A recent arti­cle from Amer­i­can Eco­nomic Review looks at the con­sumer bias in pre­fer­ring the mid­dle of three options, and the ten­dency to buy less when offered more.

Numer­ous stud­ies demon­strate that seem­ingly irrel­e­vant fac­tors influ­ence people’s deci­sions. […] When three alter­na­tives are avail­able, the mid­dle alter­na­tive is cho­sen more often than when it is paired with only one other option. […] In choice over­load exper­i­ments, cus­tomers are less likely to make a pur­chase if more prod­ucts are added to the choice set.

[…]

In this paper, I develop a model where unin­formed con­sumers learn payoff-relevant infor­ma­tion by observ­ing what goods are avail­able. The ten­dency to select the mid­dle option thus nat­u­rally arises when there are con­sumers who are unsure which option is best for them, but know their tastes are mid­dle­brow. Choice over­load comes as no sur­prise if exces­sive prod­uct lines reduce con­sumers’ infor­ma­tion about which vari­eties are likely to suit them.

Admit­tedly not the most rev­e­la­tory of papers, but I find it dif­fi­cult not to link to stud­ies on con­sumer behav­iour.

via Over­com­ing Bias