Overview
The digital world suffers from information overload. And nowhere does this seem truer than email. Grabbing and maintaining attention is crucial, especially when it comes to important emails.
Using bold text is a common formatting strategy to highlight key information, but does it actually help people remember what they've read? And could there be a trade-off, perhaps making the sender seem less warm (i.e., nice) or making unformatted text less recallable?
In this experiment, we boldly trek into the science of formatting, investigating whether bolded text in emails enhances recall of key content. We also explore the potential interpersonal cost of using bold text—does it make you appear less warm? And does it make unformatted text less memorable? Understanding these dynamics is crucial to crafting emails that are both memorable and personable.
The Experiment
763 email readers were recruited from the research platform Prolific to take part in our email study. Participants read a brief email from a manager or junior colleague about four cities to explore for market research.
Unbeknownst to participants, we randomized whether two of these cities were bolded or none of the cities were bolded. The specific text that participants read in the email is below (bold formatting randomized). Participants were told that, "The following email is from your boss at a market research company."
From: Brian, Manager
Subject: Cities
Hello,
I was reviewing the report you sent and thought of four cities we could investigate for next month's market research. Houston and Atlanta seem most promising. The others are Miami and Chicago.
Best,
Brian
Subject: Cities
Hello,
I was reviewing the report you sent and thought of four cities we could investigate for next month's market research. Houston and Atlanta seem most promising. The others are Miami and Chicago.
Best,
Brian
Participants were then asked a survey question to measure how warm (i.e., nice) the email writer seemed. “To what extent do you think each of the following words describe this person? (1 = Not at all, 7 = Very much)” with words that included “Nice” and “Smart” (the latter used as a filler to help disguise the nature of our study).
For the final outcome, we tested recall of the four cities by having participants answer three minutes of unrelated survey questions, then asking them to recall as many of the four cities as they could in textboxes provided.
For the final outcome, we tested recall of the four cities by having participants answer three minutes of unrelated survey questions, then asking them to recall as many of the four cities as they could in textboxes provided.
Results
Bolding text did have a small effect on recall. Participants remembered 11.4% more of the first two cities when they were bolded relative to when they were left unformatted (p = 0.044). However, there was a trade-off; participants remembered 7.8% fewer cities in the latter part of the email, which were all left unformatted (p = 0.075). Thus, the total number of cities recalled was statistically indistinguishable across our bold and unformatted conditions (avg. = 2.34 vs. 2.36, p = 0.849).
There was, however, no trade-off regarding perceived warmth. Participants were no less likely to perceive our email sender as less nice when he used bold or unformatted text (p = 0.285). Nor did any of the results differ by age.
The memory results did seem to interact with gender in an interesting way. Whereas the boost in recall of bolded text was largely from women (p = 0.031), the reduced recall of unformatted text was mostly from men (p < 0.001). While it’s tempting to conclude that women heed formatting signals more attentively than men, this analysis was admittedly exploratory. The result may just be spurious correlation or chance sampling. We’d want to replicate the finding before placing too much emphasis on it.
Conclusion
Bold formatting slightly enhances the memorability of your emails. But it only does so for the bolded text. And it does so at the cost of the remaining, unformatted text. Fortunately, it does not make you seem less personable, so there is no immediate image penalty here.
However, the effect is small. Using other formatting techniques, either separately or in conjunction with bolding, may further enhance your email’s memorability. Check out our studies on the use of ALL CAPS and bulleted lists for more.
Methods Note
To test for significant differences in likability between our experimental conditions, we used an independent samples t-test. For statistically significant results, the difference between the averages of the two groups would be large, and the corresponding “p-value” would be small (p < 0.05). This indicates that if we were to replicate the study with the same population, we would likely obtain a similar effect. Additionally, we utilized OLS regression analyses with interaction terms to explore potential significant interactions between the main results and participant demographics, such as age and gender.
Data and survey materials used for this experiment are available upon request.