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If asked to draw a person's portrait, many people would say “I cannot draw.” Why is observational drawing so hard? In a new paper, @judithfan.bsky.social and I answer: it's the limitations of human vision. Learning to draw is learning skills to overcome them. aaronhertzmann.com/2026/03/23/d... 1/

Drawing is a creative activity, accessible to everyone: all you need is a pen or pencil and paper, and people have been drawing for at least 45,000 years. Psychologists have extensively studied drawing for decades, but no coherent theory for the process of observational drawing has emerged. 2/

One might think that an artist draws a picture by looking at the world, forming a mental picture of it, and then drawing from that picture. Drawing errors are perceptual or motor errors. But no one draws this way, because no one actually keeps a complete picture of what they see in their head. 3/

One clue is that human vision is severely limited, both in terms of what we see at any moment, and how much of it we remember. And, we are *totally unaware* of how much we do not see, until it is pointed out. Suppose you wanted to draw a picture from this photo of a houseplant, 5/

Look at the photo, and then look away. How many branches does the plant have? How many leaves does each branch have? These questions are easy when looking at it, but nearly impossible afterward. Drawing the picture from memory—capturing details of contour or shading—would be mostly making it up. 6/

Now try the same exercise, but just staring at a single leaf on the houseplant. Can you count the leaves and branches without moving your eyes at all? Again, it's nearly impossible: you couldn't draw an accurate copy of the plant without moving your eyes. 7/

I had never seen this video before, and I'm grateful that you've shared it.