Mothers have known it for years - Give the children their regular hamburger, and they will love it; spend hours making a novel home-cooked meal, and they may leave it on the plate. Now French scientists have discovered why. According to researchers near Paris, the brain does not respond well to unfamiliar tastes. Sensations are not as strong when the mind is struggling to understand messages that come from the tongue. This provides little reason to taste new things.Human beings are naturally like rats - we are afraid of anything new. If you give rats some food that they have never had before, they will turn their backs on it out of fear. We are the same. It is possible to introduce new foods, but only in the right psychological context, like a birthday. Once the introduction has been made, the fact of having a full stomach is physically pleasing, so the next time it is easier. However, some foods are more tempting than others. Scientists are sure that we are born with a sweet tooth. This is why children have a natural desire for sugar.9. Why can some people appreciate the fine differences in food?A. They persistently eat a particular food.B. They observe food while eating.C. They seldom eat the food they dislike.D. They usually eat different new dishes.

我们来逐步分析这道题目。

题目：

Why can some people appreciate the fine differences in food?
（为什么有些人能品味出食物之间的细微差别？）

选项：

• A. They persistently eat a particular food.（他们持续吃某种特定的食物。）
• B. They observe food while eating.（他们在吃的时候观察食物。）
• C. They seldom eat the food they dislike.（他们很少吃他们不喜欢的食物。）
• D. They usually eat different new dishes.（他们通常吃各种新的菜肴。）

解题思路：

我们要找的是“为什么有些人能品味出食物之间的细微差别”的原因。

从原文中寻找线索：

原文中提到：
> "The brain does not respond well to unfamiliar tastes. Sensations are not as strong when the mind is struggling to understand messages that come from the tongue. This provides little reason to taste new things."

意思是：大脑对陌生的味道反应不好，当大脑在努力理解舌头传递的信息时，感觉不那么强烈。这让人缺乏尝试新食物的动力。

还提到：
> "It is possible to introduce new foods, but only in the right psychological context... Once the introduction has been made, the fact of having a full stomach is physically pleasing, so the next time it is easier."

意思是：新食物可以被接受，但需要在合适的心理环境下。一旦接受了，下次就更容易。

此外：
> "Scientists are sure that we are born with a sweet tooth. This is why children have a natural desire for sugar."

这说明人类对某些味道（如甜味）有天生的偏好。

分析选项：

• A. They persistently eat a particular food.
  如果一个人反复吃同一种食物，可能更熟悉它的味道，但题目问的是“能欣赏食物之间的细微差别”，这更偏向于对多种食物的辨别能力，而不是单一食物的熟悉度。

• B. They observe food while eating.
  观察食物可能会增强对食物外观或质地的感知，但原文没有提到“观察”是关键因素。

• C. They seldom eat the food they dislike.
  这与题目无关。不喜欢某种食物并不会帮助人分辨不同食物的细微差别。

• D. They usually eat different new dishes.
  这是最符合原文逻辑的选项。原文提到人类天生害怕新食物，但通过不断尝试新食物（尤其是在合适的心理情境下），人们可以逐渐适应并欣赏它们。因此，经常尝试新菜肴的人更有可能发展出对食物细微差别的感知能力。

正确答案：

$\boxed{D}$