What causes Forgetting ? Biological or organic causes are the basis for a lot of forgetting. This Usually refers to damage to the brain brought about by: Disease Injury Stroke Malnutrition Seizure Chemical Damage – due to drugs ( including alcohol). Memory loss due to any of these causes is referred to as organic amnesia. This is usually partial & selective. Total amnesia ( no memory of anything at all ) is extremely rare. Anterograde amnesia When the memory loss is only of events that occur after brain damage. Retrograde amnesia When the memory loss is only of events that occur before brain damage.
Anterograde & Retrograde effects on the Forgetting Curve: • - Anterograde amnesia prevents the formation of new memories, but what • existed in memory prior to the onset of amnesia remains much the same. • For material already in memory, forgetting would occur as predicted by • the curve. • Any memories that are being consolidated at the time of the brain trauma • would be lost. • See articles (handouts) • With retrograde amnesia, new learning is possible but recall of previously • learned information is impaired. • It is expected that memory for the new material would be forgotten in a • similar way to that suggested by the forgetting curve. • Memory of information stored prior to the amnesiac event would be affected, • and the effect would depend on the type & severity of the brain damage.
Learning Tip Antero means “forward” – I.e. the loss is of everything forward of (or after) brain damage. Retro – means “backwards” – I.e. the loss of everything backwards of ( or before) brain damage. Memory Decline over the lifespan: There is considerable evidence that our ability to remember & forget differs across various stages of the lifespan. Infantile amnesia - - is the inability to remember a large period at the start of our lives (usually somewhere under the age of 3 – 4 years). - the cause of this is unclear - it may be due to retrieval failure. It is possible that they are not forgotten but because the retrieval cues used by adults may be so different from those used by young children that the childhood memories remain inaccessible.
Memory Decline over the lifespan: • Memory in the elderly - • it is believed that as a person enters middle age & late adulthood that their memory capabilities begin to decline. • It appears that the decline is restricted to particular types of memory of • learning. • procedural memory ( how to) & semantic memory ( gen. knowledge) does NOT decline as much as episodic memory. • there is some evidence that older people take a little more time than • younger people to encode information into LTM. • storage of memory seems unaffected by age • similar levels of recognition are seen in both younger & older adults • the greatest difference is seen when memory is tested by recall – • elderly tend to remember significantly less than younger participants.