Mind is a field of bio-energy which surrounds the physical body. This field shrinks when one is depressed and expands when one is happy. This field dissipates when the mind exits along with the spirit from the body at the time of death.
The spirit is invited for a feast on the 11th day by assembling for it a transitory energy body. The transitory body is sustained through the power of Mantra chants, the emotional connection of the person performing death rituals and a certain belief which lingers in the spirit's psyche.
Food is one of the oldest impressions in the human psyche which stretches back to our evolution from lower life forms. This impression sustains the bond between a departing spirit and its emotional past in the material domain. The feast on the 11th day severes this bond and the spirit remembers its free nature with the help of Mantras chanted at that time. The spirit prepares itself for its onward journey to the domain of the ancestors on the 12th day.
Medical researchers understand the power of the placebo effect. Placebo effect is the tip of an iceberg. The iceberg in this case is a metaphor for the way in which the human psyche maintains its individuality while continuing to be a part of a conscious cosmos. A psyche merges like a wave into the ocean of consciousness when all its impressions are cleared. A spirit transitions between life and death until then.
A transmigrating psyche is thumb sized in comparison to the size of the the bio-energy field associated with an alive body. A transitory energy body is slightly larger, namely, palm sized. The rituals to assemble this palm sized body relies on the bond between the psyche of the departed spirit and the who performs the rituals. A rapidly dissipating energy field is shrunk into a "make-believe" body through rituals which demand strict adherence to rules. These rules are shrouded in awe and mystery and tinged with caution.
Long ago, an intrigued Garuda sought explanations about these rules from Lord vishnu. Rishi Veda Vyasa captured the essense of the dialogue between Garuda and Vishnu in the form of a Purana. Through symbolism and stories, the Garuda Purana explains the journey of the departed spirit. One can find many similarities between these and the recounts of those who encounter near death experiences.