The Two Factor Theory of Emotion

Let’s begin with some basic cognitive science. The framework I’ll be leaning on throughout our investigation of artificial emotions is a well-known cognitive theory called the Two Factor Theory of Emotion, by psychologists Stanley Schachter and Jerome Singer. The theory states that in order for an emotion to be felt, two factors must be present:

• Physiological change: The person feels elevated heart rate, sweaty skin and other elements of physiological arousal.
• Cognitive label of the physiological change: Based off the context of the situation, the person assigns a label to the physiological change.

Simply put, when your body reacts physically to some stimuli and you mind assigns meaning to your physical state, you synthesize an emotional response.

An intriguing experiment

The Two Factor Theory of Emotion is certainly mildly intriguing as an analytic description of how emotion works, but it has a far more practical application in the realm of game design. In the process of proving their theories on emotion, researchers spent much of their effort on figuring out how to dissect the component aspects of emotion and reassemble them into new emotions of their choice. In effect, they figured out how to reconstitute artificial emotions within their subjects. Their experiments provide us with practical examples of how we might build our own systems of generating artificial emotion in our players.

It turns out that the physiological changes that accompany many emotions, such as fear and lust, are remarkably the same. There is a wide range of stimuli, including loud noises, intense memories or even a fear of heights that activate the sympathetic nervous system, prepping the body for action in the face of stress. Your heart rate elevates. Your palms become sweaty. Your alertness increases and body hair stands on end. Different stimuli, same response.

Due to the ambiguity of the physical response you rely on your brain to determine what all this activity actually means. Should your run, should you fight, should you laugh? In a heartbeat, you brain need to figure out what is happening and synthesize the correct response. In this moment, your carefully calibrated gray matter can be tricked.

One of the colorful experiments that demonstrate this effect was performed by psychologists Dutton and Aron in 1974. They wanted to see if they could alter the context of a situation so that the subject would instead experience lust instead of fear. In their study, a highly attractive young woman approached a sample of young men and asked them to fill out a survey. The experiment had two components.

• Inducing the appropriate physiological response: Two survey situations where tested. The first was a safe location on a trail. The second was the midpoint of a very narrow bridge overlooking a deep crevasse. The researchers knew that merely standing on the bridge elevated the heart rate and caused anxiety. Standing on the path induced no anxiety.
• Setting the desired cognitive label: At the end of the survey, the woman passed each young man her phone number and encouraged them to give her a call if they had any further questions.

Almost twice as many men (60%) gave the girl a call if they had been surveyed on the dangerous bridge than on the safe path. Due to the strong contextual signals in the form of presence of the attractive woman, the men misinterpreted the fear-driven activation of their sympathetic nervous system as authentic lust.

A potion for emotion

Other experiments validated the theory by inducing both happiness and anger in their subjects. These studies suggest the following general recipe for concocting artificial emotions.

• Inducing the appropriate physiological response: Put the player’s bodies in the appropriate physical state associated with the desired emotion through any means necessary.
• Setting the desired cognitive label: Provide strong contextual clues that make the user misinterpret the physical sensation as the designed emotion.

By evoking both states in the player, the mental and the physical, designers can greatly increase the likelihood that players will experience the desired emotional response to a game.

With our theory in hand, let’s look at the set of practical techniques that help us generate the artificial emotions at the heart of Bacchus.

Technique 1: Active recall of emotional memories

“Each word she utters shimmers on screen, merging with ghostly photos from her past. In a beat, the entire room witnesses her sorrow over the death of her mother, her time alone in an empty apartment, and her first kiss.”

In Bacchus, the player recalls intensely personal emotional moments as part of a public confession. It turns out that this is a great technique for evoking a both a physiological response and a set of cognitive labels.

Theory: When you experience an intense emotion, a primitive portion of the brain called the amygdala kicks in and ensures that you store a vivid, emotionally charged memory. When you recall the memory, your brain also ensures that you remember the emotional element.

Remembering an emotional event causes that you to re-experience that associated emotion.

• The recollection of an emotional memory triggers the recall of the emotions associated with the event.
• This in turn activates the physical reactions associated with that memory.
• You understand what the physical reactions mean in context of the memory and the labels you have assigned to the emotions within.
• You experience that emotion.

For example, when war veterans recall a traumatic experience, they often experience elevated heart rate, perspiration and other signs of panic. The memory of the veteran’s traumatic event triggers a replica of the physiological response that occurred during the event. The emotional panic they feel is very real, very physical and easily measured. Other extreme examples of this phenomenon include many phobias such as fear of small spaces, flying, etc., all of which are typically rooted in some traumatic experience.