Thursday, April 12, 2012

Touchy-feel chemistry

Here’s my latest Crucible column for Chemistry World.

What does it feel like to be a molecule? Anthropomorphizing molecules is a familiar enough pedagogical trick – we’ve all seen those cutesy grinning balls-and-sticks in children’s texts on chemistry, and I’ve indulged in this exercise myself to explain the hydrogen-bonding arrangements of water. But perhaps we might stand to learn more from the opposite manoeuvre: not humanizing molecules, but molecularizing humans.

I was set thinking about this after seeing Jaron Lanier, the computer-science pioneer who coined the term ‘virtual reality’ and has done much to develop it as a technology, speak in New York about where VR may be headed. While describing exploratory research in which people are given non-human avatars (could you control a lobster body, say?), Lanier dropped one of those apercus that reveal why he is where he is. This isn’t just an extravagant computer game, he said – in such manifestations VR can be considered to be exploring the pre-adaptations of the human brain. That’s to say, it shows us what kinds of physicality, beyond the bounds of the human body, our brains are equipped to adapt themselves to. This sort of pre-adaptation is a crucial aspect of evolution: a genetic mutation might not simply alter an existing function, for better or worse, but can sometimes unleash the potentiality already latent in the organism’s genetic program. That is quite probably how Hox genes came to facilitate whole new ranges of body plans.

And then one might ask – as Lanier did – whether, as well as lobsters, our brains have the capacity to make themselves at home in a ‘molecule’s body’. Of course, molecules, unlike lobsters, don’t move of their own volition. But might our brains in some sense be able to perceive and intuit the forces that molecules experience: to assemble such sensory data into a coherent image of the molecular world?

Why ask such a seemingly arcane question? Lanier suspects that the embodied experience of VR, by engaging more sensory processes than, say, just vision or logical thinking alone, can offer us new routes to understanding and problem-solving. This is demonstrably true. Lanier, an accomplished musician, pointed out how improvising instrumentalists find their fingers accessing solutions to harmonic or melodic problems – how do I get from here to there – that would be far harder to identify by just sitting down and thinking it out.

Chemists probably need less persuading of this than other scientists. You don’t tend to work out a complex synthesis in your head: you draw out the molecular structures, and the visual information doesn’t just record your thoughts but informs them. For some problems you need to get even more tactile, building molecular models and moving them around, turning and twisting to see if they will fit together as you’d like. That has surely been evident ever since John Dalton devised his wooden ball-and-stick models.

There are already signs that molecular science wants to take this notion of ‘feeling molecules’ to a deeper level. Some years ago I tried out the ‘haptic’ (touch-based) interface of an atomic force microscope developed by Metin Sitti’s group at Carnegie Mellon University in Pittsburgh. This allows the user to feel a representation, in real time, of what the AFM tip is ‘felling’, such as the atomic topography of a surface and the forces that adsorbed molecules exert. It was certainly instructive – so much so that I remember the sensation vividly years later, just as I have never forgotten the feeling of putting my finger into mercury as a child. The haptic AFM felt quite different from the impression you’d get from an animation of what the instrument does: jerkier, somehow grittier.

Chemists have not so far made very extensive use of a more all-embracing VR. One exception is the Duke immersive Virtual Environment (DiVE) developed by the RISE science-education program at the Duke University Medical Center in Durham, North Carolina. This software can be used online, but is best experienced by the user fitted out with VR goggles and joystick manipulator in a small cube-shaped ‘theatre’ with images projected onto the walls and ceiling – a version of the CAVE created at the University of Illinois at Chicago.

Among the projects run for DiVE is ‘DiVe into Alcohol’, an experience that lets you follow the progress of ethanol molecules as they travel through an avatar’s gastrointestinal tract and become oxidized by the enzyme alcohol dehydrogenase in the liver. If you’re in Durham NC you can literally see for yourself: the RISE team offers an open house to all comers on Thursdays.

But Lanier seems to have something more ambitious in mind: the sensation of actually being a molecule. That sounds a little scary: what is it like to be oxidized by having your hydrogens pulled off? But who knows what insights we might gather in the process? Lanier is even exploring how to make such realizations governed by quantum rather than semiclassical rules. Might it be that the famously counterintuitive principles of quantum physics would become less so if we can actually experience them?

No comments: