Unseen Biases: Why You Can’t Always Trust Intuition

The human mind is far less rational than you might think. Research has consistently shown that many of our decisions are based on emotion rather than logic. The advertisements we like, the statements we trust — these preferences often persist regardless of actual cognitive content of each. We instead frequently rely on “gut feelings” to inform such preferences.

Where do these “gut feelings” — these intuitions — come from? One major contributor is processing fluency.

Processing Fluency: A hidden influencer

So what is processing fluency? Basically, it’s a fancy term for describing how easily we can comprehend information. There are multiple types of processing fluency, and all of them substantially influence our judgments. A few types of processing fluency are described below.

Memory-based fluency describes how easily one can recall or store information in their memory. People will interpret a slogan as more “fluent” if it is simple and catchy, following well-known linguistic patterns and therefore easily encoded and retrieved within the brain.

Perceptual fluency involves ease of visual perception. Something that is more perceptually fluent will have greater visual clarity. For example, printing an article in a clear font (e.g. Calibri, Times New Roman) instead of an unclear font (e.g. Onyx, Impact) improves perceptual fluency. Similarly, increasing color contrast of font compared to the background (e.g. black font against a white background vs green font against white background) also makes text more fluent. Showing a digital advertisement for a long period of time, so as to allow more time for processing, likewise increases perceptual fluency.

Linguistic fluency deals with processing word sound and structure. Certain word letter strings are easier to pronounce than others for English speakers — for example, the letter combination of a vowel flanked by consonants (HIX) is easier to pronounce than a consonant-only string (HSX). Further, fluid transitions between syllables also improve fluency. In English, glide syllables (like “ld”) are easier to say that the nonglide syllables (like “cd”). Thus, the imaginary word milden is more fluent than macden. These variables are important to keep in mind when naming products, as stock name research conducted by scientists Alter and Oppenheimer (2006) illustrates. They demonstrated that, in the short term, stock names with easy to pronounce names fare better than those whose names are difficult to pronounce: “In the 1st day of trading, the 10 stocks with the simplest names earned 11% more than the 10 stocks with the most complex names, and this difference increased to 33% across the course of a year of trading.” Further, rhyming has been shown to increase linguistic fluency, while complex grammatical structures and vocabulary decrease fluency — make sure your copy writing is simple, catchy, and concise!

Decision fluency describes ease of decision making. Size of the choice set greatly impacts decision fluency. If consumers have an overwhelmingly large array of options to choose from, they will have more difficulty making a decision. For example, researchers Iyengar and Lepper (2000) showed that people had more trouble choosing between a “disfluent” set of 24 exotic jams than a “fluent” set of 6 jams. Decision fluency is also negatively impacted when two choices are poorly differentiated from each other.

Knowledge of factors affecting decision fluency is important for consumer goods companies to keep in mind when selling their products. These companies must ensure their product choice set is large enough so that consumers feel like they have options, but not so large as to overwhelm them and disrupt decision fluency. Companies must also be sure to clearly differentiate their product from others on the market so as to aid decision making.

Conceptual fluency involves mental processing of concepts. It can be facilitated by priming people with concepts similar to the primary information being presented. For example, researchers Lee and Labroo (2004) have found that consumers more readily recognize an image of ketchup when presented with a semantically-related prime beforehand (a mayonnaise advertisement).

Lastly, imagery fluency is the ease with which someone can imagine a hypothetical event. Taking advantage of imagery fluency is key for effective marketing. Use of visuals and easy-to-follow storylines in commercials and advertisements enhances imagery fluency. For example, researchers Petrova and Cialdini (2005) demonstrated that increased use of vivid visuals in advertising caused participants to process the ads more quickly.

Evidently, processing fluency exists in many forms and is a useful tool in constructing compelling brand names, slogans, and advertisements.

How processing fluency biases us

Processing fluency not only helps people more easily recognize and process information, but also increases likability and trust of the information. An experiment conducted by Reber and Schwarz illustrates the point on trust. Reber and Schwarz (1999) showed participants statements such as “Lima is in Peru” on a computer screen. Then, they asked the participants how true they believed the statements to be, while manipulating the contrast between the text color and the white background on the computer screen. Not surprisingly, participants rated statements as more believable when the contrast was greater and the text was easier to read (more perceptually fluent). Reber, Winkielman, & Schwarz (1998) found similar results when testing for likability. Participants preferred perceptually fluent stimuli shown against highly contrastive backgrounds compared to less perceptually fluent stimuli shown against more weakly contrastive backgrounds.

This liking and trust judgement pattern holds for all types of fluency. For example, in an experiment manipulating decision fluency, researchers found that “difficult choices — those in which participants selected among an overwhelming array of options — induced less liking for the ultimate choice.” In another dealing with linguistic fluency, participants rated rhyming aphorisms as “more true” than non-rhyming aphorisms that were identical in meaning. Likewise, experiments that disrupted imagery fluency, conceptual fluency, and memory-based fluency also showed a negative impact on participants’ truth and liking judgments.

You can’t trust your intuition

These findings have large implications for the business world, particularly for marketers. Advertisements, product names, slogans, websites, and press releases with greater fluency will be preferred and seen as more legitimate, regardless of cognitive content. Two ads identical in copy can generate very different consumer responses; if an ad is written in a more fluent font, it will be seen as more trustworthy and likable.

It is important to keep in mind that seemingly minor details such as font choice, grammatical structure, phonetics, background color, and ad placement next to conceptually-related information can profoundly influence brand judgment. In fact, it can be even more impactful than the quality of information being presented.

The mental shortcuts we take to make quick judgments distort our perceptions — our truths and likes are subconsciously biased, based on somewhat arbitrary qualities that improve processing fluency. For this reason, you cannot always trust your intuition.

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Documenting insights about humanity, culture, and design. // Self-experimenter, UX Designer @ Google.

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