The 'Think of an Apple in Your Head' meme, also known as the Apple Visualization Exercise, gained viral popularity as a way for internet users to discuss aphantasia—the inability to visualize mental images. The graphic depicts a five-step progression of an apple, ranging from a vivid, photorealistic 3D fruit at level one to a completely blank, black void at level five. Originally used in psychological discussions about the mind's eye, it became a relatable meme format where users share their shock at discovering others can actually 'see' things in their heads. It is frequently used to highlight differences in cognitive processing, neurodiversity, and the subjective nature of human thought.