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Why Centred Text Slows Reading

Picture this: you’re trying to read a webpage, but something feels off. Your eyes keep getting lost. You find yourself re-reading the same lines. You’re working harder than you should be just to follow the text.

What you’re experiencing isn’t a personal failing. It’s a design problem. And this is key — when text is centred, it breaks the fundamental way our brains process written information.

This is about reading efficiency. Let’s break this down.

Research by Ling and van Schaik (2007) shows that left-aligned text significantly boosts performance over other alignment types.But, the research numbers tell only part of the story. The human story is what matters.

The Hunt for Each New Line

Here’s what happens when you centre text. Every line starts in a different place.

So what does that mean? Your eyes finish reading one line, then have to hunt around to find where the next line begins.

The Problem (Centred Text):
This text starts here.
But this line starts here.
And this one starts somewhere else entirely.
Result: Your eyes search for each new line.
The Solution (Left-Aligned Text):
This text starts here.
This line starts here.
This one starts here too.
Result: Your eyes know exactly where to go.

That hunting behaviour? It’s not intentional. People aren’t deliberately making reading harder for themselves. But centred text forces this extra cognitive work on every single line.

You can’t beat people over the head about this. They’re often subject matter experts, not typography experts. They genuinely don’t know that centring text creates barriers.

How Your Eyes Actually Move

Let’s start at the beginning.

Reading involves something called saccadic eye movements. These are rapid jumps between fixation points. Think of them as your eyes hopping from word cluster to word cluster. With left-aligned text, this hopping follows a predictable pattern. Sweep right across the line. Jump down and left to the predictable starting position. Repeat. It’s efficient. It’s automatic.

So what happens with centred text? The pattern breaks.

Studies show this creates a “ragged left edge” that impedes reading speed and comprehension.Instead of smooth, predictable movements, you get erratic searching patterns.

This is behaviour change.

We’re asking readers to work against millions of years of evolution. Our brains developed pattern recognition for survival. Consistent visual anchors helped our ancestors spot predators and find food. And that’s really important — because centred text removes those visual anchors entirely.

The Speed Problem

Imagine you’re reading a report for work. You’ve got twenty minutes before your next meeting. The text is centred, and you don’t consciously notice. But something’s wrong. You’re reading slower than usual. You’re getting less done.

So what’s actually happening?

Studies indicate that left alignment promotes reading speeds 10-15% faster than centred text. Research shows centred text can increase reading time by up to 30% due to the difficulty in tracking lines (Mobile UI Research, 2025).

Think about that for a moment. Nearly a third longer to read the same content. And this is important— your brain is allocating processing power to navigation rather than comprehension. You’re solving a visual puzzle while trying to understand meaning.

This is a paradigm shift.

We often assume that reading problems are reader problems. Lack of attention. Poor focus. But many reading problems are actually design problems.

Support the reader. Make the text work with their brain, not against it.

When Dyslexia Meets Centred Text

Now let’s talk about readers who face additional challenges.

So what does centred text mean for people with dyslexia?

The answer isn’t good.

Heightened Navigation Difficulty

People with dyslexia already experience challenges with visual word recognition and tracking, and research has shown they are more susceptible to visual crowding effects — difficulty detecting a stimulus when other stimuli surround it(Sjoblom et al., 2021).

Studies have found that dyslexic readers require greater distance between letters to identify target letters, and they show greater crowding effects compared to typical readers(Galliussi et al., 2020).

The inconsistent starting points of centred text compound these difficulties significantly.

Increased Cognitive Load

Research with dyslexic participants has shown that presentation factors significantly affect reading performance, with studies finding that customisation features like text alignment are among the most useful tools for people with dyslexia(Rello & Baeza-Yates, 2017).

The Web Content Accessibility Guidelines (WCAG) specifically recommend avoiding full justification and limiting centre justification to 1-2 line text blocks, especially for users with dyslexia and visual tracking issues(WCAG Guidelines).

It isn’t that people don’t care — they genuinely don’t know how much centred text increases cognitive load.

Studies show proper alignment reduces cognitive load from 85% to 60%. That’s massive.

What Doesn’t Work:
Centred text removes visual anchors.
Creates inconsistent starting points.
Increases crowding effects.
Result: Compensatory strategies fail.
What Works:
Left-aligned text provides visual anchors.
Creates consistent starting points.
Reduces crowding effects.
Result: Compensatory strategies succeed.

Disrupted Compensatory Strategies

Multiple studies have investigated spacing effects in dyslexia, finding that increased letter spacing can improve reading performance for dyslexic individuals(PubMed Research).

Many dyslexic readers develop personalised strategies using consistent visual anchors, but centred text undermines these helpful adaptations by removing the reliable left-margin reference point.
People with dyslexia develop ingenious compensatory strategies over years. Using fingers to track lines. Relying on consistent margins. Following predictable reference points. Centred text breaks all of these carefully developed coping mechanisms.

And that’s really important. We’re not just making text harder to read. We’re undermining years of learned adaptive behaviours.

How We Actually Read Websites

Let me paint you a picture.

Jakob Nielsen’s landmark study tracked 232 participants as they read web content(Nielsen, 2006). What did he find?

We don’t read websites like books. We scan in an F-shaped pattern. Horizontal sweep across the top. Shorter horizontal sweep lower down. Vertical scan down the left side.

So what does that mean?

The F-pattern depends entirely on consistent left alignment. The vertical scan down the left side becomes impossible with centred text. We’re literally fighting against how our brains naturally process information.

This is about supporting natural behaviour.

Supporting Research Evidence

Eye-tracking studies from the Poynter Institute and other research consistently show that users hunt for information and often ignore graphics, with 78% of first eye-fixations being on text rather than images(Poynter Institute Study).

Studies indicate that 60% of users demonstrate enhanced reading speed when text is aligned to the left compared to centred layouts(Mobile UI Research).

The Centred Heading Trap

Here’s a common mistake. You centre your headings but left-align your paragraphs. It looks balanced. It feels designed. But it’s actually creating usability problems.

Let’s break this down.

Nielsen’s research explicitly recommends keeping headers “flush left” to support vertical scanning. When you centre a heading but left-align the text below, you force readers to reset their reading pattern constantly.

Centred Heading

This paragraph starts at the left margin while the heading floats in the centre. Readers have to locate the centred heading, hunt for where the paragraph begins, then reset their reading pattern for each section.

Left-Aligned Heading

This paragraph flows naturally from the heading. Consistent left alignment throughout. No pattern-switching required. The eye knows exactly where to go.

It's about nudging, not punishing. Good typography guides the reader smoothly through the content. Bad typography makes them work unnecessarily hard.

What the Guidelines Actually Say

You might think accessibility guidelines are just bureaucratic box-ticking.

But,

The Web Content Accessibility Guidelines specifically address text alignment as an accessibility requirement(WCAG Guidelines). They’re not arbitrary rules. They’re based on extensive research.

And this is key — the guidelines explicitly recommend avoiding full justification and limiting centre alignment to just one or two lines. Why?

Because studies with 92 participants (half with dyslexia, half controls) found that both groups read significantly faster with proper spacing and alignment(Rello & Baeza-Yates, 2017).

When accessibility guidelines get this specific about typography, it’s because the research evidence is overwhelming. This isn’t about compliance theatre. This is about human outcomes.

The alignment of text can greatly affect readability and accessibility, especially for users with dyslexia, low vision, or those using assistive technologies. The Web Content Accessibility Guidelines (WCAG) recommend avoiding full justification and limiting center justification to 1-2 line text blocks(WCAG Guidelines).

A Better Way Forward

So let’s talk about solutions.

Research shows that 75% of users find left-aligned text easier to read. That’s not a small preference — that’s a clear majority backed by measurable performance data.

This is a new way of thinking.

Equally effective. Equally integrated.

The solution is straightforward:

Common Practice:
• Centre headings for visual impact.
• Centre short text blocks.
• Use justified text for “clean” appearance.
Result: Readers work harder.
Better Practice:
• Left-align all body content.
• Left-align headings for scanning.
• If you must centre, limit to 3 lines maximum.
Result: Readers focus on content, not navigation.

And that’s really important. When we follow evidence-based guidelines, we create faster reading, better comprehension, and reduced cognitive load.

Accessibility benefits everyone, not just users with disabilities.

Think of it this way: every design decision either supports the reader or creates barriers. Typography isn’t decoration — it’s infrastructure for thought.

This is about impact, not just compliance.

The research is clear. The guidelines are specific.

So what does that mean for you?

Start with left alignment as your default. Centre sparingly, and only when you have a specific reason. Test with real users, especially those who face reading challenges.

Support them. Make reading effortless, not effortful.

Sources and Further Reading

Moodle Accessibility Toolkit

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