>"We were also influenced by the introduction of the [anime]. Since the animation had them doing a variety of movements, including human-like gestures, we changed the shape of Pikachu's body to make acting easier. While Pikachu was originally very short and stout, we gradually gave it a more defined neck and elongated its spine." - Sugimori
Both Sugimori and Masuda have stated the obvious; the massive popularity of the anime influenced them to make Pikachu (and the rest of the Pokemon over time) more "human"
