The number of triangles someone notices first is usually influenced by attention, visual perception, and interpretation—not by personality traits.
In the picture, I can see 10 obvious triangular pieces arranged in a larger triangular pattern:
1 on the top row
2 on the second row
3 on the third row
4 on the bottom row
Total: 10 triangles.
If the challenge is to count all possible triangles formed by the arrangement (including larger composite triangles), that’s a different puzzle. In this particular image, the pieces are separate objects rather than connected line segments, so there aren’t clearly defined larger geometric triangles to count in the usual puzzle sense.
If you’d like, I can also help analyze it as a triangle-counting puzzle and discuss alternative counts people might arrive at.