An arrow points one way but sits on the opposite side of screen. Respond to direction, ignore location.
Spatial Stroop (also called the Simon task) tests whether you can ignore irrelevant spatial information.
An arrow appears on the left or right, pointing left or right. Respond to where it points - not where it is.
When location and direction conflict, response time increases. That's the Simon effect.
Smaller Simon effects mean stronger spatial selective attention.
Simon (1969) introduced the paradigm. The effect is one of the most replicated in cognitive psychology.
Right inferior frontal cortex activity scales with successful conflict resolution on this task.
Your ability to obey an arrow's meaning while its position screams the wrong answer.
This task isolates spatial conflict resolution: the cost your responses incur when an arrow's relevant feature (which way it points) clashes with its irrelevant feature (where it sits on screen). The reaction-time gap between aligned and conflicting trials reflects how well you suppress an automatically activated, location-based response and let the meaningful direction win.
Unlike the classic colour-word Stroop, where conflict is semantic, here the interference is purely spatial, putting it close kin to the Simon effect. Everyday correlates include reaching correctly for a control whose layout is reversed, or steering by a sign's arrow rather than its placement on a confusing junction or dashboard.
Build a steady rule-first habit before chasing raw speed.
Start with longer display times and a high share of aligned trials so the direction rule becomes automatic. As your conflict cost shrinks, raise the proportion of incongruent trials, shorten exposure, and add jitter to arrow positions. Keep your focus anchored on direction, treating screen location as noise to be actively discounted rather than read.
The common trap is letting your eyes lead: a peripheral arrow pulls a glance toward its side, and the spatial pull tags along into your hand. Hold central fixation and let direction register parafoveally. Pushing for speed too early collapses accuracy on conflicting trials, the exact ones that train suppression.
The number that matters is the gap, not the raw speed.
Read your congruency cost: average reaction time on conflicting trials minus aligned trials, with errors kept low on both. A smaller gap means tighter conflict control. Because labs differ in timing and layout, trust your own trend over weeks rather than any absolute millisecond figure, watching whether the gap narrows while accuracy holds.
This cost is state-dependent: fatigue, caffeine, screen size and how alert you feel all swing it, so judge it across sessions, not single runs. A low conflict cost shows efficient spatial filtering on this specific task; it does not measure general intelligence, memory, or how you handle non-spatial, semantic interference.