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Chapter 12

Chapter 12- Study notes.docx

Course Code
Anneke Olthof

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Chapter 12
Food Caching and Recovery
- Birds hide seed in caches and then go back to them later to recover them
- Food caching and recovery potentially involves many different factors.
1. You have to decide what food items to cache
a. Storing perishable foods is not useful unless you intend to
recover them soon
b. non-perishables don’t have to be recovered as quickly
2. Also decide where to store the food
3. Caching also involves a social component: storing food is only
useful if you, rather than a competitor, get to eat what you stored
4. The decision of whether or not to cache can be influenced by the
presence of an observer who might steal the food
5. The cache location choice may also depend on how easily that
location is for competitors to find
a. Similar issues arrive at the time of recovery.
- Recovery
1. You have to decide weather to look in the presence of a competitor
2. Which food to retrieve first
3. Whether to eat or re-store what you recovered
- Food caching and recovery has become a rich source of info about
comparative cognition.
Spatial Memory in Food Caching and Recovery
- Researchers cannot accept spatial memory as the onky option
o Need to rule everything else out
- One possibility
o Birds find caches by searching randomly among possible cache sites.
- Another possibility is they store food only in a particular types of locations
and then go around to these favoured places to recover the food
o This is not without remembering that they had put the food there
- They may also mark food-storage sites somehow (urine) and then look for
these marks when it comes time to recover the food.
- Or they are able to smell or see the stored food and identify caches in that
Study: Kamil and Balda
- Tested nutcrackers in a room that had a special floor with 180 recessed cups
of sand
- After habituation and while the birds were hungry they were given here
sessions during which they could store pine seeds in the sand cups
- During each session only 8 cups were available and the rest were covered
with lids.

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o This forced birds to store food in cups selected by the experimenter
rather than in cups or locations they could have found easily.
- After 10 days four recovery sessions were conducted on successive days
- During the recovery sessions none of the cups were covered with a lid
o The location of the seeds could not be identified because
experimenters smoothed over the sand
o Other tests show that the seeds could not be recovered by the smell
This is b/c birds visited the cup where they had placed the
seed even though it was removed
- Control studies indicate that cache recovery reflects spatial memory
Episodic Memory in Food Caching and Recovery
- Episodic memory: is memory for a specific even or episode, as contrasted
with memory for general facts or ways of doing things
o You can recall what happened, where it happened and when it
o Claims that episodic memory is a unique human trait.
Study: Clayton, Bussey, and Dickinson
- Argued that episodic memory in nonhuman species has to have certain
- More specifically the memory has to include information about what
happened, when it happened and where it happened.
o This information also has to be integrated into a coherent
representation rather than being independent bits of info.
o It also has to be available for flexible use in dealing with new
- Used the Western scrub jay because it caches both perishables and non-
perishable food engages in caching behaviour all year round, and readily
performs these activities in the laboratory.
- Experimenters have to vary the palatability of the food, in order to examine
memory for what was stored and where
o Remembering when the food was stored only when it is in relation to
the perishable food item.
- Birds prefer worms over peanuts- however worms are perishable
- First gay the jays a practice trial in which they were allowed to store worms
and peanuts in the compartments of an ice cube tray
- Each trial consisted of two storage or caching episodes
- A recovery period was then conducted 4-124hrs later with both food trays.
- On training trails with four-hour retention
o Neither food deteriorated by the time the recovery or choice test
- On training trials with 124hr retention interval, the worms had spoiled
- The birds learned to select the worms during the short recovery period and
then the peanuts after the long one.

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- To prevent responding on smell or sight, test trials were conducted at the
end of the experiment during which fresh sand was put in trays and all the
food was removed.
o The deteriorate group searched more in the worms tray than peanut
tray if the choice test occurred four hours after caching of the worms.
In contrast they searched more in the peanut trays after
o The replenish group fresh worms were always provided during the
recovery or choice periods therefore the birds never knew what
spoiled worms tasted like and they always went for the worms.
- Researchers also then believed the birds could have memorized that the
longer one was going to have spoiled worms but when they changed the
timing of them they received similar results.
- The effects of stimuli are determined by their durations and distributions in
- Habituation, sensitization and spontaneous recover from habituation are all
time- dependent
o Pavlovian conditioning, Instrumental conditioning, schedules of
reinforcement all involve time as well
- The 24-hr day-night cycle is one of the most important time cycles for
biological systems.
- Intervals that range in seconds are important for conditioning procedures
this is referred to as interval timing
- A critical methodological requirement in studies of timing is to make sure
that the passage of time is not correlated with external stimulus, such as the
noise of a clock and a gradual increase in light
Techniques for Studying the Temporal Control of Behaviour
- Duration Estimation: a duration estimation task is basically a discrimination
procedure in which the discriminative stimulus is the duration of the event
o E.g. pigeons were trained in an experimental chamber that had three
pecking keys arranged in a row
o The sample stimulus at the start of every trial was an amber light in
the center and remained on for either two seconds or 10 seconds
o Other sample was followed by illumination of one side key with a red
light and the other side key with a green light
If the sample was short the then green light was the correct
Of the sample was long then the red light was the correct
o This test shows the ability to discriminate.
- Peak Procedure: involves duration production instead of duration estimation.
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