The lizard brain is hungry, scared, angry, and horny. The lizard brain only wants to eat and be safe. The lizard brain will fight (to the death) if it has to, but would rather run away. It likes a vendetta and has no trouble getting angry. The lizard brain cares what everyone else thinks, because status in the tribe is essential to its survival.
A squirrel runs around looking for nuts, hiding from foxes, listening for predators, and watching for other squirrels. The squirrel does this because that’s all it can do. All the squirrel has is a lizard brain.
The only correct answer to “Why did the chicken cross the road?” is “Because its lizard brain told it to.” Wild animals are wild because the only brain they possess is a lizard brain. The lizard brain is not merely a concept. It’s real, and it’s living on the top of your spine, fighting for your survival.
But, of course, survival and success are not the same thing The lizard brain is the reason you’re afraid, the reason you don’t do all the art you can, the reason you don’t ship when you can. The lizard brain is the source of the resistance.
Seth Godin. “Linchpin.”