Forgetting: WACE Year 12 Psychology Unit 3
“Process of forgetting: types of forgetting, including retrieval failure, interference (proactive and retroactive), motivated forgetting and decay theory”
Forgetting is the inability to retrieve information that was once stored. The SCSA syllabus names four types: retrieval failure (the memory is stored but the right cue is missing), interference (other memories get in the way, either old disrupting new, called proactive, or new disrupting old, called retroactive), motivated forgetting (distressing memories are pushed out of awareness) and decay theory (unused memory traces fade over time).
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What this dot point is asking
You need to define each type, give an example of each, and identify which type best explains a described scenario. Questions often combine this with the memory models (which store or process has failed) and with rehearsal and the forgetting curve.
Retrieval failure
Retrieval failure is forgetting caused by the absence of the right retrieval cue. The information is available (still in long-term memory) but not accessible at that moment.
- The tip-of-the-tongue state, where you know you know a word but cannot produce it, is the classic example.
- Cues can be external, such as the place where you learned something, or internal, such as your mood or physical state at the time. Recall is usually better when the cues present at retrieval match those present at encoding.
Any stimulus that helps you access a stored memory, such as a word, a smell, a place or a feeling that was present when the memory was formed.
Interference (proactive and retroactive)
Interference theory says forgetting happens because other memories compete with the one you are trying to retrieve. It is most likely when the memories are similar.
- Proactive interference: old information disrupts the retrieval of new information. You keep writing last year's date in the first weeks of January.
- Retroactive interference: new information disrupts the retrieval of old information. After learning your new phone number, you cannot remember your old one.
Proactive: old gets in the way of new (it works forwards). Retroactive: new gets in the way of old (it works backwards). Always name which memory is the one being forgotten.
Motivated forgetting
Motivated forgetting is forgetting that happens because remembering would be distressing or threatening. It can be:
- Repression: an unconscious process in which traumatic memories are blocked from awareness (an idea from Freud).
- Suppression: a conscious, deliberate effort not to think about an unpleasant memory.
Motivated forgetting is difficult to research ethically and to verify, because a researcher cannot create trauma and cannot easily check whether a memory has been repressed or was never stored.
Decay theory
Decay theory says that a memory creates a physical trace in the brain, and if the trace is not used it gradually fades until the information is lost. It fits the way unrehearsed information fades from short-term memory within seconds, and the steep early drop in Ebbinghaus's forgetting curve (see rehearsal and the forgetting curve).
Its limitations are that time cannot be separated from what happens during it (new learning in that time could cause interference), and it cannot explain why a "forgotten" memory can return when the right cue appears.
Telling the types apart
| Type | What happens to the memory | Tell-tale sign in a scenario |
|---|---|---|
| Retrieval failure | Stored but not accessible | A cue later brings it back; tip of the tongue |
| Proactive interference | Old memory blocks a new one | Old habit or old information keeps intruding |
| Retroactive interference | New memory blocks an old one | Recent learning makes older learning hard to recall |
| Motivated forgetting | Pushed out of awareness | The memory is upsetting or threatening |
| Decay | Trace fades with disuse | Information has not been used for a long time |
Four students, four types
- Priya cannot remember a friend's name at a party, then recalls it instantly when someone mentions the netball team they played in together. Retrieval failure: the memory was available, and the cue made it accessible.
- After switching from a Samsung to an iPhone, Tom keeps swiping the wrong way. Proactive interference: old learning disrupts new learning.
- Jess learned a new locker combination this year and now cannot recall last year's. Retroactive interference: new learning disrupts old.
- Sam, who was in a frightening car accident, cannot recall the moments before the crash. Motivated forgetting is one possible explanation, although damage from a head injury would also need to be ruled out.
Marker's note: justify each label with the specific detail in the scenario, not just the definition.
Earlier versions of this page covered reconstructive memory and the reliability of eyewitness testimony (Loftus and Palmer). These are not named in the current SCSA Year 12 syllabus, so they are not examined in the WACE exam. The URL has been kept so older links still work.
- Reversing proactive and retroactive
- Anchor them by direction: proactive means old disrupts new; retroactive means new disrupts old.
- Saying the memory has gone when it is retrieval failure
- In retrieval failure the information is still stored; only access has failed.
- Treating repression and suppression as the same
- Repression is unconscious; suppression is conscious.
- Ignoring the scenario
- The mark comes from the clue in the question (a cue restores the memory, a similar old habit intrudes), so quote it.
Exam-style questions
Questions in the style of SCSA exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
Original6 marksDistinguish between proactive interference and retroactive interference, and give an example of each involving a student learning a new language.Show worked answer →
A 6 mark response needs each type defined (2 marks each) and matched to an example (1 mark each).
Proactive interference. Previously learned information disrupts the retrieval of newer information ("pro" means forward: old memories act forwards in time). Example: a student who studied French last year keeps writing French words when trying to recall new Italian vocabulary.
Retroactive interference. Newly learned information disrupts the retrieval of older information ("retro" means backward: new memories act backwards in time). Example: after a term of Italian, the student struggles to recall the French vocabulary learned last year because Italian words come to mind instead.
Marker's note: the direction of disruption is the whole point. State which memory is old, which is new, and which one is being forgotten.
Original8 marksCompare decay theory and retrieval failure as explanations of forgetting. In your answer, explain what each theory says happens to the memory trace and describe one limitation of decay theory.Show worked answer →
An 8 mark response needs each theory explained (2 marks each), a clear comparison (2 marks) and a limitation (2 marks).
- Decay theory
- A memory trace fades over time if it is not used, so the information is no longer available. It links forgetting to the passage of time.
- Retrieval failure
- The memory is still stored (available) but cannot be accessed because the right retrieval cue is missing. The tip-of-the-tongue experience and the way a cue suddenly brings a memory back support this.
- Comparison
- Decay says the information is lost from storage; retrieval failure says it is stored but inaccessible. Decay is passive and time-based; retrieval failure depends on cues.
- Limitation of decay theory
- It is hard to test because time cannot be separated from what happens during that time (new learning can cause interference). It also cannot explain why some old memories are recalled vividly, or why a forgotten memory can return when a cue is given.
Practise this
Sources & how we know this
- Psychology ATAR course Year 12 syllabus (effective from 1 January 2024) — School Curriculum and Standards Authority (SCSA)
- Psychology ATAR course: syllabus and support materials — SCSA
- Past ATAR course examinations — SCSA