Forgetting, Amnesia, and Memory Errors

1. Three Causes of Forgetting

Forgetting is the inability to retrieve information. Encoding failure occurs when information never entered long-term memory — often from inattention or shallow processing. Storage decay is the gradual fading of stored traces over time (though separating true decay from interference is hard). Retrieval failure occurs when information is stored but cannot be accessed at the moment — the "tip-of-the-tongue" state. Interference is a major source of retrieval failure: proactive interference happens when old information blocks recall of new information, while retroactive interference happens when new information blocks recall of old information.

2. Amnesia

Anterograde amnesia is an inability to form new long-term memories after an injury or event, while older memories remain relatively intact — as in patient H.M. (Topic 19). Retrograde amnesia is an inability to retrieve memories from before an injury or event, while the ability to form new memories is spared. These are descriptions of memory impairment, not casual diagnoses; real amnesia arises from brain injury, disease, or trauma and is evaluated by qualified professionals.

3. Schacter's Seven Sins and Reconstructive Memory

Daniel Schacter organized memory failures into seven "sins." The sins of omission are transience (fading over time), absentmindedness (inattention at encoding or retrieval), and blocking (retrieval failure despite the memory being present). The sins of commission are misattribution (attributing a memory to the wrong source), suggestibility (incorporating misleading external information), and bias (distorting the past through current beliefs). Persistence is intrusive, unwanted recall of memories we would rather forget. The misinformation effect, demonstrated by Elizabeth Loftus, occurs when misleading post-event information alters later memory of that event. These findings support reconstructive memory — remembering as an active rebuilding of the past, not a playback. Because memory is reconstructive, eyewitness testimony has important limitations: confidence does not reliably track accuracy, and wording, leading questions, and post-event information can change what a witness "remembers."

How it works

1. An experience is attended to and encoded — or not, producing encoding failure.
2. Over time, traces may fade (storage decay) or be displaced (interference).
3. At recall, the person searches with retrieval cues; if cues are missing, retrieval failure or blocking occurs.
4. If misleading information is encountered after the event, it can be woven in (misinformation effect).
5. The person reconstructs the event from fragments, risking misattribution, suggestibility, or bias.
6. Sometimes retrieval is too successful — unwanted memories intrude (persistence).

Common confusions

Memory aids

For interference, remember "PORN" — Proactive = Old blocks new, Retroactive = New blocks old. For amnesia, think of a time-traveling movie: anterograde cannot record the future (no new memories going forward), retrograde cannot replay the past. For the seven sins, remember "TAB-MSP-P": Transience, Absentmindedness, Blocking, Misattribution, Suggestibility, bias, Persistence.

Quick review

Topic Recap

Forgetting stems from encoding failure, storage decay, or retrieval failure, with proactive and retroactive interference as major sources of retrieval difficulty. Amnesia comes in two forms — anterograde (cannot form new memories) and retrograde (cannot recall old ones). Schacter's seven sins catalog memory's predictable failures, and Loftus's misinformation effect shows memory is reconstructive and alterable by post-event information. These findings carry serious implications for eyewitness testimony, whose confidence can outpace its accuracy.

Knowledge Check

1. You cannot recall a fact you never paid attention to. This is ______ failure.
2. Learning a new phone number makes it hard to remember your old one. This is ______ interference.
3. A person who cannot form new memories after an injury has ______ amnesia.
4. Loftus showed that post-event misinformation can alter memory. This is the ______ effect.
5. True or False: High confidence in an eyewitness's memory guarantees accuracy.

Answers and Rationales

1. Encoding. The information was never stored because it was not attended to or processed.
2. Retroactive. New information (the new number) interferes with recalling old information (the old number).
3. Anterograde. The defining feature is inability to form new long-term memories.
4. Misinformation. Misleading information after an event becomes incorporated into memory of that event.
5. False. Memory is reconstructive, and confidence and accuracy are only weakly related in eyewitness testimony.