There are two sets of synapses in the brain, those associated with short-term memory and those associated with long-term memory.
The synapses associated with long-term memory reset in a regular and specific time sequence. If they are stimulated with the correct inputs at the correct time a long-term memory can be formed.
The synapse needs to receive the same information a minimum of three times if it is to retain that information. If it receives the same information three times it will 'fix', never reset again and the memory will be formed.
That is why Download modules have three time sequenced learning inputs; to form that long-term memory.