Peter Stiegnitz (September 30, 1936, Budapest - January 20, 2017, Vienna) was an Austrian author, civil servant, and sociologist known for his groundbreaking work in the field of Mentiology.

Life: Peter Stiegnitz's lifelong fascination with the subject of deception was deeply rooted in a personal experience during his childhood. In 1944, when facing the imminent threat of deportation to a concentration camp, he saved his own life by answering "no" to the question of whether he was Jewish, using a necessary falsehood. This pivotal moment drove his exploration of lies and led to the coining of the term Mentiology, a discipline bridging the realms of social sciences and psychology.

Mentiology: Stiegnitz's Mentiology delved into various aspects of deception, including its social implications from an emotional perspective, its correlation with attributions about the behavior of others, its influence on decision-making processes in individuals and groups (such as collective lies and conformity behavior), its relationship with communication, and its role in reinforcing prejudices and its connection to discrimination. He also explored gender-specific lying behaviors, nonverbal communication in the context of deception, methods for detecting lies (like lie detectors), and the values and norms surrounding dishonesty. Notably, Stiegnitz referred to "truth" as the "elastic sibling of deception," symbolizing its flexible nature caught between the poles of falsehood and reality.