研究证明我们总是认为别人和我们有同样的想法，并且假设和我们意见不一者的人格有些极端。

许多人很自然地认为他们是“天生的心理学家” ，他们认为预测其他人的态度和行为相当容易。我们每个人所拥有的信息建立在无数以往的经验的基础上，包括我们自己和他人的经验，我们因此就理应具备可靠的洞察力了吗？

没有这样的好运气。

在现实中，人们估计他人行为及原因的时候常会表现出一些预测偏差。而这些偏见正好显示出我们为什么需要心理学的实验，以及为什么我们不能信赖我们对他人行为的直觉认识。

这些偏见之一被称为虚假一致偏差。在20世纪70年代，斯坦福大学社会心理学教授Lee Ross通过两个研究揭示出虚假一致偏差是如何起作用的(Ross, Greene & House, 1977) 。

虚假一致

在第一项研究中，实验被试要阅读一些冲突情景的描述，以及每个情境相应的两种可能的反应方式。他们要报告如下三项：

• 猜其他的人会选择哪种反应，
• 说出他们自己会选择哪种反应，
• 描述选择两种反应的两类人各自的特点。

结果表明，不论他们自己其实选择了哪个反应，更多的人都以为别人会做和他们同样的选择。这就是罗斯和他的同事所揭示的'虚假一致偏差’现象——我们每个人都觉得其他人和我们想的一样，尽管事实并不如此。

当要被试描述那些作出与自己相反选择的人时，会出现另一种偏差。相比对作出同样选择的人的描述，他们对做出不同选择的人的个性预测更为极端

简言之：人们往往认为持不同意见的人有些地方不对劲！这看起来像开玩笑，但它是人们真正表现出的偏见。

h3. 来Joe’s饭店吃饭

虽然第一项研究非常符合理论，但是我们怎么能确定人们真的会言行一致呢？毕竟，心理学家已经很好地证明了人们的看法和他们的行为之间的联系甚为细微。

因此，在第二项研究中，Ross和他的同事们放弃了假想的情境和纸笔的测试，而选择了巨大的挂在身上的广告牌。

这次来了一批新的被试，他们都是大学生。实验者问他们是否愿意挂上写着“来Joe’s饭店吃饭”的广告牌在校园里闲逛30分钟。（不告诉被试Joe’s饭店食物的质量如何，以及他们看上去有多傻。）

被试被告知他们可以从中学到“一些有用的东西”，以此作为这样做的唯一动机。不过如果不愿意，他们完全可以拒绝这样做。

这项实验的结果证实了之前的研究。在那些同意挂广告牌的人中，62%认为其他人也会同意这么做。在那些拒绝这么做的人中，只有33%的人认为别人会同意挂广告牌。

和上次一样，人们对于和自己意见不合者的人格再次做出了更为极端的预测。你可以想象一下他们会是怎么想的。那些同意挂广告牌的人可能会说：

“那些拒绝的人是怎么回事？我看他们肯定很害怕看上去像一个傻子。”

而那些拒绝挂广告牌的人会说：

“那些同意挂广告牌的只知道卖弄的到底是些什么人？我知道那样的人——他们真古怪。”

h3. 我们是蹩脚的直觉型心理学家

这项研究很吸引人，不仅因为它揭示了我们在考虑别人行为时的一种偏见，而且它证明了心理学研究的重要性。

每个心理学家在某个时候都曾在用以下两种论据解释一项研究的发现时显得心烦：

我本有机会告诉你这些——这太明显了（所以我都没必要告诉你）！

不，以我的经历来看这不对——人们的行为并不是那样的。

像这项社会心理学实验证明的那样，人们是蹩脚的直觉型心理学家。少数的几个例外之一是当答案十分、十分明显的时候，例如问别人是否应该去谋杀。但是从总体上来说，我们观点一致的问题不如我们意见不一的问题来的有趣。

人们还可能假设和自己有不同看法的人相对于自己来说有更加极端的人格。这是因为，人们有意或无意地对自己说，所有思维正常的人当然都和我想的一样。

可是，很显然不是这样。虽然知道我们不了解别人是一个很好的开始。

而这就是我们需要心理学研究的一个很好的理由。

h4. The False Consensus Bias

Many people quite naturally believe they are good 'intuitive psychologists', thinking it is relatively easy to predict other people's attitudes and behaviours. We each have information built up from countless previous experiences involving both ourselves and others so surely we should have solid insights?

No such luck.

In reality people show a number of predictable biases when estimating other people's behaviour and its causes. And these biases help to show exactly why we need psychology experiments and why we can't rely on our intuitions about the behaviour of others.

One of these biases is called the false consensus bias. In the 1970s Stanford University social psychologist Professor Lee Ross set out to show just how the false consensus bias operates in two neat studies (Ross, Greene & House, 1977).
False consensus

In the first study participants were asked to read about situations in which a conflict occurred and then told two alternative ways of responding. They were asked to do three things:
o Guess which option other people would choose,
o Say which option they would choose,
o Describe the attributes of the person who would choose each of the two options.

The results showed more people thought others would do the same as them, regardless of which of the two responses they actually chose themselves. This shows what Ross and colleagues dubbed the 'false consensus' bias - the idea that we each think other people think the same way we do when actually they often don't.

Another bias emerged when participants were asked to describe the attributes of the person who made the opposite choice to their own. Compared to other people who made the same choice they did, people made more extreme predictions about the personalities of those who made didn't share their choice.

To put it a little crassly: people tend to assume that those who don't agree with them have something wrong with them! It might seem like a joke, but it is a real bias that people demonstrate.
Eat at Joe's!

While the finding from the first study is all very well in theory, how can we be sure people really behave the way they say they will? After all, psychologists have famously found little connection between people's attitudes and their behaviour.

In a second study, therefore, Ross and colleagues abandoned hypothetical situations, paper and pencil test and instead took up the mighty sandwich board.

This time a new set of participants, who were university students, were asked if they would be willing to walk around their campus for 30 minutes wearing a sandwich board saying: "Eat at Joe's". (No information is available about the food quality at 'Joe's', and consequently how foolish students would look.)

For motivation participants were simply told they would learn 'something useful' from the study, but that they were absolutely free to refuse if they wished.

The results of this study confirmed the previous study. Of those who agreed to wear the sandwich board, 62% thought others would also agree. Of those who refused, only 33% thought others would agree to wear the sandwich board.

Again, as before, people also made more extreme predictions about the type of person who made the opposite decision to their own. You can just imagine how that thinking might go. The people who agreed to carry the sandwich board might have said:

"What's wrong with someone who refuses? I think they must be really scared of looking like a fool."

While the people who refused:

"Who are these show-offs who agreed to carry the sandwich board? I know people like them - they're weird."
We're poor intuitive psychologists

This study is fascinating not only because it shows a bias in how we think about others' behaviours but also because it demonstrates the importance of psychology studies themselves.

Every psychologist has, at some point, been driven to distraction when trying to explain a study's finding by one form of the following two arguments (amongst others!):

1. I could have told you that - it's obvious!
2. No, in my experience that's not true - people don't really behave like that.

As this social psychology study shows, people are actually pretty poor intuitive psychologists. One of the few exceptions to this is when the answer is really really obvious, such as asking people whether it is OK to commit murder. But questions we can all agree on are generally not as interesting as those on which we are divided.

People are also more likely to assume someone who doesn't hold the same views as them has a more extreme personality than their own. This is because people think to themselves, whether consciously or unconsciously, surely all right-thinking (read 'normal') people think the same way as me?

Well, apparently not. Although knowing that we don't know other people is a great start.

And that is one good reason why we need psychology studies.