At first, forgiveness may seem too vague to quantify scientifically and thus, near impossible to study. In this way, forgiveness is indicative of the problems faced in many areas of psychology, as the link between brain chemistry, psychoanalysis and correct diagnosis of a psychological disposition is incredibly hard to quantify. This is exemplified by forgiveness, as how can one assign a number to an individual’s propensity to forgive? Or indeed how does one assign a number to the effect a single act of forgiveness may make?

It turns out both of these and more are entirely possible. The first distinction that needs to be made is state vs trait forgiveness. Trait forgiveness refers to an individual’s propensity or likeliness to forgive a transgressor. State forgiveness is a single act of forgiveness in a victim.

The second necessary clarification is the definition of forgiveness. It is distinct from pardoning, excusing, denial, forgetting or condoning of the offence. It is also distinct from reconciliation with an offender. As a response (i.e state), it is defined as “a prosocial change in a victim’s emotions toward a blameworthy transgressor.” As a disposition (trait), all people can be placed on a forgiving-unforgiving spectrum based on one’s propensity to forgive in a wide variety of interpersonal circumstances. Thirdly, as a quality of social groups, forgiveness is akin to trust and commitment. For example, some marriages and families might be highly forgiving whereas an institution that readily ostracises or punishes its members would not be.

This is all good in theory, but science relies on numbers and therefore the final clarification that needs to be made is quantifying forgiveness. The methods for quantifying both state and trait forgiveness consist of questionnaires and interviews and are therefore psychoanalytic rather than neuroscientific. However, they yield results that have been proven to be exceedingly reliable (alpha coefficient > 0.9, 1 being perfect reliability). Also, despite not being physical or chemical tests, they have proven the effect of forgiveness on physical health.

The physical benefits of forgiveness have been most thoroughly researched in a 2005 study by Lawler et al. Here participants were interviewed about a time where they had been betrayed and filled out the tests of both state forgiveness of the specific incident and their individual levels of trait forgiveness. They were also tested on their health over the past month and there was found to be a roughly -0.5 (p<0.0001) correlation between both state and trait and the number of medications taken. What this means is that there was a one in ten thousand chance of this result if there were no correlation between forgiveness and medications taken; p<0.05 is the threshold for statistical significance. The correlation between these two qualities and the CHIPS scale was -0.33 (trait) and -0.48 (state) (p<0.01). The CHIPS scale is a common measure of general wellness as it measures over 40 common symptoms. Here the correlation was weaker but still very evident.

The most impressive results of this study though were the effect of forgiveness on mediators. A mediator is a quality which is affected by the independent variable (forgiveness) and effects the dependent variable (health issues). In this way they are indirect pathways by which forgiveness can affect physical health and thus good characteristics to develop in order to aid the health benefits of forgiveness. The mediators studied by Lawler et al. were spirituality, stress, negative affect (depression, tension, and anger) (NA) and conflict management skills. The greatest mediator of both trait and state forgiveness was NA as forgiveness had the greatest effect on it and it in turn had the greatest effect on health. Furthermore, it turned out that almost all of the effects of forgiveness were mediated by NA. What this means is that forgiveness had a significant impact in reducing NA, if it were present, and was least inhibited when it was not present. Interestingly, this same level of full mediation was shown by conflict management skills but exclusively for trait forgiveness, yet almost not at all for state. The same applies to stress, although this was slightly more influential on state, as it fully mediated trait forgiveness’s benefits. Spirituality, consisting of existential and religious well being, turned out to the weakest of the mediators though still a partial mediator.

These results, in conjunction with those of McCullough et al. in 2002, found that forgiveness affects depression, tension, stress, spirituality, and crucially hostility. This in turn massively aids in reducing cardiovascular issues, though it also impacts more general health as proven by the effect on CHIPS scale.

In addition to this forgiveness also provides mental health benefits. Indeed, trait forgiveness can be linked to lower rates of depression, paranoid ideation, hostility and adverse interpersonal sensitivity. The forgiveness of oneself was linked to levels of depression, anxiety and self-esteem as may be expected. The forgiveness of self scale, developed in 1992, measures one’s propensity to forgive oneself however the research into it is remarkably little. This is unfortunately due to the problem of semantic overlap. Semantic overlap refers to the inaccuracies that arise in studies based on self-reported symptoms where the questions concerning the independent and dependent variables overlap in language and thus a correlation in answers appears even if none is in fact present. Lawler et al. mitigated this effectively, however this is harder to do in the case of self-forgiveness. An area that is equally understudied is the forgiveness of God. However, Exline, Yali and Lobel (1999) found that forgiveness of God for negative life experiences also correlated with lower levels of anxiety and depression.

So, what can be done to improve forgiveness? McCullough’s findings were that intervention groups focused on forgiveness were most effective. However, these varied greatly; but in this variation it was found that just a few hours more contact with the group could increase forgiveness by 50% of a standard deviation, from 24% at 6 hours contact to 76% at 8 hours contact. However, on a more day-to-day basis, partnerships and close, personal relationships were unsurprisingly the ones in which it was easier to forgive and so the development of these relationships can increase both trait and state forgiveness in an individual. Additionally, forgiveness also increases with age and with several other factors such as the level of neuroticism in the victim, the actions of the offender etc. What is important to note in all of this is that forgiveness can be promoted by a wide array of influences and therefore we need be open to them, not only for others’ sake, but also for our own health.