"WHAT HAVE YOU CHANGED YOUR MIND ABOUT?"

JOSEPH LEDOUX
Neuroscientist, New York University; Author, The Synaptic Self

Like many scientists in the field of memory, I used to think that a memory is something stored in the brain and then accessed when used. Then, in 2000, a researcher in my lab, Karim Nader, did an experiment that convinced me, and many others, that our usual way of thinking was wrong. In a nutshell, what Karim showed was that each time a memory is used, it has to be restored as a new memory in order to be accessible later. The old memory is either not there or is inaccessible. In short, your memory about something is only as good as your last memory about it. This is why people who witness crimes testify about what they read in the paper rather than what they witnessed. Research on this topic, called reconsolidation, has become the basis of a possible treatment for post-traumatic stress disorder, drug addiction, and any other disorder that is based on learning.

That Karim's study changed my mind is clear from the fact that I told him, when he proposed to do the study, that it was a waste of time. I'm not swayed by arguments based on faith, can be moved by good logic, but am always swayed by a good experiment, even if it goes against my scientific beliefs. I might not give up on a scientific belief after one experiment, but when the evidence mounts over multiple studies, I change my mind.

KARL SABBAGH
Writer and Television Producer; Author, The Riemann Hypothesis

I used to believe that there were experts and non-experts and that, on the whole, the judgment of experts is more accurate, more valid, and more correct than my own judgment. But over the years, thinking — and I should add, experience — has changed my mind. What experts have that I don't are knowledge and experience in some specialized area. What, as a class, they don't have any more than I do is the skills of judgment, rational thinking and wisdom. And I've come to believe that some highly ‘qualified' people have less of that than I do.

I now believe that the people I know who are wise are not necessarily knowledgeable; the people I know who are knowledgeable are not necessarily wise. Most of us confuse expertise with judgment. Even in politics, where the only qualities politicians have that the rest of us lack are knowledge of the procedures of parliament or congress, and of how government works, occasionally combined with specific knowledge of economics or foreign affairs, we tend to look to such people for wisdom and decision-making of a high order.

Many people enroll for MBA's to become more successful businessmen. An article in Fortune magazine a couple of years ago compared the academic qualifications of people in business and found the qualification that correlated most highly with success was a philosophy degree. When I ran a television production company and was approached for a job by budding directors or producers, I never employed anyone with a degree in media studies. But I did employ lots of intelligent people with good judgment who knew nothing about television to start with but could make good decisions. The results justified that approach.

Scientists — with a few eccentric exceptions — are, perhaps, the one group of experts who have never claimed for themselves wisdom outside the narrow confines of their specialties. Paradoxically, they are the one group who are blamed for the mistakes of others. Science and scientists are criticized for judgments about weapons, stem cells, global warming, nuclear power, when the decisions are made by people who are not scientists.

As a result of changing my mind about this, I now view the judgments of others, however distinguished or expert they are, as no more valid than my own. If someone who is a ‘specialist' in the field disagrees with me about a book idea, the solution to the Middle East problems, the non-existence of the paranormal or nuclear power, I am now entirely comfortable with the disagreement because I know I'm just as likely to be right as they are.

DOUGLAS RUSHKOFF
Media Analyst; Documentary Writer; Author, Get Back in the Box: Innovation from the Inside Out

The Internet

I thought that it would change people. I thought it would allow us to build a new world through which we could model new behaviors, values, and relationships. In the 90's, I thought the experience of going online for the first time would change a person's consciousness as much as if they had dropped acid in the 60's.

I thought Amazon.com was a ridiculous idea, and that the Internet would shrug off business as easily as it did its original Defense Department minders.

For now, at least, it's turned out to be different.

Virtual worlds like Second Life have been reduced to market opportunities: advertisers from banks to soft drinks purchase space and create fake characters, while kids (and Chinese digital sweatshop laborers) earn "play money" in the game only to sell it to lazier players on eBay for real cash.

The businesspeople running Facebook and MySpace are rivaled only by the members of these online "communities" in their willingness to surrender their identities and ideals for a buck, a click-through, or a better market valuation.

The open source ethos has been reinterpreted through the lens of corporatism as "crowd sourcing" — meaning just another way to get people to do work for no compensation. And even "file-sharing" has been reduced to a frenzy of acquisition that has less to do with music than it does the ever-expanding hard drives of successive iPods.

Sadly, cyberspace has become just another place to do business. The question is no longer how browsing the Internet changes the way we look at the world; it's which browser we'll be using to buy and sell stuff in the same old world.

PIET HUT
Professor of Astrophysics, Institute for Advanced Study, Princeton



Explanations

I used to pride myself on the fact that I could explain almost anything to anyone, on a simple enough level, using analogies. No matter how abstract an idea in physics may be, there always seems to be some way in which we can get at least some part of the idea across. If colleagues shrugged and said, oh, well, that idea is too complicated or too abstract to be explained in simple terms, I thought they were either lazy or not very skilled in thinking creatively around a problem. I could not imagine a form of knowledge that could not be communicated in some limited but valid approximation or other.

However, I've changed my mind, in what was for me a rather unexpected way. I still think I was right in thinking that any type of insight can be summarized to some degree, in what is clearly a correct first approximation when judged by someone who shares in the insight. For a long time my mistake was that I had not realized how totally wrong this first approximation can come across for someone who does not share the original insight.

Quantum mechanics offers a striking example. When someone hears that there is a limit on how accurately you can simultaneously measure various properties of an object, it is tempting to think that the limitations lie in the measuring procedure, and that the object itself somehow can be held to have exact values for each of those properties, even if they cannot be measured. Surprisingly, that interpretation is wrong: John Bell showed that such a 'hidden variables' picture is actually in clear disagreement with quantum mechanics. An initial attempt at explaining the measurement problem in quantum mechanics can be more misleading than not saying anything at all.

So for each insight there is at least some explanation possible, but the same explanation may then be given for radically different insights. There is nothing that cannot be explained, but there are wrong insights that can lead to explanations that are identical to the explanation for a correct but rather subtle insight.

HOWARD GARDNER
Psychologist, Harvard University; Author, Changing Minds

Wrestling with Jean Piaget, my Paragon

Like many other college students, I turned to the study of psychology for personal reasons. I wanted to understand myself better. And so I read the works of Freud; and I was privileged to have as my undergraduate tutor, the psychoanalyst Erik Erikson, himself a sometime pupil of Freud. But once I learned about new trends in psychology, through contacts with another mentor Jerome Bruner, I turned my attention to the operation of the mind in a cognitive sense — and I've remained at that post ever since.

The giant at the time — the middle 1960s — was Jean Piaget. Though I met and interviewed him a few times, Piaget really functioned for me as a paragon. In the term of Dean Keith Simonton, a paragon is someone whom one does not know personally but who serves as a virtual teacher and point of reference. I thought that Piaget had identified the most important question in cognitive psychology — how does the mind develop; developed brilliant methods of observation and experimentation; and put forth a convincing picture of development — a set of general cognitive operations that unfold in the course of essentially lockstep, universally occurring stages. I wrote my first books about Piaget; saw myself as carrying on the Piagetian tradition in my own studies of artistic and symbolic development (two areas that he had not focused on); and even defended Piaget vigorously in print against those who would critique his approach and claims.

Yet, now forty years later, I have come to realize that the bulk of my scholarly career has been a critique of the principal claims that Piaget put forth. As to the specifics of how I changed my mind:

Piaget believed in general stages of development that cut across contents (Space, time, number); I now believe that each area of content has its own rules and operations and I am dubious about the existence of general stages and structures.

Piaget believed that intelligence was a single general capacity that developed pretty much in the same way across individuals: I now believe that humans posses a number of relatively independent intelligences and these can function and interact in idiosyncratic ways,

Piaget was not interested in individual differences; he studied the 'epistemic subject.' Most of my work has focused on individual differences, with particular attention to those with special talents or deficits, and unusual profiles of abilities and disabilities.

Piaget assumed that the newborn had a few basic biological capacities — like sucking and looking — and two major processes of acquiring knowledge, that he called assimilation and accommodation. Nowadays, with many others, I assume that human beings possess considerable innate or easily elicited cognitive capacities, and that Piaget way underestimated the power of this inborn cognitive architecture.

Piaget downplayed the importance of historical and cultural factors — cognitive development consisted of the growing child experimenting largely on his own with the physical (and, minimally, the social ) world. I see development as permeated from the first by contingent forces pervading the time and place of origin.

Finally, Piaget saw language and other symbols systems (graphic, musical, bodily etc) as manifestations, almost epiphenomena, of a single cognitive motor; I see each of these systems as having its own origins and being heavily colored by the particular uses to which a systems is put in one's own culture and one's own time.

Why I changed my mind is an issue principally of biography: some of the change has to do with my own choices (I worked for 20 years with brain damaged patients); and some with the Zeitgeist (I was strongly influenced by the ideas of Noam Chomsky and Jerry Fodor, on the one hand, and by empirical discoveries in psychology and biology on the other).

Still, I consider Piaget to be the giant of the field. He raised the right questions; he developed exquisite methods; and his observations of phenomena have turned out to be robust. It's a tribute to Piaget that we continue to ponder these questions, even as many of us are now far more critical than we once were. Any serious scientist or scholar will change his or her mind; put differently, we will come to agree with those with whom we used to disagree, and vice versa. We differ in whether we are open or secretive about such "changes of mind": and in whether we choose to attack, ignore, or continue to celebrate those with whose views we are no longer in agreement.

DONALD HOFFMAN
Cognitive Scientist, UC, Irvine; Author, Visual Intelligence

Veridical Perception

I have changed my mind about the nature of perception. I thought that a goal of perception is to estimate properties of an objective physical world, and that perception is useful precisely to the extent that its estimates are veridical. After all, incorrect perceptions beget incorrect actions, and incorrect actions beget fewer offspring than correct actions. Hence, on evolutionary grounds, veridical perceptions should proliferate.

Although the image at the eye, for instance, contains insufficient information by itself to recover the true state of the world, natural selection has built into the visual system the correct prior assumptions about the world, and about how it projects onto our retinas, so that our visual estimates are, in general, veridical. And we can verify that this is the case, by deducing those prior assumptions from psychological experiments, and comparing them with the world. Vision scientists are now succeeding in this enterprise. But we need not wait for their final report to conclude with confidence that perception is veridical. All we need is the obvious rhetorical question: Of what possible use is non-veridical perception?

I now think that perception is useful because it is not veridical. The argument that evolution favors veridical perceptions is wrong, both theoretically and empirically. It is wrong in theory, because natural selection hinges on reproductive fitness, not on truth, and the two are not the same: Reproductive fitness in a particular niche might, for instance, be enhanced by reducing expenditures of time and energy in perception; true perceptions, in consequence, might be less fit than niche-specific shortcuts. It is wrong empirically: mimicry, camouflage, mating errors and supernormal stimuli are ubiquitous in nature, and all are predicated on non-veridical perceptions. The cockroach, we suspect, sees little of the truth, but is quite fit, though easily fooled, with its niche-specific perceptual hacks. Moreover, computational simulations based on evolutionary game theory, in which virtual animals that perceive the truth compete with others that sacrifice truth for speed and energy-efficiency, find that true perception generally goes extinct.

It used to be hard to imagine how perceptions could possibly be useful if they were not true. Now, thanks to technology, we have a metaphor that makes it clear — the windows interface of the personal computer. This interface sports colorful geometric icons on a two-dimensional screen. The colors, shapes and positions of the icons on the screen are not true depictions of what they represent inside the computer. And that is why the interface is useful. It hides the complexity of the diodes, resistors, voltages and magnetic fields inside the computer. It allows us to effectively interact with the truth because it hides the truth.

It has not been easy for me to change my mind about the nature of perception. The culprit, I think, is natural selection. I have been shaped by it to take my perceptions seriously. After all, those of our predecessors who did not, for instance, take their tiger or viper or cliff perceptions seriously had less chance of becoming our ancestors. It is apparently a small step, though not a logical one, from taking perception seriously to taking it literally.

Unfortunately our ancestors faced no selective pressures that would prevent them from conflating the serious with the literal: One who takes the cliff both seriously and literally avoids harms just as much as one who takes the cliff seriously but not literally. Hence our collective history of believing in flat earth, geocentric cosmology, and veridical perception. I should very much like to join Samuel Johnson in rejecting the claim that perception is not veridical, by kicking a stone and exclaiming "I refute it thus." But even as my foot ached from the ill-advised kick, I would still harbor the skeptical thought, "Yes, you should have taken that rock more seriously, but should you take it literally?"

MICHAEL SHERMER
Publisher of Skeptic magazine, monthly columnist for Scientific American; Author, Why Darwin Matters

The Nature of Human Nature

When I was a graduate student in experimental psychology I cut my teeth in a Skinnerian behavioral laboratory. As a behaviorist I believed that human nature was largely a blank slate on which we could impose positive and negative reinforcements (and punishments if necessary) to shape people and society into almost anything we want. As a young college professor I taught psychology from this perspective and even created a new course on the history and psychology of war, in which I argued that people are by nature peaceful and nonviolent, and that wars were thus a byproduct of corrupt governments and misguided societies.

The data from evolutionary psychology has now convinced me that we evolved a dual set of moral sentiments: within groups we tend to be pro-social and cooperative, but between groups we are tribal and xenophobic. Archaeological evidence indicates that Paleolithic humans were anything but noble savages, and that civilization has gradually but ineluctably reduced the amount of within-group aggression and between group violence. And behavior genetics has erased the tabula rasa and replaced it with a highly constrained biological template upon which the environment can act.

I have thus changed my mind about this theory of human nature in its extreme form. Human nature is more evolutionarily determined, more cognitively irrational, and more morally complex than I thought.

I stopped cheering for the Romans

Sometimes the later Roman empire seems very long ago and far away, but at other times, when we explore Edward Gibbon's famous claim to have described the triumph of "barbarism and religion", it can seem as fresh as next week.  And we always know that we're supposed root for the Romans.  When I began my career as historian thirty years ago, I was all in favor of those who were fighting to preserve the old order.  "I'd rather be Belisarius than Stilicho," I said to my classes often enough that they heard it as a mantra of my attitude — preferring the empire-restoring Roman general of the sixth-century to the barbarian general who served Rome and sought compromise and adjustment with neighbors in the fourth. 

But a career as a historian means growth, development, and change.  I did what the historian — as much a scientist as any biochemist, as the German use of the word Wissenschaft for what both practice — should do:  I studied the primary evidence, I listened to and participated in the debates of the scholars.  I had moments when a new book blew me away, and others when I read the incisive critique of the book that had blown me away and thought through the issues again.  I've been back and forth over a range of about four centuries of late Roman history many times now, looking at events, people, ideas, and evidence in different lights and moods.

What I have found is that the closer historical examination comes to the lived moment of the past, the harder it is to take sides with anybody.  And it is a real fact that the ancient past (I'm talking now about the period from 300-700 CE) draws closer and closer to us all the time.  There is a surprisingly large body of material that survives and really only a handful of hardy scholars sorting through it.  Much remains to be done:  The sophist Libanius of Antioch in the late fourth century, partisan for the renegade 'pagan' emperor Julian, left behind a ton of personal letters and essays that few have read, only a handful have been translated, and so only a few scholars have really worked through his career and thought — but I'd love to read, and even more dearly love to write, a good book about him someday.  In addition to the books, there is a growing body of archaeological evidence as diggers fan out across the Mediterranean, Near East, and Europe, and we are beginning to see new kinds of quantitative evidence as well — climate change measured from tree-ring dating, even genetic analysis that suggests that my O'Donnell ancestors came from one of the most seriously inbred populations (Ireland) on the planet — and right now the argument is going on about the genetic evidence for the size of the Anglo-Saxon migrations to Britain.  We know more than we ever did, and we are learning more all the time, and with each decade, we get closer and closer to even the remote past. 

When you do that, you find that the past is more a tissue of  choices and chances than we had imagined, that fifty or a hundred years of bad times can happen — and can end and be replaced by the united work of people with heads and hearts that makes society peaceful and prosperous again; or the opportunity can be kicked away. 

And we should remember that when we root for the Romans, there are contradictory impulses at work.  Rome brought the ancient world a secure environment (Pompey cleaning up the pirates in the Mediterranean was a real service), a standard currency, and a huge free trade zone.  Its taxes were heavy, but the wealth it taxed so immense that it could support a huge bureaucracy for a long time without damaging local prosperity.  Fine:  but it was an empire by conquest, ruled as a military dictatorship, fundamentally dependent on a slave economy, and with no clue whatever about the realities of economic development and management.  A prosperous emperor was one who managed by conquest or taxation to bring a flood of wealth into the capital city and squander it as ostentatiously as possible.  Rome "fell", if that's the right word for it, partly because it ran out of ideas for new peoples to plunder, and fell into a funk of outrage at the thought that some of the neighboring peoples preferred to move inside the empire's borders, settle down, buy fixer-upper houses, send their kids to the local schools, and generally enjoy the benefits of civilization.  (The real barbarians stayed outside.)  Much of the worst damage to Rome was done by Roman emperors and armies thrashing about, thinking they were preserving what they were in fact destroying.

So now I have a new mantra for my students:  "two hundred years is a long time."  When we talk about Shakespeare's time or the Crusades or the Roman Empire or the ancient Israelites, it's all too easy to talk about centuries as objects, a habit we bring even closer to our own time, but real human beings live in the short window of a generation, and with ancient lifespans shorter than our own, that window was brief.  We need to understand and respect just how much possibility was there and how much accomplishment was achieved if we are to understand as well the opportunities that were squandered.  Learning to do that, learning to sift the finest grains of evidence with care, learning to learn from and debate with others — that's how history gets done. 

The excitement begins when you discover that the past is constantly changing.

The Omniscience and Omnipotence of Science

I have changed my mind about the omniscience and omnipotence of science. I now realize that science is strictly limited, and that it is extremely dangerous not to appreciate this.

Science proceeds in general by being reductionist. This term is used in different ways in different contexts but here I take it to mean that scientists begin by observing a world that seems infinitely complex and inchoate, and in order to make sense of it they first "reduce" it to a series of bite-sized problems, each of which can then be made the subject of testable hypotheses which, as far as possible, take mathematical form.

Fair enough. The approach is obviously powerful, and it is hard to see how solid progress of a factual kind could be made in any other way. It produces answers of the kind known as "robust". "Robust" does not of course mean "unequivocally true" and still less does it meet the lawyers' criteria — "the whole truth, and nothing but the truth". But robustness is pretty good; certainly good enough to be going on with.

The limitation is obvious, however. Scientists produce robust answers only because they take great care to tailor the questions. As Sir Peter Medawar said, "Science is the art of the soluble" (within the time and with the tools available). 

Clearly it is a huge mistake to assume that what is soluble is all there is — but some scientists make this mistake routinely.

Or to put the matter another way: they tend conveniently to forget that they arrived at their "robust" conclusions by ignoring as a matter of strategy all the complexities of a kind that seemed inconvenient. But all too often, scientists then are apt to extrapolate from the conclusions they have drawn from their strategically simplified view of the world, to the whole, real world.

Two examples of a quite different kind will suffice: 

1: In the 19th century the study of animal psychology was a mess. On the one hand we had some studies of nerve function by a few physiologists, and on the other we had reams of wondrous but intractable natural history which George Romanes in particular tried to put into some kind of order. But there was nothing much in between. The behaviourists of the 20th century did much to sort out the mess by focusing on the one manifestation of animal psychology that is directly observable and measurable — their behaviour.

Fair enough. But when I was at university in the early 1960s behaviourism ruled everything. Concepts such as "mind" and "consciousness" were banished. B F Skinner even tried to explain the human acquisition of language in terms of his "operant conditioning".

Since then the behaviourist agenda has largely been put in its place. Its methods are still useful (still helping to provide "robust" results) but discussions now are far broader. "Consciousness", "feeling", even "mind" are back on the agenda.

Of course you can argue that in this instance science proved itself to be self-correcting — although this historically is not quite true. Noam Chomsky, not generally recognized as a scientist, did much to dent behaviourist confidence through his own analysis of language.

But for decades the confident assertions of the behaviourists ruled and, I reckon, they were in many ways immensely damaging. In particular they reinforced the Cartesian notion that animals are mere machines, and can be treated as such. Animals such as chimpanzees were routinely regarded simply as useful physiological "models" of human beings who could be more readily abused than humans can. Jane Goodall in particular provided the corrective to this — but she had difficulty getting published at first precisely because she refused to toe the hard-nosed Cartesian (behaviourist-inspired) line. The causes of animal welfare and conservation are still bedeviled by the attitude that animals are simply "machines" and by the crude belief that modern science has "proved" that this is so.

2: In the matter of GMOs we are seeing the crude simplifications still in their uncorrected form. By genetic engineering it is possible (sometimes) to increase crop yield. Other things being equal, high yields are better than low yields. Ergo (the argument goes) GMOs must be good and anyone who says differently must be a fool (unable to understand the science) or wicked (some kind of elitist, trying to hold the peasants back).

But anyone who knows anything about farming in the real world (as opposed to the cosseted experimental fields of the English home counties and of California) knows that yield is by no means the be-all and end-all. Inter alia, high yields require high inputs of resources and capital — the very things that are often lacking. Yield typically matters far less than long-term security — acceptable yields in bad years rather than bumper yields in the best conditions. Security requires individual toughness and variety — neither of which necessarily correlate with super-crop status. In a time of climate change, resilience is obviously of paramount importance — but this is not, alas, obvious to the people who make policy. Bumper crops in good years cause glut — unless the market is regulated;  and glut in the current economic climate (though not necessarily in the real world of the US and the EU) depresses prices and put farmers out of work.

Eventually the penny may drop — that the benison of the trial plot over a few years cannot necessarily be transferred to real farms in the world as a whole. But by that time the traditional crops that could have carried humanity through will be gone, and the people who know how to farm them will be living and dying in urban slums (which, says the UN, are now home to a billion people).

Behind all this nonsense and horror lies the simplistic belief, of a lot of scientists (though by no means all, to be fair) and politicians and captains of industry, that science understands all (ie is omniscient, or soon will be) and that its high technologies can dig us out of any hole we may dig ourselves into (ie is omnipotent).

Absolutely not.