「科学美国人」究竟该不该告诉孩子“打针有些疼”
网上有篇题为《打针有些疼》的文章，讲述了不同家长面对孩子打针做出截然不同的表现，连哄带骗？一点儿都不疼？文章告诉家长们，孩子打针大哭的原因是因为恐惧和厌恶，更是家长们的欺骗以及强硬粗暴对待孩子的方式，而不是来自打针真实的疼痛。
“夸大”也好，“缩小”打针的疼痛也好，究竟该不该告诉孩子们真相，“打针确实有些疼”呢？近日，美国加利福尼亚大学（University of California）的研究团队们，对此作出了研究。
Saying "This May Hurt" May Make It Worse
60-SECOND SCIENCE
Getting a vaccine[1] can be a painful experience, especially when you're a kid. But getting told the shot might “hurt a bit” could actually make it worse.
[1]vaccine: a substance containing a virus or bacterium in a form that is not harmful, given to a person or animal to prevent them from getting the disease that the virus or bacterium causes 疫苗
“We know that expectation affects pain experience in adults. But we don't really know whether this is also true for children.”
Kalina Michalska, a developmental neuroscientist at the University of California, Riverside. She led a study to find out.
The study included 25 adults and 48 children. And 27 of the kids had a pre-existing anxiety disorder[焦虑症]. Because medical procedures make pretty much all kids anxious…and those who are anxious to start with tend to find the experience even more painful.
The researchers used a handheld wand[棍/棒/杆/杖] to apply heat to the forearm of each participant. And they asked subjects to rate the temperature in terms of discomfort. The hottest setting was about the temperature of very warm tap water—uncomfortable, perhaps, but not damaging.
But during the experiment, we were most interested in only one temperature: the one that each subject rated as medium.
That's where the “anticipation” part of the experiment comes in. Subjects were played one of two tones.
“One tone meant that low heat was coming; the other meant that high heat was upcoming.”
But here's the sneaky[2] part. No matter what tone was played, participants got the same heat applied—the one rated as “medium.”
[2]sneaky: doing things in a secret and unfair way 偷偷摸摸的；鬼鬼祟祟的
a sneaky plan
偷偷摸摸的计划
“So even though the subject heard a cue indicating high pain or low pain, the pain was only medium.”
Or at least that's how it should have felt. But what happened was that subjects reported feeling what they thought they would.
“If we tell them through this tone that they're going to experience a lot of pain, they'll actually experience more pain: they rated the pain as higher. And conversely, if we tell them that they will experience only low pain, they also rate their experiences as less painful.”
这不就是心理作用嘛...
“This is really important because it kind of reinforces the necessity of not hyping up painful experiences. And also discouraging children from ramping up the experience in their head."
And the same, it seems, goes for the grownups.
“One aspect surprised us, was that all three groups experienced a similar relationship between pain expectation and pain experience. We expected the strongest correlation among anxious children. But however all three groups showed a very large effect of expectancy on their experience of pain.”
The research is in the journal Psychosomatic Medicine. [Kalina J. Michalska et al., Anticipatory effects on perceived pain: Associations with development and anxiety]
Next up, Michalska says she'd like to examine whether negative associations can be unlearned. So next time you need a shot, remember: if you think it won't be so bad, maybe it won't be.
—来源：科学美国人