How do shamans use trance to communicate with spirits?

In the context of animism, shamans are believed to communicate with the spirit world by attaining a trance state at will. This process generally takes two primary forms:12

• Trances of possession: The shaman allows a spirit to enter their body. In this state, the shaman may exhibit intense mental or physical behaviors, such as raging or struggling, before eventually becoming a mouthpiece for the spirit, effectively acting as a medium.31
• Wandering trances: The shaman’s soul is believed to depart from their body to travel into the realm of spirits or other world strata. During this time, the shaman’s physical life functions decrease to an abnormal minimum. Upon awakening, the shaman recounts their experiences and the information gathered from the spirits.31

These states are often facilitated by the use of specific ceremonial objects, such as a drum, staff, or specialized clothing, which help the shaman navigate or lure spirits. Some traditions involve a combination of both methods, where a spirit first possesses the shaman and then guides their soul into the supernatural realm.13