by Bruce Hood
Psychologist Robert Provine, who has studied the science of laughter,24 reminds us that the mechanisms that generate laughter are largely unconscious and that we do not choose to laugh in the way that we choose to utter a sentence. It is more of a reaction that is triggered by others around us. When others in our group laugh then we laugh, too. Laughter is an emotional state – a feeling that arises from systems that work unconsciously deep in the brain that produce the arousal. But what we find funny depends on how these emotions are triggered, which is the output of the cortical systems that process content. Laughter can be triggered by a joke or it can be caused by something less intellectual and more bodily, such as tickling. Even as an infant, we can share laughter with others and this appears to be one of the primary social mechanisms with which we are equipped. When you tickle your baby and they laugh, they are displaying an ancient evolutionary mechanism – one that is shared by other animals.
Animal laughter has been a controversial claim. Until fairly recently, laughter was considered uniquely human. However, most human behaviours have evolved and so we should not be too surprised to find primitive versions in other species. As many pet owners already know, their animals display behaviour that looks like they are having fun during rough and tumble play. Puppies and kittens seem to engage in behaviour that has no obvious rewards other than the joy of play. Initially it was argued that these behaviours were precursors to adult aggression – a means of developing survival skills for hunting. Even the interpretation of animal behaviour was misguided. For example, chimpanzees who bare their teeth in a smile are generally regarded as displaying a threat or fear response.
However, animal laughter during play had to be rethought when Jaak Panksepp made an amazing discovery with rats.25 First, he noticed that rats that had been deafened for experiments on hearing did not engage in as much rough-and-tumble play as normal rats. There was something missing in these deaf rats. It turns out that it was the squeals of delight. When Panksepp placed a sensitive microphone in the cage that makes high-frequency sound audible to human hearing, they discovered a cacophony of 50 kHz chirping during the play sessions – the rat equivalent of laughing. He soon discovered that rats were also ticklish and would chase the experimenter’s hand until they were tickled. Apparently, rats are most ticklish at the nape of the neck. They would play chase with the hand and all the other familiar baby tickling games like ‘coochie-coo’. Baby pup rats laughed the most, and as the play activity declined with age so did the laughing.
What is it about tickling that is so enjoyable? There is a tactile element to it, but that is not enough to explain the behaviour because it is well known that you cannot tickle your self.26 There is something about being tickled by someone else that is necessary to induce the experience. It turns out that it is the absence of self-control that creates the pleasure of tickling. Whenever we touch ourselves, our brains keep track of our movements. We need this self-monitoring in order to guide our movements but also to know whether changes in sensations are due to our own actions or changes in the external world. We are not aroused when tickling ourselves because the action is totally under our own control and predictable. However, researchers at the Institute of Neurology in London found that you could tickle your self with a tickling machine when there was a delay inserted between the action of operating the lever and the probe that did the tickling.27 When the self no longer seems in control, we surrender to the illusion of an external agent. This also explains why schizophrenic patients can tickle themselves because their self-monitoring is believed to be disrupted and they attribute sensations and experiences generated by their own brains and bodies as coming from somewhere else.28 No doubt losing this sense of self during tactile stimulation extends beyond tickling into other areas of sensual pleasure, which is one reason why getting a massage can be so enjoyable!
Laughter has been considered one of the primitive universal emotions recognized in every culture. Of all the different emotional expressions, laughter is one of the few that adults who have been deaf and blind from birth can generate, indicating that it predates other emotions in our evolution. If it is so old and shared with other species, this suggests that it may have a really important function. Although we all have moments of solitary mirth, private jokes that make us smile, laughter is predominantly a social phenomenon that has its roots both early in human development and also early in the development of our species.
We like to laugh and make others laugh. Not only does laughter have a multitude of benefits in terms of coping with stress and illness, but it works to bind individuals together in social coalitions. It is a deep emotional response activated by the emotional regions of the amygdala and associated brain networks, but it operates in conjunction with higher order processes related to social cognition – thinking about others. We use laughter to signal our willingness to be members of the group and we also laugh at others to ostracize them. In this way, laughter is a powerful weapon of group coalition and identity. However, sometimes this weapon can go off on its own. We know this because various disorders that disrupt the connectivity of the different brain regions associated with laughter can lead to impulsive and socially inappropriate outbursts.29 Multiple sclerosis, strokes, Alzheimer’s disease, Parkinson’s disease and other forms of brain lesions can damage the communications between different parts of the brain that control social behaviour. Even in healthy adults, the stress of highly emotional situations such as funerals can cause us momentarily to lose the capacity to suppress our giggling. It’s also one of the reasons that alcohol and comedy go hand in hand. When you drink you are partially disinhibited because alcohol impairs cortical suppression. We are more at ease and less concerned about our behaviour in public. We become louder, sillier and find jokes funnier, or at least laughing at them more acceptable. Socially appropriate laughter requires not only interpreting complex social situations but also regulating impulses that may be inadvertently triggered. This is why children must learn to control laughter. We may be born to smile and laugh, but eventually our cultures take over and tell us when it is appropriate to do so. This may explain why comedians are continually pushing the boundaries of socially acceptable humour and yet deep down we are egging them on. We take delight in testing the boundaries of our own self-control.
Securely Attached to Apron Strings
Initially most babies are party animals – staying up all night and willing to be friendly with anyone. They find all adults fascinating. It may be true that in comparison to other women, young babies prefer to look at their own mother’s face, listen to her voice and prefer the taste of her breast milk as well as her smell,30 but when it comes to socializing, young babies initially don’t care who the adult is so long as they interact with them in a meaningful way. Meaningful for a young baby means attentively. So long as our interactions are timed to the babies’ activity they pay attention to us.31 As noted, babies have been shown to copy adult facial expressions but in reality most of the copying goes in the other direction. That’s why they don’t like adults who hold impassive faces.32 On the other hand, adults who engage in an overly animated manner, too much ‘in your face’ as it were, are equally upsetting.33 The perfect combination is one of harmony with infant–adult interactions coordinated in a synchronized ballet of behavioural exchanges.34 For the baby, it is as if the first six months have all been about discovering that they are human and paying attention to other humans. Now the task switches to constructing their unique sense of self.
This is where our early relationships seem to play a critical role in shaping our self. Initially babies like everyone but that changes somewhere around the first half-year of life. Now babies become increasingly discerning. Not only do they restrict their preference to their own mother, they can become terrified of strangers. This fear will increase over the next year until they start daycare school. You can even gauge the age of an infant if they burst into tears when you approach them. This phase of social development marks the b
eginning of mother–infant attachment and the corresponding appearance of stranger anxiety.35 Of course, most parents, especially mothers, have already formed a strong emotional bond with their infants from birth. For a start, our babies look cute because of ‘babyness’, a term coined by our bird expert, Lorenz, to describe the relative attractiveness of big eyes and big heads that is found throughout the animal kingdom.36 Big-headed, doe-eyed babies are adorable to adults, which explains why we think that puppy dogs, pop star Lady Gaga, who manipulates the size of her eyes, and even cartoon characters such as Betty Boop or Bambi look cute. They all have relatively big heads and big eyes. It’s one reason why women (and some men) from cultures around the world have used makeup to emphasize the eyes for beauty. Babyness also explains why pre-pubescent girls prefer to look at pictures of adults, but when they hit puberty, they prefer to look at babies.37 Nature has wired in baby love for those ready to have them.
Social bonding with babies is a chemically coordinated event that engages the reward centres of both brains – mother and child.38 The potent hormonal cocktails that flood the reward centres generate the feelings that accompany our thoughts. Just as hormones regulate social bonding, they are also released in times of social stress. This is why most mothers and their offspring cannot be easily separated. If you try to take an infant rhesus monkey away from its mother, you get maternal rage, a violent reaction typified by extreme aggression, arousal and the release of cortisol.39 Cortisol is the hormone that floods the body to motivate and prepare for action. It breaks down fats and proteins to generate extra energy while putting other systems on temporary hold. Combined with other hormones, such as adrenaline, our arousal system is activated to prepare us for life’s three big Fs: fighting, fleeing and fornication.
When it comes to fighting, people can rarely be more aggressive than a mother separated from her child. During a routine security check at an airport, my wife Kim was travelling with our first daughter and nanny through immigration. At one point, she handed the baby to the nanny in order to retrieve the necessary documentation. However, the nanny and baby were ushered through security to the next stage of processing and a glass barrier slid across to separate mother and baby. Realizing the situation, Kim attempted to push through the barrier, whereupon the security guard raised an arm and told her to wait. Kim, with her cortisol raging, threatened to overpower the armed guard and smash through the barrier to retrieve her newborn if the gate was not opened immediately. The male guard recognized the maternal rage and crazed look and immediately let the young mother through. This is why most animal experts caution against approaching young offspring when the mother is about.
At about six months, babies start to show the same strong emotional reactions to separation from their mothers. Now they do not want to be held by others and will scream and wail if you try to separate them from their mother. As their cortisol levels spike,40 they unleash that piercing wailing on separation that is almost unbearable until the infant is consoled and returned to the comforting arms of the mother. This is no laughing matter. There are few things more distressing to a mother than the sound of her own infant crying. This ‘biological siren’41 ensures that even if they are not yet mobile, the Machiavellian baby can still control the movements of their mother from within the confines of the playpen. When they do actually begin to crawl and toddle, towards the end of the first year, babies will literally hold on to their mothers’ apron strings as they go about their routines. A colleague of mine, Annette Karmiloff-Smith, made a television documentary42 where she filmed a young toddler and his mother as the mother went about the house doing her daily chores. When speeded up, it was as if the toddler was attached to his mother by an invisible elastic band, never letting her get too far away.
John Bowlby, the British psychiatrist, was one of the first to describe this early social attachment behaviour.43 He had been very influenced by Lorenz’s imprinting in birds and reasoned that attachment was a similar evolutionary mechanism that ensured that mother and infant remained in close proximity. In Bowlby’s view, children are a bit like batsmen in a game of baseball or cricket – they feel secure when they are touching the bases or while behind their creases, but become increasingly anxious and insecure as they step farther and farther away from them. The mother serves as a secure base from which to explore the world.
Bowlby predicted that children not given the opportunity to form a secure attachment as infants would end up as maladjusted adults. Much of this was based on his observations of children separated from their parents during the Second World War and relocated to institutions that did not provide the nurturing environment for attachments to form. He found that children separated early in life failed to develop normally with many exhibiting antisocial behaviour as adolescents. In France a similar picture emerged out of war-torn Europe when children were separated from their families.44 The way children were treated during early development had influenced the way they behaved as adults. Their reflected self, which had emerged in a chaotic, uncontrollable social world, had led them to shun social cohesion and conformity as adults.
In the 1960s, one of Bowlby’s colleagues, Mary Ainsworth, invented an experiment to reveal the nature of young children’s attachment using a temporary enforced separation from the mother in a strange environment.45 It began with the mother and her infant in a waiting room. A strange woman would come in and begin a conversation with the mother. At this point the infant was usually happy playing nearby with the toys in the room. After a couple of minutes, the mother would leave her infant in the company of the stranger as she left the room for three minutes. The stranger would try to interact with the infant until the mother returned. This sequence was then repeated. What Ainsworth discovered was that infants reacted to their mother’s separation in different ways.46 Most would start crying when their mother left but would settle again when she returned. These infants were described as securely attached, demonstrating the appropriate strategy of raising the alarm when the mother was too far away but settling on her return. Other infants were insecurely attached which was described as ‘avoidant’ or they were inconsolable and ‘resistant’ even when she returned to try and settle them.
There are two important limitations of the attachment account of the developing self. First, emotional attachment to the mother is found across the world but it is displayed in different ways, depending on the individual child and the way they are raised.47 Second, as any parent will know, especially those who have raised twins, children come with a whole batch of dispositions and tempers that shape how they interact with others. Some kids are just clingier than others and this temperament reflects how they respond to stress and uncertainty. Their emotional brain centres are trip-wired to overreact to uncertainty and they probably inherit that part of their personality from their parents. My former Harvard colleague, Jerry Kagan, called this natural disposition ‘inhibition’, which reflects the reactivity of the amygdala. In his research, Kagan found that around one in eight children were born inhibited and destined to respond fearfully to new situations.48 At the other extreme, around one in ten infants are born disinhibited, which makes them more fearless and able to cope with uncertainty and new situations. The remaining babies lie somewhere in between. Kagan found that he could identify the temperament of the infant at as early as four months of age, and this would predict their personality seven years later.
The emerging social behaviour of the child must reflect the interaction between the child’s disposition and the environment. Parents instinctively adapt to the temperament of their children, but this can be shaped by cultural norms. For example, some cultures, such as in Germany, seem to encourage independence, whereas Japanese children traditionally spend more time with their mothers and do not cope with Ainsworth’s strange situation so well. This indicates that both the natural disposition of the child and the environment work together to shape the emotional and social behaviour of the child.
Remarkably, studies of in
fants followed up as adults reveal that the way we respond as infants to social separation stays with us to some extent as adults. Our infant attachment patterns appear to influence our emotional attachment to partners later in life.49 Those infants who develop a normal pattern of wanting their mother, and then settling easily back in when they are reunited, are more likely to go on to form relatively stable relationships as adults. They find it relatively easy to get close to others and are comfortable being dependent on others and having others depend on them. They do not worry about being abandoned and are comfortable in intimate relationships. In contrast, those who had formed an insecure attachment to their mother are either too needy and clingy for fear of being abandoned or, if they were avoidant as infants, they typically do not want to get too close to others or allow others to get close to them.50 Of course, if these adults go on to have children, then it is easy to see how adult attachment can influence the shape of the environment of the next generation.
Who would have thought that our first love would be the deepest, having long-term effects on how our romantic relationships work out as adults? You can just hear Freud tutting in the background, ‘I told you so.’ However, not everything is cast in stone. Relationships come and go and can change over the course of a lifetime, and some may have more impact than others. Circumstances and environments are constantly changing and unpredictable. The early attachment effects, like other individual differences, are more likely to be dispositions that interact with the multitudes of factors that shape our personality over a lifetime. These early attachment effects may reflect temperaments, cultural variations, parenting styles and all of the above but it seems unlikely they will determine how we turn out with any certainty. One thing that is certain is that whatever may be the role of early factors, it is critical that they play out in some form of social environment. We need others in order to develop, not just for nurturing and care, but to become socialized.