Memory transfer was a biological process proposed by James V. McConnell and others in the 1960s.
[2][3][4] This explained the results of McConnell's experiments in which planarians retained memory of acquired information after regeneration.
[5] In McConnell's experiments, he classically conditioned planarians to contract their bodies upon exposure to light by pairing it with an electric shock.
[5][7] As the nervous system was fragmented but the nucleic acids were not, this seemed to indicate the existence of memory RNA[5] but it was later suggested that only sensitization was transferred,[6] or that no transfer occurred and the effect was due to stress hormones in the donor or pheromone trails left on dirty lab glass.
[2] However, other experiments seem to support the original findings in that some memories may be stored outside the brain.