"When two attributes have different levels of evaluability, extending the range of the background set would shift preferences towards the option that has a greater quantity of the high evaluability attribute," write Catherine W. M. Yeung (University of Singapore) and Dilip Soman (University of Toronto). However, "range effect" occurs at the expense of mid-priced products, particularly at stores where quality ranges from moderately good to moderately very good.
"We show that widening the range of encountered options increases the choice of the cheaper option relative to the more expensive option," write the authors.
Yeung, Catherine W.M. and Dilip Soman. "Attribute Evaluability and the Range Effect." Journal of Consumer Research, Dec 2005.