Friday Grey Matters: Parrots Have Object Permanence


Object permanence refers to the notion that objects are separate entities that continue to exist even when we can't see them. Its the opposite of "out of sight, out of mind" in the sense that the person (or animal) realizes the object still exists in space somewhere. This may lead to searching behavior, or a memory of where the object last was placed. Human children are not born with object permanence--it develops over the first two years of our lives. This was quite a big discovery that made a psychologist named Piaget very famous in the 1950s. Turns out, African grey parrots share this ability as well! How that became known and tested is continued below the fold.

Piaget showed that, in children, object permanence happens in stages. In Stage 1, children do not search for an object once it is covered up. They just assume it no longer "is." In Stage 2, children track an object, in stage 3 they recover a partially-visible item, and in stage 4 they recover a fully occluded item. In stage 5, a child will recover an item hidden, exposed, and rehidden several times. And in stage 6, they can retrieve an item hidden in a secondary box even when they did not see the item being transferred to another box (think "the shell game"). This is the "Piagetian framework." The stages occur in order, progressively and are dependent on the age of the child.

Object permanence has also been examined in other species:higher primates, some parrots, and perhaps dogs were thought to reach stage 6, while cats, monkeys, doves, rodents, and chickens did not. Irene Pepperberg published a study in 1997 tracking how developing African Grey Parrots exhibited object permanence as they matured. The primary subject of the test was a African Grey named Griffin, who was 8 weeks old at the beginning of the study. This is an extremely young parrot who neither has his feathers, or is weaned.

Pepperberg would hide one of his toys, or a bit of food, similar to the stages of the Piaget framework and observe when Griffin was able to uncover the item. Experimenters were changed during the trials to eliminate the possibility of the bird reading the handler's cues. The results are listed in this table View image".

The results showed that by 21 weeks old, Griffin had obtained stage 6 object permanence although he could not succeed at the shell game specifically until week 52. In addition, Griffin showed a gradual and step-wise development along the Piaget framework, in a similar cognitive development pattern as higher primates (such as humans). While this task can only hint at the cognition behind the behavior, it is interesting and fascinating to see complex and phase-dependent cognitive development on a task which indicates a high level of environmental awareness in a very different species than us.


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for some reason i can't view the entry when I click below the fold, but CAN when i view comments.

this is just more of your parrot-psychic mind-blendering in order to make us all pirates. You shall not blender my Mind Shelley Batts. My un-god is too strong.

I bet your psychic parrot didn't see THAT one coming.

Actually he warned me, but stupid doubting human that I am, I scoffed. Never again, Pepper! Never again! (should be fixed now, I put the chart in a psychic popup. The link *knows* what you want to see.)

I really enjoy your friday grey matters series. I too am a fan of Irene Pepperberg - though I prefer to call her by her full name Irene Maxine Pepperberg. When it comes to naming pets after kick ass neuroscientists, however, I think I will always go for Rita Levi-Montalcini. It just rolls off the tongue, don't you think?

I really like your blog. I just discovered it recently.
I admit it still feels amazing when I see a blonde attractive woman doing something that involves so much intelligence. Yes people will say I'm an idiot for saying that, but I'm just not used to it. I think its great though. Hope I didn't offend.

By Paul Atreides (not verified) on 04 Aug 2006 #permalink

Paul, you can't offend someone by calling them attractive. :)

One of the things I like to do it blow that stereotype away, because stereotypes are usually very wrong. Its sad the way blondes get portrayed, by the media etc, but I won't be like "woe is me i'm a cute smart blonde." Cause actually, I'm pretty happy about it. :D

Hi Shelley. Just spent the last week at my sister-in-law's farm. She has a Gery whose best friend is a smalll dog of uncertain pedigree. The parrot will actually feed the dog food pellets when the dog begs. The dog sits before the cage on it's haunches wimpering - the bird then filcks pellets at the dog who jumps for them. This behaviour developed between the two without human intervention. The parrot only throws pellets, not any of it's soft fresh food. It really is something thing to watch.

"while cats, monkeys, doves, rodents, and chickens did not"

What about squirrels? Do they realize that their acorns etc. still exhist after they hide them (and over a long time at that)?

I wonder how that could evolve if other rodents don't have object permanance.

By Eric Irvine (not verified) on 07 Aug 2006 #permalink

Interesting question Eric, an I have no idea. One of the distinctions here is levels of object permanance; parrots, people and apes get to 6, I'm not sure about rodents. Lemme know if you find out!

The link to the chart is broken! Very interesting article even without it, but I'd like to see it with it. :D

Hey, um, I've been helping out at Irene Pepperberg's lab, and I'm actually making t-shirts for the Alex Foundation (Alex just turned 30!). If you wanted, you could buy a shirt from them, to benefit the lab. They look like this.
More pictures of Alex and Wart and Griffin in there, too.

Oh yeah, and Irene has this story about how once some screech owls perched near the window of her house, and the parrots saw them and freaked out pretty badly. She said, 'and I couldn't even close the blinds and calm them down, because they have object permanence!'
She ended up having to drive them back to the lab for the night. Poor guys.

GASSSSSPPPP! Gasp gasp gasp! Must....have....parrot....shirt.....

thanks for coming by Zusty. I'm making a post about that right now.

The comment about squirrels, remembering where they hid their nuts, raises a thought in my brain: shouldn't you control for animals' ability to smell in object permanence experiments?

A squirrel may not see where you hid his nuts, but maybe he can smell it out!

African Greys are a hoot. My mother raises them for a living. She doesn't even have to teach them to talk anymore, there are so many of them they teach each other. A few of them have perfected the whistles and calls for the family dog, and they drive that poor thing nuts; one will call him to one side of the aviary, and then another on the OTHER side gives him a whistle! The dog ends up going in circles!
Well, a little off topic, but meh....

I really like your blog. I just discovered it recently.
I admit it still feels amazing when I see a blonde attractive woman doing something that involves so much intelligence.

I have the same thoughts about you.Keep your way.:)