An alternative approach might be to consider emotional feelings to fall on a continuum as dimensions, e.g., weak vs. strong; approach vs. avoid, etc. A version of this approach was proposed by Jeffrey Gray as noted below.

Jeffrey Gray's Reinforcement Sensitivity Theory

Rather than claim a limited number of distinct emotions, the British psychologist, Jeffrey Gray (1934-2004), proposed that the brain has three systems which are particularly sensitive to reward, threat, and punishment and they lie at the root of our experience of emotion. As we grow up and have so many different experiences in the world, these brain systems via classical and operant conditioning are able to very quickly evaluate and respond to the environment. They serve to prompt us toward doing (or not doing!) things.

Reinforcement Sensitivity Theory

Behavioral Approach System (BAS): involves (a) the mesolimbic system including the nucleus accumbens [dopamine-based] and (b) the left hemisphere (LH) frontal/temporal lobes and leads to low/moderate arousal of the ANS and a tendency to approach a situation in order to get a reward, i.e., happiness (when rewarded) or anger (when not rewarded).

Behavioral Inhibition System (BIS): involves (a) the amygdala and (b) the right hemisphere (LH) frontal/temporal lobes and leads to inhibition of activity and tendency to fear, anxiety, and disgust.

Fight-Flight-Freeze System (FFFS) is associated with the amygdala and its activation is associated with fear. In the next class, we'll look in more depth at the amygdala, particularly in light of Joseph LeDoux's research. Note that in many animals other than humans, the response to fear is to freeze in place and not move.

Positive Emotions: For many years, psychologists focused mostly upon negative emotions like sadness or anger. A major thrust of current research has to do with the nature and number of positive emotions (Shiota et al. 2017). What are these emotions? A listing of those being studied in recent years include amusement, awe, contentment, desire, ecstasy, gratitude, interest, joy, love, pride, relief, sympathy, & triumph (Keltner, 2019). Another proposed grouping by Shiota et al. (2017) suggests a "positive emotion family tree" that links important positive emotions to important reward-system neurotransmitters in the brain (Fig. 4, see below)


FredricksonBroaden-and-Build Theory of Positive Emotions of Barbara Fredrickson. One of the major figures in promoting this research has been Barbara Fredrickson who has argued for the last two decades that "positive emotions help us acquire long-term informational, social, and material resources that are important for survival" (Shiota et al., 2017, p. 618, emphasis added). As Fredrickson (2001) proposes in her "Broaden-and-Build Theory of Positive Emotions," some of the important contributions that these emotions as a group make to human well-being include

3. The Function of Emotions

   A. Moral Decisions and Emotions

[Trolley Car Dilemma]

You see a runaway trolley car rushing down the tracks and know that the trolley will kill five people walking along the tracks who don't realize it is headed their way. There is a switch in front of you which would immediately divert the trolley to a different set of tracks. However, there is a man walking on those tracks who would be killed if you threw the switch.

What do you do?


From a footbridge above the tracks, you see a runaway trolley car rushing toward five people walking along the tracks who don't realize it is headed their way. They will be killed if the trolley doesn't stop. But, there is a man near you on the bridge. If you push him off the bridge, he will topple onto the tracks, be killed, but stop the trolley. You have to decide whether to push him and save the five people or not push him and watch them die.

What do you do?

Our text also proposed two other scenarios

The Lifeboat Dilemma: If you and 5 other people are in a lifeboat that is beginning to sink, would you consider throwing one person off the lifeboat in order to save yourself and the other 3 people who remain?

The Hospital Dilemma: A surgeon has 5 patients dying because they are missing organ transplants. Each patient needs a different organ. You haven't been able to find any donors. Then, you get word that there is a person visiting the hospital who has the required tissue type needed by each of your 5 patients. Do you kill the hospital visitor to save your 5 patients?

Most people are open to throwing the switch in the Trolley Dilemma and a few are willing to sacrifice the one person in the Footbridge and Lifeboat Dilemmas. But no one would kill the hospital visitor in the Hospital Dilemma.

Although one person is sacrificed in each case in order to save more people, moral decisions based on these examples create strong emotional arousal, especially if it involves actually touching another person to kill them. Indeed, the stronger the level of autonomic arousal, the less likely people are to kill anyone. Hence, we may conclude that decision-making is not purely a "logical" process.

Joshua G[Emotional Activation in the Brain]reen (Harvard University) and his colleagues (2001) found that, when we make decisions, we activate different brain areas if the decision is laden with emotion. The areas associated with increased emotionality (see diagram) include the

  • Cingulate gyrus
  • Angular gyrus
  • Medial frontal gyrus
   B. Brain Damage, Emotions, and Decision-making

For many centuries it was believed that there was an utter separation between rational intellectual decision making on the one hand and irrational emotional responsiveness on the other hand. As Keltner (2019) reflects, "Fifty years ago it was axiomatic to assume that emotions are disruptive forces that undermine higher forms of reason" (p. 3). Then, a large number of research studies examined how reasoning and emotions affect each other. A particularly important area of study was the impact of brain damage on the abilities of individuals to make good decisions. What did this research find?

Individuals with brain damage affecting their emotions make very poor decisions (Antonio Damasio)

Case #1: Man with prefrontal cortex damage
Case #2: Young adults who suffered injury to prefrontal cortex in infancy.

Keltner (2019) summarizes what psychologists and others have understood about the impact of emotions: ""today it is widespread to recognize the wisdom of the emotions, and how they shape thought in deeply rational ways " (p. 3, emphasis added)



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Barrett, L. F. (2020). Seven and a half lessons about the brain. Boston, MA: Houghton Mifflin Harcourt

Beck, J. (2015, Feb. 24). Hard feelings: Science's struggle to define emotions. The Atlantic. Retrieved from https://www.theatlantic.com/health/archive/2015/02/hard-feelings-sciences-struggle-to-define-emotions/385711/

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This page was first posted April 5, 2005.