Forgetting Objectives The forgetting curve Causes of forgetting

Forgetting

Objectives The forgetting curve Causes of forgetting Biological causes Retrograde amnesia Anterograde amnesia Alzheimer’s disease Decay of memory traces Psychological causes Retrieval failure Motivated forgetting

Forgetting We rely on our memory to perform a wide variety of tasks in our everyday lives, from recalling conversations with friends, to remembering information we learnt in class Memory plays such a large role in our lives that we often take it for granted until it fails us and we forget Forgetting is the inability to retrieve information that has been previously stored in our memory

Forgetting Sometimes forgetting can be embarrassing or frustrating e. g. Forgetting valuable information in an exam Other times, forgetting can be useful, as it contributes to our sanity. Imagine if you remembered every single thing that ever happened to you – all of the clutter would make our brains very difficult to navigate There also events in your life that you probably don’t want to remember…

The Forgetting Curve The forgetting curve, which plots the amount of forgetting that occurs over time, and the rate at which it occurs, typically has a characteristic shape The biggest decline in recall occurs within an hour of learning new information After an hour, the rate of forgetting tends to be more gradual Slow learners typically forget at around the same rate as faster learners When trying to retain information, spending time each day to review information will greatly decrease the effects of the forgetting curve

The Forgetting Curve

Learning Activity 7. 2 Discuss with the person next to you: Based on what you have just learned about forgetting and the forgetting curve, what advice would you give to students preparing for exams to minimise the amount of information forgotten?

Causes of Forgetting There are many explanations as to why we forget Generally, the causes of forgetting can be classified as biological or psychological Biological: factors associated with some sort of damage to the brain e. g. Head injury or stroke Psychological: causes of forgetting that are not primarily due to biological factors are often referred to as psychological causes. Psychological causes are person-related factors which result in forgetting information in LTM e. g. Incorrect retrieval cue

Biological Causes of Forgetting: Amnesia Anterograde amnesia is loss of memory for experiences occurring after the amnesia-causing event (anterograde = forward-moving in time) In general, memory of experiences prior to the amnesia-causing event still remains Example: H. M. 50 first dates https: //www. youtube. com/watch? v=Kka. XNvz. E 4 pk&feature=youtu. be

Biological Causes of Forgetting: Amnesia Retrograde amnesia is loss of memory for experiences occurring before the amnesia-causing event (retrograde means backward--moving in time) With retrograde amnesia, loss of episodic memories of recent personal experiences is particularly common. However memory loss of all sorts may be experienced Memory loss can extend back for varying lengths of time – a few minutes, years, decades… In time, the memories from the ‘lost’ period gradually return, until the amnesia disappears altogether, however it is common that the affected person never recovers any memory of what happened immediately before/after the event

Alzheimer’s Disease Alzheimer’s disease is characterised by the progressive degeneration of brain neurons, resulting in the increasingly severe deterioration of cognitive abilities, behaviour and personal skills Plaques and tangles of brain fibres develop, causing large numbers of brain neurons to die off at a greater rate than normal Alzheimer’s affects 1/8 people over 65, and 1/4 people over 80 There is currently no test which will confirm the presence of Alzheimer’s in a living person. After death, a diagnosis can be made by microscopically analysing the brain tissue

Alzheimer’s Disease The exact trigger of brain neurons is unknown, however up to 20% of cases are said to be genetically caused Alzheimer’s is a degenerative disease Alzheimer’s can begin with simple forgetfulness, but gets much worse as the disease progresses Alzheimer’s can also affect personality Alzheimer’s differs from other forms of amnesia, in that there is not only a difficulty in remembering old information, but also in retaining new information

Alzheimer’s Disease Areas of red and yellow indicate activity in those areas of the brain, while blue areas indicate inactivity What do you notice about the brain on the right?

Learning Activity 7. 3 Read pages 231 -233 and complete the following questions: 3. b) Describe the main symptoms of Alzheimer’s disease c) How is Alzheimer’s disease distinguished from other biological causes of forgetting?

Psychological Causes of Forgetting A retrieval cue is a prompt, clue or signal that assists in the process of locating and recovering information stored in memory e. g. If a teacher asks you a question about information previously learned in class, the teacher is using retrieval cues to help you locate the stored information Sometimes we lack a retrieval cue or fail to use the right cue to locate and recover a piece of information stored in LTM. This results in forgetting. The information is not permanently lost, it is simply inaccessible at that moment This is called retrieval failure or cue-dependent forgetting

Retrieval failure helps explain why we sometimes cannot retrieve information even though we are positive that we know it e. g. “It’s on the tip of my tongue” There are two different kinds of retrieval cues Context-dependent retrieval cues State-dependent retrieval cues

Context-dependent retrieval cues Context-dependent cues depend on the environment/context in which the memory was formed These cues can include the senses associated with that environment Example: Context dependency helps to explain why you may struggle to remember the answer to a question in an exam, and yet remember it with ease when you are at home in your favourite chair, where you were studying the night before

State-dependent retrieval cues State-dependent cues depend on the person’s psychological or physiological state at the time the memory was made When in a particular state, you are more likely to recall a memory formed when you were previously in that state Example: A study showed that heavy drinkers are often able to recall where they hid something (e. g. a bottle of alcohol), however, when they are sober, they are unable to recall the location

Interference from Other Memories Sometimes we forget because of interference from the presence of other information. Interference occurs when one piece of information makes storing or recalling information more difficult This can take place in both LTM and STM There are two types of interference: Retroactive Interference: when new info interferes with the ability to recall info that is already in the memory Proactive Interference: when info in the memory interferes with the ability to remember new info

Motivated Forgetting Remembering a traumatic experience stored in LTM can bring up unpleasant thoughts and feelings Motivated forgetting takes place when we consciously or unconsciously block these memories from conscious awareness There are two types of motivated forgetting: Repression: unconsciously blocking the memory or event Suppression: making a deliberate attempt to forget

Learning Activity 7. 11 Complete Learning Activity 7. 11 (p 241)

Summary The forgetting curve Causes of forgetting Biological causes Retrograde amnesia Anterograde amnesia Alzheimer’s disease Decay of memory traces Psychological causes Retrieval failure Motivated forgetting