There are a lot of different factors that you could point to, and which could have further influenced each other.

• Reliance on pack animals instead of inventing the wheel; pack animals that were less efficient than the horse, ox, elephant, etc. of the Old World
• Reliance on wood and bone as tool materials instead of transitioning to iron
• Lack of written languages and the printing press to allow learning without a face-to-face teacher-pupil relationship
• Lack of widespread agriculture sufficient to support a scholarly class, universities, and monasteries
• Lack of a philosophical foundation that led to the concept of scientific laws to be identified and utilized
• Lack of a cross-continental conquest leading to a shared language that could be used across tribal boundaries for communication and trade
• Lack of feudalism/strongly hierarchical societies creating incentives to increase food and goods production as much beyond subsistence levels