In psychology, when you suffer an injury, loss of consciousness or start having a disease (like dementia) you can get retrograde amnesia, which is the phenomenon by which you forget the events that took place just before the injury.
As opposed to the anterograde amnesia in which you forget the events that take place after the injury and therefore they cannot be stored into the long-term memory.
In this example, we are asked for the phenomenon that occurs when an individual experiences a loss of memory for experiences that occurred shortly before a loss of consciousness. Thus, this would be retrograde amnesia.
The reason why Zinn opined that we shouldn't trust histories written from point of view of Governments and leaders is that they tend to use attempts through politics and culture, to ensnare ordinary people in a giant web of nationhood hiding under the canopy of common interest.
