Digit Symbol Substitution
Use a nine-pair key to match digits and symbols. After ten untimed practice items, the scored block lasts 90 seconds and records correct matches, errors, and response time for correct answers.
Processing speed
Processing speed test: notice, decide, respond
Processing speed describes how efficiently you carry out relatively simple mental operations. A timed result also reflects attention, perception, decision demands, motor response, and the testing setup, so it is not a pure measure of thinking ability.
2 tasksAbout 7 minutes togetherNot a diagnosis
One response, several stages
DetectTake in the visual signal
DecideSelect the matching response
ActMake the motor response
The construct
How is processing speed measured?
Processing speed is measured with timed or time-limited tasks that record how quickly and accurately you respond. For example, Neuropsych's Symbol Coding task counts correct matches between digits and symbols in 90 seconds, while its Reaction Time task measures the delay between a visual signal and your response.
Different tests place different weights on visual scanning, learning a rule, making a choice, sustaining attention, and pressing a key or screen. Symbol coding and reaction time are therefore related views, not interchangeable measurements of one fixed inner speed.
Do not turn “slow” into a global label. A result from one device on one day cannot establish intelligence, a disorder, or the cause of an everyday difficulty. Interpretation should start with the exact task and conditions.
Two ways to sample it
01 · VISUAL CODING
02 · RESPONSE SPEED
Which processing speed test should I try?
The two Neuropsych tasks record different performance patterns. Open the full task runner only when you can work without interruption.
Simple and Choice Reaction Time
First respond when a visual signal appears; then choose between left and right arrows. The task records median response times, valid trials, choice accuracy, and the added time associated with making a choice.
Timed attention tasks such as Go / No-Go and Flanker are part of the ADHD check, an attention profile for adults.
Reading the result
What these tasks can and cannot show
They can record
- Speed and accuracy from this attempt under these conditions.
- Differences between a coding task and a rapid-response task.
- A result you may choose to discuss with a qualified professional.
They cannot establish
- A diagnosis or the cause of feeling slow in everyday life.
- Your overall intelligence, potential, or ability to reason.
- Equivalence to a standardized test given under clinical conditions.
Conditions matter especially for timed tasks. Sleep, fatigue, stress, medication, distraction, vision, motor access, strategy, practice, screen size, browser, and input hardware can all change performance. Compare retests cautiously and, when possible, use the same setup.
Evidence
Research behind careful interpretation
- Carlozzi et al. (2014): the NIH Toolbox Pattern Comparison Processing Speed Test, including construct validity, age effects, and practice effects.
- Salthouse (1996): The processing-speed theory of adult age differences in cognition.
- Anwyl-Irvine et al. (2021): realistic timing precision across online platforms, browsers, and devices.
Begin with the task, not a label
Symbol Coding is a short first sample of visual scanning and coding under time pressure. Your result describes that attempt; it does not diagnose a condition.