A text-only guide to the drawings, sounds and memory activities. You can read everything here without playing a clip, taking part or enabling JavaScript. The instructions below describe what each activity asks you to do in the playground; this page has no interactive tasks.
These are educational adaptations, with no clinical interpretation, population norms or overall score. Effects vary. Our drawings, synthesised tones and word lists are original, and the linked sources explain the underlying ideas.
Vision · Brightness
A shade of context
What the activity asks
Look at the small grey square in each panel. Which one looks lighter to you?
This is a visual comparison. You can read the explanation instead, with a description of the drawing.
What is happening?
Both small squares in the activity use exactly the same grey. One sits on a light background and the other on a dark background, which can make their shades look different. The activity lets you bring the backgrounds to the same grey while leaving the small squares unchanged.
Why it matters
Appearance depends partly on context. When comparing paint, fabric or an image edit, putting samples on the same background can help.
The effect may be subtle or absent. Screen settings, surrounding light and the way you look at it can change the experience.
Go deeper
This is called simultaneous brightness contrast. Vision responds to relationships across a scene as well as the light reaching the eye. Several processes contribute; this small demonstration cannot identify which mattered most for you. Matching RGB values means matching the colour specified in this drawing. It is not a measurement of your screen’s luminance.
Compare the two filled centre circles. Which centre looks bigger?
Compare the filled circles, not the outlined circles around them. A text explanation is available if the drawing is not useful to you.
What is happening?
The activity places two equal-sized centre circles among neighbours of different sizes. The surroundings can change how big each centre looks. Hiding and restoring the neighbours leaves the centre circles unchanged.
Why it matters
Nearby things can influence a size judgement. A direct measurement can settle a comparison that appearance leaves uncertain.
You might see a clear difference, a small one or none. This drawing is an illustration, with no assessment of your visual ability.
Go deeper
This is an adaptation of the Ebbinghaus illusion. The size, spacing and arrangement of the surrounding circles can all matter. People also differ in how strongly they experience it. The neighbours are not simply a universal “make it bigger” or “make it smaller” switch.
Compare only the two horizontal lines between their end points. Which horizontal line looks longer?
The angled fins are context. Judge the horizontal shafts. You can skip the visual task and read its explanation.
What is happening?
The activity shows two horizontal lines of the same length with differently angled fins at their ends. The fins can make the lines look different in length. Hiding the fins reveals guides at the matching end points.
Why it matters
The context around an edge can change a length judgement. Checking the end points is often more useful than relying on a first impression.
The strength of the effect varies across people and drawings. Familiarity can also change what you report.
Go deeper
This is a version of the Müller-Lyer illusion. Changing the angle and length of its fins can change the effect. Researchers have proposed several explanations, involving visual processing, context and experience. There is no single settled account that this demonstration proves.
If comfortable, close your left eye. Keep your right eye on the cross on the left. Slowly adjust the dot’s position, or your distance from the screen. Keep looking at the cross. What happens to the dot?
This activity depends on one-eyed fixation. Skip it if that is difficult or uncomfortable. Stay in a comfortable position and stop if you strain.
What is happening?
Each eye has a blind spot where the optic nerve leaves the retina. There are no light-detecting cells at that point. In the activity, the dot stays on screen. If its image lands on that blind spot, it may disappear from view while the background still looks continuous.
Why it matters
A continuous-looking view does not mean every part comes from a light signal at every point. Usually, the other eye and surrounding visual information help cover the gap.
Finding the effect can take a little adjustment. Not finding it here says nothing about your eye health. This activity cannot check your vision.
Go deeper
Fixation matters: with the left eye closed, the target belongs to the right of the fixation cross. Looking straight at the dot moves its image away from the blind spot. This drawing is deliberately uncalibrated; it does not locate or measure your blind spot.
Play the short sequence at a quiet, comfortable volume. What seems to happen to the pitch?
What is happening?
This sequence combines tones an octave apart. As their pitches step around a repeating pattern, the louder parts shift gradually between octaves. It can sound as though the sequence keeps climbing or falling, even though it loops.
Why it matters
A sound’s ingredients and its apparent direction are different kinds of information. A repeated pattern can support a strong impression of ongoing movement.
The effect is not guaranteed. Your speakers, hearing and listening context can change it. There is no need to turn it up to make it happen.
Go deeper
These are Shepard tones, synthesised here from scratch. The notes at positions 1, 13 and 25 are identical digital sounds. The overlapping octave components and a fixed loudness envelope across frequency help make the octave boundary less obvious. Some listeners hear the repetition readily.
Listen to sound A, then sound B. Focus on their musical pitch, even if their tone colour differs. How does B compare with A?
What is happening?
Sound B leaves out the lowest component present in A. Their remaining frequencies still line up as multiples of the same 220 Hz base. Many listeners hear a similar pitch, with a change in tone colour, even when that lowest component is absent.
Why it matters
Pitch is an interpretation of a sound’s pattern. It does not always correspond to a frequency physically present in the signal.
Small speakers, headphones and audio processing can change the comparison. A different answer does not indicate a hearing problem.
Go deeper
This is an example of the missing fundamental. A contains 220, 440, 660, 880, 1100 and 1320 Hz; B contains the same set without 220 Hz. Both are adjusted to comparable digital energy. Pitch perception can use relationships among harmonics and timing information. Changes in timbre (the quality of a sound) can still be quite obvious.
Listen to clip A and describe how its pattern groups together. Then do the same for clip B. Each clip lasts 8 seconds and starts only when you press Play. You can replay the current clip or read the explanation instead.
What is happening?
Both clips follow the same high–low–high–gap timing. In B the high and low tones are further apart in frequency. Wider separation can make the high notes and low notes sound like separate streams.
Why it matters
Listening includes organising sounds into possible sources. That grouping helps us follow a voice or an instrument in a busy soundscape.
Eight seconds may not be enough for grouping to develop. You might hear one pattern, two, a switch between them or no clear difference. A always comes before B here. That fixed order and repeated listening can influence grouping, so one pair of descriptions cannot establish an individual effect of pitch separation.
Go deeper
Auditory stream segregation depends on frequency separation, rate, attention and time spent listening. A high–low–high sequence can seem like one galloping rhythm, or it can split into a faster high stream and a slower low stream. Both clips use 1400 Hz high tones: the low tones are 1320 Hz in A and 500 Hz in B. Only that low frequency changes; the timing stays the same. These short clips illustrate the idea; they cannot reliably measure a person’s grouping threshold.
Read 12 words, one at a time. Then decide whether each of 10 words appeared. Give your confidence each time; the answers stay hidden until the end.
Choose your own pace or a steady pace. The words can be read by a screen reader. There is no response deadline.
What is happening?
The activity asks about words from a list alongside new words. One new word is closely related to the list’s theme. Related words can feel familiar even when they were never shown.
Why it matters
Familiarity is useful information, but it can come from a connection or a theme as well as a specific encounter. Checking a source can help separate those possibilities.
You may remember every word accurately. Repeating the activity changes expectations. A brief word game cannot establish whether a personal-life memory is accurate, or assess your memory health.
Go deeper
This is an original adaptation of the Deese–Roediger–McDermott word-list approach. Research distinguishes memory for exact items from connections and shared meaning across them. Gist-based and activation-and-monitoring accounts offer different explanations of related-word errors. These newly assembled lists have not been validated as a test.
Read 15 words, one at a time. Afterwards, type as many as you remember, in any order. You do not need to remember their positions.
Choose your own pace or a steady pace. Spelling and language familiarity affect the matching here. You can always read the explanation instead.
What is happening?
Across many lists, words near the beginning and end are often recalled more than words in the middle. One run can differ. The activity compares typed entries with the original list and shows where each matched word appeared.
Why it matters
What we remember can depend on where an item appears, how we rehearse it and what happens before recall. A single short list is only a small sample.
There is no expected score. Own-pace and steady-pace runs use different conditions. Exact word matching can miss misspellings, so the activity’s word-by-word review matters more than treating the count as a precise measure.
Go deeper
In free-recall research, words near the beginning and end of a list are often remembered more frequently than words in the middle. These are called primacy and recency effects. They are patterns across observations, not a curve everyone must produce. List length, presentation pace, rehearsal and delays can change the pattern. This version has no population norms.
Watch a short sequence of numbered tiles. Then select the same tiles in the same order. Choose a length that feels comfortable.
Tiles keep their numbers throughout. Use touch, mouse or Tab and Enter. Own pace lets you control each step, and each active tile is also named in text.
What is happening?
The activity shows numbered tiles in an order and asks you to repeat that order. Afterwards, it displays the presented sequence alongside your response. Remembering the places and remembering their order are both parts of the activity.
Why it matters
Even a short sequence asks you to hold information while using it. An everyday example is remembering a few directions long enough to act on them.
This activity does not estimate memory span, IQ or a clinical result. Practice, strategy, attention, input method and pace can all change a run.
Go deeper
Spatial-sequence tasks have a long history in memory research, including block-tapping tasks. This is a bespoke numbered-grid activity, not a standardised Corsi test. Its regular layout, number labels and selectable pace change the task, and people can use different strategies, such as words, shapes or movement.
Your responses are processed in the playground page. Saving is optional: the local journal keeps up to 100 recent descriptive observations, dates, confidence choices and presentation conditions in your browser. It does not save the words you type for free recall. Turning saving off keeps existing entries until you clear them. Download a copy if you want to keep it; browser storage may be unavailable or cleared.
No responses or journal results are uploaded to Nousophy. Ordinary page and asset requests may appear in hosting logs. There is no microphone access, account or automatic audio playback.
Confidence describes how a response felt at the time. A few short activities cannot establish a general ability, a health finding or how well confidence predicts accuracy.
