Lecture 2: Finding and Hoarding Food

Resource Distribution

• Milton, 1981, discusses the relationship between resource distribution and brain size.
• Spider monkeys, which are frugivores with a patchy food distribution, have large home ranges and large brains. Details about why:
  • Patchy food distribution necessitates larger home ranges to find sufficient resources.
  • Larger brains may be required for spatial memory and navigating complex environments to locate food sources.
• Howler monkeys, which are folivores with abundant food distribution, have small home ranges and small brains. Details about why:
  • Abundant food distribution allows for smaller home ranges.
  • Smaller brains may suffice as less spatial memory and navigation are needed.

Outline of Topics

• Resource distribution in space and time (p.29-30)
  • Discusses how resources are spread across different locations and how their availability changes over time.
  • Considers factors like seasonality, local abundance, and predictability.
• Rodents, mazes, and the hippocampus (p.30-34)
  • Explores how rodents use spatial memory to navigate mazes and the role of the hippocampus in this process.
  • Discusses different types of mazes and their relevance to studying spatial cognition.
• Object permanence: a comparative perspective (p.34-36)
  • Compares object permanence abilities across different species.
  • Examines the cognitive challenges involved in understanding that objects continue to exist even when out of sight.
• Inhibition: a socio-ecological perspective (p.36-37)
  • Considers the role of inhibitory control in social interactions and ecological contexts.
  • Explores how the ability to inhibit certain behaviors can be advantageous in different environments.
• Timing mechanisms (p. 37-41)
  • Describes the internal mechanisms that allow animals to perceive and respond to time.
  • Covers different time scales and the neural substrates involved.

Ingestive Behavior

• Foraging: Finding food.
  • Strategies and techniques animals use to locate and acquire food resources.
  • Includes searching, detecting, and recognizing edible items.
• Hoarding: Saving food.
  • The act of storing food for future consumption.
  • Discusses why animals hoard, which species do it, and the cognitive skills required.
• Feeding: Consuming food.
  • The process of eating and digesting food.
  • Considers different feeding behaviors and nutritional adaptations.

Rodents, Mazes, and the Hippocampus

• Path integration (Etienne et al., 1998).
  • Definition: The ability to continuously compute one's current location based on self-motion cues.
  • Involves integrating information about direction and distance traveled.
• Geometric cues (Cheng, 1986).
  • Definition: The use of spatial geometry to orient and navigate.
  • Examples: Using the shape of a room or the angles of walls to find a location.
• Landmarks (Collet et al., 1986).
  • Definition: The use of notable objects or features in the environment for orientation.
  • Examples: Trees, rocks, or buildings.

Mazes

• Radial maze (Olton & Samuelson, 1976).
  • Tests reference and working memory.
  • Rats use a random but accurate search strategy. Details:
  • They typically avoid revisiting arms they have already explored in a single trial (working memory).
  • They remember which arms consistently contain food across multiple trials (reference memory).
  • Mice use a sequential search strategy. Details:
  • They tend to explore the arms in a systematic order.
  • This strategy may be less flexible but still effective.
• Water maze (Morris, 1981).
  • Landmark 'independent'.
  • Extensively used with rats.
  • Hippocampus-dependent. Details:
  • Spatial learning and memory heavily rely on the hippocampus.
  • Rats learn to find a hidden platform using spatial cues.

Morris Water Maze

• Illustrates the impact of lesions on maze completion.
• Normal rats can locate a hidden platform. Details:
  • They use spatial cues to efficiently navigate to the platform.
    \text{Distance} = \sqrt{(x2 - x1)^2 + (y2 - y1)^2}
• Rats with neocortical control lesions are impaired. Details:
  • Neocortical lesions affect sensory and motor functions, leading to difficulties in maze completion.
  • Performance is better than rats with hippocampal lesions but worse than normal rats.
• Rats with hippocampal lesions are severely impaired. Details:
  • Hippocampal lesions disrupt spatial memory, making it difficult to learn and remember the platform location.
  • Rats often swim randomly without a clear strategy.

Food Caching and Spatial Abilities

• Mating systems (Polygamous vs. monogamous voles).
  • Males (and sometimes females) of polygamous vole species have larger home ranges.
  • Better spatial abilities correlate with larger hippocampal volume (Jacobs et al., 1990; Sherry, 2006).
• Convergent evidence from food-storing vs. non-food storing birds.
  • Parids (tits & chickadees) and corvids display better spatial abilities.
  • These birds also have larger hippocampal volumes (Basil et al., 1996; Sherry, 2006).

Examples of Food Caching Species

• Clark’s nutcracker (Kamil & Balda, 1990).
  • Task: 180 holes.
  • 10 days later, 50% accuracy.
  • Estimated to cache 33000 seeds in the wild.
• Black-capped chickadee (Shettleworth, 1983; Pravosudov & Clayton, 2002).
  • Task: 97 holes in trees.
  • 2 hours later, above chance accuracy.
  • Regional differences exist in hippocampus size, neural density, and recovery accuracy.

Inter-specific comparisons of relative hippocampal volume (%)

• Caching songbirds have larger relative hippocampal volumes compared to non-caching songbirds.
• Ward et al., 2012, Biol. Lett.

Additional examples of Food Caching Species

• Female vs. male brown-headed cowbird.
  • Cowbirds keep track of multiple nest sites due to brood parasitism.
  • Better spatial abilities correlate with larger hippocampal volume (Guigueno et al., 2014; Sherry et al., 1993).

Object Permanence

• Six stages (Piaget, 1954).
  • Stage 4: Recovery of hidden objects.
  • Stage 5: Visible displacements.
  • Stage 6: Invisible displacements.
• Natale et al., 1986; DeBlois & Novak, 1994; Dumas & Brunet, 1994, Pepperberg, 2002; and many others).
• Successful vs. Unsuccessful.

Tracking displacements transpositions

• Studies by Barth & Call, 2006, J. Exp.Psych. Anim. Behav. Proc. Amici, Aureli & Call, 2010, Am. J. Phys. Anthrop. and Rooijakkers, Kaminski & Call, 2009, Anim. Cog.

Socio-ecology

• Discipline that studies the effect of ecological factors on the interactions between individuals and on the social organization of groups (=social structure).
• Cohesive vs. Fission-fusion.

Inhibitory Control in Primates

• Tasks used to assess inhibitory control:
  • A-not-B (Piaget, 1954).
  • Middle cup (Call, 2001).
  • Reaching (Amici et al., 2008).
  • Swing door (Vlamings, 2003).
  • Delay of gratification (Rosati et al., 2006).

Phylogeny and Sociality

• Monkeys.
• Apes.
  • Low fission-fusion.
  • High fission-fusion.

Results of Inhibitory Control Tasks

• Table 1 summarizes mean scores, number of trials, performance rank, and statistical comparisons across species for each task.
• Tasks include A not B, Middle Cup, Plexiglas Hole, Swing Door, and Delay of Gratification.
• Species compared include Chimpanzee, Orangutan, Bonobo, Spider monkey, Gorilla, Capuchin monkey, and Long-tailed macaque.
• Kruskall-Wallis test results (\chi^2) and p values are provided for each task to assess statistical significance.
• Pairwise comparisons highlight significant differences between species performances.

Species Illustrations

• Bonobo, Spider monkey, Chimpanzee, Orangutan, Capuchin monkey, Long-tailed macaque, Gorilla.
• Amici, Aureli & Call 2008 Curr. Biol.

Timing Mechanisms

Definition

• Endogenous timing mechanisms that predict changes in the environment and synchronize the physiology and behavior accordingly with appropriate times of day or year.

Effects on

• Behavior: Feeding, Reproduction
• Perception & Cognition: learning in rodents
• Physiology: Body temperature, heart rate

Types

• Circadian rhythms
  • Neural substrate: Hypothalamic suprachiasmatic nuclei (SCN), Hypothalamic-pituitary-adrenal axis, Hypothalamic-pituitary-gonadal axis
• Tidal cycle (12.4 hrs)
• Light-dark cycle (24 hrs)
• Season

Time Span

• Short arbitrary durations (seconds to minutes)
• Interval timing
  • Perform an action for a specific duration
  • Anticipate an event once a particular interval has elapsed
  • Judge which one of two intervals was shorter
  • Determine which