Play a shape game for a couple of hours and something odd can happen. You close your eyes and still see the pieces. You look at a bookshelf and start working out how the books would fit better. This is known as the Tetris effect, and it's been studied properly.
Seeing blocks in your sleep
In 2000, Robert Stickgold and colleagues had people play Tetris for several hours over three days, then woke them as they fell asleep and asked what they were seeing. Many described falling Tetris pieces. That included people with severe memory loss who couldn't remember playing the game at all.
The finding suggests that as you drift off, the brain replays recent, intense visual experiences. It's thought to be part of how new skills get consolidated during sleep. It's also a sign of how much work a spatial game gives your visual system.
Getting better while working less
In the early 1990s, Richard Haier's team scanned people's brains while they played Tetris, before and after several weeks of practice. As players got better, their brains used less energy in the areas being measured, not more.
The usual reading is that practice made the task more efficient: the brain found a cheaper way to do it. A later study by Haier (2009) found small increases in cortical thickness in some areas after three months of practice. That's interesting, but it was one small study, and it doesn't mean Tetris makes you smarter in general. It means the brain adapts to what you practise.
A game that may help after a bad experience
The most unexpected research comes from Oxford. Emily Holmes and colleagues (2009) showed volunteers a distressing film. Those who then played Tetris had fewer intrusive flashbacks over the following week than those who didn't.
The idea is that visual memories and spatial games compete for the same limited mental resources. Keep that system busy soon after an event and the memory is stored less vividly. This work is still going on in clinical trials. It's not a treatment you should try on your own for anything serious, but it's a striking example of how much a "simple" game engages the mind.
What spatial reasoning is for
Spatial reasoning means picturing shapes and space in your head: rotating them, fitting them together, following a path. You use it when packing a car boot, reading a map, arranging furniture, or following flat-pack instructions. Engineers, surgeons and architects rely on it every day.
It's also one of the skills that clearly improves with practice. A large review by Uttal and colleagues (2013) found that spatial training works, lasts, and carries over to related spatial tasks better than most kinds of brain training.
Practise it here
A few of our games give spatial thinking a workout, each in a different way:
- Geo Construct: build fences, floors, triangles and circles to an order ("20 m of fence", "a 24 m² floor"), then estimate angles by eye. After the first level of each chapter the running total is hidden, so you picture the shape and do the sum yourself before you press Build. Some levels ask for two things at once, like a set fence and a set floor, and only one rectangle fits.
- Laser Nexus: rotate mirrors to steer a laser into every target. You have to trace the beam's path in your head before you turn anything.
- Cargo Master: move crates between stacks to match a blueprint in as few moves as possible. It's planning in space.
Geo Construct, level 1: drag the corner of the fence. At 6 × 4 it's exactly 20 m, so build it.
Geo Construct, level 2: the total stays hidden until you build. A 3 × 3 pen is 12 m, 2 m short of the 14 m order.
Laser Nexus, level 1: click the mirror to rotate it and send the beam to the target.
Play one for ten minutes, then look at your bookshelf.