Read 13 Things That Don't Make Sense Online
Authors: Michael Brooks
That’s not to say there isn’t some truth to the standard theory of sexual selection. One much-cited example is the elephant
seal: the males fight each other for access to the females. The biggest, strongest male wins and gets to mate. Over successive
breeding cycles this has led to the male elephant seal becoming much bigger and heavier than the female; since the biggest
male in a group gets to sire the next generation, that next generation’s males are going to be bigger than those of the last
generation.
Nevertheless, in Roughgarden’s view there are so many exceptions to this idea that we should look elsewhere for an explanation
of courtship displays. Secondary sexual characteristics, such as the peacock’s tail, might not be indicators of good genes,
but of general good health, she suggests. An animal in good health will also be able to help raise and protect more offspring,
and producing a larger number of offspring that grow to maturity also makes a contribution to offsetting the cost of sexual
reproduction. This idea certainly fits with Forsgren’s discovery that some female fish choose a better, not a bigger, male.
What’s more, a failure to impress doesn’t make the less desirable members of the group walk away; they just take on different
roles. Animals not directly involved in reproduction are still often involved in the group’s welfare and cohesion, gathering
food, offering protection, grooming—perhaps in return for a chance to copulate later. Such bonding activities, Roughgarden
suggests, might be the root of the homosexual behavior that is so ubiquitous in the natural world.
Bruce Bagemihl’s ten-year labor of love,
Biological Exuberance: Animal Homosexuality and Natural Diversity
, reports that more than 450 species have been documented engaging in nonprocreative sexual behavior—including long-term pairings.
Two male black swans, for example, have been observed setting up a nest together, hatching (stolen) eggs, and raising perfectly
well-adjusted cygnets. Better than well-adjusted, in fact; homosexual swans have a higher success rate in raising young than
do heterosexual pairs.
Roughgarden has supplemented Bagemihl’s work: in her book
Evolution’s Rainbow
she took the total number of vertebrate species observed in “nonstandard” couplings up to three hundred or so. Many more examples
may yet be exposed. Bagemihl’s work took a decade partly because biologists suppress reports of homosexual behaviors in the
natural world. One biologist told him that admitting the animals he was observing were living in a homosexual society was
“emotionally beyond [him].” Others admitted documenting homosexual behavior in animals but not publishing until they had tenure.
These couplings certainly do not fit with the mainstream idea that genes, or at least organisms, are hell-bent on reproducing
themselves. They do fit, however, with the idea of a social role for sex, and they fit with the idea that sexual reproduction
is a spandrel, a by-product of some other phenomenon.
If Roughgarden is on to something, she believes it could have cultural as well as scientific implications. The orthodoxy of
biology has corroded our culture like battery acid, she says. In general, we play out the roles prescribed for us by that
culture—aggressive male and coy female—because deviation from its “norm” results in emotional and physical violence, bigotry,
personal guilt, and criminalized behaviors. If biology has been getting it wrong, though, the new orthodoxy could trigger
an infusion of tolerance; perhaps the anomalous prevalence of sexual reproduction will end up having deeper repercussions
outside of science than within it.
Not everyone is convinced by Roughgarden’s argument, however—indeed, most aren’t. “I find this no less—but no more—compelling
a theory than sexual selection, at least for social species,” Steven Rose wrote when reviewing
Evolution’s Rainbow
in the
Guardian
. Nevertheless, at the moment, evolutionary theorists need to look at all comers in considerations of sexual reproduction,
and social selection is an intriguing possibility.
Easily the most intriguing thing about this possibility is that, if death is the root of sex (sex being necessary for life
in an oxygen-rich environment), and passing on genes to the next generation is a spandrel and not the primary driver in the
natural world, then it may be that, in evolution, group selection is not the perversity that Dawkins pronounced it to be.
That would bring Joshua Mitteldorf’s take on death—that it evolved from its initial appearance as a feature of eukaryotic
life into a system that makes room for new generations—back into the realm of the possible. Mitteldorf’s view is essentially
the same one that August Weismann came up with in 1889 (but subsequently disavowed), so it could be said that by changing
our view of sex we might also clear up the dark matter of death—with the first and most obvious theory. It almost seems too
easy, but perhaps the answer has been staring us in the face all along. Could it be that sex is not the most important thing
in life, and that group selection lies behind both sex and death? Can we solve two anomalies in one?
IF
the descent toward death, and the subsequent rise of sex, began in the oceans, the tale of the female octopus provides a fitting
conclusion to the story—and a nod toward our next anomaly. This creature is George Williams’s dream organism, a tentacled
testament to the power of antagonistic pleiotropy. She spawns once in her life and then loses the will to live; within ten
days of her brood’s hatch, she has starved herself to death. And this is death by programming. In 1977 the psychologist Jerome
Wodinsky removed a female octopus’s optic glands after she had spawned, preventing the hormone secretion that precipitates
the self-starvation. Having thus been deprogrammed, she went on to live a long postreproductive life.
The female octopus is—quite literally—a martyr to her hormones. But we are no different. If we think we choose to eat, or
get out of bed in the morning; if we think we choose to do anything much at all, we are sorely mistaken. The illusion—rather,
the delusion—of free will is our next anomaly. And, perhaps, our most disturbing.
Your decisions are not your own
I
n the spring of 2007, in a basement laboratory in central London, I played Pinocchio to Patrick Haggard’s Gepeto. Haggard,
a professor at University College, London’s Institute of Cognitive Neuroscience, held a contraption that looked like an enormous
cartoon key, something you’d use to wind up a clockwork mouse the size of a human being, over the left side of my skull. When
he got the position right, he pressed a foot pedal and my right index finger moved. He slid the key along a bit, and my middle
and then third fingers twitched. If he had mapped my skull properly, and turned up the power, he could have moved my leg or
my arm. With this key, he can do almost anything.
This trick is a favorite tool of neuroscientists. It is called
transcranial magnetic stimulation
, and it uses two electrical coils to create a magnetic field that induces currents in the brain. With it, researchers can
investigate the functions of particular areas of the brain. Haggard does this on himself a lot, he says. I was happy to experience
it just this once. I don’t really like it when someone else has control over my body.
I should count myself lucky, though; some people have to live with this lack of control on a daily basis. Those who suffer
from
alien hand syndrome
, for example, can find themselves fighting one hand with the other. One of their hands, they often report, has a “mind of
its own.” They might be trying to put a cup down with their left hand and find the right hand is trying to pick it up. Or
they are buttoning a shirt with their left hand while the right hand undoes the buttons. In extreme cases the alien hand tries
to strangle the person; only a fight with the other hand saves them. These unfortunates sleep with their alien hand tied to
the bed. Just in case.
Peculiar as this is, it has a straightforward explanation. It arises from lesions in the patient’s brain. There are plenty
of other examples: the man whose brain tumor turned him into a pedophile; the man whose damaged brain meant he famously mistook
his wife for a hat. The lesson we learn from all this is that our minds do not exist separately from the physical material
of our bodies. Though it is a scary and entirely unwelcome observation, we are brain-machines. We do not have what we think
of as free will.
This inference can be drawn from decades of entirely reproducible experiments, and yet it doesn’t make sense. As human beings
we are utterly convinced of our autonomy, our self-determination, our free will. Almost everyone you talk to will say that
such experimental results are anomalous; they don’t fit into the framework of our conscious experience. Talk to Patrick Haggard,
though, and he will tell you the anomaly, the curiosity, lies in our self-deception, the illusion of free will that we cling
to so tightly. Haggard is not alone; most neuroscientists agree with him. But a few are still clinging to free will and casting
the experimental results as the anomaly. The stakes in this fight couldn’t be higher. Something about free will certainly
doesn’t make sense, and the resolution of this anomaly will determine what it means to be a human.
TELL
most people they don’t have free will, and they will defiantly tell you you’re wrong. “Man defends himself from being regarded
as an impotent object in the course of the universe,” Albert Einstein wrote in 1931. If his disciplines, astronomy and cosmology,
are leading the way in pushing human beings away from the center of the universe, the other sciences are not far behind, and
free will is just about all that is left to mark us humans out as special. Even this may soon be lost, however.
In 1788 the philosopher Immanuel Kant put the problem of free will on a par with God and immortality. These, he said, were
the only three things beyond the power of human intellect. Kant may have been wrong, however; little by little, neuroscientists
are learning how to pull aside the curtain.
The first person to tear a hole in the illusion of free will was Benjamin Libet. Libet, who died in 2007 at the age of ninety-one,
is a legend in neuroscience. But not, perhaps, for the reason he would have liked.
In the late 1970s Libet was in a round-table discussion on free will with the Nobel Prize–winning physiologist John Eccles.
Eccles referred to a recent finding that a brain signal that precedes any voluntary action, called the
readiness potential
, kicks off a second or more before the action. At the time, Eccles believed that conscious free will initiates any and every
voluntary action. Therefore, he said, conscious will must precede a voluntary act by at least a second. Immediately Libet
recognized that this was a statement of faith; there was no evidence to back it up. So he went in search of the evidence.
Libet took a group of volunteers, wired them up with some scalp and wrist electrodes, and asked them to perform a very simple
task. They had to stare at a clock and flick their wrists whenever they felt like it. Then they were to report when it was
that they were first aware of the intention to make the movement.
With the scalp electrodes, Libet measured the steadily climbing signal of the readiness potential. The wrist electrodes gave
precise timing for the muscle activity. When the subjects gave their timings for awareness of their intention to move, the
intention always came before the action.
So far so good. But that’s as far as the good news goes. Libet found that the brain’s preparatory work, the readiness potential,
preceded conscious intention—and by a lot. The brain was getting ready for the movement up to half a second before it happened,
and on average that was 350 milliseconds before the subject was even aware he was going to move. By the time the subject experienced
a conscious intention to move, his brain was going full speed ahead. Whatever he thought he was consciously deciding to do,
it wasn’t to make that movement.
Libet was completely taken aback by this discovery and immediately sought to rescue human free will in the only get-out he
could find. There is time in between awareness of the intention to act and the action itself, he said, for a veto. We can
make a conscious decision to not follow through with the action our brain is about to perform. And thus the lines were drawn
in the battle for the essential nature of humanity.
ON
the wall of Haggard’s office is a piece of verse written by his daughter. It is called “A poem for Dad” and describes the
reasons why she loves him. To a child, a parent’s love is taken for granted; the child, though, has feelings that he or she
feels can be rationalized and justified. Haggard earned his daughter’s love by doing things, she says in her poem: helping
with her homework, taking her swimming, and so on. Most of all, though, she loves him because he loves her.
Is this how machines behave? Do we really want science to be allowed to reduce human behavior—swimming, homework, love—to
the firings of neurons that are independent of any individual’s conscious will? And then there is the issue of right and wrong;
we have built our civilizations, religions, and societies on the concept that people ought to be held responsible for their
actions. Surely we only want to develop a scientific theory of human will if it legitimizes our concepts of moral responsibility?
That was certainly Libet’s view—especially since, he felt, his experiment might have been flawed. “The intuitive feelings
about the phenomenon of free will form a fundamental basis for views of our human nature,” he said. “Great care should be
taken not to believe allegedly scientific conclusions about them which actually depend upon hidden
ad hoc
assumptions.” He suggested that any theory that denies free will is “less attractive” than one that accommodates it. Unless
there is some further evidence to the contrary, why not simply “adopt the view that we do have free will”?
Libet was right on one count, at least. The idea of free will has certainly not been killed stone dead by neuroscience; the
protocols behind Libet’s experiment are too loose for that conclusion to be drawn. While we talked in his second-floor office,
Patrick Haggard had put a laptop computer on the table in front of me. I should try a version of Libet’s experimental routine,
he said. That, more than anything else, would show me why Libet’s experiment has not yet put a definitive end to free will.
There certainly are difficulties with the experiment. In Haggard’s version I have to press the F9 key while using a fast-spinning
digital stopwatch on the screen to mentally note the time I am “aware of the will” to move my finger. There is plenty of room
for experimental error here. How, for instance, do I get over my desire to press the key when the clock reaches a certain
point in its cycle? And how do I disentangle my perception of the clock reading when I decide to press the key from my perception
of its reading when I feel my finger press it? What does it even mean; how do I define “aware of the will to move”?
Many people have been here before me, Haggard says. To counter the first problem, a researcher carrying out the experiment
tells the subjects over and over again that
they
are in charge, not the clock. Then they test the data, looking for patterns in timings that might skew the results. The second
objection is more interesting and involves something called
cross-modal synchronization.
If you have ever watched a badly dubbed movie, you will have experienced an annoying difficulty in following the dialogue.
That arises because of problems with your cross-modal synchronization. You are watching the actors’ lips move, and your brain
is taking in this visual input quite happily. The trouble is, the audio input comes in through a separate channel. Your brain
knows that it is easiest to understand speech when you have the visual input—the lip-reading—so it attempts to put the two
channels, or modes, together.
Your brain is surprisingly forgiving here. If the soundtrack is out of sync by around 50 milliseconds, it doesn’t matter;
your brain can’t tell. That’s the level of error you’re allowed when dubbing a movie; anything more, and people will start
throwing things at the screen.
The same is true when Libet’s subjects are synchronizing their view of the clock with their awareness of intention. The awareness
is an internal mode, while the clock reading comes through the visual mode. Tests show the errors people make in synchronization
are between 50 and 150 milliseconds. And that is nowhere near big enough to close the 350-millisecond gap between the unconscious
initiation and the conscious urge to perform a movement.
Haggard is convinced there is no such thing as free will. The third objection, defining “aware of the will to move,” is problematic,
Haggard admits. But, he says, we’re arguing semantics now; I’m playing a fool’s game to try to close the gap by disputing
the details of the experiment. It’s there, he says, get used to it. Yes, the experiment has lots of flaws. Yes, it’s not the
perfect way to pin down the exact nature of voluntary versus involuntary action. But—and he is on the offensive now—what is
the alternative? Do I really think I have free will? Do I really think that conscious thought can make my brain do things?
Where is this thing, somewhere within my physical brain, that would make my brain leap into action and move my finger? There’s
no escaping it, Haggard says: our conscious “intentions” are by-products of something that is already going on. Proving this
beyond doubt is difficult, of course. But, in Haggard’s mind, one man has come closer than any other. And it is not Benjamin
Libet.
In the early 1990s Itzhak Fried, a neurosurgeon at Yale University School of Medicine, was operating on the brains of patients
with severe epilepsy. Their condition was so bad that part of their brains was to be cut out in order to stop the debilitating
rapid fire of the neurons. To find out which neurons to excise, Fried attached a grid of electrodes to certain regions of
the brain’s surface; the idea was to monitor the neurons for overactivity.
Besides its clinical use, the situation also provided an unprecedented opportunity to fire up small regions of the brain with
an electrical current to see what happens. It was a mapping opportunity, if you like, something that could help advance our
understanding of how the brain works. Fried grasped this opportunity with both hands—and gained some unexpected results.
Altogether, Fried and his team stimulated 299 brain sites in thirteen patients; 129 of those sites gave a response. Most of
those responses were simply movements of the body. I say
simply
, as if that weren’t extraordinary enough. Fried and his team were applying currents to specific regions of the brain and
evoking movements—sometimes just one joint would flex or one muscle group in the face would contract. Sometimes they could
evoke a larger response: the patient would adopt a certain posture, extending her neck then rotating her head to the right,
for example. That is, by any standards, extraordinary.
But it wasn’t the most extraordinary thing. What really shocked the researchers was the patients’ reports that they were
feeling “urges.” An urge to move my right arm. An urge to move my right leg inward. An urge to move my right thumb and index
finger. And when the researchers ramped up the current a little on each case, that’s exactly what happened: the urge turned
into the action, the very action the patients had reported wanting to perform.
All this at the flick of a switch. The researchers had taken over the patients’ will, and then—by giving it a bit more juice—they
took over their body.
I could tell, as he described them, that Patrick Haggard is enthralled by these findings. “It would be riveting to have this
done to you,” he says.
He doesn’t want anyone tinkering directly with his brain, though—which is why we ended up in his basement lab. Transcranial
magnetic stimulation is an indirect, and consequently less effective, version of what Itzhak Fried did to his epilepsy patients.
But, in essence, it is the same.