Vernier Acuity

Here's a really neat thing we learned about in my psych class last quarter (disappointingly, one of the few neat things we learned). It's called vernier acuity. It's the ability to discern an offset in a supposedly continuous line. A related term is visual acuity, how small the smallest discernable visual feature is; it's analogous to the resolution at which we can view the world. This is affected by the size of a each cone on your retina.

You'd think that one is limited by the other. You'd think that our ability to detect an offset in a line is limited by our visual acuity, or how "pixelated" the world is to us as a function of the anatomy of our photoreceptors. Surprise! Vernier acuity has a resolution five to ten times greater than our visual acuity! WHAT?!? Where could all that extra precision come from?

This is an interesting demonstration of the critical role that visual processing systems in the brain play in how we sense our world. Our eyes don't just "tell" our brain how the world is put together. The brain must sort, refine, and compile the bits of data from photoreceptors into a cohesive image that we see. As a result, vernier acuity actually transcends the capable resolution offered by our retinas by somehow harnessing the computing power of the brain.

A further and slightly tangential question: as the brain processes raw sensory input signals from the retina, how can we be sure it is accurately tracking real world phenomena? What keeps the saliency of refinements in check if the only information we receive comes from our photoreceptors in the first place? How "real" is our "real"? Maybe our real is just what is most practical. (In other words, a possible answer to ponder: evolutionary advantage is given to those with certain visual interpretations, so these were the cortical processing systems developed).

A cool, INTERACTIVE (YAY! :D) demonstration can be found at the following link.

http://www.michaelbach.de/ot/lum_hyperacuity/index.html

I also used this source to supplement my ailing memory about the subject. Seems legit!

TLDR; We see with our brains (rather than strictly with our eyes) more than we might think. Vernier acuity is a really cool example of this.

An Essential Epistemological Question, and Why it Cannot Be Answered

Science is certainly an amazing thing. Within the past 100 years or so, human society has been able to formulate countless models and theories of explanation where before there was complete mystery or obliviousness. Space feels less far away, the oceans seem less deep, and our own minds are beginning to be treated a lot more like brains.

With all of this rapid progress, it might be useful to think about human knowledge and whether there are limits to this seemingly exponential trend of understanding.

Q : Will we ever know ALL the things? Is it even conceivably possible that there is a point in humankind's future when nothing will remain a mystery, and our understanding of the natural world can be declared to be virtually complete?

A : Eh. Not so fast.

In order to have a answer (at least, one that's justified and supported), we have to fully understand the question at hand. Gut reactions of "yes!" or "no!" won't be very informative. Let's look at the implications of yes and no replies.

The "yes!" people see the current trends and have full confidence that the rate of scientific progress will continue steadily or grow. They also assume that there is a finite amount of information to be gathered about the universe.

The "no!" people assume that there either limitations to what human minds can grasp or be aware of, or that the amount of information to collect and synthesize about the world is so vast that it (might as well be?) infinite.

I think that none of these assumptions have much bearing because none of them can really be shown to be truer than the others. They are assumptions, after all. One of our reasons for feeling like the question is interesting in the first place is that we don't know how much we know in relation to how much there is to know. But without knowing how close we are to knowing everything about the natural world there is no way to answer this question. Some things we know we don't know, and maybe these seem solve-able mysteries to us. But there are plenty of other things we don't know we don't know, and for all we know these could evade our understanding indefinitely.

The answer to our question is therefore one other thing that is perhaps appropriate to add to the list of unknowns.