He attended the Presbyterian Church in Glendale, California and observed a sermon delivered by a "dynamic and histrionic preacher" who encouraged him to come forward to be saved.

[21][24] He also attended an informal Christian fellowship at "The Barn" in La Crescenta, California, where he described enjoying the social aspects of religion, especially the theological debates.

[21] In 1972, he graduated from Crescenta Valley High School[23] and enrolled at Pepperdine University, intending to pursue Christian theology.

[21] Shermer changed majors to psychology once he learned that a doctorate in theology required proficiency in Hebrew, Greek, Latin, and Aramaic.

After she was in an automobile accident that broke her back and rendered her paralyzed from the waist down, Shermer relayed, "If anyone deserved to be healed it was her, and nothing happened, so I just thought there was probably no God at all.

[21] Shermer began competitive cycling in 1979 and rode professionally for ten years, primarily in long distance ultramarathon road racing.

This suggestion led to their model, the V1 Pro, which looked like a black leather hairnet, but functioned on the inside like a motorcycle helmet.

In 1982, he worked with Wayman Spence, whose small supply company, Spenco Medical, adapted the gel technology Spence developed for bedridden patients with pressure sores into cycling gloves and saddles to alleviate the carpal tunnel syndrome and saddle sores suffered by cyclists.

[33] Shermer participated in the Furnace Creek 508 in October 2011, a qualifying race for RAAM, finishing second in the four man team category.

[25][34] Shermer has written on the subject of pervasive doping in competitive cycling and a game theoretic view of the dynamics driving the problem in several sports.

He lost interest in psychology and switched to studying the history of science,[21] earning his PhD at Claremont Graduate University in 1991.

His dissertation was titled Heretic-Scientist: Alfred Russel Wallace and the Evolution of Man: A Study on the Nature of Historical Change.

[45] Shermer’s early writing covered cycling, followed by math and science education for children which included several collaborations with Arthur Benjamin.

He is the author of a series of books that attempt to explain the ubiquity of irrational or poorly substantiated beliefs, including UFOs, Bigfoot, and paranormal claims.

[1][47] Writing in Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time (1997), Shermer refers to "patternicity", his term for pareidolia and apophenia or the willing suspension of disbelief.

[citation needed] In February 2002, he characterized the position that "God had no part in the process [of the evolution of mankind]" as the "standard scientific theory".

[50] Shermer's book In Darwin's Shadow: The Life and Science of Alfred Russel Wallace: A Biographical Study on the Psychology of History (2002) was based on his dissertation.

It garnered several critical reviews from academics, with skeptic Robert T. Carroll saying: "He has been blinded by his libertarianism and seduced by the allure of evolutionary psychology to explain everything, including ethics and economics.

"[55][56][57] In May 2011, Shermer published The Believing Brain: From Ghosts and Gods to Politics and Conspiracies: How We Construct Beliefs and Reinforce Them as Truths.

"[47] In January 2015, Shermer published The Moral Arc: How Science and Reason Lead Humanity Toward Truth, Justice, and Freedom.

"[76] That same year, Shermer participated in an Intelligence Squared debate titled "Science Refutes God" paired with Lawrence Krauss, and opposing Dinesh D'Souza and Ian Hutchinson.

[81][82] In 2019, Illinois Wesleyan University canceled Shermer’s visit for the President’s Convocation at that institution after it learned of the sexual assault allegations.

[85][86] In a 2015 interview, Shermer stated that he preferred to talk about individual issues after previous experience with people refusing to listen to him after learning he held libertarian views.

[87] In 2000, Shermer voted for libertarian Harry Browne, on the assumption that the winner of the Al Gore – George W. Bush contest would be irrelevant.

Shermer named Thomas Jefferson as his favorite president, for his championing of liberty and his application of scientific thinking to the political, economic, and social spheres.