In this series of blogs, we will discover that chickens demonstrate many cognitive abilities and skills that we would never attribute to them in the first place. Did you know that chickens – similarly to many other birds – are able to track occluded objects, a skill that infants also acquire during their first months of life! Or that they show similar physiological responses to dangerous stimuli as humans, such as reduced heart rate? Even more interesting is the fact they chickens can memorize and recognize individuals in their surroundings!¹

Let’s start with perception and short-term memory. In psychology, short-term memory refers to memory that we use to store information for a limited period of time. We use it in everyday situations, for example when you temporarily store a phone number in your mind to dial it a few seconds later. Now, although this ability appears to be very basic and easy to perform, we humans develop a very simple form of working memory only around the age of one. It was one of the discoveries that made psychologist Jean Piaget famous. In the eighties, Piaget proposed that infants aged 8-12 months develop an understanding that an object exists even if it’s not visible. This early form of working memory (called object permanence) is observed when an infant removes a cover from your face during a peekaboo game, or removes a blanket covering their favorite toy. This stage of development follows a simpler skill when an infant reaches not for fully but only partially hidden object.²

Do chickens show similar skills? To find out the answer, researchers have performed a similar occluding experiment with the new born chicks. The chicks were first imprinted into geometric shape such as a red triangle to which they have become accustomed to. Next, the researchers presented a chick with either a partially hidden red triangle on the one side, and a triangle with a missing piece as a control on the other side. The chicks choose to be near a hidden imprinted triangle, which suggests that – similarly to humans – chicken’s visual system fills in the part of occluded object, allowing them perceiving it as a whole.³

In yet another study, the researchers were interested whether the chicks would follow the location of the familiar object if it was totally hidden. As in the previous experiment, the chicks were first familiarize with a small object. Subsequently, the chicks were shown the object disappearing behind one of the two identical screens and were allowed to follow it, which in most of the cases they did. So the chicks learned that they can find their favorite objects behind one of the straight screens. In the final phase of the experiment, the object was again moving towards one of the two screens and when it was half way, the chick’s view of the object was blocked. During this time, the slant of one of the screens was changed, and after the partition blocking the view of the chicks was removed, they could again decide where to go. The dominant behavior of the chicks as to walk towards the unchanged – straight screen, where they would have previously found the familiar object.

These studies suggest that chickens can recognize partially hidden objects and even remember their location if they are fully hidden. This is particularly the case for items with whom the chicks created a social bond (e.g., during the first days of life).


References:
¹Marino, L. (1997). Thinking chickens: a review of cognition, emotion, and behavior in the domestic chicken. Anim Cogn: 20(2): 127-147.
²Piaget, J. (1954). The construction of reality in the child. London: Routledge and Kegan Paul.
³Regolin L, Vallortigara GPercept Psychophys. (1995). Perception of partly occluded objects by young chicks. Percept Psychophys: 7(7):971-6.
⁴ Chandetti, C., Vallortigara, G. (2011). Intuitive physical reasoning about occluded objects by inexperienced chicks. Proc Biol Sci: 278(1718): 2621:27.

_{Image credits:
Chick: Animals vector created by terdpongvector – www.freepik.com
Grass: Summer vector created by macrovector – www.freepik.com
Ball: Banner vector created by pch.vector – www.freepik.com}