认知失调理论最早是由Festinger提出的，它可以被定义为“影响不一致的认知”。这意味着，如果一个认知与另一个冲突，那么这两个认知不和谐，使人的心理矛盾。心理矛盾是由萨比尼提出的，一个人拥有两个信念互相矛盾；和由此产生的内部冲突，这是由于这一矛盾。Colman给出的一个例子，吸烟者知道吸烟对他们的健康有害但却继续吸烟。这表明他们的行为与他们的态度不一致，导致认知失调。有许多方法可以克服这种不一致，最常用和最有效的方法是改变态度。但是，为什么要这样做呢？本文将讨论态度变化及其背后的原因。
Cognitive dissonance theory was first developed by Festinger (1957; as cited in Baron & Byrne, 2003; Hogg & Vaughan, 2005; Sabini, 1995; Taylor, Peplau & Sears, 2006) and it can be defined as "the effects of inconsistent cognitions" (Colman, 2009). This means that if one has two cognitions that conflict with one another, then these two cognitions are dissonant, causing the person psychological inconsistency (Sabini, 1995). Psychological inconsistency is defined by Sabini (1995) as a situation in which a person holds two beliefs which contradict each other; and the resulting internal conflict which is due to this contradiction. An example given by Colman (2009) is that of a smoker who is aware that smoking is dangerous for their health yet they continue to smoke. This shows that their behaviour is inconsistent with their attitude, resulting in cognitive dissonance. There are many ways to counter this dissonance, the most used and most effective one being to change one's attitude. However, why is this necessary? This essay will discuss attitude change and the reasons behind when it follows cognitive dissonance.
When cognitive dissonance occurs, the person who is subject to the contradiction feels discomfort. Hogg & Vaughan (2005) describe this as post-decisional conflict, and they say that the best way to relieve this discomfort is by "bringing the attitude into line with the behaviour". Zimbardo, Weisenberg, Firestone and Levy (1965) conducted an experiment which studied how this is dealt with by participants when they are not acting at the request of others, they name this 'induced compliance'. Zimbardo et al (1965) had participants comply with eating grasshoppers by an authority figure who either made the request in a positive or negative way. Before the experiment, the participants were asked to rate how much they would like to eat grasshoppers. The authority figure was careful to ensure that the pressure on the participants was subtle so that the decision felt like a free choice. They claim that in this type of situation the post-decisional conflict should be greater with the communicator being negative, as in theory the participant would find it harder to justify their behaviour. With the positive communicator, however, the participant may view it as doing him a favour (Hogg and Vaughan, 2005). Those in the negative condition would therefore experience greater dissonance. As a result, more than 50% of participants in the negative condition claimed to have an increased liking for grasshoppers, this change in attitude was done in an attempt to ease the dissonance of the situation. However, this feeling of dissonance, and resulting behaviour change does not occur when the behaviour is forced upon you (Taylor, Peplau & Sears, 2006). Taylor, Peplau & Sears (2006) also note that behaviour change does not result from dissonance if the person is threatened to perform the behaviour, if the person has a irrevocable commitment which results in the behaviour and if they have responsibility for the behaviour. However, Baron and Byrne (2003) contradict this by claiming that when people experience the level of discomfort which occurs with dissonance, they alter their attitude even in the absence of external pressure. They say that attitude change directly reduces dissonance with the focus being on the discrepancies regarding attitude and behaviour which is the cause. Hamilton (2005) tries to describe the reason behind using change in attitude to ease the feeling of discomfort. He says that "change occurs because the cognition...is dissonant and therefore painful". Hamilton goes on to explain how this discomfort is avoided with a change of opinion about behaviour. This gives
