Chronistic Serendipity

Much is made of the importance of serendipity to scientific discovery. Here are some well-known examples:

  • Roentgen’s discovery of x-rays.

    Antenna used by Penzias & Wilson

  • Becquerel’s discovery of radioactivity.
  • Hoffmann’s accidental first trip on LSD.
  • Fleming’s discovery of penicillin.
  • Bell’s discovery of pulsars.
  • Penzias and Wilson’s discovery of cosmic background radiation.

All of these “accidental” findings resulted from trained minds being capable of recognizing something unusual and unexpected as worthy of further study. I argue that all of these breakthroughs would have occurred at some point–these folks simply happened to notice them. There was nothing special about the time when the discovery occurred, except that the technology had been developed that allowed it to happen. Once that technology existed, the discovery was inevitable.

However, I suggest that an important discovery in neuroscience–so important that it led to a Nobel Prize–occurred in large measure because of the time when the research was done. The technology that allowed it did not exist a few decades earlier, and a few decades later the technology had changed to the point that the discovery would not have occurred. I’m talking about Hubel and Wiesel’s discovery of the receptive fields of visual cells in the brain’s cortex.

These neuroscientists found that the simplest visual stimulus that activates cells in our cortex is a line, in a particular place and oriented a particular way. Even Hubel has admitted that the discovery was accidental. Cells in the retina and thalamus were known to respond to spots of light (or dark), so Hubel and Wiesel were shining all sorts of spots in front of their anesthetized cats in a failing effort to make the cortical cells fire. 

The scientists used spots painted on glass slides, which were moved around in a projector and displayed on a projection screen in front of the cat. The cortical cells did not respond to the spots, but when the edge of the glass slide moved through the projector, casting a faint line on the screen, a cell responded.  Hubel and Wiesel realized that cortical cells respond not to dots or spots, but to lines, as a result of this accidental finding.

So what was special about this point in time, the 1950s, that allowed this discovery? It is almost certain that, had they done this work in the 1980s or later, they would not have used a glass slide in a projector. Instead, it is likely that they would have used a computer to generate the spots and move them around on a screen in front of the cat. What’s missing in the scenario? The edge of the glass slide. No glass slide, no edge, no line presented to the cat. Their serendipitous finding that cells respond to lines would not have occurred.

The discovery of the nature of the receptive fields of visual cortical neurons rested on the scientists doing the work not after a particular point in time, but in a particular time window. This is an example of chronistic serendipity. I would love to hear examples of others if someone can identify any. Post them as comments below.

Share if you like this.Share on FacebookTweet about this on TwitterEmail this to someone

WordPress Themes