去超市买东西的时候，标价2.99元的商品似乎总是比3元的商品受欢迎。市场销售圈的人管这叫“左位数效应”。说的是，人们购物时只关注价签最左侧的数字，只要这个数字在自己承受范围之内，后面的数字就不会太在意了。

A new study, published in the latest issue of the Journal of Consumer Research, shows that an occurrence known by marketers as the “left-digit effect” drastically influences the choices that people make while buying various items. Simple experiments have proven that too little attention is paid to the digit on the right hand side of a price tag. For instance, people would rather buy something that is priced at $3.99 than those priced at $4.00. In actual stores, this is encouraged, as producers and managers have the final two numbers of the price printed with much smaller fonts than the first one or two.
最新一期《消费者研究杂志》发表的一份研究显示，一种被市场推广人员称为“左位数效应”的现象很大程度上影响人们购物时的决定。实验证明，人们在购物时对价签上小数点右侧的数字并不是太在意。例如，人们更愿意购买标价为3.99美元的商品，而不选择4美元的商品。这种现象在实体商店中也得到进一步放大，商家打出的商品价格中，最后两位数字印得明显比前两位数字小很多。
“Shoppers pay a disproportionate amount of attention to the leftmost digits in prices and these leftmost digits impact whether a product's price is perceived to be relatively affordable or expensive,” the study says.
该研究指出：“消费者大部分的注意力都放在商品价格最左侧的数字上面，而这些数字决定了该商品价格是否在可承受范围之内。”