PSYC 356 FINAL

What did Darwin suggest?

the evolution of both physical and mental traits

How did Romanes define intelligence?

The ability to make adjustments or modify old ones, in accordance with the results of its own individual experience

Cognition

“knowledge or thinking”

• Often a causal discourse that is voluntary, deliberate and conscious

  • “Did I leave the coffee pit on?”

• Cognition may lead to actions not clearly explained by external stimuli

• Infringing more on Descartes

Cognitive Ethology

the study of the ability of animals to express conscious thought and intention

• Ex: Clever Hans (horse) could “spell”, “calculate fractions”, and “tell time”

Animal Cognition

models and constructs used to explain behaviors not characterized by simple S-R associations

• A mirrored enclosure → happily-marked → mark-touching

• Plotnick et al., 2006; Amazing Apes: Self Awareness

• Elephants and Apes display “self-awareness” they have mental representation

Learning and cognition are…

not necessarily in opposition:

• CS evokes a “mental representation” of the US (SS learning)

• R-O and S-O associations are “internal”

Memory

ability to respond to or recount information that was experienced earlier

Ex: who was your 1st grade teacher? Rules and skill of an old sport

Components of Learning and Memory

Acquisition, Retention, and Retrieval

Acquisition pt 1

exposure to stimuli or information

Retention

time period in which information is retained

Retrieval

tests of memory for the original experience / recovery of stored information used to guide behavior / the recollection of memories to working memory

Studies of learning

manipulate acquisition parameters

Studies of memory

focus on retention and retrieval

Studying Memory in Animals: Hunter (1913)

• Subjects: raccoon, dog, rat

• Phase 1: Training

  • Subject placed in start box (S)

  • Light on above baited box (1, 2, or 3)

  • Immediate choice

• Phase 2: Memory Task

  • Subject placed in S

  • Light on above 1, 2, or 3

  • Delayed choice

• Result:

  • Dogs: 5min

  • Raccoon: 25 sec

  • Rat: 10 sec

• Findings reflect working AND reference memory

Working memory

operates when info needs to be maintained long enough to complete a task (test trial)

• ex: Remembering items you just put in a Bloody Mary

Reference memory

long-term retrieval of rules necessary for the use of incoming and acquired info (training) - Rule

• ex: Remembering the items needed to make a Bloody Mary

Delayed-Matching-To-Sample:

the SAMPLE identifies the correct response on a trial. The SAMPLE is removed before the subject is allowed to respond (DELAY). The subject is then asked to identify the MATCHING SAMPLE for reinforcement

What determines accuracy? Grant, 1976:

• Pigeons trained on DMS

• Test sample duration:

  • 1, 4, 8, and 14 seconds

• Test sample-tria; delay:

  • 0, 20, 40, 60 seconds

• Results:

  • Accuracy increase as sample duration increased

  • Accuracy decreases as sample-trial delay increased

Trace Decay Hypothesis:

presentation of a stimulus produces changes in the CNS that decay after the stimulus is removed

• Weak stimuli will decay quickly (ex: what did you eat last sunday?)

• Strong stimuli will be maintained in memory (ex: what did you eat when you got food poisoning?)

Does training impact DMS? Sargisson and White, 2001:

• Training on DMS

  • Sample-trial delay:

    • 0, 2, 4, or 6 sec (gets used to training parameter)

  • Trained to 80% correct

• Test: DMS w 0-10 sec sample-trial delay

• Results:

  • Decay prominent in 0-sec grup

  • BUT, overall performance is best when tested w training delay (circled)

  • stimulus control: delay

What is learned on the DMS Task?

General and Specific Rule

General Rule

“choose the stimulus that is the same as the sample”

• will get correct

Specific Rule

“select green after green” - learned to guide behavior

• will get 50% correct 

Tests of Transfer

Once DMS is learned to 80% with two samples, a new pair is employed. Does the subject transfer (generalize) the rule?

• Transferring rules onto new stimuli

• Oden et al., 1988: Chimp

Trials-Unique Procedure

Forces organism to learn general rule. On each trial, different stimuli serve as matching and non-matching samples. Do they learn DMS?

• Once organism gets to 80%, its guaranteed they learned a general rule

• impossible for specific because sample never shows up again

For us to survive in our environment

we need to know how it is laid out

Radial Arm Maze: Rodent spatial memory

• 8 arms with “baited” end ups, Rodent is placed in center

• Allowed to pick up food, Cups are not refilled

Strategies

• Inefficient - random arm entrance

• Efficient - remember when it has or has not yet visited

Correct response on performance in the radial arm maze

entering an unvisited arm

• requires little training

• Rodents perform this task well

Mirrors natural foraging tendencies

• Rodents can remembers 24 arms w/ no errors

• Can retain 24 arm food placements for up to 4 hours

How do the nutcrackers and rodents remember?

spatial memory requires an INTERNAL MAP

Extramaze (outside maze) cues are critical. Examples of extramaze cues:

• Light

• Posters

• Humans

Switching cues disrupts performance

If cues are removed, rats use…

intramaze (inside maze) cues

• perform above change, but less efficiently

Beatty and Shavalia, 1980:

Using external environment to create map to internalize then use for later

• 8 arm radial maze

• Rats allowed 4 arm choices

• Wait for 5 min - 24 hrs

• Upon return, correct choices was entrance to un-entered arm

• Rats performed with up to 4 h delays at 95% correct

How does memory guide? Hoffman et al., 1999:

• post-training , they repeated the maze test. But let rats step off maze

1. Efficient

2. Path

3. Random

4. Wall 

• It's b. path, they continue to use visual cues

• If arms are removed altogether, they still follow path

On the Delayed Matching to Sample, a monkey who has performed to 80% criterion on a pair of samples is able to switch fluidly to another pair of samples. As such we know he has learned a ________ rule based on the ________ .

General Rule; Test of Transfer

Stimulus Coding

the transformation of acquired information for retention and later retrieval

How do we code spatial information?

• List of individual maps? Not likely, we have a limit

• A cognitive map? Sort of, but a bit vague

• Navigational mechanisms? definitely

  • this is because NM is most predictive of a correct response

Beacon Following

association with the goal (navigational mechanism)

• Ex: rock near food patch

Landmark

goal at a fixed location away from a stimulus (navigational mechanism)

• Ex: shrub by rock

Relation between landmarks

goal located between landmarks (navigational mechanism)

• Ex: space between tree and shrub, containing rock and food patch

Coding strategies:

1. Retrospective Memory: remember what you've had (memory load increases over time)

2. Prospective Memory: remember what you have yet to try (memory load decreases over time)

Switching strategies reduces memory load and increases remembering…

start with retrospective coding, switch to prospective coding

Kesner and DeSpain, 1988: Rats

• Subjects: rats 

• 12 arm radial maze

  • Train: to criterion

  • Pre-test: rats allowed varying arm entities

  • Test: 15 min delta

    • In maze, given choice between

1. A previously entered alley

2. A new alley

• Reinforced answer: choosing a new alley

• Results:

  • Errors increase on 1st 8 trials (retrospective)

  • Errors decrease on trials 9-12 (prospective)

Kesner and DeSpain, 1988: Undergrads

• Subjects: undergrads

• Student test: 16 square grid

  • Test: “X” moved square to square

  • Number of squares visited varied

  • After last square, delay of 5 seconds

  • Choice between two squares

    • Did the “X” visit Square 1?

    • Did the “X” visit Square 2?

• Results:

  • Errors increase on 1st 8 trials (retrospective)

  • Errors decrease on trials 9-16 (prospective)

Memory retention is impacted by:

1. An unpredictable stimulus (interference)

2. Cues indicating whether something should or should not be remembered

Direct forgetting

a process by which info not relevant to a task is actively ignored

• R-cue - Remember Cue

• F-cue - Forget Cue

  • This is stimulus control!

Failure of memory in the healthy organism is more likely a result of ___ than loss of information

retrieval failure

Retrieval cues

 reminders that produce retrieval of memory

Borovsky and Rovee-Collier, 1990:

Stimuli presented during acquisition can serve as retrieval cues

• Subjects: 6 month old infants

• Training: playpen liners (retrieval cues)

  • Patterned (striped or checkered)

• Operant response

  • Response - leg kick

  • Outcome - mobile movement

• Test: 1 day post-training

  • Performance is best with SAME liner (retrieval cue)

  • Lasted up to 14 days

☆ Children have capacity for learning and memory very early

Forgetting

memory failure resulting in lack of response in accordance with past experiences or learning

Negative forgetting

has a negative impact on performance

• ex: explain the reinforcer devaluation procedure? - cant

Positive forgetting

positively impact performance, increase response variety

• ex: learning new password

Proactive interference

A source of negative forgetting; previously learned info disrupts new memories

• ex: say it w me.. “Omission training!” “positive punishment??”

Retroactive interference

A source of negative forgetting; new memories disrupt previously learned info

• ex: oh shoot, who did i meet when we got here?

Retrograde Amnesia

graded memory loss of info close to the cement that induced the loss

Ex: seizure, blackout, concussion

Zhou and Riccio, 1995:

• Rats in single shock avoidance trial

• Going to dark side of box gives shock

• Mild concussions then various

  • Training-concussion intervals

• Avoidance: latency to visit shock side

Results: reduced avoidance when training-concussion intervals short

Zhou and Riccio, 1995: Post-concussion

a retrieval cue can reverse amnesia

• G1: concussion

  • Avoidance trial, concussion (1 min)

• G2: Reminder

  • Shock avoidance trial, concussion (1 min later)

+ shock (reminder) in novel environment

• Findings:

  • Concussion group is amnesic

  • G2 rats w/ reminder show avoidance

  • Retrieval is facilitated!

By starting with prospective memory coding, over time, the memory load will:

Decrease

Learning and memory must have a neutral substrate!

The Brain

Where is memory located?

Engram - physical representation of learning and memory

Lashley, 1929

• Cuts in the cortex before/after maze

  • No single cut, big or small impaired learning

  • Only amount removed predicted impairment

• Lashley concluded the search for the engram is a “hopeless endeavor”

Acquisition of knowledge

engages several brain circuits

Complex memories are

retained in multiple areas

Memories are

retrieved from many brain areas

Acquisition

the strengthening or weakening of neutral connections as a result of experience with the environment

• When cells fire together (associate), they wire together

Bliss and Lomo, 1973:

How does neutral stimulation affect the activity of downstream targets?

• Stimulated hippocampus input:

  • Moderate

  • Strong

  • Weak

• Recorded downstream activity

• Results of stimulation:

  • Moderate - moderate activity

    • No change in synaptic strength

  • Strong - long-term potentiation (LTP)

    • Enhanced synaptic strength - LEARNING

  • Weak - long-term depression (LTD)

    • Reduced synaptic strength - LEARNING

• These changes last days to weeks

• Memory must have structural component 

LTP (long-term potentiation) increases

the efficiency of memory paths:

• Increase number of dendritic spines

• Increase size of dendritic spine head

• Increase excitatory receptor density on dendritic spine head

  • More stable and receptive to input

Retention

the permanent physical change in neutral circuitry coding for the information 

• Once rehearsal conditions are met, information is consolidated and retained in PERMANENT memory stores

Wilder Penfield, (1891-1976)

• Medial temporal lobe stimulation induced specific memories

• MRI confirms that consolidated memory is stored in and retrieved from cortex

Retention and consolidation are dependent upon

…the rehearsal of the information

The Rehearsal Circuit

1. Hippocampus

2. Basal forebrain

3. Thalamus

4. Amygdala