On neuroscience, telephone poles and accurate drawing

What is the common point between neuroscience, telephone poles and accurate drawing?

I was listening to a fascinating podcast, The Brain Science Podcast. In Episode 73, Doctor Ginger Campbell was interviewing Doctor Shapiro, Professor of Philosophy and author of the book “Embodied Cognition (New Problems of Philosophy)"

A discussion around the end of the podcast caught my ears.

Source: MorgueFile [Image URL]

Dr. Shapiro gave an example on how problems that seem complicated can sometimes get resolved easily by focussing on one parametre.

Dr. Shapiro: “Yes. Gibson has lots of examples of what appear to be computationally onerous tasks, but it turns out that there are very simple solutions that rely on picking up certain information in the environment. So, here’s a neat example: If you have two telephone poles that are the same height—50 feet tall, let’s say—and one of them is behind the other, the question is: how do you figure out which one is closer and which one is further. No, sorry; the question is: are they the same height—let’s make that the question. And in order to answer that, it seems like a computational problem: you have to figure out how far they are from you, and then certain trigonometric relationships will tell you whether they’re the same height.

But what Gibson realized was that objects at the same height will have the same proportion of themselves below the horizon and above the horizon. So, two telephone poles that are 50 feet tall, if one is 100 feet away and the other is 50 feet away, they’ll still be cut by the horizon with the same proportion beneath the horizon and above the horizon. And that tells you that they’re the same height.


You don’t have to do any sort of computations.”

You can reverse the statement made in the paragraph I highlighted in bold: If you are drawing telephone poles along a road vanishing towards the horizon their size will get smaller, but they will be cut by the horizon with the same proportion beneath the horizon and above the horizon (because you know they are the same height).

Knowing this principle can be useful when drawing a vanishing series of posts or lamposts.

 Brain Science Podcast Doctor Ginger Campbell Doctor Shapiro perspective drawing