How does the human brain operate? How does it recognize certain concepts? And how does it perceive the world?
Some human neurons react to specific concepts. Ideally, within the human brain, there is a group of cells that specifically react to the concept of "grandmother"—not just "activated when seeing a grandmother" but activated when seeing or thinking about all things related to "grandmother."
This includes "the appearance of a grandmother," "the taste of a grandmother's cooking," "a grandmother's phone call," and even "an old lady who looks like a grandmother."
This hypothesis is known as the "grandmother cell" hypothesis. It represents an ideal model of the brain's "sparse coding" theory.
Of course, this is just a metaphor. The human brain isn't actually so "theoretical."
However, "sparse coding in the face of simple abstract concepts" is something that has been observed experimentally.
