About the blog

This blog is more than five years old now. The About the blog introduction has been overdue for revision.

Life has been present on earth for about three billion eight hundred million (3,800,000,000) years. These brief posts discuss bits of that history, ones that I find fascinating and satisfying to learn about. They include the single-celled organisms that evolved slowly over two billion years before life grew larger; trees and other plants that stay alive in ways more alien and more familiar than we expect; approaching or avoiding, the primary decisions all organisms make, and how they play out in species including our own; how our bodies, including our brains, work.

Such subjects bring the ingenuity of living things up closer than I have known them and they speak to me about life’s biggest issues. The eons over which living things have persisted, linked through chains of DNA, ease my fear of death. The trees and plants thriving around me gladden me with their calm, slow-motion purposefulness. Cooperation and competition, team-work and battle—the engines of our social and moral lives—perplex me less knowing how embedded they are in other organisms. And glimpsing the workings of the mind helps me untangle my consciousness from my self-consciousness from my self.

Since I’m not a scientist, I come to this biology like someone who is seeing the ocean for the first time. The vista is more intricate and greater than I imagined, and I am smaller and fuller in its presence.

Peter Wohlleben’s “The Hidden Life of Trees”

Until recently I was quite sure that a broad difference between animals and plants was that animals, because they are mobile, readily interact with each other (flocking, pursuing, etc.) while plants, anchored to the ground, don’t do so because they can’t. Except to attract insect pollinators, plants, I thought, live a life of exquisite solo struggle, seeking only the sun and water.

I’ve been steadily learning how far off I was. German forester Peter Wohlleben’s popular book, The Hidden Life of Trees: What They Feel, How They Communicate, is the most compelling lesson yet.

Among his many descriptions of communication and mutual assistance is Wohlleben’s account of how trees defend not only themselves but also each other. Observers have noted, for example, that umbrella thorn acacias in the African savannah pumped toxins into their leaves when they felt giraffes nibbling on them. “The giraffes got the message and moved on to other trees in the vicinity. But did they move on to trees close by? No, for the time being, they walked right by a few trees and resumed their meal only when they had moved about 100 yards away.” They passed by the nearest trees because the trees being nibbled, in addition to pumping a repellent, “gave off a warning gas that signaled to neighboring trees that a crisis was at hand.” The giraffes knew these trees would not taste any better and kept walking.

hidden life of trees (pri.org)


Many trees also have the ability to call in the air force. Reacting to bites from hostile insects, such trees emit scents that attract predators that devour the pests. “For example, elms and pines call on small parasite wasps that lay their eggs inside leaf-eating caterpillars.” The growing larvae devour the caterpillars from the inside.

The book brims with information and appreciations of this kind. Three more examples:

  • Trees that spend their lives in the forest fare much better than trees raised in one place and then transplanted to the forest. “Because their roots are irreparably damaged,…they seem almost incapable of networking with one another.” Like “street kids,” they “behave like loners and suffer from their isolation.”
  • Time for trees is slow and long. Internally, they, like animals, send alerts to parts of their body via chemicals and electrical impulses. But in a tree the electrical impulses move only about a third of an inch per second. (In our bodies, pain signals move  through our nerves about two feet per second, muscle impulses a hundred times faster.) No wonder it seems to us that plants are unresponsive.
  • Conifers (evergreens) “keep all their green finery on their branches” throughout the winter and have been doing so for 270 million years. Then deciduous (leaf-bearing) trees came along 100 million years ago, growing and discarding annually millions of delicate green solar panels. Was this an improvement? Why go to all that trouble? Wohlleben asks. Because “By discarding their leaves, they avoid a critical force—winter storms.” Between high winds, muddy soil, and a surface area equivalent to that of a large sailboat, tall evergreens take a battering in European winters. Growing and then dropping their huge surface area every year proved well worth while for the leafy new comers.

Wohlleben’s liberal use of human descriptors to explain the actions of trees delights many readers and annoys others. Andrea Wulf, in her review of the book, has both reactions.

I’m usually not keen on anthropomorphizing nature—and here trees are “nursing their babies” and having “a long, leisurely breakfast in the sun” while…fungus mushrooms are “rascals” who steal sugar and nutrients. These cutesy expressions make me cringe….But I have to admit that Wohlleben pulls it off—most of the time—because he sticks with scientific research and has a knack for making complex biology simple and thoroughly enjoyable.

I agree. While the vocabulary may bestow on trees a dignity and affection that we usually reserve for our own kind, it is scientists’ growing understanding of trees that creates the real story here. At a time of rapid environmental change, the book is as fascinating a revelation as one could ask for that life is even more intricate and purposeful than we knew.

The Gambler’s Fallacy and Other Biases of the Brain

If you’re feeling cynical about people and our foolish ways, a place to go to buttress your mood is Wikipedia’s List of Cognitive Biases. It describes more than 150 ways in which our thinking systematically deviates from objective observation and rational thinking. It’s a humbling list, a reminder that the evolution of our brains has left us with some thought processes that, though useful in certain situations, don’t make it easy for us to see the world as it actually is.

Here’s a sampling. Quotations are from Wikipedia.

Gambler’s Fallacy: “I’ve flipped heads with this coin five times consecutively, so the chance of tails coming out on the sixth flip is much greater than heads.” No, it’s not. The odds are 50-50 for every flip, regardless of the length of any previous sequence that produced one result. Applicable to apparent batting slumps and other so-called streaks of good or bad luck or performance.

False Consensus Effect: “The tendency for people to overestimate the degree to which others agree with them.” I’m sure you’ve all found this to be true.



Actor-Observer Bias: If you cut me off in traffic, you’re a complete jerk. I blame you and your rotten personality. But if I make a quick turn in front of you, I had good reasons for doing so and my character remains untarnished. On the whole, we’re not very perceptive about our own characteristics and motivations—or those of other people. We are, however, for evolutionary reasons, quick to identify whatever might be a threat and attribution errors create plenty of misunderstandings and conflict.

IKEA Effect: “The tendency for people to place a disproportionately high value on objects that they partially assembled themselves, such as furniture from IKEA, regardless of the quality of the end result.”

Illusion of Truth Effect: “A person is more likely to believe a familiar statement than an unfamiliar one.” Perhaps this has been a safety measure for our species in the long run.

Reminiscence Bump: “The recalling of more personal events from adolescence and early adulthood than personal events from other lifetime periods.” Perhaps the vivid imprinting of our first mistakes and successes has helped us survive. In general, our memories are biased towards thinking highly of ourselves.

Illusion of Transparency: “People overestimate others’ ability to know them, and they also overestimate their ability to know others.” Such overestimating gives us confidence about forming social bonds. If we were realistic about how difficult it is for one person to know another, we would be less likely to go to the trouble or take the risk.

These and other biases have either served our species in the distant past or result from the brain’s limited processing capacity. Since they won’t go away anytime soon, we have to compensate for them as best we can. Wisdom often amounts to an effort to do just that: if we strive to be humble, nonjudgmental, and cautious, our cognition may be more on target.