Animal Cognition: Memory Mechanisms

Animal Cognition

• Neural representation of some past experience as a basis for action
• Model
  • Representations of reality
  • Analogies
  • Need not be real
• Encodes various information

Inferences

• Most facts observed in psychology: behaviours
• The internal condition is not observed: it is inferred
• Ideas formed from inferences: constructs

Memory

• Ability to reproduce information experienced at an earlier time
  An inference
• Three phases
  • Acquisition
  • Retention interval
  • Retrieval

Types of Memory

• Working memory
  • Temporal
  • Task at hand
• Reference memory
  • Long term
  • Often necessary for the use of working memory information

Delayed Matching to Sample

• Behaviour that suggests memory

Factors in Memory

• Delay interval
• Exposure period

Working Memory: Passive and Active

• Trace decay hypothesis
  • Emphasis on physical characteristics of sample
  • Passive
  

• Active?
  • Practice
  • Surprise

General vs. Specific Rule Learning

• Specific
  • Small stimuli set
  • Will not tax memory
• General
  • Large stimuli set
  • Extrapolation
• Some species specificity

Spatial Memory

• Food
• Shelter
• Mating
• Dynamic environment
  • Need working memory

Cataglyphis, the Long Legged Desert Ant

• Twisting outbound path
• Direct return path

Path Integration

• Angle
• Distance
• "Running calculation"
  

• Store path integration information in working memory
  • Angle and distance stored
• To get near nest

Landmarks

• Use to find nest entrance
• To get into nest
• First trip out, no landmark knowledge
  • Start acquisition
  • Builds up

Storage of Path Integration and Landmark Memories

• Reset path integration each return to nest
  • Hour
• Keep landmarks
  • 4-5 days

Hummingbird

• Need to remember locations of flowers
• Drink nectar
• Avoid flowers they have drained or are already empty
  • Will return to flowers which still have food

Experiment

• Delayed matching to location
• Used artificial flowers
  

• Fed from red focal flower, left half food
• Flew away for 5-60 minutes
  • Add red or yellow distractor flower
  • Distractor flower near, medium, or far away
• Which flower will the hummingbird feed from?

Results

Conclusions

• Hummingbirds remember:
  • Colour
  • Distance
• Working memory
  • Will "erase" old colour and distance memories when new flowers found