Our Ancient Laughing Brain. 1. Why do we laugh?. What makes us laugh?. Is humor the main ingredient of laughter?. Scientific investigation of laughter. Public places - only 10 to 20% has to do with humour (1200 conversations ). Dr.Robert Provine Neurobiologist.
Is humor the main ingredient of laughter?
What were the results???
“Laughter disappears just when we are ready to observe it -- especially in the laboratory”
Laughter disarms people, creates a bridge between them,
and facilitates amicable behavior
The function of laughter is .....
It seems to be a message that we send to other
people communicating joyful
disposition, bonding, happiness, willining to play.
We need to build
social structures in order to live well in our society and laughter signalize this disposition.
We rarely laugh alone
“If we see someone laughing
alone he or she would seem to be crazy”
Processing“Black Box” approachfor studying laughter
“Laughter has powerful influences on the body”
Dr. J. Mercola, MD
You must get unobstructed upper airways in order to laugh
Therefore a spasm occurs, so that neck and head are
thrown back to provide a free respiratory intake.
Compare the contrast between waves of sound during
Laughter is accompanied by a strong increase of amplitude and frequency of respiratory movement with a consequent increase in the intake of oxigen and output of carbon dioxide
“Laughter is a good aerobic exercice that ventilates the lungs”
Dr. William Fry Jr.
The venous return from the face by the jugular veins is partially blocked due to a strong contraction of neck muscles
Arterioles in the face dilate provoking an increase in the blood flow
Shedding of tears
The repeated contraction of the muscles around the eyes compressess the lacrimal glands provoking the outflow of tears.
Repeated short, strong contractions of the muscles of thoracic wall, abdomen, and diafragm increase blood flow into our internal organs
Muscle tension decreases, and we may temporarily lose control of our limbs.
“Being weak with laughter”
heart rate and blood pressure increase
The arteries then dilate, causing blood pressure to fall
Loss of control of urinary sphincter
“Shared laughter creates a bond of friendship. When people laugh together, they cease to be young and old, master and pupils. They have become a single group of human beings, enjoying their existence."
W. Grant Lee
“Laughter is a powerful sound”
Dr. Joseph M. Mercola
A Sociobiological Perspective
detectorContagious laughter:Roots in the neurological mechanism of laugh detection and replication
"The old saying that 'laughter is the best medicine,' definitely appears to be true”
Michael Miller, M.D.
University of Maryland Medical Center
Scientists wondered if there was any cross- cultural differences in social context of laughter.
Eibl-Eibesfeldt documented laughter’s universality recording unstaged and undisturbed social interactions in a number of traditional societies
Native Brazilians, African tribesmen, Greek fishermen, etc.
Do we learn to laugh?
Or is laughter innate in human beings?
Evidences point to an innate, preprogrammed basis recording unstaged and undisturbed social interactions in a number of traditional societies
Congenitally blind, deaf, and dumb
Video Analysis of Laughter Sequence recording unstaged and undisturbed social interactions in a number of traditional societies
Laughter is not unique to humans recording unstaged and undisturbed social interactions in a number of traditional societies
Apes open their mouths wide, expose their teeth, retract the corners of their lips, and emit loud and repetitive vocalizations
Apes recording unstaged and undisturbed social interactions in a number of traditional societies
Produce a pant “ah” for every expiration and inspiration
Produced by interrupting a
single expirationContrast of chimpanzee and human laugh production.
"The true origins of laughter lie in the rough-and-tumble
play of our primate ancestors”
AMAZON recording unstaged and undisturbed social interactions in a number of traditional societiesPlaying in the rain forest with monkeys
Monkeys also laugh when they are playing with humans
Fighting in make-believe aggression is not for real. Laughter indicates that aggressive play is just fun
Breath exalation recording unstaged and undisturbed social interactions in a number of traditional societies
Standarts pantsPlayful Behaviour
Dogs make a specific noise during play that is distinctive from other sounds made during passive or aggressive confrontation.
Rats emit short, high-frequency, ultrasonic vocalizations during rough-and-tumble play.
“Laughter also can serve as a weapon to
humiliate and ostracize its victims”
Is there a common evolutionary origin of laughter
They mean to keep the stranger:
Outside the group
Inside the group
Animals are able to modify the sound of their vocalization. threatening behaviour against strangers
“I am no threat to you”
It is trying to sound bigger than it actually is. They mean that they can bite
Contrast between laughter and aggression
Both involve showing the teeth
Definite function: communicative signal
Laughter involves the whole brain
Basic structures of the brain threatening behaviour against strangers
Pleasure, happiness, joy
Vocalization, respiration, gland excretion
Motor cortex threatening behaviour against strangers
BrainstemA Brain Alight with Laughter…
Areas involved with
Damage provoked in the neural circuit
responsible for the motor expression of laughter, may cause a "desinhibition" of the laughter
Fits of abnormal laughter, producing an inappropriate, unrestrained, uncontrollable laughter dissociated from any stimulus.
It is a disorder of emotional expression
All these conditions provoke an imbalance in the laughter expression mechanism
Supplementary threatening behaviour against strangers
Motor Area (SMA)
SMA - Is associated with the control of speech
Electrical stimulation in supplemental motor area triggered peals of mirthful laughter.
Sensory cortex threatening behaviour against strangers
Anatomy of Tickling
(Area that registers touch)
Tickling stimulates touch receptors in the skin. These receptors, when stimulated carry information in sensory neurons that goes to the spinal cord.
Then this information travels up to the sensory cortex via the thalamus.
The sensory cortex is involved in processing information from the skin.
We do not laugh when we tickle ourselves, only when other people tickle us.
Why is it impossible to tickle ourselves? threatening behaviour against strangers
Cerebellum threatening behaviour against strangers
Brain region that helps to control voluntary movement and balance
Predicts the sensory consequences of movements - supplying the brain with information that reduces the sensation of touch information.
Charles Darwin threatening behaviour against strangers
“For tickling to be effective, you must not know the precise point of stimulation in advance”
Somatosensory threatening behaviour against strangers
When you try to tickle yourself, your cerebellum sends to your somatosensory cortex precise information on the position of the tickling target and therefore what sensation to expect.
Robotic arm threatening behaviour against strangers
She used robotic arms to tickle people and found it to be as effective as real people in provoking laughter.
However, when her subjects used a joystick to control the tickling robot, they couldn’t make themselves laugh.
Somatosensory threatening behaviour against strangers
Part of the brain that registers touch
fMRI detected more neuronal activity in somatosensory cortex, when people were tickled than when they tickled themselves.
To compare brain activity when a subject's hand was tickled by an experimenter or by himself.
Somatosensory cortex helps interpret external stimuli registered by nerve endings that sense touch.
“Play and laughter not only fertilize the brain but they fertilize the human spirit. These are the types of systems that allow us to be joyous, to build stable social structures and sharing creatures that do the right things in the world. If other people are interacting with us in positive ways and we respect the way they feel, then I think we have a better world. And play and laughter are a big part of that”.
Our ancient Laughing Brain
By Silvia Helena Cardoso
Avaliable on-line at:
Laughter: A Scientific Investigation
A Book by Robert R. Provine