Picture this: You’re at a movie theater food stand loading up on snacks. You have a choice of a small, medium or large soda. The small is $3.50 and the large is $5.50. It’s a tough decision: The small size may not last you through the whole movie, but $5.50 for some sugary drink seems ridiculous. But there’s a third option, a medium soda for $5.25. Medium may be the perfect amount of soda for you, but the large is only a quarter more. If you’re like most people, you end up buying the large (and taking a bathroom break midshow).

    If you’re wondering who would buy the medium soda, the answer is almost no one. In fact, there’s a good chance the marketing department purposely priced the medium soda as a decoy (诱饵), making you more likely to buy the large soda rather than the small.

    I have written about this peculiarity in human nature before with my friend Dan Ariely, who studied this phenomenon extensively after noticing pricing for subscriptions (订阅) to The Economist. The digital subscription was $59, the print subscription was $125, and the print plus digital subscription was also $125. No one in their right mind would buy the print subscription when you could get digital as well for the same price, so why was it even an option? Ariely ran an experiment and found that when only the two “real” choices were offered, more people chose the less-expensive digital subscription. But the addition of the bad option made people much more likely to choose the more expensive print plus digital option.

    Brain scientists call this effect “asymmetric dominance” and it means that people gravitate toward the choice nearest a clearly inferior option. Marketing professors call it the decoy effect, which is certainly easier to remember. Lucky for consumers, almost no one in the business community understands it.

    The decoy effect works because of the way our brains assign value when making choices. Value is almost never absolute; rather, we decide an object’s value relative to our other choices. If more options are introduced, the value equation changes.

解析：D。根据题目中的the medium soda和priced可定位至第二段第二句。该句指出，事实上，营销部门可能故意把中杯汽水当做诱饵来定价，使你更有可能买大杯汽水而不是小杯。也就是说，考虑到定价，人们通常不会买中杯，但大杯的定价只比中杯多一点，所以相比之下，中杯的存在让人们觉得买大杯更划算，因而更愿意买大杯，D项表述符合文意，因此选D。

错项排除：文章指出，人们更容易购买大杯汽水，所以中杯并没有吸引到人们购买，A项与文意相悖，故排除。B项利用常识，对price和amount进行主观臆断，但文章并没有中杯物有所值的相关描述，而且中杯也是最不划算的，故B项排除。C项利用文中说小杯饮料撑不到看完全场电影（may not last you through the whole movie），大杯又会导致中途去洗手间（taking a bathroom break midshow）进行意义上的推断，但是文中并没有明确指出中杯的量是恰到好处的，中杯的设定是为了诱使消费者购买大杯，故C项排除。