Human memory Recall of Tragic events Selective Selective

Three types of memory 1. SENSOR MEMORY: acts as a buffer for stimuli received through the senses. Information passes through sensory memory into short-term memory by attention, thereby filtering the stimuli to only those of interest at a given time

2. SHORT-TERM MEMORY decays rapidly (200ms) and has a limited capacity. Chunking of information can lead to an increase in the short-term memory capacity (ie: a hyphenated phone number is easier to remember than a single long number). Interference often causes disturbance in short-term memory retention decays rapidly (200ms) and has a limited capacity. Chunking of information can lead to an increase in the short-term memory capacity (ie: a hyphenated phone number is easier to remember than a single long number). Interference often causes disturbance in short-term memory retention

3. LONG-TERM MEMORY is intended for storage of information over a long time. Information from short-term memory is transferred to it after a few seconds. Two types of long-term memory: Two types of long-term memory: a) episodic: memory of events and experiences in a serial form b) semantic: a structured record of facts, concepts and skills that we have acquired

Memory Activities There are three main activities related to long-term memory There are three main activities related to long-term memory 1.Storage 2.Deletion 3.Retrieval

Storage Information from short-term memory is stored in long-term memory by rehearsal Information from short-term memory is stored in long-term memory by rehearsal The repeated exposure to a stimulus or the rehearsal of a piece of information transfers it into long-term memory The repeated exposure to a stimulus or the rehearsal of a piece of information transfers it into long-term memory Affected by passage of time, frequency and length of exposure and new information Affected by passage of time, frequency and length of exposure and new information

Deletion Mainly caused by decay and interference Mainly caused by decay and interference Emotional factors also affect long-term memory Emotional factors also affect long-term memory

Retrieval Two types of retrieval: Two types of retrieval: 1.Recall: the information is reproduces from memory 2.Recognition: the presentation of the information provides the knowledge that the information has been seen before. This is less complex since the information is provided as a clue

Effects of trauma on memory Marked deficiencies in memory may occur when individuals suffer either physical or psychological trauma Marked deficiencies in memory may occur when individuals suffer either physical or psychological trauma The extent of this is very individual The extent of this is very individual For some, there are unprocessed memories that may appear unexpectedly as flashbacks which are the unexpected and unwelcome reliving of a traumatic incident For some, there are unprocessed memories that may appear unexpectedly as flashbacks which are the unexpected and unwelcome reliving of a traumatic incident May be triggered by a chance remark, sight, smell, sound, taste or touch May be triggered by a chance remark, sight, smell, sound, taste or touch

Post event information effect After witnessing an event, we are exposed to new information that can actually change our memory After witnessing an event, we are exposed to new information that can actually change our memory People can reconstruct inaccurate memories after witnessing an event as a result of discussing the event with others People can reconstruct inaccurate memories after witnessing an event as a result of discussing the event with others

Eyewitness testimony Eyewitness testimony is, at best, evidence of what a witness believes to have occurred Eyewitness testimony is, at best, evidence of what a witness believes to have occurred Up to a 50% error rate Up to a 50% error rate Memory is not a tape recorder Memory is not a tape recorder Ability to identify a stranger is diminished by distress Ability to identify a stranger is diminished by distress Cross racial identification unreliable Cross racial identification unreliable People who are certain are no better at it, just more confident People who are certain are no better at it, just more confident

Impediments to memory Ability to Judge time & distance Ability to Judge time & distance Age & health – sensory acuity Age & health – sensory acuity Personal bias & expectations Personal bias & expectations Viewing conditions Viewing conditions

After the incident Make notes as soon as possible Make notes as soon as possible Write them alone Write them alone Don’t discuss the incident Don’t discuss the incident You may be asked to give a statement to police You may be asked to give a statement to police - you may give information other than the person’s medical history & findings - you may be called as a witness in court to recall statements made by the patient