Fearful Symmetry
The science behind attraction (and testicular asymmetry)
Is one arm longer than the other, your knuckles grazing the ground like a gorilla? When you practice smiling in the mirror, mon petit American psycho, does your upper left incisor strike you as toothier than the one on the right? Symmetry is next to godliness, you know. It’s high time I added to my attractiveness tips by expounding upon that beacon of haleness and handsomeness.
But first, let us scrutinise the scrotum.
Testes it out
Turns out, scrotal asymmetry may have an important function. Hang on, hold up, hold up. It occurs to me this asymmetry may have escaped your notice. Well, this fact was certainly captured (and immortalised in marble) by the sculptors of Antiquity. Perhaps that’s where we ought to begin.
A British psychologist by the name of Chris McManus thought to investigate whether the Ancient Greeks depicted testicular asymmetry in their sculptures. And further, to elucidate whether this owed to keen observation of the male form or deference to left/right symbolism and its association with femininity and masculinity.
(The Ancient Greeks believed the male child originates from the right testicle, whereas these days, thanks to advancements in science, we know boys are the twinkle in their father’s right eye.)
Sculptors from the days of yore certainly took artistic licence per the belief the smaller one's genitalia, the greater one's intellect and moral fortitude—a balm to soothe disappointed lovers, no doubt. Thus, it stands to reason their depiction of testicular asymmetry, too, may have been in service to symbolism rather than anatomic accuracy.
My hero and dedicated scientist, bar none, McManus scrutinised precisely one-hundred and seven “stone scrota” before bemused museum and gallery patrons across Italy. (Though I’d like to think the Italians are more than used to tourists who invoke “scienza” whenever transfixed by marble appendages.)
Most men are right-handed and likewise, it is the right testicle that develops to be slightly larger than the left one, as noted by the aforementioned artists. It also sits higher, a fact they overlooked. Naturally, Ancient Greek sculptors assumed the lower hanging testicle would be the larger, heavier one. Still, they got it half right.
McManus published the results of his great undertaking in Nature and was subsequently bestowed an Ig Nobel Prize. You can read his synthesis of the structural and functional asymmetries of the human body and the impact it has had on all human cultures in his book Right Hand, Left Hand. (I hope you do!)
As I was saying: thank goodness for testicular asymmetry. Consider the tragic fate that would befall your family jewels ‘twere it otherwise. Not only would your testicles knock together like some sort of sad and spongy Newton’s Cradle every time they became desynchronised, but they’d also take up too much pantaloonular real estate hanging at the same height.
My creative theorising aside, the likely reason is that this way one testicle can reside further away from the body. Consequently, this creates cooler conditions favourable to sperm production. While nude, mean scrotal temperature is indeed “significantly lower on the left than on the right” according to an article published in Human Reproduction.
Trousers, however, complicate matters, disproportionately increasing the temperature of the left testicle, which is why I continue to advocate for a glorious and fecund nudist utopia. (Subscribe to my newsletter if you’d like to know more.)
Symmetry signals superiority
Although internal organs (and testicles which have descended to escape the body's core temperature) are meant to be asymmetrical, the more symmetrical our outward appearance, the healthier and therefore more attractive we are. (Sorry, Les Demoiselles d'Avignon, but that’s just the way the cookie crumbles.)
Average faces are appealing not only because they are typical and we love nothing better than the easy to process, but because they are symmetrical. When scientists create chimeric faces which are the average of many individual faces they are producing a face that’s more symmetrical than its constituent parts. Subsequently, this phoney face is judged as being more attractive by human lab rats.
In the womb, the cells of your developing body are at the mercy of environmental factors such as heat, cold, radiation, toxic chemicals, and viral infections, whilst trying to follow the instructions coded in your genes to produce a right leg the same length as your left one—no mean feat.
Ideally, the subdividing cells on both sides of your body follow through with their instructions, so that every paired body part—whether tooth or claw—is its twin’s equal. After all, these cells have no way of communicating that “things on one side have gone a little pear-shaped so if you could please increase production on your side perhaps everything will even out and we won’t have to die alone”.
The ability to buffer against confusing “biological noise” (the aforementioned environmental stressors) means you have a high level of developmental stability—a trait you can pass down to your children and the reason everyone wants to split a milkshake and go square dancing with you.
Developmental stability results in low fluctuating asymmetry (random deviations from perfect bilateral symmetry) which, particularly as it relates to the length of your limbs, is indicative of your overall biological quality in a highly visible way. In a nutshell, high levels of symmetry signal your suitability to suitors. Not to add insult to asymmetry, but the symmetrical are not only better looking but also more intelligent. (But I suppose I have my phrenology calipers to tell me that.)
Now, barring extensive surgery (which I do recommend), you’re as symmetrical as you’re going to get. Fear not, simply swipe a chimeric face for more swipes on dating apps. (You can pass off the grainy black-and-white image as a fondness for artsy filters.)
Sadly, this deception can’t weather your meeting face-to-face. It’s best to use your own face, digitally augmented to look more symmetrical. Then you’re only half a catfish, really, and your date will only see your good side. (I recommend a mirror image of your left side, as it’s more emotionally expressive, rendering your smile just that bit more magnetic.)
As we (right-handed individuals) mostly focus on the part of a person's face that's on our left visual field, a face that is two left halves will be nowhere near as recognisable as one composed of two right halves. That is to say: people who know you in real life won't realise they've swiped left—as though guided by the benevolent noodly appendage of the Flying Spaghetti Monster itself—right past your frankly shameful face-fishing.
When you do meet that potential special someone for a romantic—read: poorly illuminated—candlelit dinner, be sure to obscure one-half of your face. (Um, the correct half.) I recommend you cower behind a menu or a conveniently placed centrepiece the entire evening—but you were probably going to do that anyway. For the more theatrical, a domino mask a la the Phantom of the Opera or Veronica Lake’s iconic waterfall hairstyle’s the ticket to tickety-boo night.
Sexy and mysterious, who could withstand your fearful symmetry?
Favourable bodily asymmetry
Vent your spleens
People born with isometric defects have decidedly more symmetrical innards than a respectable person ought to have—sometimes with disastrous consequences. A heart needs not two right atrial appendages, nor do you need lungs with the same number of lobes on both sides. However, you certainly need a spleen, an organ a person whose left is a mirror of their right is lacking.
A person with isometric defects biased to the left, in contrast, would possess two spleens, presumably giving them preternatural venting powers. I envy them—to the extent my inferior production of black bile allows.
Hands and hemispheres
The brain is also asymmetrical. The two cerebral hemispheres have specialised functions and unique structures, collaborating through the connective tissue known as the corpus callosum.
Compartmentalising tasks is efficient, reminiscent of a factory with purpose-built machinery and well-oiled workers. Just as people with isometric defects have heart and lung problems, a lack of cerebral asymmetry is associated with cognitive and emotional difficulties.
Humanity is unique in the preponderance of right-hand dominance. Although other species exhibit a left-hemisphere bias for processing vocalisations, they do not exhibit handedness on anything other than a per-animal basis.
Michael Corballis of the University of Auckland theorises that in humans, language evolved from manual gestures with vocal elements incorporated over time. This explains why handedness evolved alongside the lateralisation of language, as well as that other feather in humanity’s cap: tool use. Lesions in the left hemisphere can impair the ability to use tools, which, like language, is a gesture behaviour, lending credence to this theory.
Language is lateralised mostly to the left cerebral hemisphere. I say “mostly” because this left-side dominance won't be the case for 27% of left-handers, 15% of ambidextrous individuals, and even 4% of strong right-handers. Furthermore, “language” encompasses many different skills, some of which require the right cerebral hemisphere, dominant in emotional and holistic processing.
To be an effective communicator, you need to understand a lot more than syntax, the logical ordering of a sentence. You'll need your right hemisphere to process prosody, the emotional tenor of speech, as well as to be able to interpret humorous, ironic, or sarcastic remarks.
Ironically, because our emotions are transmitted more strongly through the left hemisphere of our face (controlled by the right hemisphere), this information is received directly by the hemisphere less adept at processing emotional stimuli, such as a sad, fearful, or happy face.
In the literature, this has been dubbed the “double dissociation between the laterality of expression intensity and that of recognition efficiency”. Anger is the exception, perhaps due to the evolutionary advantage inherent in being quick to realise Grogg’s about to club you with a mammoth tusk.
The right hemisphere also specialises in performing spatial tasks, including the composition of a painting and the pitch, tempo, and melody of music. Rhythm, however, is the remit of the left hemisphere, meaning your rap career isn’t over if you sustain a right-side brain injury. (Regrettably, only mumble rap will be within your abilities following bilateral brain damage—and yet, you’ll still be the belle of the IQ ball.)
Alien appendages
When the corpus callosum is severed, as it used to be in a desperate bid to reduce epileptic seizures, a person effectively becomes two minds in one body. In rare cases, a “split-brain” patient may suffer alien hand syndrome, their non-dominant hand appearing to act independently, as though no longer under (conscious) control.
In non-sinister folk, the left alien hand, controlled by the right hemisphere, finds itself deaf to the dictates of the left hemisphere. Consequently, the “you” who can put their thoughts into words is left in the dark regarding the whys and wherefores of the alien hand's complex—yet baffling—goal-directed behaviour.
Fortunately, though you haven't the foggiest why your left hand alternates between tenderly stroking your face and attempting to strangle you, it’s not exactly opposed to helping you, er, the two of you out.
When Lefty’s not undoing buttons—not bottoms, thank you for that autocorrect—as you valiantly try to get ready for work, it’s hardly derelict in its duties. Given a spatial task, the alien hand is happy to take over, sometimes going as far as to swat the bumbling right hand away as it bollocks up—and no, we’re not revisiting your right testicle—a 3D puzzle. (Given how often patients smack their wayward hand, perhaps turnabout is fair play.)
What happens to right-hemisphere dominant (in terms of language lateralisation) alien hand sufferers? Well, most are left-handers, and in my new regime, they’ll be sent to the labour camps just as soon as the left-handed sledgehammer’s been invented. (That’ll learn 'em to slightly jostle my forking arm at dinner!)
Let the right one in
Some functions are under ipso (same side) rather than contralateral (opposite side) control. Like movement, the processing of aural and visual stimuli is contralateral. On the other hand, the same-side hemisphere processes pain and smell-related signals as received by the corresponding side of the body.
If you present a stimulus to the hemisphere specialising in its processing, it will be dealt with faster and with greater ease. People overwhelmingly prefer stimuli that are easy to process; this phenomenon is known as perceptual fluency. It seems familiarity is likelier to breed complacency than contempt, unlike that hoary old chestnut suggests—again, though it may seem otherwise, we are no longer discussing any shrivelled and hirsute parts of the human body.
Plug up your left nostril anytime you want the nostalgia of caramel corn to tickle you in the right (pun intended—all puns intended) hemisphere, transporting you to that time your father’s manservant took you to the circus circa 1938. At any given moment, one nostril receives more inflow of air than the other, with this switching every few hours, so it's best to smell the roses with your right nostril for maximum olfactory satisfaction. But why stop there?
As language is mostly lateralised to the left hemisphere, speech directed into the right ear is processed directly, while input into the left ear must traverse the connective tissue between the two hemispheres first. This means the right side’s the right side when asking for a favour due to right-ear dominance for verbal stimuli.
In a study by Marzoli and Tommasi (2009), nightclub goers were twice as likely to let a female stranger bum a cigarette if she whispered into their right ear. Although a greater percentage of men were keen to curry favour compared with women, both groups were almost twice as receptive to a right ear request. I guess when it comes to getting your way, you’ve got to play it by ear.
Further reading
McManus, I. C. (2002). Right hand, left hand: The origins of asymmetry in brains, bodies, atoms, and cultures. Harvard University Press.
Corballis, M. C. (2014). Left brain, right brain: facts and fantasies. PLoS biology, 12(1), e1001767. doi: 10.1371/journal.pbio.1001767
Matthew 6:3
Subscribe or buy me a coffee if you’d like to support my overuse of the word “appendages” and incessant punning. How did that article make you feel? Informed? Attractive? Emasculated? Like you ought to move your pen to your right hand? Let me know.