Incidental Emotion

What it is

The word incidental separates two kinds of feeling. An integral emotion is a reaction to the thing being judged: fear of a risky investment, pleasure in a product. An incidental emotion comes from elsewhere, such as an earlier situation or the music playing in the room, and has no logical bearing on the choice. If people were consistent about this, incidental emotions would change nothing. The research on the concept asks whether they do.

The account that explains why they might is mood as information. On that view a feeling is read as evidence about whatever is in front of the person, and the reading is corrected only when the real source of the feeling is made obvious. An incidental emotion is therefore a feeling that is mistaken for a reaction to the task. The mood as information page covers that mechanism; this page covers the carry-over into economic and fairness decisions.

The vault could not trace who coined the term incidental emotion, so no originator is credited on this page. The carry-over finding it relies on is the 2004 study by Jennifer Lerner, Deborah Small and George Loewenstein.

In effect

Lerner, Small and Loewenstein studied whether specific emotions affect the endowment effect, the tendency to ask more for an object one owns than one would pay to get it. Their paper, in Psychological Science in 2004, reported 199 participants. Disgust from an unrelated situation carried over into the economic choices: it lowered both selling and buying prices and removed the endowment effect. Sadness also carried over, but it had the opposite effect on buying prices, creating a reverse endowment effect in which buying prices exceeded selling prices. The authors drew the point that emotions of the same positive or negative sign can push a decision in opposite directions, and that incidental emotions can shape decisions involving real money.

Cuizhen Liu, Jing Wen Chai and Rongjun Yu extended the question to fairness in 2016, in Scientific Reports. Across three experiments using the ultimatum game, they induced seven emotions, among them disgust, sadness, anger, fear, happiness, surprise and a neutral state, and measured how often participants rejected unfair offers. Disgust, sadness, anger and fear all increased rejection. Happiness and surprise did not. The authors suggest that negative emotions in general make people focus on the negative aspects of a situation, which raises their sensitivity to fairness.

For price, the two studies fit together in one way and not in another. They agree that an unrelated emotion can move a money judgement. They disagree, or at least do not line up, on direction: the first found that the effect depended on which emotion was induced, and the second found that four different negative emotions behaved alike.

What it does not say

Neither study asked about the price of a product. Lerner and colleagues measured buying and selling prices for an object in an endowment task, and Liu and colleagues measured acceptance of a split between two people. Neither tested whether a shopper in a given mood judged a shelf price fair, and the searches run for the article that cites them found no study that did.

Lerner and colleagues induced disgust and sadness, not happiness. Their result therefore says nothing direct about what a good mood does to a price. Liu and colleagues did include happiness, and found that it did not increase rejection, which is a statement about the absence of one effect, not about a positive effect of its own.

Both papers were read at the level of the abstract and the first page, not in full, so details such as how each emotion was induced and what the neutral comparison looked like were not checked. Laboratory inductions are also brief. The concept is a description of what these experiments found, and its evidence status here is primary-cited, not established.

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