Lecture 22: Animal Cognition I
(Memory)
Learning, Psychology 3510
Fall, 2015
Professor Delamater
Historical Issues of Comparative
Cognition
1. Grew out of evolutionary theory and search for evolution of mind
2. However, strongly experimentally focused. It developed as a reaction against
anthropomorphic approaches that emphasized consciousness and intentionality
3. Also, it has been influenced by general-process approaches to the study of learning
where in addition to searching for general cognitive processes, there is
recognition of the importance of species-specific processes.
Learning versus Memory
1. These are really intertwined processes. The focus of learning and memory
researchers is usually on different aspects of a learning experiment.
• Whereas learning experiments focus on acquisition processes, memory experiments
Focus on retention and retrieval processes.
Types of Memory
1. Procedural vs declarative (episodic) – learning to do something (S-R association?)
vs learning that such and such will occur (S-S association?). Episodic memory
is usually thought of as a memory that binds together what, when, and where
information.
2. Working vs reference – Working memory is retention of information long enough
for use in a particular task (keeping track of a phone number, etc).
Reference has to do with long-term storage of acquired information.
• How do we study these different types of memory?
1. S-S vs S-R studies in Pavlovian and instrumental learning are instructive…
2. Lots of different paradigms employed to study working/reference memory…
Working & Reference Memory Paradigms
1. Delayed Matching to Sample task (DMTS)
2. Spatial Memory tasks
Morris Water Maze, Radial Arm Maze
• Three popular paradigms that have been used with lots of different animal species.
Working & Reference Memory Paradigms
1. Delayed Matching to Sample task (DMTS)
Working and Reference Memory
Sargisson & White (2001) study
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Birds trained with a 0-s delay show decreased accuracy when tested with longer delays.
But notice that birds trained with longer delays show less of an effect of delay in testing.
This suggests that the normal delay gradient does not simply reflect a trace decay process
Working memory appears to be more active than that.
Reference memory in this task refers to animals learning to always choose the matching
stimulus
Working & Reference Memory Paradigms
1. Delayed Matching to Sample task (DMTS)
Do animals learn a General Rule or Specific S-R associations?
• This question can be studied by varying the number of
stimulus sets one uses to train the animals.
• If only one set is used (Red, Green), then animals seem to
learn specific rules. This is known because when the
animals are transferred to a new stimulus set, they do
not spontaneously match to sample. They have to learn
to do that. Had they acquired a general “matching” rule
then they should have spontaneously transferred this rule
to new stimulus sets.
• However, if you train the animal with more stimulus sets
then their transfer increases, suggesting that they may be
using a general matching rule under those circumstances.
• The trials-unique procedure is another one that can be used to assess learning of
general rules.
Working & Reference Memory Paradigms
2. Spatial Memory – Morris Water maze
• Animals learn to find the hidden platform.
• They generally do so by relying on external
spatial cues (window, door, etc).
Working & Reference Memory Paradigms
2. Spatial Memory – Morris Water maze
• Animals learn to find the hidden platform.
• They generally do so by relying on external
spatial cues (window, door, etc).
• However, if a beacon is placed above the platform,
then they learn to approach those cues and some
research suggests that this interferes with them
learning about other spatial cues.
• They may also learn about the general geometry of
the pool (e.g., circular, or rectangular, etc).
• Thus, they may “code” the stimuli in various ways:
specific stimuli, spatial landmarks, geometry relations
• Some have suggested that the animals develop an
internal representation of the spatial arrangement of
the pool, a “cognitive map,” and base their swimming
behavior on that.
Working & Reference Memory Paradigms
2. Spatial Memory – Radial Arm Maze
• Animals learn to retrieve all food rewards at the ends of
each arm without revisiting arms.
• This task obviously involves “working memory” since
the animal must keep track of where its been or
where it needs to go to find food within each trial.
Working & Reference Memory Paradigms
2. Spatial Memory – Radial Arm Maze
• Animals learn to retrieve all food rewards at the ends of
each arm without revisiting arms.
• This task obviously involves “working memory” since
the animal must keep track of where its been or
where it needs to go to find food within each trial.
Crystal and Babb (2008) study
• The effects of memory delays can be studied:
4 Arms – Delay – 4 Arms Procedure
Delay = 1 or 25 hours
Train with either 24 or 48 hour ITI
• Memory declines with the delay (as expected), but
also memory is slightly better with longer ITI in training.
Working & Reference Memory Paradigms
2. Spatial Memory – Radial Arm Maze
• Animals learn to retrieve all food rewards at the ends of
each arm without revisiting arms.
• This task obviously involves “working memory” since
the animal must keep track of where its been or
where it needs to go to find food within each trial.
• The effects of memory delays can be studied:
4 Arms – Delay – 4 Arms Procedure
Delay = 1 or 25 hours
Train with either 24 or 48 hour ITI
• Memory declines with the delay (as expected), but
also memory is slightly better with longer ITI in training.
• In addition, Reference Memory can also be studied:
4/4 Baited-Unbaited task: In this case, the same 4 arms
are always baited with food and the other 4 never baited.
The rats learn which ones are baited (reference memory) and they also learn not to
revisit arms they’ve previously visited (working memory).
Memory Processes: Stimulus Coding
1. Stimulus Coding
a. spatial codes (beacons – landmark-goal relations, geometry)
b. Prospective vs Retrospective codes
Chickadee study: Gp Expt – Eat Sunflower Seeds, 30 min later mealworms
Gp Control – Eat Sunflower Seeds (no mealworms)
• The birds consume fewer sunflower seeds,
presumably because they expect to get the more
preferred mealworms later (prospective code).
Memory Processes: Stimulus Coding
1. Stimulus Coding
a. spatial codes (beacons – landmark-goal relations, geometry)
b. Prospective vs Retrospective codes
12-arm Radial maze study (Cook, Brown, & Riley, 1985)
Prospective vs Retrospective Codes
Prospective code (memory for where you have NOT been)
Errors should be greater early, and less later in the task.
Retrospective code (memory for where you HAVE been)
Errors should be less early, and greater late in the task.
• Different groups were allowed to retrieve food from 2, 4, 6, 8, or 10 arms before
being taken out of the maze for a 15-min delay interval. After this, they were
placed back in the maze and allowed to retrieve the remaining food items.
The number of errors (revisits) made was assessed in all the groups.
Memory Processes: Stimulus Coding
1. Stimulus Coding
a. spatial codes (beacons – landmark-goal relations, geometry)
b. Prospective vs Retrospective codes
12-arm Radial maze study (Cook, Brown, & Riley, 1985)
Prospective vs Retrospective Codes
Prospective code (memory for where you have NOT been)
Errors should be greater early, and less later in the task.
Retrospective code (memory for where you HAVE been)
Errors should be less early, and greater late in the task.
Cook, Brown, & Riley (1985) Study
Probobility of an Error
• Errors increased with number of choices,
but then decreased thereafter.
• This suggests that rats use a retrospective
code early and then switch to a
prospective code later in the task.
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
2
4
6
8
Number of Choices Before the Delay
10
Memory Processes: Retention
1. Stimulus Coding
2. Retention (Rehearsal) Processes
Directed Forgetting/Remembering Task
• On some trials a cue occurs which signals
that there will be no comparison
choice.
• These are called “forget cue” trials.
• At issue is whether on a probe choice
that occurs on such a trial, performace
will be low. If it is, this suggests that
there are active memory processes
occurring during the retention interval.
Memory Processes: Retention
1. Stimulus Coding
2. Retention (Rehearsal) Processes
Directed Forgetting/Remembering Task (DMTS)
• Performance on Forget Cue probe trials is worse than on Remember Cue trials
• This suggests that memory is not merely a passive process, but is active
Memory Processes: Retrieval
1. Stimulus Coding
2. Retention (Rehearsal) Processes
3. Retrieval Processes
Reminder (i.e., retrieval) cues are thought to reactivate items into working memory.
This can make them more available for use in a task.
Rovee-Collier Mobile Task
• Baby can move the mobile by kicking. They
learn to increase their kicking responses
• This is an example of simple instrumental
conditioning in the human baby.
Memory Processes: Retrieval
1. Stimulus Coding
Rovee-Collier Mobile Task
2. Retention (Rehearsal) Processes
3. Retrieval Processes
Reminder (i.e., retrieval) cues are thought to reactivate items into working memory.
This can make them more available for use in a task.
• Baby can move the mobile by kicking. They
learn to increase their kicking responses
• This is an example of simple instrumental
conditioning in the human baby.
• This study shows that 6-month old babies
remember better when they are tested in the
crib with the Same liner as was used during training.
• This shows that retrieval cues were effective.
Memory Processes: Retrieval
1. Stimulus Coding
Rovee-Collier Mobile Task
2. Retention (Rehearsal) Processes
3. Retrieval Processes
Reminder (i.e., retrieval) cues are thought to reactivate items into working memory.
This can make them more available for use in a task.
• Baby can move the mobile by kicking. They
learn to increase their kicking responses
• This is an example of simple instrumental
conditioning in the human baby.
• This study shows that 6-month old babies
remember better when they are tested in the
crib with the Same liner as was used during training.
• This shows that retrieval cues were effective.
• In this study, babies normally forget when tested
one week after training. But if they are exposed
to the retrieval cue one day before testing
(Same odor condition) they remember better.
Memory Processes: Forgetting
1. Is the memory lost or is it non-retrievable?
• Rats learned a one-way shuttle avoidance task
• Placed in the white compartment and shocked
once entering the black compartment.
• Latency to reenter the black compartment is
the measure of learning.
• This latency is long in conditioned animals, but
it is shorter in animals given extinction.
• However, a hypothermia treatment administered
immediately or 30 min later, but not 60 min,
disrupted memory of extinction.
• Hypothermia caused amnesia for extinction.
Briggs and Riccio (2007) study
Memory Processes: Forgetting
1. Is the memory lost or is it non-retrievable?
Briggs and Riccio (2007) study
• Rats learned a one-way shuttle avoidance task
• Placed in the white compartment and shocked
once entering the black compartment.
• Latency to reenter the black compartment is
the measure of learning.
• This latency is long in conditioned animals, but
it is shorter in animals given extinction.
• However, a hypothermia treatment administered
immediately or 30 min later, but not 60 min,
disrupted memory of extinction.
• Hypothermia caused amnesia for extinction.
• But, reexposure to the hypothermia treatment before testing brought back the extinction
memory, suggesting that the amnesia was a retrieval deficit and NOT a permanent
disruption of the consolidated memory.
Memory Processes: Consolidation,
Reconsolidation, Memory Updating
1. Traditional View:
Rehearsal within STM leads to consolidation in LTM
2. Modern View:
Memories are either active or inactive
Active memories can be consolidated into an
inactive state.
Previously stored (inactive) memories can be
made active again through a retrieval
process.
But this places the memory in a vulnerable
active state where it can be altered.
Memory Processes: Consolidation,
Reconsolidation, Memory Updating
Nader, Schafe, and LeDoux (2000) study
• Rats underwent Pavlovian fear conditioning
(Tone – Shock Pairings)
• Then, one group was exposed to Tone alone,
but this was followed by an infusion of
a protein synthesis inhibitor into the
amygdala.
• A control group received infusion of a control
solution.
• Both groups were then tested the next day for
fear to the Tone CS.
• The protein synthesis inhibitor group showed
very little fear CRs in this test.
• The result means that reactivating the Toneshock memory induced reconsolidation of
the memory, but this also placed it in a
vulnerable state of rewriting.
• The protein synthesis manipulation may have
updated the memory by wiping it out.