Working Memory2–4 minBurden: MediumEMA: Medium

Change Detection

A visual working-memory capacity task in which participants detect whether a colour in a briefly shown array changed after a blank interval.

Visual working memoryAttentionCapacity
Category
Working Memory
Typical duration
2–4 min
Participant burden
Medium
EMA suitability
Medium

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Task parameters

Set sizes 2, 3, and 4 are tested. Outputs: K capacity per set size (Cowan formula: K = N × (hit rate − false alarm rate)).

2–4 minBurden: MediumEMA: Medium

This is a researcher preview. No participant data is recorded.

Simulated participant view

9:41

Change Detection

A visual working-memory capacity task in which participants detect whether a colour in a briefly shown array changed after a blank interval.

No data is recorded

Participant experience on smartphone

A set of coloured squares is shown briefly, followed by a blank interval, then the array reappears — one colour may have changed. The participant taps Same or Changed.

When to use

Useful when the study needs an estimate of visual working-memory capacity (K) rather than verbal or executive measures. Particularly relevant in attention, ageing, and neuroscience research.

When not to use

Less suitable for very high-frequency EMA because each block requires study, blank, and test phases, which add interaction time compared to single-tap tasks.

How to use in a study

Use the default three set sizes (2, 3, 4) to obtain K estimates across the capacity range. Ensure the screen is large enough to render arrays clearly without items touching.

Researcher-configurable parameters

  • Set sizes tested
  • Trials per set size
  • Study array duration
  • Blank interval duration
  • Practice enabled / disabled

Outputs collected

  • Accuracy per set size
  • Hit rate and false alarm rate per set size
  • K capacity estimate per set size (Cowan formula)
  • Maximum K

Interpretation notes

K = N × (hit rate − false alarm rate) per Cowan (2001). Values typically range from 2–4 items in healthy adults. Lower K scores reflect reduced visual working-memory capacity.

Scientific evidence

  • Change detection is among the most widely used paradigms in visual working-memory research and translates effectively to touchscreen formats.

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