 Analyzing accounts of early Pentecostal religious ecstasy, historian Grant Wacker concluded that communal cues helped religious communities determine whether specific incidents were instigated by the Holy Spirit or not.Other explanations of the phenomenon have also been proposed, such as autosuggestion, peer pressure, or a desire to experience what others have experienced.In addition, sociologists note that similar phenomena, such as spirit possession and trance, can be found in other religions.