What is positive feedback loop?

Example: Your body temperature rises above 37 degrees Celsius. Thermoreceptors in your skin and hypothalamus detect the deviation. The hypothalamus triggers sweat production and vasodilation — blood vessels near the skin dilate to release heat. Temperature drops. The thermoreceptors detect the return toward baseline and reduce the cooling response. This is a balancing feedback loop: a circular relationship where the output (cooling) counteracts the input (rising temperature). Walter Cannon coined the term homeostasis in 1926 to describe exactly this kind of self-correcting circularity. Your body runs thousands of these loops simultaneously — regulating blood sugar, blood pressure, pH levels, hydration — each one a circular relationship that keeps a variable within a survivable range. You are, at the most fundamental biological level, a collection of feedback loops.

This concept is part of Relationship Mapping in the How to Think curriculum.