Overview
Parentheses are often used to add extra information, but how do they affect the experience of your readers?
On the one hand, may make your text appear more detailed and informative. On the other hand, it could clutter the message, annoying your readers. These questions are particularly relevant in professional settings, such as emails and online articles, where clarity and tone are paramount. They reflect not just what is written, but the image of the writer.
In this study, we tested whether including supplemental information, both with and without parentheses, affects the reactions of readers, specifically informativeness, ease of reading, and how annoying and detail-oriented the writer seems to be.
The Experiment
1,200 people were recruited from the research platform Prolific to take part in a study that involved reading a paragraph and rating their perceptions of the information and the writer. For our experiment, we randomly assigned whether each participant’s paragraph contained (a) just the essential text, (b) supplementary text with no parentheses, or (c) supplementary text enclosed in parentheses. We also randomized the context of the paragraph for generalizability, either an email about career advice or an excerpt of an online article about relationship advice. Example paragraphs are below.
The following email is from HR at your job, with a summary of career advice.
From: Human Resources
Subject: Career Advice
Hi team, below is a recap of my presentation on career advancement.
To excel in your career, it's essential to master both hard skills (like technical abilities) and soft skills (such as communication and teamwork). Always seek opportunities for professional development (many companies offer workshops and seminars). Build a robust network within and outside your company. And remember, consistency in your efforts and a proactive attitude (not just for performance reviews) are key.
From: Human Resources
Subject: Career Advice
Hi team, below is a recap of my presentation on career advancement.
To excel in your career, it's essential to master both hard skills (like technical abilities) and soft skills (such as communication and teamwork). Always seek opportunities for professional development (many companies offer workshops and seminars). Build a robust network within and outside your company. And remember, consistency in your efforts and a proactive attitude (not just for performance reviews) are key.
Below is an excerpt from an online article providing relationship advice.
"Strong relationships are built on consistent communication (both listening and expressing yourself clearly). It’s important to recognize and appreciate the differences in each other (this diversity can actually strengthen your bond). Prioritize making time to connect regularly (weekly dinners or walks can be a great start). And remember, the foundation of any (lasting) relationship is trust and understanding."
"Strong relationships are built on consistent communication (both listening and expressing yourself clearly). It’s important to recognize and appreciate the differences in each other (this diversity can actually strengthen your bond). Prioritize making time to connect regularly (weekly dinners or walks can be a great start). And remember, the foundation of any (lasting) relationship is trust and understanding."
Following the paragraph, participants were asked a series of survey question to measure our outcomes of interest. These questions, presented below, were all measured on a 1-7 scale (1 = Not at all, 7 = Very much).
- “How informative is this [email/article]?”
- “How easy was this [email/article] to read?”
- “To what extent do you think each of the following words describe the writer?” “Detail-Oriented,” “Annoying”
Results
Parentheses, and the supplemental text enclosed within them, appear to be more helpful than harmful. Participants rated the longer text, both without parentheses (avg. = 5.54; p < 0.0001) and within parentheses (avg. = 5.49; p < 0.0001) as significantly more informative than the shorter text (avg. = 5.07). These effects equate to an 9.3% and 8.3% increase, respectively.
Perceptions of the writer were also boosted by parentheses and supplemental text. Participants rated our writers as significantly more detail-oriented when supplemental text was included, either within parentheses (avg. = 5.20; p < 0.0001) or without parentheses (avg. = 5.03; p < 0.0001), relative to our shorter paragraph (avg. = 4.51). These effects equated to a 15.3% and 11.5% increase, respectively. There were no significant effects for annoyance.
There was, however, a slight trade-off when it came to ease of reading. Paragraphs with parentheses were rated as 3% less easy to read (avg. = 5.82) relative to the same paragraph without parentheses (avg. = 5.99; p = 0.051) and relative to the shorter paragraph that omitted the supplementary information (avg. = 6.01; p = 0.035). Nevertheless, this decrease was minimal compared to the gains in informativeness and how detail-oriented the writer seemed. None of the results differed significantly based on participants’ gender or age.
Conclusion
Parentheses seem to provide nuance without being a nuisance. They increase the informativeness of your text, make you appear to be more detail-oriented, and don’t make you seem annoying. They do, however, reduce readability by a very small margin, so as with any linguistic device it’s probably best to avoid overusing them. But overall, the benefits of parentheses seem to outweigh the costs.
Methods Note
We used ordinary least squares (OLS) regression analysis to test for significant differences in outcomes between our experimental conditions. For significant differences, the coefficient would be large, and the corresponding "p-value" would be small (p < 0.05). We also conducted OLS regression analyses with interaction terms to assess whether these differences varied by participants' gender or age.
Data and survey materials for this study are available upon request.