Why Did I Believe the Lies? Understanding the Truth Bias

Picture a lie detector device printing out "TRUTH" to reinforce the concept of truth biases.
Are you guilty of the truth bias?

“As relationships become more intimate, people develop a truth bias in which they are more likely to judge their partners as truthful and less likely to detect deception.”

In hindsight, betrayed partners often wonder, “How could I have believed all the lies? Why didn’t I pay more attention to that tiny seed of doubt? How could I have been so stupid?” The answer is rather simple and no different from that of partners in relationships that are not characterized by betrayal.

Once trust is given in a relationship, the perception of truth follows and we selectively attend to information that confirms our bias. Consequently, when we give our trust we look for the evidence that supports our bias that we have been given the truth, rather than focus on what disconfirms it. The formula we use for a committed relationship is: Trust = Truth. We give those we trust the benefit of the doubt. Psychologists who research the social rules that humans tend to apply in relating to others call this a truth bias.

It is important to note that research indicates the truth bias is a commonly held assumption that occurs as a result of being in a committed relationship; it is not a belief that results from codependency, co-addiction, or simply being naive. We can be very quick to see the lies in someone else’s relationship because we don’t look at that relationship through the lens of the truth bias.  

The truth bias occurs despite regular media coverage of high rates of divorce and the frequency with which unfaithfulness contributes to the divorce rate. In fact, even those who should be most aware that spouses can and do live double lives involving lies, infidelity, and sexually addictive behavior – those engaging in extramarital betrayals – also demonstrate a truth bias. Research indicates that 90% of the unfaithful husbands surveyed and 81% of the unfaithful wives surveyed believed their spouse had remained faithful – highly unlikely given the statistics.

To avoid the truth bias: put truth first! Watch behavior to see if words and actions are in synch. Notice behavior that both confirms and disconfirms truth. Calibrate your level of trust based on how consistently words and behavior match up across time. Look for truth before giving trust so that you change the formula to Truth = Trust.

From Not “Just Friends”: Rebuilding Trust and Recovering Your Sanity After Infidelity by Shirley Glass.

Original source: Stiff, Kim & Ramesh (1992). Truth biases and aroused suspicion in relational deception. Communication Research, 19(3), 326-345.


Dr. Janice Caudill is the founder and Clinical Director of McKinney Counseling & Recovery. MCR offers individual, couples, group therapy and multi-day intensives for partners of sex addicts and wounded hearts struggling with sex addiction, infidelity, love addiction or love avoidance, intimacy anorexia, or relational trauma in the McKinney, Plano, Allen, Richardson, Frisco, Carrollton, Lewisville, Dallas and surrounding areas.

All content provided on this blog is for informational purposes only. It is not intended to diagnose or treat any condition, does not create a client-therapist relationship, and is not a substitute for care by a trained professional. The owner of this blog makes no representations as to the accuracy or completeness of any information on this site or found by following any link on this site. The owner will not be liable for any errors, omissions, losses, injuries, or damages from the display or use of this information.

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