Why do people recall unpleasant memories so often?

The left hemisphere of our brain focuses on positive experience, whereas the right focuses on negative experience. The question, however, is why do we remember negative experiences more often than the positive ones?

Researchers claim that humans’ brain is negatively biased and they give several explanations for this:

• People pay more attention to unpleasant issues, so the negative message becomes more profound.
• Negatine experiences and memories are easily accesible.
• People weigh negative information more than positive information.
• Negative information is more credible than positive information.
• People weigh negative information more than positive information because that is how they think it should be weighed.