The document discusses laughter from an evolutionary and neurological perspective, explaining that laughter evolved as a social bonding mechanism and involves activation of brain regions related to pleasure and emotion. It describes how different animals use laughter-like vocalizations for social purposes and reviews research on the brain activity and facial muscle involvement during human laughter.
3. 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
4. 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)
5. 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.
6. 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).
7. 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
8. More than Humans
Animal Laughter
We know
that apes,
chimps, dogs
and event
rats “laugh”
when they
play and
when tickled.
9. 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
10. 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
11. 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
12. 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
13. 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
14. 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.
15. 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.
16. 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
17. 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.
By Camazine from Wikimedia
18. 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.
19. 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
20. Regulates mood and
emotions.
Controls laughter,
friendship, affection and
love.
21. 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.
22. 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?"
23. 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?
24. Famous for the most
contagious laughter in
the world.
Tragic story of loss and
a surprising discovery
of fame at the Comedy
Barn.
Montreal Gazette 05/05/2009
It‟s contagious!