Does it seem like your brain always brings up unpleasant memories, making you feel bad, while ignoring all the enjoyable ones? There maybe a scientific reason for it.
This phenomenon called “Negativity Bias” has an evolutionary hypothesis behind it: Negative experiences and traumas often carry a much higher survival cost (like death) that typicially far outwieghs the potential benefits we might gain from positive experiences. And so our brains, the hypothesis goes, are wired to be more sensitive to negative experiences, such as through vivid memories and rumination.
In short: on the whole, the wisdom to be learned from negative events tends to be more valuable to our breeding chances than the wisdom that might be learned from positive experiences.
Unfortunately, in our modern society we have largely conquered our hostile environment and so this negativity instinct no longer serves us so well as it once did. In fact, it can cause us a lot more harm today than good. It tends to leave us with a lot of emotional baggage later in life that can really weigh us down and can even provoke self-defeating behavior patterns.
Our natural tendency to obsessively ruminate over past traumas and mistakes can cause depression, insecurity, addictive escapism, anger problems, sociability disfunction, career problems, etc. It takes a lot of counter-instinctual emotional maturity and mental discipline to stop ourselves from dwelling too much on mistakes and regrets and instead to focus on positive aspirations, optimism, and hope.
There is an excellent book by Rick Hanson PhD (Berkeley): Resilient
The book is about how you can use mindfulness practices (mental workouts, really) to train your brain to weaken negative thought habits and to get better at constructive thought patterns.
The brain is like a muscle and it gets good at what we use it for. If we constantly ruminate over negative experiences then our brain will get increasingly good at doing that. This book is a training manual for breaking that negative cycle and achieving a healthy mind.
The book is highly practical, well organized, easy to read, and is solidly based on science and professional practices in the fields of psychology and neuroscience. It also comes in audiobook format, which you might even find in your library.
Humans have the unique ability to use reason to defy our natural instincts when they are counterproductive and to modify our behavior patterns in more positive directions. This book teaches practical ways to achieve that end.
He also has a pretty helpful website.
Emotion is a huge modulator of memory formation and recall.Strong emotional states (good or bad) tend to heighten the vividness and durability of memories formed while under their effects.If there is a bias towards negative thoughts and reflection it may be due to our evolutionary past.On the other hand, obsessing over past failures and potential threats/danger might convey some benefit.While this is not a pleasant subjective state to exist in, it nonetheless lowers the chances of ending up tiger food (if there’s a realistic chance of that happening).