We report an “Aha!” experience which differs from conventional Aha's studied over a
century in psychological science. The Aha we introduce is driven by touch instead of the
visual and verbal modalities widely studied to date. It can occur when gripping a
baseball, with a simple input that the red seam on the ball has a direction. Aided by a
symmetry analysis and subsequent survey over literature, we show how our mental and
physical representation of a baseball can change suddenly by the seam direction and
unravel the factors that make the tactile sense into a joyful-and-insightful sensation.
Our study sets a new category of Aha driven by touch, opens a new path to investigate the
role of touch in our cognition process, reveals the seam direction as a new degree of
freedom in baseball aerodynamics and pitching mechanics, and deepens the insights into
throwing a baseball from our fingertips.