An instinctive reaction is an immediate response that happens automatically without thinking. It is like a natural reflex or a gut feeling when your body or mind responds without conscious thought. Full definition
An old parenting style «urge» is an automatic, almost instinctive reaction of forcing my will upon my child because it seems like the easiest and fastest solution. (positive-parenting-ally.com)
As Steel explains it, the tendency results from the tension between the cerebral cortex — the thoughtful part of the brain — and the limbic system, from which our more instinctive reactions derive. (canadianbusiness.com)
In our own case I think we have such sophisticated potential actions we no longer have these simple instinctive reactions. (religion-online.org)