Washington D.C. [USA], Apr 19 : A recent study claims to answer the much-debated question - Why people make certain moral decisions? Some people may rely on principles of both guilt and fairness and may switch their moral rule depending on the circumstances, study suggests. 
The study was published in the journal of Nature Communications.  
"Our study demonstrates that with moral behavior, people may not in fact always stick to the golden rule. While most people tend to exhibit some concern for others, others may demonstrate what we have called 'moral opportunism,' where they still want to look moral but want to maximize their own benefit," said lead author Jeroen van Baar.
"In everyday life, we may not notice that our morals are context-dependent since our contexts tend to stay the same daily. However, under new circumstances, we may find that the moral rules we thought we'd always follow are actually quite malleable. This has tremendous ramifications if one considers how our moral behavior could change under new contexts, such as during war," explained co-author Luke J. Chang.
To examine moral decision-making, the researchers designed a modified trust game called the Hidden Multiplier Trust Game. The game allowed them to classify decisions in reciprocating trust as a function of an individual's moral strategy.
With this method, the team could determine which type of moral strategy a study participant was using. The strategies were - 
(A)  Inequity aversion - where people reciprocate because they want to seek fairness in outcomes),
(B)  Guilt aversion - where people reciprocate because they want to avoid feeling guilty. , greed, or moral opportunism.
The researchers also developed a computational, moral strategy model that could be used to explain how people behave in the game.
The findings reveal for the first time that unique patterns of brain activity underlie the inequity aversion and guilt aversion strategies, even when the strategies yield the same behavior.
For the participants that were morally opportunistic, the researchers observed that their brain patterns switched between the two moral strategies across different contexts.
 "Our results demonstrate that people may use different moral principles to make their decisions, and that some people are much more flexible and will apply different principles depending on the situation. This may explain why people that we like and respect occasionally do things that we find morally objectionable," explained Chang.