Research has shown that domestic cats never forgive. They fail to show signs of reconciliation as other animals do.
The scientific literature on forgiveness came to the fore only in 1989 but some researchers suggest that we're seeing more public figures seeking forgiveness because we are becoming more aware of the importance of achieving reconciliation.
Cats never forgive. Social primates, like bonobos, mountain gorillas, and chimps, often follow confrontations with friendly behavior like embracing or kissing. Similar behavior has been observed in non-primates such as goats and hyenas. However, one species that has so far failed to show outward signs of reconciliation is the domestic cat.
No offense is unforgivable "I have never found a particular injustice in the world that I don't know of at least one person who has forgiven those who have perpetrated it" says Robert Enright, a psychologist who is one of the pioneers of the study of forgiveness.
But betrayal is the worst. According to a study from 2010, the most common type of offense people find impossible to forgive is betrayal, including affairs, deceit, broken promises, and divulged secrets.
There are different kinds of forgiveness. Decisional forgiveness is a sincere decision to change the way you intend to behave towards someone who has wronged you, even though you may still feel negatively towards the person. Emotional forgiveness is a change in the way you feel towards this person – resentment giving way to positive emotions like empathy, sympathy, compassion, and even love.
Younger kids forgive easily. Unlike ten and 11-year-olds, seven and eight-year-olds in one study didn't need an apology to forgive; they tended to judge offenders who had apologized and those who hadn't as equally worthy.
Carrying a grudge can weigh you down. Researchers at Erasmus University in the Netherlands asked a group of students to write about a time when they either gave or withheld forgiveness. The human guinea pigs were then asked to jump as high as they could, five times, without bending their knees. The forgivers jumped highest, about 30 cm on average, while the grudge holders jumped 22 cm – a huge difference and a startling illustration of how forgiveness can unburden you.
Extroverts need forgiveness sooner. Outgoing types are more proactive in seeking out forgiveness than introverts are (and also, notably, quicker to forgive others). Introverts tend to be initially more concerned with forgiving themselves than making amends with a person they've offended.