Laughter and the Brain

Introduction to PsychologyJanuary 2013

D. Bambic

LAUGHTER: THE UNIVERSAL LANGUAGE

Ancient Roots

Abraham called the name of his son who was born to him, whom Sarah bore him: Isaac (i.e. ‘he laughs’) … and Sarah said, ‘God has made laughter for me; everyone who hears will laugh over me’.

Genesis 21:3 and 6

Resistant to Analysis

Analysing humour is like dissecting a frog.

Few people are interested and the frog dies

of it.

E. B. White

(Elements of Style by Strunk and White)

What’s so funny?

Have you ever wondered why we laugh? What happens in our body and brain when

we laugh? Can we control laughter? Why do they say “laughter is the best

medicine”?

This presentation will answer these questions and examine the pleasure/reward brain circuitry in the act of laughing.

More Than Humour

Laughter is not the same thing as humour.

It is triggered by sensations (hearing other people laugh, being tickled), thoughts and social cues.

Laughter is the body’s involuntary and unconscious response to humour (and so it includes a subjective appreciation of the humorous situation or stimulus).

Evolutionary Advantages

Charles Darwin in his 1872 Book, Expression of Emotions in Man and Animals, wrote…

“the evolutionary basis of laughter was its function as a social expression of happiness, and that this rendered a cohesive survival advantage to the group.”

cited: Neural Correlates of Laughter and Humour in Brain: A Journal of Neurology

More than Humans

We know that apes, chimps, dogs and event rats “laugh” when they play and when tickled.

Animal Laughter

Laughing Rats – Not Only Tickles

50 kHz Ultrasonic Vocalization – chirps

Laugh in anticipation of rewards, nervousness, to diffuse aggressive situations, display social bonding.

Laughing rats…higher social status.

Jaak Pankseep YouTube video

Laughing Rats are Optimistic

Trained to press ‘positive’ lever (2,000 Hz + sucrose) and ‘negative’ lever (9,000 Hz + avoidance of shock)

Introduction of ambiguous sound (5,000 Hz)

Potential risk, danger

Rats who laughed when tickled demonstrated more optimistic behaviour = pressed the positive lever during ambiguous sound

Study on how emotions bias decisions

Laughing Before Speaking

Responsive smiling after 5 weeks

Begins around 3-4 months

Deep-seated brain function

Hearty laughter despite minimal language acquisition

Evolutionary purpose: social bonding with caregiver

Gestures and Sounds

Fifteen different facial muscles come into play

The larynx half closes, creating the irregular air intake or the characteristic sound of (gasping) laughter.

Tear ducts can be activated and the person can appear to be gasping for air. Patrick J. Lynch,

medical illustrator - Wikimedia

The structure of laughter Linguists = laughter is like punctuation

because it usually occurs at the end of phrases or during pauses.

Analysis shows that it is very regular in its sound waves, not like speech.

Neurobiologist Robert Provine: sonic structure of laughter consists of variations on a basic form of short, vowel-like notes repeated every 210 milliseconds.

Ha-ha-ha OR ho-h0-ho but not both types

Laughter as a Social Activity

The average person laughs approximately 17 times per day.

We are 30 times more likely to laugh in a social situation than by ourselves.

Laughter is an effective way to control group behaviour. Think of how it is used to diffuse tempers and shift the emotional climate of a situation.

Laughter strengthens relationships. Dominant individuals use laughter more

than their subordinates.

Gelotology: the study of the brain laughing!

Electroencephalograph (EEG) measures brain activity and researchers saw that the brain produces a regular electrical pattern. Within four-tenths of a second of exposure to something potentially funny, an electrical wave moved through the cerebral cortex, the largest part of the brain. If the wave took a negative charge, laughter resulted. If it maintained a positive charge, no response was given.

What Happens in the Brain

The left side of the cortex (the layer of cells that covers the entire surface of the forebrain) analyzed the words and structure of the joke.

By Camazine from Wikimedia

What Happens in the Brain

By Camazine from Wikimedia

The brain's large frontal lobe, which is involved in social emotional responses, became very active. The right hemisphere of the cortex carried out the intellectual analysis required to "get" the joke.

What Happens in the Brain

Brainwave activity then spread to the sensory processing area of the occipital lobe (the area on the back of the head that contains the cells that process visual signals).

Stimulation of the motor sections evoked physical responses to the joke.

The limbic system

The limbic system is a network of structures located beneath the cerebral cortex. This system is important because it controls some behaviors that are essential to the life of all mammals such as forming memory and experiencing pleasure.

Can you imagine if people could not do these things?

What would motivate parents to care for offspring?

Neurotiker from Wikimedia

Limbic system= hippocampus + amygdala

Regulates mood and emotions.

Controls laughter, friendship, affection and love.

Laughter is the Best Medicine Reduces pain and allows

us to tolerate discomfort. Shuts down the stress

hormones released in stressful situations.

It helps your blood vessels function better. It acts on the inner lining of blood vessels, called the endothelium, causing vessels to relax and expand, increasing blood flow. In other words, it's good for your heart and brain, two organs that require the steady flow of oxygen carried in the blood.

Voted the World’s Funniest Joke

Two hunters are out in the woods when one of them collapses. He doesn't seem to be breathing and his eyes are glazed. The other guy takes out his phone and calls the emergency services.

He gasps: "My friend is dead! What can I do?"

The operator says: "Calm down, I can help. First, let's make sure he's dead."

There is a silence, then a gunshot is heard. Back on the phone, the guy says: "OK, now what?"

Tickle Experiment

Here's a challenge. Do you think that you can be tickled with your own finger if someone else controls its movements? To check this out, you'll need to relax enough so that your partner moves your finger without any resistance. First, remove your shoe and sock. Cross your legs so that your left foot extends horizontally across your right thigh. Have your partner sit on your right side. Let them take your right hand and hold it so that your index finger extends outward. Relax and give up control of your right arm, finger, and hand. Challenge your partner to tickle your exposed arch using your index finger. Can it be done? Even though you are not in control of the movements, does your body have automatic feedback that tells you where and what your body parts are doing?

Doug Collins’ Story

Famous for the most contagious laughter in the world.

Tragic story of loss and a surprising discovery of fame at the Comedy Barn.

It’s contagious! Montreal Gazette 05/05/2009