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Impact bias

Impact bias is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Impact bias rather than just read about it. In short: In the psychology of affective forecasting, the impact bias, a form of which is the durability bias, is the tendency for people to overestimate the length or the intensity of future emotional states. Overview People display an impact bias when they overestimate the intensity and durability of affect when making predictions about their emotional responses.

Key takeaways

  • Impact bias belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Impact bias to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Impact bias from memory before moving on to harder problems.

Reference excerpt

In the psychology of affective forecasting, the impact bias, a form of which is the durability bias, is the tendency for people to overestimate the length or the intensity of future emotional states.

Overview People display an impact bias when they overestimate the intensity and durability of affect when making predictions about their emotional responses. It is a cognitive bias that has been found in populations ranging from college students (e.g. Dunn, Wilson, & Gilbert, 2003; Buehler & McFarland, 2001), to sports fans (Wilson et al, 2000), to registered voters (Gilbert et al, 1998).

Affective forecasting

Research shows that people often make errors about how much positive or negative effect an event will have on them. People mispredict their emotional reactions (how much pleasure or displeasure an event will bring them) when they mispredict how the event will occur. These mistaken projections can lead to mistaken assumptions about the impact of an event on their happiness. Generally, people accurately predict the valence, if an event will generate a positive or negative reaction, but people are less accurate in their predictions about the intensity and the duration of these effects.

Mistaken projections To make decisions, people try to predict how an event will play out and what it will make them feel. However, when making these predictions, people are subject to many cognitive biases, including the impact bias. Research shows that people’s projections are often mistaken (e.g. Wilson & Gilbert, 2005; Buehler & McFarland, 2001; Loewenstein & Schake, 1999). Early studies revealed that this phenomenon is a result of people’s inability to anticipate how their feelings will be affected by external factors, and change over time (e.g. Kahneman, 1994). People are more prone to make errors about intensity and duration of affect, than about valence. These mistaken projections affect people’s ability to make decisions that maximize their happiness.

Example Gilbert et al. (1998) conducted a study on individuals participating in a job interview. The participants were separated into two groups; the unfair decision condition (where the decision of being hired was left up to a single MBA student with sole authority listening to the interview) and the fair decision condition (where the decision was made by a team of MBA students who had to independently and unanimously decide the fate of the interviewee). Then, certain participants were chosen to forecast how they would feel if they were chosen or not chosen for the job immediately after learning if they had been hired or fired and then they had to predict how they would feel ten minutes after hearing the news. Then following the interview, all participants were given letters notifying them they had not been selected for the job. All participants were then required to fill out a questionnaire that reported their current happiness. Then after waiting ten minutes, the experimenter presented all the participants with another questionnaire that once again asked them to report their current level of happiness. The predictions made by the participants in both the unfair and fair groups were about the same regarding how they would feel immediately after hearing the news as well as ten minutes later. Both groups accurately predicted how they would feel immediately after hearing the news. The study showed that both groups felt much better than they had originally predicted, ten minutes later, demonstrating the impact bias.

Causes Explanations for the occurrence of the impact bias include the following:

Misconstrual problem Misconstrual of future events: When predicting how an experience will impact us emotionally, events which have not been experienced are particularly difficult. Often what we think an event may be like does not relate to what the experience is like. People know that the future is uncertain, but fail to recognize their projections as construals, subjective perceptions or interpretations of reality. (Griffin & Ross, 1998; Wilson & Gilbert, 2003). Misconstruals can be responsible for a great range of mispredictions because there is no limit to the degree of error one can make. It leads to the impact bias when misconstruals are accurate about the valence of an event, but overpredict intensity and duration of emotional reaction. Inaccurate theories: People have created cultural theories and had experiences that greatly influence beliefs of how an event will affect us. For example, American culture has emphasized a correlation between wealth and happiness, however despite this belief; money does not necessarily bring happiness. Motivated Distortions: When faced with a negative event people may have forecasts that are overestimated and can evoke either comfort or fear in the present. The overestimation however can often be used to soften the effects of an event or make it easier by the reality not being as extreme as the forecasted impact. Under correction (anchoring and adjustment): People anchor their prediction on how they currently feel and never accurately adjust their predictions. An illustrative example proposed by Wilson and Gilbert (2005), is that if you are currently in bed with a cold, and are invited to a party a month from now, it will be very difficult to separate your negative feelings from your prediction of how you will feel on a Saturday night a month later. This process is sometimes referred to as the projection bias (Loewenstein et al., 1999) whereby people’s affective forecasts are unconsciously or consciously influenced by their current state.

Focalism Often when making a prediction of the impact of an event people focus solely on the event in question. This ignores the fact that with the passage of time, other events will occur that influence happiness. Disregarding the effect of unrelated events on future thoughts emotions, leads to erroneous predictions of our emotional reactions. Whereby, since we are focusing on the impact on one specific event, we simultaneously overestimate the intensity and duration of our emotional reaction to that event and underestimate the effect of other unrelated events. However, we fail to consider that these unrelated events can moderate our emotional responses.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Impact bias

Start with the simplest possible case. Write down what Impact bias claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Impact bias before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Impact bias ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Impact bias

In research
Impact bias appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Impact bias in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Impact bias is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cognitive biases, so understanding it makes those chapters shorter.
In everyday life
Look for Impact bias outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Impact bias in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Impact bias means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Impact bias out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Impact bias in simple terms?

In the psychology of affective forecasting, the impact bias, a form of which is the durability bias, is the tendency for people to overestimate the length or the intensity of future emotional states. Overview People display an impact bias when they overestimate the intensity and durability of affec…

Why does Impact bias matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Impact bias?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Impact bias.

Tags

  • Cognitive biases

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