Spot the Difference

What is Spot the Difference?

Two pictures of the same scene sit side by side. Five things have been changed in the second one, and you tap each change you find in either picture. Something is missing, something has changed colour, something has moved, a count is different, and something new has appeared. Find all five and the puzzle is done.

The reason it holds attention is that your eyes are far better at recognising a scene than at comparing two of them. You take in the living room, the sofa and the bookshelf almost instantly, and that fluency is exactly what gets in the way: your brain hands you the gist and skips the detail. Finding the differences means overriding that and looking at parts instead of the whole.

How to play

1. Compare the two pictures and tap a difference in either one.
2. A green ring marks it in both pictures when you get it right.
3. Five differences per puzzle, seventeen puzzles in the set.
4. Stuck on the last one? Take a hint, or reveal them all and move on.

How to find them faster

• Scan in bands, not at random. Take the top third of both pictures, then the middle, then the bottom. Random scanning is how people miss something obvious for two minutes.
• Count things. Books, birds, buttons, chickens. A changed count is the difference type people miss most, because nothing looks wrong until you actually count.
• Check the edges last but do check them. Puzzle makers cluster changes near the middle, so a corner change catches almost everyone out.
• Defocus. Letting your eyes go soft makes a difference pop out of the field. Peripheral vision is better at detecting change than central vision is at identifying detail.
• Look for colour before shape. A recolour registers faster than a missing object, so sweeping for colour first usually banks two or three quickly.

Three ways to play it

Relaxed has no timer at all and counts up rather than down, which is the mode to pick if you want something to do while thinking about other things. Three minutes is a comfortable challenge on most puzzles. Ninety seconds is genuinely tight and rewards the banded scanning approach above.

In the timed modes a wrong tap costs three seconds and a hint costs fifteen, so there is a real price for guessing, but you can never lose a life or get stuck. Your best time is saved separately for every puzzle and every mode.

Why this is harder than it looks

There is a well-studied effect behind this called change blindness: people fail to notice surprisingly large changes to a scene when the change does not draw attention to itself. In the best-known demonstrations, participants missed a person they were speaking to being swapped for someone else during a brief interruption. Your visual system does not store a detailed picture of what you just saw. It stores enough to recognise the scene again, and fills in the rest from expectation.

Side-by-side puzzles like this work because they remove the interruption and still catch you out. Both pictures are in front of you the whole time, and a missing picture frame can sit unnoticed for a minute because nothing about it demands attention. That is not a failure of effort, it is how looking works.

About the puzzles

Seventeen hand-checked scenes: a park, a farmyard, a workshop, a kitchen, a snowy street, a beach, a music room, a vet's waiting room, a garden shed, a children's bedroom, a coral reef, a market stall, a pizza kitchen, a classroom, an airport gate, a campsite and a train station. Each has exactly five differences, verified rather than assumed. Your progress and best times are saved in your own browser, with no account and nothing sent to a server.