Black Sabbath performs during their Heaven and Hell tour in 1980. The band helped revive the long-feared “Devil’s interval”—a dissonant sound once shunned by medieval choirs—as the backbone of heavy ...

The world was supposed to end on December 21, 1954. At least that’s what a small religious group called The Seekers firmly believed. But for psychologist Leon Festinger, the far more important date ...

"We can be blind to the obvious, and we are also blind to our blindness." –Daniel Kahneman Cognitive dissonance, a psychological phenomenon first identified by Leon Festinger in 1957, refers to the ...

The tritone has been blamed for chaos, banned by choirs, and embraced by metalheads. Here’s what the 'devil's interval' really does to your brain. Black Sabbath performs during their Heaven and Hell ...