demonstrations:serial_position_effect

Serial Position Effect

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Senses and Perception, Psychology

Alternative titles: Primacy and Recency Effects

Summary

This demonstration shows that people recall items at the beginning and end of a sequence better than items in the middle. It illustrates how primacy and recency shape memory when information is presented in order.

Procedure

  1. Prepare 3–5 different lists of 12–16 common, unrelated words (or simple pictures), each in a unique random order.
  2. Tell participants they will try to remember as many items as possible from each list.
  3. Present the first list at a steady pace (about 1 item per second) using slides or reading aloud.
  4. Immediately after the final item, give participants 60 seconds to write down all items they remember in any order.
  5. Collect responses and quickly plot recall by position (1st, 2nd, … last) to reveal higher recall at the beginning and end.
  6. Repeat with a second list, but insert a 20–30 second distractor task (for example, simple math problems) before recall to reduce the recency effect.
  7. Repeat with a third list, but preview that the first few items are especially important to encourage rehearsal, strengthening primacy.
  8. Compare the three recall curves and discuss how immediate recall favors recency, delay reduces recency, and rehearsal enhances primacy.

Serial Position Effect - Chris Gatt:


The Serial Positioning Effect Explained with Examples - Psychology Exposed:


📄 Why do we better remember items at the beginning or end of a list? - The Decision Lab: https://thedecisionlab.com/biases/serial-position-effect

Variations

  • Use numbers, nonsense syllables, or category-mixed items instead of common words to test how meaning affects recall.
  • Present items auditorily versus visually to compare modalities.
  • Change list length (8–20 items) and presentation rate to see how load and pacing influence the curve.
  • Have small groups study collaboratively versus individually to test effects of shared rehearsal.
  • Insert different lengths or types of distractor tasks (counting backward, copying shapes) to systematically reduce recency.
  • Compare native versus second-language lists to explore language proficiency effects on primacy.

Safety Precautions

  • No physical hazards; normal classroom safety is sufficient.
  • Avoid personally sensitive words or images; keep materials age-appropriate.
  • Obtain assent for data collection and anonymize all responses if results are recorded or shared.

Questions to Consider

  • Why are early items remembered better than middle items? (Early items receive more rehearsal and transfer to long-term memory, producing the primacy effect.)
  • Why do we remember the last few items so well in immediate recall? (They remain active in short-term/working memory, producing the recency effect.)
  • What happens to the recency effect when we add a brief distractor before recall? (It typically decreases because short-term memory contents are displaced.)
  • How would slowing the presentation rate change the curve? (It often increases primacy by allowing more rehearsal of early items.)
  • If the test is delayed by several minutes, which part of the list should dominate recall? (Primacy should dominate because long-term memory traces persist while recency fades.)
  • How can we apply this in studying or teaching? (Place key points at the beginning and end, and rotate item order so each point sometimes appears in primacy or recency positions.)