Episodic-like Memory and other Behavior in Scrub Jays
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Episodic-like Memory and other Behavior in Scrub Jays. Lecture 7 Psych 1090. I’ve done things a bit differently in this lecture…. assigning only a review paper for the earlier material. and giving the details in the lecture. What is episodic memory?. unique, personal, past experience.

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Episodic like memory and other behavior in scrub jays

Episodic-like Memory and other Behavior in Scrub Jays

Lecture 7

Psych 1090


Episodic like memory and other behavior in scrub jays

Ive done things a bit differently in this lecture

assigning only a review paper for the earlier material

and giving the details in the lecture


Episodic like memory and other behavior in scrub jays

What is episodic memory?

  • unique, personal, past experience

  • recalled in terms of a time frame or temporal-spatial relation

  • thus tells what, when, and where

  • not expected in nonhumans


Episodic like memory and other behavior in scrub jays

Explanation in terms of other forms of human memory:

  • Procedural memory

  • inaccessible to conscious recall

  • examples are some motor skills, or simple classical (Pavlovian) conditioning

  • Declarative memory

  • involves propositional material, symbols

  • used to guide inference, reasoning, true/false statements


Episodic like memory and other behavior in scrub jays

Declarative memory is subdivided:

  • semantic memory

  • factual knowledge of the world

  • what one knows from books, etc.

  • episodic memory

  • factual knowledge of past experience

  • what one knows from living ones own life


Episodic like memory and other behavior in scrub jays

According to Tulving and Marlowitsch, episodic memory is

  • unique to each episode

  • allows recall of past experiences rather than facts

  • develops later in children; is impaired faster in age than semantic memory

  • related to unique cortical activity


Episodic like memory and other behavior in scrub jays

Supposedly, animals remember facts (semantic memory) but not personal experiences (episodic memory)

plenty of evidence to show that animals remember that x indicates y, or if x, do y,

but not necessarily when I saw x, I then remember doing y


Episodic like memory and other behavior in scrub jays

The point may seem trivial, but its not..

The difference is in knowledge that is assumed to represent the way the world works for everyone (semantic memory)

And knowledge that is understood to represent only what one has personally experienced (episodic memory)


Episodic like memory and other behavior in scrub jays

Which brings up another issue:

Some researchers argue that to understand that an experience is personal, a being must have full consciousness.

an attribute that is generally denied to animals.


Episodic like memory and other behavior in scrub jays

To get around the argument that a being must be conscious in order to have personal memoriesi.e., to have episodic memorywe can simply agree

to define episodic-like memory as retrieval of what, where AND when


Episodic like memory and other behavior in scrub jays

Thus the issue of personalization and of self-projecting past to future

And of assuming that others experience life similarly

Such a definition puts emphasis on the episode aspect of episodic memory, and is one that can be tested in animals


Episodic like memory and other behavior in scrub jays

Note that other types of memory that have been studied may seem to involve time, but are not truly episodic.

For example, animals trained on delayed match-to-sample or delayed nonmatch-to-sample

may seem to be recalling previous, personal events.


Episodic like memory and other behavior in scrub jays

That is, being shown a red sample at time T and then, at T+20 seconds, being shown red and green samples,

they have learnedvia trial and errorthat they get rewarded

only for matching or not matching the original sample shown at time T


Episodic like memory and other behavior in scrub jays

One could argue that the animals are responding based on personal, event-based memories..

They may, however, simply be choosing or avoiding the most familiar object.

Which really has nothing to do with episodes


Episodic like memory and other behavior in scrub jays

Specifically.

There is a distinct difference between

  • recognizing something as familiar

and

  • a specific recollection of where and when it has been seen before


Episodic like memory and other behavior in scrub jays

Another example.

The difference between knowing a face is familiar

and

remembering that you saw this person last Saturday night at the bar in Harvard Square


Episodic like memory and other behavior in scrub jays

But many animals likely demonstrate some kind of episodic memory in nature.

Nest parasites, like cuckoos, must keep track of the location and state of nest-building and egg laying in their hosts

so as to know when to drop their eggs


Episodic like memory and other behavior in scrub jays

And because recently researchers found that cuckoos will destroy the nests of hosts who dump their eggs

Some connections might be made in terms of personal experience for both hosts and cuckoos


Episodic like memory and other behavior in scrub jays

But probably the best example are food-caching birds

As we learned last lecture

They store thousands of food items in the autumn in thousands of locations, and recover them over the course of several winter months


Episodic like memory and other behavior in scrub jays

And even though the scrub jays that are used by Clayton et al.

dont cache nearly as much as the nutcrackers and pinyon jays

they do cache some food, and for times a bit longer than chickadees


Episodic like memory and other behavior in scrub jays

To connect to episodic memory:

  • information guiding recovery is based on a single, past, personal memory

  • retrieval requires precise spatial data

  • birds need to remember the order of caching to prevent spoilage

  • birds need to remember precisely what was stored in which cache to prevent spoilage


Episodic like memory and other behavior in scrub jays

To get clear data on such behavior, Clayton and Dickinson performed a series of experiments with scrub jays

Birds were allowed to cache wax-worms (perishable and preferred) and peanuts (non-perishable and liked) in visually distinct sites in the laboratory

Sites were ice cube trays with Lego blocks in varied patterns


Episodic like memory and other behavior in scrub jays

Birds were divided into two groups, Degrade and Replenish

Birds in the Degrade group were given the chance to cache peanuts and wax worms in two different trays

and then recover at both 4 hours and 124 hours, and to learn that the worms would be horrid after 124 hours


Episodic like memory and other behavior in scrub jays

They then were tested by being allowed to cache and recover the two different foods at the two intervals

But now the experimenters removed all the food items before recovery,

so birds couldnt possible smell the degraded worms.


Episodic like memory and other behavior in scrub jays

The researchers found that after 4 hours, the birds preferred to visit the sites where they had cached the worms

but went to the peanut sites after 124 hours

suggesting that they knew precisely what was where and the time delay


Episodic like memory and other behavior in scrub jays

But maybe the birds just remembered which caches they had already emptied

Or maybe they just more rapidly forgot worm sites

i.e., maybe some evolutionary rather than memory process was at work


Episodic like memory and other behavior in scrub jays

So the researchers worked with the Replenish group

who never learned that the worms degraded

because the researchers put in fresh ones before allowing recovery at 124 hours


Episodic like memory and other behavior in scrub jays

When tested with all food removed, these birds preferentially went to the worm sites, at both 4 and 124 hours

Thus the behavior of prioritizing which food to recover was learned, and not some genetic instinct

And was nice preliminary evidence of episodic-like memory


Episodic like memory and other behavior in scrub jays

But this design still didnt examine whether the birds in Degrade

understood more than time makes worms decay

i.e., just that something about the time at which they stored the various foods was important


Episodic like memory and other behavior in scrub jays

So now the birds could store both foods (nuts and worms) in one tray at one time

then a few days later could again store both foods in another tray

and after a short interval after the last caching, were allowed to recover


Episodic like memory and other behavior in scrub jays

So, in order to get worms and nuts appropriately (avoid yucky worms)

they had to remember which tray was cached when

And not just better memory for nicer food

And they succeeded on that task


Episodic like memory and other behavior in scrub jays

To tease this out even further, the researchers designed another experiment

in which the birds got to store the different foods at different times,

and then recover them at the same later time


Episodic like memory and other behavior in scrub jays

  • Birds were thus allowed to cache one type of food in one side of the tray at first

  • were made to wait 120 hours

  • and then were allowed to cache the other type of food in the other side of the tray.

  • the type of food altered with respect to time in two different sets of trials


Episodic like memory and other behavior in scrub jays

Test: predict worms

Peanut, then Worm

P

W

P

W

120 h

4 h

Worm, then Peanut

Test: predict nuts

W

P

P

dW

120 h

4 h


Episodic like memory and other behavior in scrub jays

Birds with experience with degraded worms

chose worms at a significantly higher rate than peanuts when the worms were cached last

and peanuts at over twice the rate when the worms were cached early and likely degraded


Episodic like memory and other behavior in scrub jays

Interestingly.and critically.birds with no experience with degraded worms chose the worms in both cases

that is, they just chose on preference

not as to what was likely to have happened to the worms


Episodic like memory and other behavior in scrub jays

Thus:

  • The peanut-side preference shown by the Degrade group was not simply due to differential forgetting of worm caches

  • the preference to search for worms 4 hrs after caching and peanuts 120 hrs after caching does not reflect a genetic predisposition, because it was learned


Episodic like memory and other behavior in scrub jays

But what if the birds were trained on something totally counter-intuitive.

That worms were yuckky after a couple of hours

But somehow were ok after a few days?


Episodic like memory and other behavior in scrub jays

Test: predict nuts

Peanut, then Worm

dW

dW

P

P

120 h

4 h

Worm, then Peanut

Test: predict worm

W

P

P

W

120 h

4 h


Episodic like memory and other behavior in scrub jays

And the birds acted as predicted

functioning on the basis of what they had learned about worms

And it wasnt what they learned during the test phase

because they acted OK from trial 1


Episodic like memory and other behavior in scrub jays

Moreover, the birds behavior was not just a matter of familiarity of the tray

that is, somehow associating tray with the issues

because the tray exposure was the same for each type of caching


Episodic like memory and other behavior in scrub jays

The switch by the birds in the Degrade group

requires the birds to recognize a particular cache site

in terms of both its content and the relative time that has elapsed between caching and recovery


Episodic like memory and other behavior in scrub jays

The birds HAD to recall information about

  • what (worms vs. peanuts) was cached

  • where it was cached (right vs. left)

  • when (4 hrs vs. 120 hrs)


Episodic like memory and other behavior in scrub jays

Toothe information was acquired on the basis of a single, trial-unique personal experience

That is.something getting quite close to episodic memory


Episodic like memory and other behavior in scrub jays

Note the result cannot be explained by the simple rule

search the side of the tray in which food was stored most recently, regardless of food type.

birds couldnt use recency, because each food was cached at the same time in different trials


Episodic like memory and other behavior in scrub jays

Researchers next wanted to make sure that the birds remembered

not only which sites have been depleted (data from experiments by Kamil and Balda that we discussed)

but also exactly WHAT was recovered


Episodic like memory and other behavior in scrub jays

not just the choice of spoiled vs. unspoiled,

but also what might be more appealing at a particular time.

which relies on a very personal memory for what has been consumed recently

not just always go for X if its fresh


Episodic like memory and other behavior in scrub jays

So, they tested whether what they fed the birds just prior to recovery would affect what they recovered.

and also made them remember where the different foods were stored in two different trays.

The trials are quite complicated!


Episodic like memory and other behavior in scrub jays

(1) cache P in one side of each tray

(3) 3 hrs later, allowed to recover P from one tray and K from the other

A

P

A

P

/

K

B

P

P

/

K

B

A few mn

(2) cache K in one side of each tray

(4) Prefeed bird P, see what it does

A

P

K

/

P

K

A

B

P

K

B

P

/

K


Episodic like memory and other behavior in scrub jays

Assumption is that bird that is full of peanuts

will choose the kibble, and remember where the kibble still was

even after additional time delay


Episodic like memory and other behavior in scrub jays

Of course, during test, all food was removed by the experimenter to prevent any odor or disturbance cues

So birds should not rely on a scent or preference for food

but on satiation


Episodic like memory and other behavior in scrub jays

Note that birds have to INTEGRATE information as to

  • what it cached where

  • what it recovered where

  • what was same/different from what it had just eaten


Episodic like memory and other behavior in scrub jays

9 of 12 birds upheld the prediction of feeding from the tray

that held food different from what it had just eaten

Birds made twice as many searches to the place where there was intact different food


Episodic like memory and other behavior in scrub jays

as to where there was intact same food

birds made very few searches to depleted sites

And this did not depend on training about good or bad types of food


Episodic like memory and other behavior in scrub jays

Three main conclusions from these data

  • Birds encode info about what they store in a site

  • Birds can update their memory as to whether they have depleted one of two sites, even if they essentially bated them simultaneously

  • Birds can integrate these two bits of information


Episodic like memory and other behavior in scrub jays

Now, those of you who have been mulling about the peanut/mealworm study may have realized a possible flaw in the experimental design

Maybe the birds just have a differential memory for remembering stuff that spoils versus stuff that does not.


Episodic like memory and other behavior in scrub jays

rather than remember when stuff was cached

In other words.

Birds that experienced degradation not only learned something about what is good to eat when


Episodic like memory and other behavior in scrub jays

But also that, in general, its best to remember where peanuts are stored because they are a more reliable source of food

So dont clog memory with information about degradable mealworms.

Thus researchers had to figure out a way around that problem..


Episodic like memory and other behavior in scrub jays

They did so by replicating the experiments with crickets instead of worms

Crickets degrade more slowly than worms,

so the researchers could see if birds progressively recovered crickets more slowly as the days went by


Episodic like memory and other behavior in scrub jays

Thus, if birds were just not bothering to remember where a degradable food was cached

and they didnt like the degradable crickets as much as the degradable worms

but they liked the crickets only as much as the peanuts


Episodic like memory and other behavior in scrub jays

they should start skipping the crickets immediately

If, instead, they remembered crickets as well as peanuts,

and when they cached

they should go for the cricket for the first day or so after caching and stop after about 3 days


Episodic like memory and other behavior in scrub jays

Interestingly, almost none of the 6 birds involved went for peanuts on the first three days

By day 5, all 6 birds went to peanuts first..

The birds seemed to make a categorical decision as to change their behavior around day 4


Episodic like memory and other behavior in scrub jays

Thus, it could still be that the birds were not directing a lot of resources to remembering crickets

or had some kind of intermediate range memory in which they stored information about degradable food

compared to long-range memory for nondegradable items.


Episodic like memory and other behavior in scrub jays

So, the idea was to give the Degrade birds staggered caching and then see what the birds did on progressive days.

Cache day 1

Cache day 2

Cache day 3

C

P

P

C

P

C

1

2

3

Recover day 4

Recover day 5

Recover day 6

P

P

dC

dC

?

?

1

2

3

This time, tho, some birds were givendegraded crickets on Day 3


Episodic like memory and other behavior in scrub jays

Before, remember, crickets were still pretty good on Day 3

If they really remembered what they cached and when

they would go for peanuts on day 6 in the last tray that was cached

only if they experienced degraded crickets on day 3


Episodic like memory and other behavior in scrub jays

But if they were the group that had not had rummy crickets on Day 3 for the first two trays,

they should still go for crickets on day 3

because crickets were usually good until day 4


Episodic like memory and other behavior in scrub jays

And, to make sure that the birds just now didnt decide that any cached crickets were worthless,

they were given good crickets on a Day 1 recovery trial

The idea was to see if the researchers could tweak the encoded information.


Episodic like memory and other behavior in scrub jays

Showing that the information was indeed encoded

and not just that crickets were relegated to a specific memory bin

Most of the birds that got degraded crickets on Day 3 for trays 1 and 2 did search for peanuts on Day 3 for tray 3.


Episodic like memory and other behavior in scrub jays

In general, the birds had encoded some kind of semantic memory about the state of crickets over time (i.e., that they degrade in a few days)

And then integrated this information with respect to where and when they had cached the crickets..


Episodic like memory and other behavior in scrub jays

And they were able to update their general semantic knowledge of the world based on new information.

These data fit with the ethology of the scrub jays, who cache items under varying conditions.

and thus must determine the effects of, e.g., a hot spell on their caches


Episodic like memory and other behavior in scrub jays

So, these data suggest that birds fulfill the criteria for episodic memory:

What, When, Where

But is this behavior identical to that of humans, as Suddendorf and Busby question?

We still do not know.


Episodic like memory and other behavior in scrub jays

We dont know if the birds are simply reacting on the basis of semantic memory.

That is, on some version of this is just how the world works

versus some understanding that the situations are specific to themselves or allow them to project ahead.


Episodic like memory and other behavior in scrub jays

Specifically, one can argue that the birds have each remembered a setalbeit a very complex setof facts and integrated these facts.

Thus demonstrating an extremely high level of complex cognitive processing


Episodic like memory and other behavior in scrub jays

What is needed is to show that the animal remembers a specific episode

that is, where I was and what I was doing on September 11, 2001.

And not just a collection of facts that allow me to solve a problem


Episodic like memory and other behavior in scrub jays

because what you were doing was dissociated from the events

Is there any way to get around that problem?

Possibly, by designing experiments in which a bird has to separate out its own experiences from that of other birds..


Episodic like memory and other behavior in scrub jays

This strategy isnt perfect

because it still cant separate out the bird as a dispassionate observer from what is going on around it

But it is a start in the right direction


Episodic like memory and other behavior in scrub jays

Researchers realized that scrub jays will steal from one anothers caches..

And that as a precaution, some jays will re-cache items

if their initial caching is observed by other jays.


Episodic like memory and other behavior in scrub jays

So maybe researchers could work with that knowledge to see if they could personalize the birds memories

And also see if the birds could project their knowledge to the future


Episodic like memory and other behavior in scrub jays

So, one group of birds watched another group cache, and then was allowed to pilfer.

Another group of birds never had this experience of being allowed to pilfer.

although they could watch caching


Episodic like memory and other behavior in scrub jays

Both sets of birds were then allowed to cache in the presence of a competitor.

Both sets of birds were then given the opportunity to re-cache their hoards in private.

Pretty much only those that had pilfered other birds stores did re-cache


Episodic like memory and other behavior in scrub jays

These data begin to suggest that birds do have memories that, if not specific to themselves,

at least suggest some sense of attribution to others.

Specifically.if I pilfered another birds hoard whom I watched, someone watching me may pilfer mine


Episodic like memory and other behavior in scrub jays

Of course, one can always come up with alternative explanations.

Something a bit less mentalistic.any ideas???

Wellit seems that birds are acting as tho if they do something, all other birds will do the same thing.

that is, generalization


Episodic like memory and other behavior in scrub jays

Such behavior does not really impute intentionality or personal experience.

What one would really have to show is that birds recognize specific individuals

and that these individuals are indeed pilferers


Episodic like memory and other behavior in scrub jays

and react only in the presence of a bird that they have reason to expect will pilfer their food.

not simply react on a generalized basis

Testing this with respect to actual knowledge is difficult


Episodic like memory and other behavior in scrub jays

But possibly testing it with respect to the birds having some idea

of what a potential pilferer may or may not be able to see might work

Some evidence exists for ravens


Episodic like memory and other behavior in scrub jays

If other ravens are around

the storer will wait until those birds are distracted or have moved away

or will make false caches and false recaches

or store behind barriers


Episodic like memory and other behavior in scrub jays

But, again, are the birds acting as if they really have a Sally-Ann sense of theory of mind

or are they also working on a sort of generalization of this is what should be done in this circumstance

without fully knowing why?


Episodic like memory and other behavior in scrub jays

One can set up an experiment in which the storer sees who is stealing some of its cache

And determine if the storer will then respond in a way that suggests it knows something about this specific competitor

compared to how it treats food stored in private


Episodic like memory and other behavior in scrub jays

So, storers had three trials where they could store in private

And three trials where they knew that one potential pilferer was watching

In each case, two trays were available, at different ends of their cage


Episodic like memory and other behavior in scrub jays

The same potential pilferer saw all three trials

Interestingly, storers also sometimes cached outside of the trays, but experimenters removed those caches

Experimenters also noted how much was eaten


Episodic like memory and other behavior in scrub jays

Then, in the presence of the storer, the pilferer was given one tray

while the other tray was out of reach of both birds (trays marked w/ Legos)

And pilferers could eat a cache or re-cache it in same or different site


Episodic like memory and other behavior in scrub jays

In contrast, after the storer had stored in private

the trays were observed by both birds, but no one could reach either tray

thus observation time for all four trays was equal


Episodic like memory and other behavior in scrub jays

Then the storer, now in private, got back two trays

  • two trays had been cached in private and seen by both birds

  • two trays had been cached in public, both seen by both birds, but only one accessible to the pilferer

What did storer do?


Episodic like memory and other behavior in scrub jays

For whatever reason, birds cached a bit more when being observed

Pilferers got about 50% of what had been stored when they could access a tray

But overall, about the same number of items were left for recovery remember, 3 unpilfered trays


Episodic like memory and other behavior in scrub jays

The original storers didnt differ in how much they ate or checked their caches when they got the trays back in the two conditions

But they did re-cache more items in the trays that the pilferers had observed than in trays stored in private


Episodic like memory and other behavior in scrub jays

They discriminated the particular trays that the pilferer had observed

And, interestingly, they took food out of the observed trays more often

Stuffing it in sites in the cage that could not be accessed by the pilferer at all


Episodic like memory and other behavior in scrub jays

They also ate a lot more after being in trials in which the observer ate some of their caches

Here they werent just observed, but actively saw their caches being pilfered,

which is a fairly strong condition


Episodic like memory and other behavior in scrub jays

In a separate study on other cachers, the Grey jay

This species would cache in front of a nutcracker because nutcrackers dont pilfer

but wouldnt cache in front of Stellar jays that do


Episodic like memory and other behavior in scrub jays

None of these observational studies, however, deal with social effects

In the wild, many of these birds have social hierarchies that affect who has access to food

And may affect caching if good sites are limited


Episodic like memory and other behavior in scrub jays

In a 2005 paper (Dally, Clayton, and Emery, Behaviour) looked at caching in an aviary in which there existed a social hierarchy

They found that the alpha pair would cache more than the beta pair

And that the alpha pair knew where each other cached and didnt care who recovered the cache


Episodic like memory and other behavior in scrub jays

But the alpha pair seemed to defend their caches from the other birds

And when the alphas were removed, the betas then became the alphas

And took over the caching


Episodic like memory and other behavior in scrub jays

Probably the subordinate birds knew they could not defend cache sites from the domiants

And basically just gave up on it

The effect might, however, have to do with being in an aviary


Episodic like memory and other behavior in scrub jays

In the wild, the subordinate might need to cache more.

Here, the birds were basically well-fed and limited only slightly

Might be a totally different story in the wild w/ limited food available and the need to steal and cache


Episodic like memory and other behavior in scrub jays

In yet another 2005 study (Animal Behaviour, Dally, Emery and Clayton) looked at positional factors in social settings

Here birds had a choice of where to store under conditions of being watched or not

sites were either close or far


Episodic like memory and other behavior in scrub jays

If the bird had a general theory of just storing as far away from any possible observer

it would always use the far tray

Even if, in this case, the bird saw a screen being pulled down between it and a neighbor


Episodic like memory and other behavior in scrub jays

If, however, it was sensitive to the condition of not being viewed

It should cache randomly in the two possible trays

The expt would show whether the bird was really aware of what the other bird could see


Episodic like memory and other behavior in scrub jays

Now, this time the birds did not see anyone eat their food before the trays were removed

And they had successive trials so that they could learn what was happening to their hoardes

Which could all affect results


Episodic like memory and other behavior in scrub jays

Again, for whatever reason (maybe fear of pilfering?) more food was cached when the birds were observed

And more food was put in the far tray when the birds were observed

suggesting that being observed had an effect


Episodic like memory and other behavior in scrub jays

More food from the near trays were re-cached during recovery

Note that in the three hours in between caching and recovery, the screen was installed

So the storers had no idea what had happened to their trays


Episodic like memory and other behavior in scrub jays

This condition is quite different from the one in which the storers saw the pilferers go to work

But the fact that the storers re-cached in private suggests that they knew that by caching all the stuff initially in the far space wouldnt be good either


Episodic like memory and other behavior in scrub jays

Although this might suggest a sort of awareness, it may not

Could just be a simple idea of trying to avoid being near a conspecific during caching

And moving stuff away from the site it was at


Episodic like memory and other behavior in scrub jays

What if you put non-cacheable food near the observer?

Would the bird go near the observer?

What if you played with the details of where the observer could be?


Episodic like memory and other behavior in scrub jays

Birds happily ate in view of the observer

So they werent simply avoiding another bird

And their behavior during caching wasnt just due to avoiding the other bird


Episodic like memory and other behavior in scrub jays

In terms of playing with the spacing, the experimenters set up the cages so that the birds could see one another in a limited way

and sometimes the observer was stuck on one side or the other

but the storer could move


Episodic like memory and other behavior in scrub jays

Up close, pilferer can see only one site


Episodic like memory and other behavior in scrub jays

No matter which side the potential pilferer was on

The storer cached in the far and unseen location

Interestingly, the caches were moved more often when the potential pilferer could move about


Episodic like memory and other behavior in scrub jays

And sometimes the birds would cache in view and then recache several times

As if the confuse the pilferer as to where the item was.

Of course, the cacher could just be dithering here


Episodic like memory and other behavior in scrub jays

Another problem is that the unseen site is always the further one away.

So we still dont know if the bird is acting upon what it thinks is the sight of the potential pilferer

Or it just wants to store in a far location.


Episodic like memory and other behavior in scrub jays

Hence, another setup:

Seen and unseen are now equi-distant


Episodic like memory and other behavior in scrub jays

Here jays could also cache totally in private

But, for whatever reason, they did not!

But when they were viewed, they put more in the out-of-sight tray than the one in-sight


Episodic like memory and other behavior in scrub jays

But, this still could be some kind of out of sight, out of mind behavior.

What is needed is a system in which the pilferer can be seen by the storer

But the storer knows it is unseen


Episodic like memory and other behavior in scrub jays

In yet another study, jays seemed to understand which bird was the observer and react appropriately

So, for example, it didnt care if its partner saw a cache (all in the family)

But did react if a dominant saw it cache


Episodic like memory and other behavior in scrub jays

And the experimenters had problems because some birds stopped caching at all in the presence of observers

And birds would respond differently when birds that observed recovery were not birds that observed caching

So the birds seemed to attribute some knowledge to the observer


Episodic like memory and other behavior in scrub jays

Or at least some memory of the observer and some memory of what might have happened in a related situation.

We are getting closer and closer to some kind of TOM

But its always difficult to know for sure


Episodic like memory and other behavior in scrub jays

In terms of planning, however, a recent paper (Nature, 2007, 445: 919-921) does show clever behavior on the part of the jays.

First experiment involved planning for breakfast to see if birds would provision themselves depending upon their knowledge of the future


Episodic like memory and other behavior in scrub jays

Powdered nuts

No food

Later in day, learned that they could eat in B, too, but just powdered nuts


Episodic like memory and other behavior in scrub jays

Then they were given whole nuts in B in the evening.

They put more nuts in C than A

Ostensibly to compensate for lack thereof


Episodic like memory and other behavior in scrub jays

But to make sure the birds werent simply associating caching and hunger

The experiment was repeated with nuts in A and kibble in C

And then they were given both nuts and kibble in B

And they put kibble in A and nuts in C

Showing some level of planning


Episodic like memory and other behavior in scrub jays

Overall, the data demonstrate incredible abilities that were not thought to exist in any nonprimate other than humans and apes, much less in a bird!


Episodic like memory and other behavior in scrub jays

Which, of course, brings up the monkey paper..what about other nonprimates?

Now, of course, rhesus monkeys do not normally cache

It does not make ecological sense


Episodic like memory and other behavior in scrub jays

Most of their food is perishable

And most of the time it is not limited in any real way

So that the idea of worrying about caches is not likely


Episodic like memory and other behavior in scrub jays

What may be true for monkeys, however,

is when a particular tree is fruiting

with respect to a particular location in the forest

Maybe this is less precise, or is seasonalbut could be episodic


Episodic like memory and other behavior in scrub jays

So, although monkeys might not be the best possible subjects

There might be some reason why they might have something like episodic memory.

But will this task show it?


Episodic like memory and other behavior in scrub jays

Monkeys had two different foods, one yummy and one less so

They could then go back after either a long or a short delay

Both foods were available after short delay; only less yummy food after a long delay


Episodic like memory and other behavior in scrub jays

Would they learn, over training,

which food would be available after different delays?

Note how this differs from the jays

in what is available


Episodic like memory and other behavior in scrub jays

Learning that something just disappears over time can be seen as just someone else eating it up if you dont get to it first

which is a subtle difference from something that has to do with time per se


Episodic like memory and other behavior in scrub jays

And this task used some monkeys with hippocampal lesions

Now we know that the hippocampus involves spatial memory

But some areas of the hippocampus also seem to be involved with episodic memory


Episodic like memory and other behavior in scrub jays

or possibly, as we saw in the last lecture, the connections between the hippocampus and other parts of the brain

One idea is that the where and when of the what-where-when may be closely tied together.

which might explain corvid success on both sets of tasks


Episodic like memory and other behavior in scrub jays

So, monkeys had three foraging sites, one empty and two w/ foods of differing appeal

In training, the placement of the sites vary between, but not within, sessions

So monkeys had to forget between sessions (time not given) and remember within session placement


Episodic like memory and other behavior in scrub jays

Although there is no report of within-session timing, it sounds as tho it was just a few minutes between runs.

Enough to pull monkeys to cage, cover w/ tarp, and re-bait the sites

We are not told the time delay between sessions


Episodic like memory and other behavior in scrub jays

But this time delay is crucial

Because it sets up what delay the monkeys expect during which the expected sites have been altered!

The assumption is 24 hrs, given that food preference tests were given on a 12 trial/day basis


Episodic like memory and other behavior in scrub jays

Monkeys were considered trained if they went to preferred food on the last 3 of 4 runs in a session.

They acquired what is known as a learning set

where they learn a task, and small variations on the task are learned successively more rapidly


Episodic like memory and other behavior in scrub jays

Then they were tested.

They went into the room, had, again, a unique set of placements

had the chance to learn where the good food had been hidden

Both the controls and lesioned animals quickly learned to find treat


Episodic like memory and other behavior in scrub jays

They also learned to avoid the less tasty food

So at least for these very short delays (a few minutes) within sessions

lesions had no effect on how well the animals remembered the two sites


Episodic like memory and other behavior in scrub jays

Then they were tested after each of the study trials

Now with first 1 hr and then 25 hr delays


Episodic like memory and other behavior in scrub jays

After a 1 hr delay, the monkeys were allowed into the site

Nothing had changed

Researchers noted which food was chosen first, but monkeys had to visit both sites to end a trial

After choosing the good food, the marker was removed to encourage choice of the second site


Episodic like memory and other behavior in scrub jays

After 25 hrs, the monkeys went back into the experimental room

Nothing had changed in the placement, UNLIKE the previous training phase

Now, however, the good food was degraded to be yuckky


Episodic like memory and other behavior in scrub jays

Now remember, each test trial consisted of 8 runs for the animals to learn where the foods were

Then one run an hour later and another run 25 hrs later

Each monkey had 30 of these test trials; not sure of the time between test trials


Episodic like memory and other behavior in scrub jays

The experimenters expected that, with time, the monkeys would stop going to the preferred food after the 25 hr delay.

Remember, the jays learned that worms got yuckky after 4 days

But the monkey data didnt quite work out that way.


Episodic like memory and other behavior in scrub jays

First of all, the monkeys didnt bait the areas themselves

Second, the sites changed initially from one day to the next

So after a 25 hr break, they may have expected the room to look different.


Episodic like memory and other behavior in scrub jays

But now, sometimes, instead of seeing a different setup

which they had learned meant some trial-and-error choice

they saw a familiar pattern

How easy would it be to learn to ignore that????


Episodic like memory and other behavior in scrub jays

We know that reversals are tough to acquire

And thats what the monkeys had to learn

So its likely there was a lot of interference going on


Episodic like memory and other behavior in scrub jays

The lesioned monkeys more often examined unbaited sites

suggesting that they indeed had a poorer memory for the location of any kind of foodgood or bad

Toward the end of the paper, the authors admit that their training might have skewed the results


Episodic like memory and other behavior in scrub jays

But they then discount the possibilityfor what seem to be odd reasons

The point is that the continued shifting of the sites for the animals during training blurs the situation

What IS an episode for them?


Episodic like memory and other behavior in scrub jays

Unlike the Clayton studies, the monkeys were trained in a particular way, then tested with a glitch

and then were expected to figure out a correlation that was obvious to the researchers

but one that would not necessarily be obvious to an individual experiencing the task


Episodic like memory and other behavior in scrub jays

Too, although Clayton couldnt put every control in every experiment

each experiment was a consistent whole, with no claims as to having controlled for every variable

Although one could see the work as really on large paper instead of several individual ones


Episodic like memory and other behavior in scrub jays

These studies, of course, get into the realm of questioning what it is that the animals actually do know

and, of course, what they know that they knowi.e., metacognition

The suggestion is that metacognition is necessary for episodic memory


Episodic like memory and other behavior in scrub jays

But do you need to know that you know that worms degrade?

Metacognition might be more important in the pilfering study

in terms of getting to a kind of theory of mind behavior

But none of these cases are clear


Episodic like memory and other behavior in scrub jays

An animal might know what food is hidden where and whether it is still good

but not know HOW or WHY they know it

No reasoning would be involved, just some memory returning when visiting the area


Episodic like memory and other behavior in scrub jays

Humans use language to declare this information

How can we get at it in animals that have no, or only very limited, interspecies communication skills?

Some studies purportedly allow monkeys to state if they do or do not remember the answer to a task


Episodic like memory and other behavior in scrub jays

But in reality the animals reporting of uncertainty just allows them a third choice when a first choice doesnt surface quickly

It may not be any more conscious than any other type of choice they are given


Episodic like memory and other behavior in scrub jays

Some researchersSuddendorfargue that episodic memory is really a means of future planning

using the past to project to the future

How would that help us understand animals?


Episodic like memory and other behavior in scrub jays

Clearly the jays store for the future and monkeys do not

But that doesnt get to the idea of whether the jays behavior is a mixture of instinct and knowledge

or self-awareness of what is individually needed


Episodic like memory and other behavior in scrub jays

Would seem that the jays actions in preparing for the contingency of another animal pilfering

might actually tell us more than the caching behavior itself

Wouldnt it be great to ask Jay A where he thought Jay B would search after A re-cached?


Episodic like memory and other behavior in scrub jays

The implication is that Jay A thinks Jay B will look in the old site and be fooled

Otherwise why would Jay A re-cache?

But Jay A re-caches in sight of Jay B;


Episodic like memory and other behavior in scrub jays

Such would seem to be a silly behavior, and thus researchers make an argument for confusion

But is Jay A really pondering such an outcome, or just kinda freaking out and maybe trying to find a slightly better hiding place?

or hoping B will lose interest?


Episodic like memory and other behavior in scrub jays

The take-home message is basically the cleverness of the birds and the need for truly complicated experiments in order to uncover their cleverness


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