What if we added another?

So a single neuron has a hard limit. What if we used more than one?

Take a dog deciding whether to bark. It has two senses feeding signals into its brain: smell and sound. Each sense is a neuron. It fires when it detects something, and sends that signal forward.

The dog should only bark when it smells and hears something at the same time. Either sense alone, a distant smell, a random noise, isn't enough. Both together means something is actually there.

A single neuron in the middle can't figure this out. It has to score smell and sound separately and add them up. But since each sense alone is usually nothing, both scores are low. Added together, they still don't cross the threshold. The neuron stays quiet, even when the dog should bark.

What if there were a second neuron whose only job was to watch for smell and sound together? When both fire at once, that neuron fires. The output listens to it. Now the combination has somewhere to live.

Click the senses to turn them on and off. Switch between one neuron and two. Watch when the dog gets it right.