Can't see the forest for the trees? Is your perceptual acuity what it used to be? Try this test to find out.

Two panels appear, one containing two overlapping shapes and the other containing just one shape. Is the single shape identical to one of the overlapping shapes or is it subtly different?

Click MATCH if two of the shapes are the same, or MISMATCH if not. If you get it correct, the next problem will be more difficult. If you get it wrong, the next problem will be easier. Solve as many problems as you can in 90 seconds

Optimizing Performance

In this test:

  • Accuracy does matter; wrong answers subtract from your score, and lower the difficulty of the next puzzle.
  • Speed does matter; you have 90 seconds to solves as many puzzles as you can.

So to get maximum points, take care to answer accurately, but do it as quickly as you can.

Video instructions.

Performance tips:

  • Differences can be very subtle! A slightly different angle or small rotation mean there is a mismatch. On your first few tries at the test, take your time to spot the smallest of changes.
  • More difficult puzzles are worth more points, but the same points will also be subtracted from your score if you get the puzzle wrong.
  • Determining how much time to take, especially as you get into more difficult puzzles, is part of a strategy to reach your highest scores.
  • Experiment to find out how much you can trust your "gut." Methodically examining every angle can always lead to a correct answers, but is slow. Always guessing based on a quick look can be faster, but lead to incorrect answers. Only you can determine how trustworthy your initial guesses are.

Domain Scores

Your score on this test contributes to:

  • Your reasoning score (a lot).
  • Your verbal ability score (a bit).

The contribution of each test to each performance category is based on a "factor analysis" that looked at how tests tend to clump together when measuring a massive set of data. The results were published in Neuron in 2012 (Hampshire, Highfield, Parkin, & Owen, 2012). The exact contribution of each test to each performance category may change as more data is collected.

The Science Behind Polygons

In this task, when you mentally compare complex images to one another you are using your brain's visuospatial processing skills. A task similar to this is used in the Mini Mental State Examination (MMSE), a simple paper and pencil tool for doctors to assess cognitive function. In the MMSE, instead of comparing images of pentagons, the patient is asked to draw the interlocking polygons from memory. This task can help to diagnose Alzheimer's disease in some patients. A common and early sign of Alzheimer's disease is impaired visuospatial processing. As a result, those suffering with the disease tend to perform poorly at this task.

Alzheimer's disease is a form of dementia. Patients with Alzheimer's disease suffer from a general decline in mental abilities, memory loss, and language problems, as well as confusion, irritability and mood swings. The cause of this disease is unknown, but is closely associated with "plaques" and "tangles" in neural brain fibres. Scientists in many research institutions, including the MRC Cognition and Brain Sciences Unit in Cambridge, have been trying to work out how the brain changes as a result of Alzheimer's disease. For example, when undertaking visuospatial memory tasks, we have found that Alzheimer's patients do not compensate by engaging additional brain regions, but rather, show greater engagement of the same areas that are activated by healthy volunteers. We believe that this increased brain activation may be a result of Alzheimer's patients finding these tasks much more difficult than healthy volunteers (Gould et al., 2006).

Polygons in the Real World

Together with our colleagues in the Departments of Experimental Psychology and Psychiatry, Cambridge, we have also looked at whether medication for Alzheimer's disease can produce beneficial effects on cognitive function. We gave tests similar to BrainLabs' to Alzheimer's disease patients who were taking the drug tetrahyrdoaminoacridine (THA) and found that this treatment produced its cognitive benefits through improving attention (Sahakian et al., 1993). Our cognitive tests are available to pharmaceutical companies via CBS Trials, and are used to assess cognitive function when developing new medicines.

Exercise has been shown to reduce cognitive decline from Alzheimer's and other diseases. One large study (Lytle et al., 2004) of elderly people demonstrated that a higher exercise level was associated with the absence of substantial cognitive decline, as measured by the MMSE, two years later. Use BrainLabs to track your own exercise and cognition over time, to measure both short-term and long-term effects.

Performance on this test has also been linked with sleep in healthy adults. In one study (Fang et al., 2016), performance on Polygons and other reasoning-heavy tests was correlated with "sleep spindles" - squiggles of brain activity that can be detected on electroencephalogram (EEG) recordings of sleeping people. Sleep spindles are also related with sleep quality. However, spindles tend to be stable within people, so it is unknown if increasing your sleep quality can improve performance via this type of brain activity. Try improving your own sleep and measuring your performance on Polygons to see if you detect any differences.


Fang, Z., Sergeeva, V., Ray, L. B., Viczko, J., Owen, A. M., & Fogel, S. M. (2016). Sleep spindles and intellectual ability: Epiphenomenon or directly related? Journal of Cognitive Neuroscience, 29(1), 167-182. Download PDF

Gould, R. L., Arroyo, B., Brown, R. G., Owen, A. M., Bullmore, E. T., & Howard, R. J. (2006). Brain mechanisms of successful compensation during learning in Alzheimer disease. Neurology, 67, 1011-1017. View Abstract

Lytle, M. E., Vander Bilt, J. , Pandav, R. S., Dodge, H., & Ganguli, M. (2004). Exercise level and cognitive decline: The MoVIES project. Alzheimer Disease & Associated Disorders, 18(2), 57-64. Download PDF

Sahakian, B. J., Owen, A .M., Morant, N. J., Eagger, S. A., Boddington, S., Crayton, L., Crockford, H. A., Crooks, M. M., Hill, K., & Levy, R. (1993). Further analysis of the effects of tetrahydroaminoacridine (THA) in Alzheimer's disease on attentional and mnemonic function using CANTAB. Psychopharmocology (Berl), 110(4), 395-401. View Abstract

Did this answer your question?