Heart Words vs Sight Words: What Changed with the Science of Reading

Heart words are high-frequency words taught by connecting each sound to its letters, with only the irregular part marked with a heart to learn “by heart”; traditional sight words were usually memorized as whole shapes with flashcards. The words on the list can be the same. What changed with the Science of Reading is how we teach them. Research on how the brain stores words shows that readers remember words by linking sounds to spellings, a process called orthographic mapping. The heart word method uses that process; whole-word memorization mostly doesn’t. This article explains the difference and gives you a five-step routine you can use tomorrow.

What “sight words” used to mean

For decades, “sight words” meant a list of common words (often from the Dolch or Fry lists) that students practiced on flashcards until they could say them on sight. The idea was that many of these words “can’t be sounded out,” so they had to be memorized as whole units, sometimes by their shape.

Two problems with that approach:

• Most high-frequency words are mostly decodable. In said, the s and d are regular; only the ai is unusual. In was, the w and s are regular. Treating the whole word as unpredictable throws away useful information.
• Visual memory for word shapes is unreliable. Many words have similar shapes (was/saw, then/them). Students who rely on shape and first letter often guess.

What changed: orthographic mapping

Researchers describe how skilled readers build a store of words they recognize instantly. That store is built by connecting sounds to letters in a word, then storing the connection. Once a word is mapped, it’s a “sight word” in the true sense: recognized instantly, without sounding out. This applies to every word, not just high-frequency ones.

So the goal hasn’t changed (instant recognition of common words). The path has: through sounds and letters, not shapes.

Heart words vs sight words at a glance

Temporarily irregular vs permanently irregular

Some words are only “irregular” because students haven’t learned the pattern yet. Like is irregular in September of kindergarten, before silent-e, but fully decodable once silent-e is taught. Others, like of or said, stay irregular.

That’s why many teachers talk about “heart words for now”: once the phonics pattern is taught, the heart comes off.

A 5-step heart word routine (about 5 minutes per word)

Use this with two or three new words a week, matched to your phonics sequence.

1. Say the word and use it in a sentence. “The word is said. She said hello.”
2. Count the sounds. Students tap or push a chip into a sound box for each sound: /s/ /ĕ/ /d/. Three sounds.
3. Map the letters. Write the letters under each sound box: s | ai | d. Ask: “Which letters do what we expect?” (s and d.) “Which part is tricky?” (ai says /ĕ/.)
4. Mark the heart. Draw a heart above the ai. “This is the part we learn by heart.”
5. Read and write it. Students read the word, spell it aloud while writing it, then read it again in a short sentence or decodable text.

Review previous heart words briefly each day, reading and spelling them, and look for them in connected text.

Ideas for practice that stays connected to sounds

• Heart word wall or sound wall: organize words by their first sound, not alphabetically by letter, with the heart marked.
• Spell and read: students write the word from dictation, then read it in a sentence.
• Word chains: for words that become decodable (like → bike → hike), build chains when the pattern is taught.
• Sentence reading: short sentences with this week’s heart words and decodable words.
• Heart word hunts in decodable books.

If you still use flashcards, add the mapping step before the card drill. Cards help with speed once the word is mapped; they don’t do the mapping for you.

Where heart words fit in the literacy block

Heart words aren’t a separate subject. They belong in the daily phonics lesson, next to phonemic awareness work like the routines in our phonemic awareness activities for kindergarten. Students who can’t yet segment a spoken word into sounds will have trouble mapping, so oral sound work comes first.

What about Dolch and Fry lists?

The lists are still useful as a reference for which words appear most in early texts. The change is in the method: teach the words through sounds, in an order that matches your phonics sequence, rather than by working down the list in alphabetical or frequency order.

For students who are struggling

Students with reading difficulties, including dyslexia, especially need high-frequency words taught through mapping, because whole-word memory is often their weakest route. Extra repetition, multisensory tracing while saying the sounds, and spaced review help. Accommodations for content-area reading are a separate support; see dyslexia accommodations.

When you describe this progress to families, use the same language: “reads 18 of our heart words automatically” is clear and specific, as in our reading report card comments.

For the full picture of structured literacy, the five pillars, and decodable texts, see our Science of Reading guide.