The backfire effect results from the human desire to retain their own opinions or false beliefs even when confronted by contradictory evidence. When a person's beliefs (whether legitimate or not) are challenged by facts and figures it is normal for them to argue for the "correctness" of their own beliefs. Research shows that when an individual's false beliefs are contradicted by evidence or facts instead of realizing their belief is incorrect this information "backfires" and instead their false beliefs are strengthened.
For instance, in social media one person might express a controversial opinion or false idea and other people will present their evidence and express opinions that are totally opposite and contradictory to the original statement. Under these circumstances, all parties will impart information that they believe supports their opinions because cognitive biases such as this are making them uninterested in changing their mind. The individuals involved, instead of changing their minds or opinions, will instead have their original beliefs strengthened by these arguments.