The fairy tale of Goldilocks and the Three Bears has a long history and has been interpreted in various ways.  It’s unlikely that it was intended as an object lesson in physiology, but the story provides a perfect metaphor for the basic response system that keeps us alive.

Like Goldilocks, the cells inside your body are fussy about many things, and require a relatively constant internal environment, a dynamic condition known as homeostasis.  If your internal temperature or body chemistry are not “just right”, the intricate chemical pathways that sustain us will begin to fail.

In order to achieve homeostasis, the body makes constant small corrections.  For example when you exercise, the metabolic heat produced increases your body temperature, causing your body temperature to exceed the optimum.  In response, you produce sweat to bring your temperature back down.  Conversely, if you find yourself underdressed in a blizzard, your body temperature will drop below normal, causing you to shiver and generate more heat.

This process of counteracting a deviation by bringing about an opposing change is called negative feedback.  It’s a vital process that’s commonly misunderstood by physiology students.  In our day-to-day lives, we have grown accustomed to seeking out “positive” feedback from friends, colleagues and customers.  But it’s the negative feedback that plays a vital and sustaining role, by correcting perturbations to our physiological state.  Without negative feedback, not only our body temperature, but pH, osmolarity, acid/base balance and many other internal properties would easily spin out of control.

So next time you receive negative feedback from someone, remember it’s a blessing in disguise!  By letting you know when things aren’t right, it can set you back on the right course.