Memory Flashcards
Define memory
Process by which information is stored and retrieved, the ability to retain information over time
Memory is necessary for learning - Shettleworth 1998
How long does short term memory (STM) store information? Long term memory? (LTM)
STM seconds->hours
LTM years
How do studies of memory differ from studies of learning?
Learning- how relationships between events are learnt, which are learnt, how fast?
Memory- How information is encoded, stored and retrieved, what affects ease of this, how is information consolidated, mechanisms?
Who studied Western Scrub jays?
Tarbell 2004 - food storing animals, appear to remember which trees food is hidden in. May be a rule - eg. go to smallest tree first etc.
Neurally, what is short term memory doing?
Strengthening synaptic connections
How does consolidation from STM->LTM occur?
Gene expression and protein synthesis - growth of NEW synaptic connections
How may STM give behavioural outputs?
Behaviour alone or cued behaviour
How may LTM give behavioural outputs?
Spontaneous behaviour (recall memory) Cued behaviour (recognition memory)
Which factors affect encoding to STM?
Duratino of exposure to stimulus, no. of discriminable features a stimulus has, interference from other stimuli, salience of stimuli (surprise/distinctiveness/motivational relevance/value/stress/emotional state)
What must be considered when used delayed match to sample tasks to look at STM?
LTM is also used just to understand the task in the first place
Give a study looking at duration of exposure to stimulus and STM encoding
Grant 1976 - pigeons delayed match to sample, extending time between first and second stimuli
Give a study looking at no. discriminable features of a stimulus and encoding to STM
Zentall et al 1990 - pigeons adding colour to different shaped stimuli (delayed match to sample)
Give a study looking at interference from other stimuli and encoding to STM
Whitlow 1975- Habituation in rabbits to a tone demonstrated.
Then, light flashed between two tones same distance apart, habituation ruined and same initial response occurs upon second play of tone - information has been overwritten following encoding (RETROACTIVE INTERFERENCE)
Then, light and tone played first, again when tone played alone second time same initial response occurs - information has been interfered with during the encoding process (PROACTIVE INTERFERENCE)
What are primacy and recency effects?
Primacy - the first stimulus/picture/event is most memorable/ better recognition
Recency - the last stimulus/picture/event is most memorable/ better recognition
NB: Serial position curve of proactive and retroactive interference
What phenomenon is displayed in the serial probe recognition task? In what species?
Pigeons, monkeys and humans. Different retention intervals (RI) -> different prevalence of primacy/recency effects
- Short RI = Recency effects, last stimulus best memorised
- Medium RI = U shaped
- Long RI = Primacy effects, first stimulus best memorised
NB: Exact RI depends on species (Long RI = pigeons 10s, monkey 30s, human 100s)
Give two studies showing salience of stimulus affecting encoding to STM
Roberts 1980 - if matching to sample and all stimuli are circles, then one is a line, will be more easily matched
Laughlin and Mendl 2004 - pigs searching for food in 4 armed maze, when arms become costly to enter and search make fewer errors and remember better
What is the effect of stimulus saliency on STM encoding known as in humans?
Von Restorff effect
How does stress or emotional arousal impact encoding to STM?
Attention narrowing/focus - {task relevant }
Flashbulb memories - { stressors}
Attention shifts/lapses (task irrelevent stressors)
- Yerkes-Dodson Law
Why is the salience of a stimulus able to impact its encoding?
The value or importance of the information attempting to be memorised
What factors affect coding into LTM?
Cahill et al 1994 - Physiological responses to emotional stories increase memorisation. If given B blockers memory decreased
What did Sandi and Rose 1994 do?
Chicks - food aversion with corticosterone/control injection. Corticosterone (HPA response) chicks showed markedly more avoidance
Also shown with adrenaline
Which hormones are produced in response to an emotionally arousing or important stimulus? How do these act to affect memory?
Glucocorticoids and Catecholamines - GCs cross BBB -> Hippocampus directly, Catechols do not cross BBB but increase blood glucose enabling the brain to work more efficiently
What did Cahill et al 1996 show?
Increased amygdala glucose associated with remembering more of an emotional film
What are the two types of memory recall?
Recognition - cue similarity to stored information influences retrieval success. Context is important (external - location, odour, weather etc. Internal - affect, body clock etc.)
Recall - Apparently not cued, but possible that context and subconscious cues are registered
What did Robinson and Rollings 2011 show?
Effect of neutral/emotional film on accuracy of recall and recognition
At what stages may “forgetting” happen?
- Failure of encoding and temporary stooge in STM (limited capacity, interference effects, decay of STM trace, low salience/value ->v attention)
- Failure of consolidation into LTM (decay of STM trace, severe stress)
- Failure to retrieve information (inappropriate clues/context . decay of LTM)
- Active forgetting
At what stage of encoding do early and late stage dementia affect?
Early - failure of encoding and temporary storage
Late - failure to retrieve information
Outline a study regarding active forgetting
Maki and Hegvik 1980 Delayed match to sample in pigeons - learnt cue that meant forget and one that meant remember. If presented with task following forget cue did not perform well
What did Karlsson and Frank 2009 investigate?
Spatial awareness memory in rats - hippocampal place cells fire in sequence as move around a maze. Replay during sleep indicating consolidation of memory.
Outline a recall and recognition study in animals
Basile and hampton 2011 - Recall: touch space where rest of shape should be (recall of shape even in its absence)
Recognition: delayed match to sample, or if not correct press “wrong” logo
Results shown are similar to human recall and recognition therefore good indicator
What are the two main forms of long term memory system?
Explicit (Concious, declarative) -> Episodic (personal events, and episodic future planning) and semantic (facts)
Implicit (Non-concious, procedural) -> Habits and skills, priming (where stimulus before test influences outcome, even if only subconsciously) simple classical conditioning
How may episodic memory be demonstrated in animals?
Demonstrate that animals remember what happened, where and when -> episodic like memory
Who argued that the human ability to travel mentally in time constitutes a discontinuity between us and other animals?
Suddendorf and Corballis 1997
In which animals has episodic like memory been demonstrated?
Clayton and Dickinson 1998 - Florida scrub jays - cache food, prefer waxworks to peanuts, can be trained that worms decay after time. Show food, then let eat later, see which is preferred. Will choose peanuts if after time period where waxworms decayed
Raby et al 2007 - planning for breakfast in western scrub jays again - will cache a range of food to give themselves a choice in the morning
How may study of memory impact animal welfare?
Pigs and rats remembering a familiar animal - memory acquisition and consolidation (length of time together, group size, rank)
Memory storage, interference and decay (duration of separation, interference stimuli, reminder cues)
Memory retrieval (social and contextual clues)
- recognition disrupted if introduced to new individual during separation and enhanced if subject is well acquainted with stimulus animal
(Burman and Mendl 2000, 2003, 2004)
