Final answer:
Amnesia can manifest as retrograde amnesia, loss of past memories, or anterograde amnesia, the inability to form new memories. Case studies like that of Scott Bolzan and H.M. illustrate the effects of such memory loss. Hermann Ebbinghaus's forgetting curve explains how memory retention declines over time.
Step-by-step explanation:
Retrograde vs Anterograde Amnesia
Amnesia refers to the loss of long-term memory that can result from disease, physical trauma, or psychological trauma. There are two common types of amnesia: retrograde amnesia and anterograde amnesia. In retrograde amnesia, individuals lose memory for events that occurred prior to a trauma, which means they have trouble recalling their past or certain episodic memories. This type of memory loss was depicted by the story of Scott Bolzan, who experienced a head injury leading to the loss of 46 years of life memories. On the other hand, anterograde amnesia prevents the formation of new memories following an injury, affecting the ability to transfer information from short-term to long-term memory.
Patients with anterograde amnesia may have difficulties remembering new people or reading materials, as demonstrated by the case of H.M., while they might still improve in skills such as solving puzzles over time due to procedural memory retention. This indicates that different types of memory are stored and accessed in distinct ways within the brain.
Memory Functioning and Decay
Memory performance, including its decay over time, was first systematically studied by Hermann Ebbinghaus, who formulated the famous Ebbinghaus forgetting curve. The curve shows that memory retention drops sharply soon after learning, although subsequent loss happens more gradually. Issues concerning memory, including the unreliability of eyewitness testimony and the debate over repressed memories, are significant within the context of understanding amnesia and memory problems.