Look at shapes A and B. Are they the same size and shape?

The answer, surprisingly, is yes. To most people, shape A appears to be shorter and wider than shape B. But it's just a matter of alignment; shape B is simply aligned further to the right than shape A.

Despite knowing they are the same exact shape and size, your brain may still be having trouble perceiving them that way.If you were to print the 2 shapes out on paper and cut them out, you could see that they are exactly the same in all dimensions. Or, you can take a look at the proof image below, which shows shapes A and B with parallel red lines superimposed on them, and it's easy to see that they are just out of alignment.

As one more proof that the shapes are equal, you can use your mouse to move the red shape on top of the blue shape and see for yourself!

This is called the Jastrow Illusion. Because the leftmost diagonals of the shapes are in a continuous line, our brains subconsciously follow that line and perceive that the two shapes are sitting on top of one another. But in reality, one is just slightly shifted on the horizontal axis.

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Observe the two sets of circles below. Which of the orange circles is larger?

You may be surprised to find out that they are exactly the same size. The deception occurs because of the size of the surrounding blue circles and their relative distance from the central orange circle. These adjustments cause the brain's visual perception system to distort the relative size of the inner circles. Another factor at play is the "completeness" of the surrounding circles; if we removed a few of the blue dots or spaced them out, the illusion would not persist.

Titchener Circles are also called an Ebbinghaus Illusion, for its original discoverer. The illusion is similar to a Delboeuf Illusion, shown below.

The two black circles appear to be different sizes, but they are the same. The one on the left appears larger because of its context within the white outlined circle.

Interestingly, these illusions are perceived differently by adults and children, which provides evidence that they are context-sensitive. Because adults have higher sensitivity to context, illusions of this type fool them more often and more easily. Since children are not as context-sensitive, they are less often deceived by this kind of illusion.

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Comparing Your Performance in BrainHQ
About 10,000 BrainHQ participants of different ages and backgrounds have reported their demographicinformation including age, gender, and education level. We can now usethis information to provide feedback on how an individual’s performancecompares to others in a similar demographic.

It'swell known that as we age our ability to hear, see, encode, remember,attend to and make decisions about the stimuli in our environmentgradually decreases. Not surprisingly, these changes were clearlyvisible in performance on the different training tasks available in BrainHQ. In each of the 723 levels of BrainHQ exercises, averageperformance declined across the age range that we considered (from about20 to about 100).

The figure below shows a typical pattern, displaying participants' bestthreshold values on one level of the Eye for Detail exercise. As you cansee, there is a wide variability in performance at each age, but onaverage (roughly shown by the green line) there is a slow, consistentdecline with age.

We also asked you to provide a few other bits of demographic information, including your gender and educational background. With a few exceptions, differences were not seen related to these variables.

What does my score mean?
As you can see from the display above, even within a given age range there is a fair bit of variability in performance on the task. Your percentile score within a given group roughly corresponds to theproportion of people in that group that you are performing better than or equal to. The blue dot on the left shows a 25-year-old with a score slightly above average (shown by the green line) for 25-year-olds. This score ranks that person in about the 60th percentile. The same score for a 75-year-old (the blue dot on the right), comes in closer to the 80th percentile for 75-year-olds.

Tocompute the number you see in the center of your personalized display,we simply average your percentile scores for all the levels on which youhave done enough training to make a good measurement (those levels forwhich you have beat your original baseline at least once). The levelsyou have done--and your performance on them--are also shown in thecolors of the individual suites (the center ring), exercises (middlering) and levels (outer ring) you have completed. For example, the twopictures below show a beginning BrainHQ user (left) and a very experiencedone (right). Note a few things:

• The user on the left shows lighter colors in most areas, indicating lower individual scores.
• Matchingthe number in the middle, the ring is nearer to making a completecircle for the experienced user, showing higher overall performance.
• There are also more gray segments, indicating completely untrained areas, for the beginner.
• These areas don't contribute to the overall shape of the graph or the number in the middle.

What can I do to improve my standing?
Lookingagain at the top image, notice again that although performance decreases withage, there is fairly wide variability within an age group. This isbecause age is not the only factor contributing to performance in ourtasks, just as it is not the only factor contributing to perception ormemory in real life.

Thegood news is that the main thing influencing performance is entirelyunder your control: practice. Across exercises and also across age, thegreatest predictor of the threshold reached by a BrainHQ user tends tobe the amount of time that user has spent training. This is true notonly at the beginning of training where (as many users have noticed)threshold scores are sometimes limited by the number of trials in alevel, but even after dozens of sessions in an exercise.