05 / 07
Variants of the Stroop Task — Emotional, Numerical, Spatial and Counting Stroop
The Stroop structure — information you must ignore overlapping with the answer — has spread to many tasks. What the emotional Stroop, numerical Stroop, spatial Stroop, counting Stroop and picture-word interference each measure.
The backbone of the Stroop task is a stimulus in which the dimension you must ignore overlaps with the dimension you must respond to. This structure has spread to many fields, and even when a task has “Stroop” in its name, what it measures differs somewhat.
Emotional Stroop
You still name the ink color, but the words are not color words — they are emotionally charged words (such as “failure”, “spider” or “hospital”). People with anxiety or specific worries tend to be slower at naming the ink color of words related to those worries (Williams, Mathews & MacLeod, 1996).
Here the word's meaning does not clash with the response: “failure” does not overlap with any color name. So rather than the response conflict of the classic Stroop, it is interpreted as attention being captured by emotional words, and some have criticized the effect as inconsistent across studies.
Numerical Stroop
You are asked to pick which of two numbers is printed larger (or which has the larger value). When a small “8” appears next to a large “3”, the judgment slows down. This is the size congruity effect reported by Henik & Tzelgov (1982), used as evidence that numerical value is processed automatically.
Spatial Stroop
Position and meaning clash — for example, the word “left” appears on the right side of the screen, or an arrow pointing up appears at the bottom. It is a close relative of the Simon effect, in which responses slow down when the stimulus position and the responding hand's position do not match, and many studies try to tell the two apart.
Counting Stroop
Several number words are shown, as in “two two two”, and you answer how many words there are. The word's meaning (two) clashes with the count (three). Bush et al. (1998) designed a button-response version for use inside brain imaging scanners, where speaking is difficult.
Picture-word interference
A different word (e.g., “cat”) is superimposed on a picture (e.g., a dog), and you name the picture. The closer the word's meaning, the greater the interference, so this task is used to study how we select the word we are about to say (Rosinski, Golinkoff & Kukish, 1975; Lupker, 1979).
Auditory Stroop
The word “high” is played at a low pitch and the word “low” at a high pitch, and you judge the pitch. This shows that similar interference occurs in senses other than vision.
Comparison at a glance
| Task | Dimension to respond to | Dimension to ignore | Main focus |
|---|---|---|---|
| Color-word Stroop | Ink color | Word meaning | Response conflict, inhibition |
| Reverse Stroop | Word meaning | Ink color | Direction of interference by response type |
| Emotional Stroop | Ink color | Emotional word | Attentional bias |
| Numerical Stroop | Print size | Numerical value | Automatic processing of quantity |
| Counting Stroop | Number of words | Meaning of number words | Conflict (for brain imaging) |
| Picture-word | Picture name | Superimposed word | Lexical selection |
The main task on this site is the classic color-word Stroop (pick the ink color), and the second task is the reverse Stroop (pick the word's meaning). Emotional, numerical and spatial tasks are not offered because their stimuli and interpretation differ.
References
Williams, J. M. G., Mathews, A., & MacLeod, C. (1996). The emotional Stroop task and psychopathology. Psychological Bulletin, 120(1), 3–24.
Henik, A., & Tzelgov, J. (1982). Is three greater than five: The relation between physical and semantic size in comparison tasks. Memory & Cognition, 10(4), 389–395.
Bush, G., Whalen, P. J., Rosen, B. R., Jenike, M. A., McInerney, S. C., & Rauch, S. L. (1998). The counting Stroop: An interference task specialized for functional neuroimaging. Human Brain Mapping, 6(4), 270–282.
Rosinski, R. R., Golinkoff, R. M., & Kukish, K. S. (1975). Automatic semantic processing in a picture-word interference task. Child Development, 46(1), 247–253.
Lupker, S. J. (1979). The semantic nature of response competition in the picture-word interference task. Memory & Cognition, 7(6), 485–495.