Blue–seven phenomenon

The blue–seven phenomenon is a social phenomenon in which a purported statistical majority of people in the US choose the color blue and number seven when asked to randomly select a color and a single digit number. The cause of the cognitive bias is not understood,^[1][2][3][4] though it has been posited that both colors and numbers are imbued with layers of significance.^[5]

The existence of the phenomenon has been disputed.^[6][7] Outside of the US, these preferences may not hold.^[8][9] In other countries, differences occur, particularly in Northern Ireland where a noted bias of green and eight results in a green–eight phenomenon.^{[citation needed]}