Is the Mozart effect real? No.
Listening to Mozart makes you cleverer — and played to a baby, raises its IQ.
Rauscher, Shaw & Ky (1993) found a lift on one spatial task in 36 undergraduates that lasted about fifteen minutes. That became “classical music raises IQ”, and in 1998 the state of Georgia began handing classical CDs to new mothers. Pietschnig, Voracek & Formann’s meta-analysis of 39 studies (2010) put the effect near zero. Nantais & Schellenberg (1999) got the same short-lived bump from a Stephen King audiobook in listeners who preferred it. What was being measured was arousal and mood, not Mozart.
Check it yourself: doi.org/10.1016/j.intell.2010.03.001
The arousal bump is real, just small and brief and not musical. Use whatever genuinely lifts you right before a demanding task, and do not expect it to outlast the first ten minutes.
Every law on Useful Mind tells you how strong the evidence behind it is. The ones that failed are kept here rather than quietly deleted, because knowing which advice is wrong saves you as much as knowing which is right.
See the ones that held up