kinesin-walking-oIs who we become in life decided by chance, or by choice?

Our genetic composition was determined when our parents (and all prior ancestors) selected mates, but these weren’t our decisions, so our stock of genes is a chance outcome as far as we’re concerned. Likewise, the quality of early childhood, although strongly relevant to our trajectory later in life, cannot count as personally chosen. So right away we see that many dice were cast before we began to make decisions of any import.

What about our early friendships, that so shape our values? We seemed to choose people with whom to associate, but we were drawing from a limited pool. A neighborhood or school is a small place, after all; most of those we meet come from circumstances roughly similar to our own. For instance, I attended a public high school in an upper middle class neighborhood of Los Angeles. None of my classmates were truly poor, and few were truly rich. Although some very wealthy families lived in the same general area, the richest kids went to private schools. So my classmates were mostly white and upper middle class, like me.

But my potential friends were more limited still. As an introverted youth from a deeply troubled home, I was too shy and insecure to be accepted by the most popular circles. And because of my older sister’s influence (itself modeled after my father’s and stepmother’s addictions), I’d been abusing intoxicants since age twelve. Thus I was shunned by the kids who stayed clean and studied hard (aka, the ‘nerds’). Prospective pals could only be drawn from that set of youngsters who looked like outcasts, enjoyed getting high, and ignored schoolwork. In short, my friends were all ‘druggies.’ I didn’t choose them consciously, and I wasn’t proud to be one of them; I joined by default.

And why was I so insecure and so prone to addiction?

It’s as if dysfunctional strategies were uploaded into my psyche. Having witnessed, as a toddler, my father and mother fighting frequently and loudly, and having felt devastated by their divorce, then by my mom’s severe depression, and finally by her suicide (when I was six), I was well and truly exhausted by the time my sister and I took up residence in my stepmother’s house.

Yet that was just the beginning of our problems. Living in a city far from other relatives, in a home which Della (our stepmother) considered hers alone, we were both physically and emotionally mistreated. Della was quick to discover vulnerabilities that allowed her to manipulate me into tearful despair.

No wonder my sister and I turned to alcohol and drugs. By high school I could see that intoxicants were undermining my development, but breaking free took years. My peers ridiculed talk of quitting; there was no support within my family; and even a court-ordered counselor declared me unlikely to succeed.

Even after I eventually achieved sobriety in my late twenties, I was shackled to the effects of my prior habits. I’d failed to develop ordinary social skills, and I’d adopted an avoidant style (“when stressed, escape”) that poisoned relationships and undermined careers for decades to come.

The point is, a lot of my difficulties in life grew out of situations that I would have avoided, given alternatives.

Yet it also true that we all choose some of our actions, and that these can generate long term consequences. For instance, I deliberately decided to go to medical school, and that affected my life from then on. Even though with better guidance I’d have pursued a career as an ecologist, I did not stumble into medicine by accident. Getting accepted was a tedious process, during which I justified my desire to become a doctor in lengthy submissions and grueling interviews. I plunged toward medical training with high enthusiasm, fully determined to succeed. It’s hard to imagine a career being more deliberately chosen.

But looking closer, it’s obvious that the possibility of medical school depended on a decent education and an interest in biology; both were the result of family influence, not unrestricted choice. Thus although I remember ‘discovering’ life science in high school (a key step in my becoming disillusioned with drugs and delinquency), my curiosity about living things had been piqued much earlier. Growing up I’d spent summers in rural areas of the midwest, where relatives had encouraged curiosity about how plants and animals grow. So while an exceptional high school teacher helped launch my career in biology, he only reawakened a passion that my grandfather, and others, had installed long before. And if my childhood interest in living things wasn’t chosen, but shaped by circumstance, it follows that entering medicine was also circumstantial, since it was a direct consequence of that earlier preparation.

All this comes to mind because of a fascinating book by Peter Hoffman, entitled Life’s Ratchet: How Molecular Machines Extract Order from Chaos. It’s a story of living on the nanoscale. Hoffman describes how bio-molecular complexes perform repetitive and highly efficient actions essential to life. For instance, kinesin is a protein assembly that ‘walks’ (more accurately, waddles) along tracks of microtubules within cells. Its two ‘feet’ alternately move past one another, so that in animations the little structure looks almost purposeful as it steps its way forward.

What’s interesting is the mechanism that propels the feet onward. Kinesins don’t have internal force generators; they sport no muscles. Instead, feet tethered to loose cords get whipped around by the chaotic motion of surrounding water molecules, which shove them this way and that. The random influence of particles bombarding from all sides drives the kinesin foot to flip hither and yon until it happens, by chance, to land in the ‘right’ orientation on the track ahead. At that instant, it grabs hold. Then the trailing foot can release and rise up into what Hoffman calls ‘the molecular storm’ until random currents knock it forward onto the track; once in place, this second foot grabs hold a little ahead of the first. In this way the kinesin complex ‘walks.’

It’s odd how action on this unimaginably small scale seems like a metaphor for life on more familiar ones. We don’t choose how fate buffets us from chance to chance. But we do choose the grab points. A person conditioned to love biology but with minimal exposure to art is far more likely to become a doctor than a painter. But he’s also more likely to become an ecologist, or a neuroscientist. In fact, multiple life science professions may offer themselves, as happened in my case. At which point, we choose our direction in much the same way that the kinesin makes its next step: by grabbing on. The target of our grasp can be chosen consciously, even if the pool of available options is a product of chance. An impoverished African-American teenager on the rough streets of Richmond scans a set of targets quite different from that available to the offspring of European-American software engineers in Mountain View. In both cases, a youngster grabs, but given different options, different lives result.

We get propelled this way and that by the storm of circumstance, and we catch hold of whatever seems most promising as life whips by. Our trajectory isn’t traced by a mind in isolation, but by a mind in context. Given this psyche, in this situation, this line gets drawn. Then this, then this.

Although we judge ourselves and others by our ‘choices,’ we select but occasional handholds as life buffets us with forces beyond our control, such as socioeconomic histories shaped over dozens of generations, evolutionary constraints accumulated over millions of years, and so on. In this swirling cyclone of circumstance, handholds appear at random, while the pool of choices is unique to each particular storm. No matter how heroic our actions, happenstance plays the dominant role in shaping the ‘self.’ Teenagers in Mountain View and Richmond grab whatever pivot points they can find, as life rages on with chaotic blindness. Thus does one youth launch a file-sharing website in his parents’ garage, while the other loads a clip into his brother’s semiautomatic and swaggers into the night.