positive feedback loop
An engineering term meaning some of the output from a system is fed back in as an input into the same system, processed (often amplified), then output again, then fed back in again, in an ongoing loop. An easy example is microphone feedback. The slightest sound going into a microphone is fed through a speaker system which amplifies it then outputs it, whereupon it goes into the mic again for another round of amplification, and so on until there is quickly a deafening whine coming out of the speakers.
An example of positive feedback in the human mindbody is the emotion-thought loop. An initial fear emotion can generate a thought (which is simply an interpretation of that emotion). If the thought interprets the emotion negatively, those outcomes are fed back into the emotions (via fearful verbal commands (your “inner voice”), or via fearful internal imagery). The base areas of the brain cannot distinguish between internally- and externally-generated content, so respond the same resulting in more fear emotion, which then feeds back into more fearful verbal and visual thoughts, creating a positive feedback loop. This is how initial low-level fear can quickly become paranoia and terror.
Positive feedback loops govern much of human experience. Luckily they can work in your favour, too. E.g. good luck tunes the system to find more good luck (“I’m on a hot streak!” or “I’m a lucky person!”).
Personal development can be thought of as a process of organizing the system so that it processes input in beneficial ways, and/or ignores (or converts) unfavourable input, so that positive feedback is growth- and love-orientated rather than contraction- and fear-orientated.