If we consider that the voices are a transmission from a reconfigured form of human intelligence, existing independently of a physical brain, the desire to communicate to a living counterpart would be unsurprising. However the study does not provide evidence that EVP originates from a discarnate source, only that anomalous voices are captured on recordings.
The ability to capture a voice on more than one device at the same time would indicate that the EVP is a recorded transmission of a physical sound wave and not a mechanical or electrical fault inherent to a recording device. This does not in itself provide evidence of an incorporeal source but it does suppose a source of physical generation. It also leads to the unanswerable question; how would an etherical intelligence commute thought to a sound wave that is able to be recorded at the same pitch and volume as human speech but that is not heard in the environment at the time of recording?
It would be logical having only read the study to conclude that EVP does not provide evidence of post mortem communication. However had you taken part in a sitting, witnessed the recording and were satisfied that no deception took place, but on playback were able to hear an anomalous voice in reply to yours, it would be logical to explore all alternative explanations, regardless of how unlikely they were. We are fortunate in continuing to experience and report physical phenomena and EVP in our sittings, the study and recordings will continue.
My thanks to the Gilbert Roller Fund, who kindly provided support to purchase equipment used in the study and to group members Tracey Martin, Richard Crane and Debbie Townsend for their contribution to recordings.