The term “lizard brain” is often used colloquially to refer to the most primitive and basic part of the brain, also known as the reptilian brain. This part of the brain is responsible for instinctual behaviors, survival instincts, and basic functions like breathing, heart rate regulation, and fight-or-flight responses.

When someone says their “lizard brain is engaged,” they typically mean that they are reacting to a situation in a very instinctual or reactive manner, without much conscious thought or rationalization. It’s like acting on automatic impulses rather than making decisions based on higher-level thinking or reasoning.

For example, if someone is faced with a sudden threat or danger, their lizard brain might take over, causing them to react quickly without thinking about it. This can be useful in certain situations where split-second reactions are necessary for survival, but it can also lead to impulsive or irrational behavior in less critical situations.

In essence, saying that your lizard brain is engaged implies that you’re operating on a more primal and reactive level rather than relying on higher cognitive functions.