If A is bigger than B but smaller than C, which letter is the biggest? How long did it take you to figure it out?

The Grammatical Reasoning Test measures your ability to reason about relationships among objects. A statement will appears at the top of the screen with two shapes underneath (e.g., a square and a circle). Your task is to click on "True" or "False" to indicate whether or not the sentence accurately describes the relationship between the shapes.

Optimizing Performance

In this test:

  • Accuracy does matter; incorrect answers are subtracted from your score.
  • Speed does matter; you have 90 seconds to solve as many problems as you can.

So to get maximum points, try to work as quickly as possible without making mistakes.

Video instructions.

Performance tips:

  • Try rewording the sentence to simplify it; mentally changing "not smaller" to "bigger" could make it easier to solve.
  • Try describing the relationship between the shapes for yourself. Does the sentence say the same thing? Click True!

Performance Categories

Your score on this test contributes to:

  • Your verbal score (a lot).
  • Your reasoning 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), where the Grammatical Reasoning Test was referred to as "verbal reasoning." The exact contribution of each test to each performance category may change as more data is collected.

The Science Behind Grammatical Reasoning

Your performance on the Grammatical Reasoning Test reflects how well your brain can combine grammatical skills with reasoning skills. The difficulty of each problem depends on the statement presented; problems with simple active sentences (A follows B) are more easily solved than those with passive or negative statements (A does not precede B), which require complex reasoning to solve.

This task is an adaptation of the Grammatical Reasoning Test developed in 1968 by Alan Baddeley, the previous Director of the UK Medical Research Council (MRC) Cognition and Brain Sciences Unit (then known as the MRC Applied Psychology Unit).

Grammatical Reasoning in the Real World

The original task was developed to measure mental capabilities of divers suffering from nitrogen narcosis: an altered mental state akin to drunkenness that develops when divers breathe compressed air at extreme depths. Cognitive impairments were observed at depths of around 30 meters. Interestingly, these impairments were more severe when divers were actually at sea compared to when they were in a compression tank, a possible result of increased stress in the "real world" situation (Baddeley & Flemming, 1967; Baddeley et al., 1968).

Grammatical reasoning has been linked with other real-world activities, such as performance of residents providing medical care. It is also affected by lifestyle—for example, the sleep deprivation that residents are often subjected to can have a small effect on Grammatical Reasoning Test performance (see Deaconson et al., 1988). Grammatical reasoning tends to be more resilient to impairments like sleep loss and alcohol than other cognitive tests (Williamson & Feyer, 2000), but can still be affected. Interestingly, fatigue impairs response time, while alcohol impairs accuracy (Lamond & Dawson, 1999).


  • Baddeley, A.D. (1968). A three-minute reasoning test based on grammatical transformation. Psychometric Science, 10, 341-342. Read Abstract
  • Baddeley, A.D., and Flemming, N.C. (1967). The efficiency of divers breathing oxy-helium. Ergonomics, 10, 311-319. Read Abstract
  • Baddeley, A.D., de Figueredo, J.W., Hawkswell Curtis, J.W and Williams, A.N. (1968). Nitrogen narcosis and performance under water. Ergonomics, 11, 157-164. Read Abstract
  • Deacons, T. F., O'Hair, D. P., Levy, M. F., Lee, M. B. F., Schueneman, A. L., & Condon, R. E. (1988). Sleep deprivation and resident performance. The Journal of the American Medical Association, 260, 1721-1727. Read Abstract
  • Hampshire, A., Highfield, R. R., Parkin, B. L., & Owen, A. M. (2012). Fractionating human intelligence. Neuron, 76, 1-13. Download PDF
  • Lamond, N., & Dawson, D. (1999). Quantifying the performance impairment associated with fatigue. Journal of Sleep Research, 8, 255-262. Read Article
  • Williamson, A. M., & Feyer, A. (2000). Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occupational and Environmental Medicine, 57, 649-655. Read Article
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