I usually like to scan the science section of the New York Times just to see what interesting breakthroughs have been made. There is, of course, way too much knowledge being created everyday for anyone to be able to keep up with it all. Nevertheless, most creativity gurus recommend that you spend at least some time reading about things far afield from your everyday activities in order to stimulate your thinking and broaden your knowledge. To that end, let’s examine a few recent articles from biology and neurology. Let’s start with the plant world and an article by Carol Kaesuk Yoon [“Loyal to Its Roots,” New York Times, 10 June 2008]. She begins with the intriguingly named “sea rocket” plant.
“From its diminutive lavender flowers to its straggly windblown stalks, there is nothing about the beach weed known as the Great Lakes sea rocket to suggest that it might be any sort of a botanical wonder. Yet scientists have found evidence that the sea rocket is able to do something that no other plant has ever been shown to do. The sea rocket, researchers report, can distinguish between plants that are related to it and those that are not. And not only does this plant recognize its kin, but it also gives them preferential treatment. If the sea rocket detects unrelated plants growing in the ground with it, the plant aggressively sprouts nutrient-grabbing roots. But if it detects family, it politely restrains itself. The finding is a surprise, even a bit of a shock, in part because most animals have not even been shown to have the ability to recognize relatives, despite the huge advantages in doing so. If an individual can identify kin, it can help them, an evolutionarily sensible act because relatives share some genes. The same discriminating organism could likewise ramp up nasty behavior against unrelated individuals with which it is most sensible to be in claws- or perhaps thorns-bared competition.”
Imagine if scientists manage to isolate the “kin recognition gene” and are able to transplant it into vegetables or grasses. The defensive mechanisms demonstrated by the sea rocket may help produce weed free gardens or lawns. A lot of farmers, casual gardeners, and ordinary home owners would appreciate the help. The scientist who discovered the sea rocket’s abilities was surprised by it.
“‘I’m just amazed at what we’ve found,’ said Susan A. Dudley, an evolutionary plant ecologist at McMaster University in Hamilton, Ontario, who carried out the study with a graduate student, Amanda L. File. ‘Plants,’ Dr. Dudley said, ‘have a secret social life.’ Since the research on sea rockets was published in August [2007] in Biology Letters, a journal of the United Kingdom’s national academy of science, Dr. Dudley and colleagues have found evidence that three other plant species can also recognize relatives. The studies are part of an emerging picture of life among plants, one in which these organisms, long viewed as so much immobile, passive greenery, can be seen to sense all sorts of things about the plants around them and use that information to interact with them.”
While the ability to recognize kin may sound very animal-like, the mechanisms that plants use to distinguish relatives from other plants are very different, Yoon reports, from the ways that animals distinguish members of their family.
“Plants’ social life may have remained mysterious for so long because, as researchers have seen in studies of species like sagebrush, strawberries and thornapples, the ways plants sense can be quite different from the ways in which animals do. Some plants, for example, have been shown to sense potentially competing neighboring plants by subtle changes in light. That is because plants absorb and reflect particular wavelengths of sunlight, creating signature shifts that other plants can detect. Scientists also find plants exhibiting ways to gather information on other plants from chemicals released into the soil and air.”
Yoon next describes a parasitic weed (called dodder) that “hunts” using seek and destroy search patterns similar to those used by destroyers to hunt submarines using sonar in the Second World War.
“Dodder is unable to grow its own roots or make its own sugars using photosynthesis, the process used by nearly all other plants. As a result, scientists knew that after sprouting from seed, the plant would fairly quickly need to begin growing on and into another plant to extract the nutrients needed to survive. But even the scientists studying the plant were surprised at the speed and precision with which a dodder seedling could sense and hunt its victim. In time-lapse movies, scientists saw dodder sprouts moving in a circular fashion, in what they discovered was a sampling of the airborne chemicals released by nearby plants, a bit like a dog sniffing the air around a dinner buffet. Then, using just the hint of the smells and without having touched another plant, the dodder grew toward its preferred victim. That is, the dodder reliably sensed and attacked the species of plant, from among the choices nearby, on which it would grow best.”
Plant behavior that seems animal-like is surprising, Yoon notes, because it doesn’t rely on sense organs typically found in animals.
“Although a view of plants as sensing organisms is beginning to emerge, scientists have been finding hints of such capabilities and interactions for 20 years. But discoveries have continued to surprise scientists, because of what some describe as an entrenched disbelief that plants, without benefit of eyes, ears, nose, mouth or brain, can and do all they are seen to do. … The problem, for many scientists, is that as obvious as the behaviors sometimes are, they can seem just too complex and animal-like for a plant. … It does not help credibility that scientists in the field often find themselves having to distinguish the results of careful experimental studies from decidedly nonscientific, even kook-fringe, discussions about phenomena like plant sentience and emotion. Plants are not ‘sensitive new age guys who cringe when something around them gets hurt and who love classical music and hate rock,’ Dr. Dudley said as she referred to depictions in popular works of plants living tender, emotion-soaked existences, in particular the 1970s ‘The Secret Life of Plants.’ Even mainstream researchers do not always completely agree on which ideas are clearly within the realm of science and which have gone a bit too far.”
Yoon concludes her article by describing heated debates between “new wave botanists” who are pushing what they call “plant neurobiology” and more traditional scientists who fume at the very mention of the term. Although both sides agree that plant “brains” are unlikely to be discovered, the debate about the purpose of electrical signals sent from one part of a plant to another is bound to continue.
“Thirty-six authors from universities that included Yale and Oxford were exasperated enough to publish an article last year, ‘Plant Neurobiology: No Brain, No Gain?’ in the journal Trends in Plant Science. The scientists chide the new society for discussing possibilities like plant neurons and synapses, urging that the researchers abandon such ‘superficial analogies and questionable extrapolations.'”
That is an excellent segue into the next article [“Brainpower May Lie in Complexity of Synapses,” by Nicholas Wade, New York Times, 10 June 2008].
“Evolution’s recipe for making a brain more complex has long seemed simple enough. Just increase the number of nerve cells, or neurons, and the interconnections between them. A human brain, for instance, is three times the volume of a chimpanzee’s. A whole new dimension of evolutionary complexity has now emerged from a cross-species study led by Dr. Seth Grant at the Sanger Institute in England. Dr. Grant looked at the interconnections between neurons, known as synapses, which until now have been regarded as a standard feature of neurons. But in fact the synapses get considerably more complex going up the evolutionary scale. … In worms and flies, the synapses mediate simple forms of learning, but in higher animals they are built from a much richer array of protein components and conduct complex learning and pattern recognition, Dr. Grant said. The finding may open a new window into how the brain operates. ‘One of the biggest questions in neuroscience is to answer what are the design principles by which the human brain is constructed, and this is one of those principles,’ Dr. Grant said.”
In a recent post [Looking towards the Future with Ray Kurzweil], I noted that futurist Kurzweil predicts that eventually computers will be able to think like humans. I also noted that others doubt that computers will be able to mimic human thought because the brain evolved in a haphazard manner. Wade agrees that human thought involves more than just an enormous number of synapses.
“If the synapses are thought of as the chips in a computer, then brainpower is shaped by the sophistication of each chip, as well as by their numbers. ‘From the evolutionary perspective, the big brains of vertebrates not only have more synapses and neurons, but each of these synapses is more powerful — vertebrates have big Internets with big computers and invertebrates have small Internets with small computers,’ Dr. Grant said. … The computing capabilities of the human brain may lie not so much in its neuronal network as in the complex calculations that its synapses perform, Dr. Grant said. Vertebrate synapses have about 1,000 different proteins, assembled into 13 molecular machines, one of which is built from 183 different proteins. These synapses are not standard throughout the brain, Dr. Grant’s group has found; each region uses different combinations of the 1,000 proteins to fashion its own custom-made synapses. Each synapse can presumably make sophisticated calculations based on messages reaching it from other neurons. The human brain has about 100 billion neurons, interconnected at 100 trillion synapses.”
Grant’s cross-species work is unique and is opening an entirely new field of research into brain function. The final article I’d like to review also deals with brain function [“Anticipating the Future to ‘See’ the Present,” by Benedict Carey, New York Times, 10 June 2008].
“Staring at a pattern meant to evoke an optical illusion is usually an act of idle curiosity, akin to palm reading or astrology. … Scientists have investigated such illusions for hundreds of years, looking for clues to how the brain constructs a seamless whole from the bouncing kaleidoscope of light coming through the eyes. Brain researchers today call the illusions perceptual, not optical, because the entire visual system is involved, and their theories about what is occurring can sound as exotic as anyone’s. In the current issue of the journal Cognitive Science, researchers at the California Institute of Technology and the University of Sussex argue that the brain’s adaptive ability to see into the near future creates many common illusions.”
The term “see into the near future” is a bit of a misnomer. The brain, it turns out, guesses about (or anticipates) what is coming next and the mind sees the results (which are often a mere illusion).
“‘It takes time for the brain to process visual information, so it has to anticipate the future to perceive the present,’ said Mark Changizi, the lead author of the paper, who is now at Rensselaer Polytechnic Institute. ‘One common functional mechanism can explain many of these seemingly unrelated illusions.’ His co-authors were Andrew Hsieh, Romi Nijhawan, Ryota Kanai and Shinsuke Shimojo. One fundamental debate in visual research is whether the brain uses a bag of ad hoc tricks to build a streaming model of the world, or a general principle, like filling in disjointed images based on inference from new evidence and past experience. The answer may be both. But perceptual illusions provide a keyhole to glimpse the system.”
In other words, the old adage “what you see is what is you get” is not necessarily true. We all know this, however, from watching movies. Even though we know that we are watching still frames in rapid succession to get the illusion of movement, we nevertheless call them “motion” pictures. We enjoy being tricked.
“When shown two images in quick succession, one of a dot on the left of a screen and one with the dot on the right, the brain sees motion from left to right, even though there was none. The visual system has apparently constructed the scenario after it has been perceived, reconciling the jagged images by imputing motion. In an experiment originated by Dr. Nijhawan, people watch an object pass a flashbulb. The timing is exact: the bulb flashes precisely as the object passes. But people perceive that the object has moved past the bulb before it flashes. Scientists argue that the brain has evolved to see a split second into the future when it perceives motion. Because it takes the brain at least a tenth of a second to model visual information, it is working with old information. By modeling the future during movement, it is ‘seeing’ the present. Dr. Changizi and his colleagues hold that it is a general principle the brain applies to a wide variety of illusions that trick the brain into sensing motion.”
The fact that we instinctively move to the right location to catch an object that has slipped out of our hands probably uses the same system of “seeing the future” to help us respond. But the things that intrigue scientists are the optical illusions that continue to fascinate us. To prove the point that the mind anticipates motion, Carey included two examples of optical illusions that you can try for yourself if you follow the link. In one of them, which involves leaning towards a precise checkerboard, the image seems to bulge because the center squares appear to be approaching the eye faster than the outer squares.
“Dr. Changizi says such illusions can also occur in real life. When a golf ball or baseball rolls through the grass and suddenly drops into a hole, the brain sometimes perceives a trace of the ball on the other side of the hole. ‘But these are things that we don’t experience very often,’ he said, ‘because the brain is so good at covering up its mistakes.'”
It’s too bad that our mental acuity isn’t quite as good as our visual acuity. If it were, maybe we could cover up our mistakes and never say some of the dumb things that escape our mouths before we realize they’re going to get us in trouble!
