Reduce the Phonetic Size of Prices

Prices feel smaller with fewer syllables.

For example, $167 could be spoken as:

• One hundred and sixty seven dollars (10 syllables)
• One sixty seven (5 syllables)

Say the latter (Coulter et al., 2012).

In fact, every additional syllable decreases memory for a price by 20% (Vanhuele et al., 2006; Luna & Kim, 2009).

You can also modify other aspects of your price.

Commas

Remove commas to reduce the phonetic size:

• $1,625: One thousand six hundred and twenty five (10 syllables)
• $1625: Sixteen twenty five (5 syllables)

Or try a decimal abbreviation:

• $1500: fifteen hundred dollars (6 syllables)
• $1.5k: one point five kay (4 syllables)

Cents

Should you remove cents from prices, like $28.16?

Not always. Cents can be effective because precise numbers feel smaller (Thomas et al., 2010).

So it depends on the medium:

• Add cents in written prices to increase precision.
• Remove cents in spoken prices to reduce the phonetic size.

Phonemes

Certain sounds can feel smaller or larger. For example, vowels can be front or back based on the location of the tongue.

• Front Vowels: bee, bit, bait
• Back Vowels: boot, but, brought

These vowels are found in digits:

• Front Vowels: 3, 5, 6, 7, 8, 9
• Back Vowels: 1, 2, 4

In the sensory world, high-pitched sounds are produced by small objects. Thanks to this recurring experience, objects seem smaller when they contain front vowels because these phonemes are higher in pitch. Indeed, prices with front vowels (e.g., $35) feel smaller when spoken or heard (Coulter & Coulter, 2010; Klink, 2000).

Parentheses

As you read this sentence, you're speaking these words inside your head because of inner speech.

Research shows that inner speech adapts to any vocal traits that are implied in writing (e.g., tone, accent, speed; Yao & Scheepers, 2015).

For example, if you see an exclamation point in a purchase button, your brain will shout "Buy Now!" with an excited tone. But nobody feels genuinely excited during an ordinary purchase, so this syntax will likely reduce sales because something will feel wrong.

However, parentheses can trigger the opposite effect: Prices that are enclosed in parentheses will be internally spoken in quieter tones that imply less importance, size, or relevance. Perhaps they could boost conversions. Try adding them whenever it makes sense (e.g., list of add-on prices).

Stronger For

• Auditory Cues. Even if customers read silently, their brain still encodes phonetic versions of prices. But this effect is stronger if customers speak these prices aloud or internally.

• Coulter, K. S., Choi, P., & Monroe, K. B. (2012). Comma N’cents in pricing: The effects of auditory representation encoding on price magnitude perceptions. Journal of Consumer Psychology, 22(3), 395-407.
• Coulter, K. S., & Coulter, R. A. (2010). Small sounds, big deals: Phonetic symbolism effects in pricing. Journal of Consumer Research, 37(2), 315-328.
• Dehaene, S. (1992). Varieties of numerical abilities. Cognition, 44(1-2), 1-42.
• Klink, R. R. (2000). Creating brand names with meaning: The use of sound symbolism. Marketing letters, 11, 5-20.
• Luna, D., & Kim, H. M. C. (2009). How much was your shopping basket? Working memory processes in total basket price estimation. Journal of Consumer Psychology, 19(3), 346-355.\
• Thomas, M., Simon, D. H., & Kadiyali, V. (2010). The price precision effect: Evidence from laboratory and market data. Marketing Science, 29(1), 175-190.
• Vanhuele, M., Laurent, G., & Dreze, X. (2006). Consumers' immediate memory for prices. Journal of Consumer Research, 33(2), 163-172.
• Yao, B., & Scheepers, C. (2015). Inner voice experiences during processing of direct and indirect speech. Explicit and implicit prosody in sentence processing: Studies in honor of Janet Dean Fodor, 287-307.