In Petrov’s case in particular, the new satellite-based early warning system was unproven so he didn’t completely trust it, and he didn’t believe a US first strike would use only one missile, or later, only four more, instead of hundreds. Furthermore, ground radar didn’t confirm. And, of course, attacking on a false alarm would be suicidal because he believed the Enemy would push the button, so striking first “just in case”, failed his cost-benefit analysis.
In Petrov’s case in particular, the new satellite-based early warning system was unproven so he didn’t completely trust it, and he didn’t believe a US first strike would use only one missile, or later, only four more, instead of hundreds. Furthermore, ground radar didn’t confirm. And, of course, attacking on a false alarm would be suicidal because he believed the Enemy would push the button, so striking first “just in case”, failed his cost-benefit analysis.
It was not “just” a commitment to pacifism.