Stroop vs Gorilla[1]
Gorilla is the behavioural scientist's builder for new paradigms. Stroop runs the routine IAT, scored for you, in the same study as your usability and diary work.
30 study-days free. No card.
Gorilla's side of every comparison on this page comes from gorilla.sc, checked 17 October 2026. Where Gorilla wins, the table says so.
Who should choose Gorilla
- You're building a new paradigm, writing custom code, or need its game, shop or multiplayer builders. We support a fixed set of tasks and won't pretend otherwise.
- You want timing backed by a published validation paper. Gorilla links to one. We publish how we time stimuli and responses, and our tests on real displays aren't done yet.
- You're an academic. Its academic rate is £1.09 a respondent, and its Prolific, CloudResearch and Sona integrations are built for that world.
If that describes your team, choose Gorilla. The rest of this page is for the teams it doesn't describe.
For a routine IAT, the rest of the project comes with it.
A usability test and an IAT on the same people
Put a Figma test, a SUS and an IAT in one study. The brand team's question and the product team's question share a participant link, and the findings sit in one set of results.
The client opens it in your brand
Results go to the client on a share page with your logo and colour, beside the clips and findings from the rest of the study. They open it from a link, with no account.
An IAT arrives scored.
D-scores with the improved algorithm, the error penalty and speed exclusions applied, and the method linked. Beside it, what Gorilla's pages say about analysis.
What Gorilla lists
- Download your data in long form or short form
- Its commercial partnership page lists “a data scientist on the team” among good-fit clients
- Consultancy and training to get a first study pilot-ready
From gorilla.sc, checked 17 October 2026.
Line by line, with Gorilla's wins marked.
Gorilla's side comes from gorilla.sc, checked 17 October 2026. Where it wins, the row says so.
| Row | Gorilla | Stroop |
|---|---|---|
| Paradigms | GorillaAny: 2,000+ ready-made tasks and a code editorThey win | StroopIAT, brief IAT, single-target IAT, go/no-go, priming, AMP, reaction-time grid |
| Game, shop and multiplayer builders | GorillaTeam Standard and aboveThey win | StroopNot offered |
| Timing evidence | GorillaA published validation paperThey win | StroopMethod published. Real-display tests not done yet |
| Scoring | GorillaRaw data to analyse yourself | StroopD-scores, error penalty, exclusions computed |
| Usability, surveys and diary | GorillaQuestionnaires | StroopEvery method, in the same study |
| Client sharing | GorillaNot offered | StroopWhite-label share pages, no login |
| Recruitment | GorillaProlific, CloudResearch and Sona integrationsThey win | StroopPanel links with redirects, Prolific included |
| Price unit | GorillaPer respondent, £2.32 commercial | StroopPer study-day, $8 |
| Annual plans | GorillaTeam Basic £2,760 a year for 2,000 respondents | StroopNone. Monthly, cancel any time |
| Academic pricing | Gorilla£1.09 a respondentThey win | StroopNone |
The same study, priced both ways
One week of an IAT. Move the slider to your sample size.
Stroop
$56
7 days live. 400 respondents or 4000: the same price.
Gorilla
$1,288
Commercial price, £2.32 a respondent ($3.22 on its US price list), 25-token minimum.
Team Basic is £2,760 ($3,760) a year for up to 2,000 respondents.
List price, checked 17 October 2026
Switching takes a weekend.
- Participant lists come across as CSV or XLSX. Map the columns once and each person lands in the right workspace with their attributes.
- Gorilla experiments don't import. Stroop's IAT is set up from blocks and stimulus lists, so a standard IAT takes an afternoon to rebuild.
- Your Gorilla data stays with Gorilla. Download it before you stop buying tokens.
Questions
Is browser reaction-time data good enough for an IAT?
- For difference scores like the D-score, a constant lag on someone's device slows both blocks equally and drops out. We publish how we time stimuli and responses and what we have checked. We don't claim parity with lab software. If your paradigm needs lab timing, use Gorilla, Inquisit or a lab.
Which implicit tasks does Stroop run?
- The IAT, brief IAT, single-target IAT, go/no-go, evaluative priming, the affect misattribution procedure and an implicit reaction-time grid. Each is scored in the product with exclusions counted and the method linked. Anything outside that list, including custom code, belongs in Gorilla.
How do the prices compare for 400 respondents?
- On Stroop a 7-day IAT is $56 with any number of respondents. At Gorilla's commercial price of £2.32 a respondent ($3.22 on its US price list), 400 respondents come to $1,288. Gorilla's Team plans lower the per-respondent price for steady annual volume.
What is Stroop?
- Stroop is the all-in-one research and testing platform. Run usability tests, prototypes, surveys, tree tests, diaries and IATs in one study, and get results back transcribed, scored and charted, with every finding linked to the session it came from. The first 30 study-days are free, with no card.
Every finding, traced to the moment it came from.
30 study-days free. Any method. No card.