Barnum Effect is the tendency for people to think that vague statements apply to them personally. this effect is exploited by astrologers, mind-readers and religious gurus.

consider the following statement, “at times, you tend to be critical of yourself”. for the majority, it’ll feel spot on, but its because its so vague and general. i could say that to 100 people and I’ll be right 98 times.

barnum effect is stronger when statements are vague, being told by an authoritative figure or after a ‘personalised’ test.

Weber’s Law states that the amount of difference in stimulus required to produce a noticeable change is proportional to the intensity of the original stimulus. if you’re holding a 1kg dumbell and and add another kg over it, you’ll notice it clearly. but if you’re holding a 20kg dumbbell and i add a kg, you won’t be able to tell the difference clearly.