Tag Archives: Cognition

Did you know that jays fall for magic tricks and don’t always like it?

Eurasian jay

Some time ago, a video of an orangutan vividly reacting to a disappearing fruit trick circulated on the internet.

Besides collecting YouTube likes, showing magic tricks to animals can also help to understand animals’ cognitive processes and their perception of the world.

Recently, scientists studied how Eurasian jays (Garrulus glandarius) react to magic tricks and unfulfilled expectations. Jays are corvids – a group of birds known for their highly developed cognitive skills. They even use tricks themselves – when they know they are being watched, they act as if they are hiding food in many places, but only truly do so in some, cleverly manipulating the food with their beak.

Recently, scientists showed jays a trick in which they pretended to insert a treat in one of two plastic cups, but actually hid the treat in their hand, just as a magician would do when trying to fool people. They then turned both cups upside down and the bird could turn them over to get the treat. The trick was that beforehand, the scientists had already put a treat into the chosen cup, either of the same kind as they showed the jay, or a different one. If they put in a different one, it could be either more or less desirable to the particular jay than the shown treat.

The trick of ‘swapping’ food. Diagram from the original article

The jays consistently picked up the cup into which the scientist ‘inserted’ the food, but reacted differently depending on what they expected and what they found. If the birds found the same treat that they ‘saw’ being placed in the cup, they just ate it quickly, regardless of whether it was their favourite treat or not. However, if the bird found a better treat under the cup than the one the human showed to it, it took a little longer to eat it and sometimes the jay would look into the cup as if to check where the expected food was. However, the most dramatic reaction occurred when the bird expected a favourite treat but found an inferior one. Then it often checked the cup again, looked under the other one and in about half of the cases did not eat the food at all (even if it would normally eat this treat when it was expecting it).

This strong reaction to an unpleasant surprise is similar to how humans react when they lose something. No one likes it if they are promised something but they don’t get it. And just like in humans, those jays that were more dominant showed stronger dissatisfaction – they were more likely to reject food that was worse than they expected.

I am curious to see what future experiments using magic tricks will teach us about animals.

If you want to see recordings from this experiment, click here.

Jay photo by Steffi Wacker from Pexels.

Did you know that cuttlefish show self-control?

Common cuttlefish (Sepia officinalis)

While working in the lab, behavioural ecologist dr. Alex Schnell noticed a curious behaviour of Franklin, one of the cuttlefish. In the morning when Alex would enter the lab to start experiments, Franklin would drench her with water she ejected through her syphon. However, in the evening when Alex would come to the lab to feed the cuttlefish, Franklin would not “attack” her. Alex started wondering whether this behaviour was a sign of simple associative learning of mornings with experiments that the animal didn’t like and evenings with a meal. Or maybe it showed something more: self-control and resistance of the temptation to drench the scientist in the evening.

Franklin inspired Alex Schnell and her colleagues to test whether cuttlefish can show self-control.

Marshmallow test for children

In children self-control (the ability to delay gratification) can be tested using the so-called marshmallow test. A child is seated in a room with just a table and a chair. In front of them the experimenter leaves a marshmallow (or another treat) and tells them that they can eat it straight away or wait for a while when an experimenter leaves the room. They are told that if they wait, they will get another treat later. In the original test children waited on average 3 min before they eat the treat, but self-control increases with age.

… and for cuttlefish

Although one can’t just tell cuttlefish to wait, the researcher devised an experiment that could test for self-control in these animals. First*, they taught six cuttlefish that one compartment in their tank provides less-tasty food directly, while another compartment opens only after a delay, but contains their favourite food. Both compartments were transparent, so the cuttlefish could see both food items. Further, whenever the animal ate from one compartment, the other one was emptied of food.

Once the cuttlefish seemed to understand the rules, the real test started. Both compartments were placed in the tank and an individual was positioned at an equal distance to them. The delay for opening the compartment with favourite food was increased between experiment, causing some animals to give up and just eat the less-tasty prey. All cuttlefish were willing to wait at least 40s for their favourite food. However, many cuttlefish waited for more than a minute and one even two minutes – close to young children’s score. Interestingly, like children, chimpanzees, dogs and parrots, some cuttlefish seemed to try to distract themselves from the temptation of the direct reward, by turning away from the directly available food item.

Why wait?

A high degree of self-control has been shown for example in chimpanzees, corvids (birds from the crow family) and parrots. This was usually explained by the animal’s highly social lifestyle, long life and ability to use tools. After all, to keeps social bonds healthy sometimes it’s better to let others eat and delay one’s own gratification. Tool use also demands waiting for all the components to be assembled before it can be used. However, a cuttlefish lives for only two years, is not particularly social and does not use tools – so what could explain its self-control? Dr. Schnell speculates that it improves the foraging success of cuttlefish. They often lie motionless, camouflaged, on the sea bottom. Waiting for their prey to get close enough not only increases their attack success, but also reduces the chances of being seen by predators.

For a long time, people though that only humans have self-control, but this is definitely not the case; instead, it seems to be widely spread in the animal kingdom.

* Here I explained only the core of the experiment. The whole experiment was more complex and can be found in the original paper.

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Photo: By Jarek Tuszyński / CC-BY-SA-3.0 & GDFL, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=7798599

Did you know that bumblebees find efficient ways to move a ball to a target?

Have you ever watched a bumblebee collecting nectar from flowers? At first sight, this does not seem like a very difficult task, requiring sophisticated cognitive skills.

However, bumblebees have an amazing ability to learn. Not only where to find the nectar, but also how to perform human-designed tricks that require behaviours not needed in nature. For example, bumblebees have learned to pull strings, pull caps aside, and rotate disks to get to a reward.

Not so long ago, scientists (and bumblebees) have taken it a step further. The scientists, in various ways, demonstrated to their subjects that moving a ball into a target (a circle drawn on the experimental platform) led to a reward. The bumblebees quickly learned to do so themselves, and even improved their tactic to be more efficient than those demonstrated.


First, the researchers trained the bumblebees to move a wooden ball, larger than them, to a target – the demonstrator was an artificial insect (on a stick held by the experimenter) pushing the ball. The bumblebees quickly got the idea, but preferred pulling the ball while moving backwards over pushing it. These bumblebees were the demonstrators in the next phase.


In the main experiment, new, untrained bumblebees were divided into three groups. Each insect in the first group could watch another bumblebee dragging one of three available balls to a target and they both received a reward – a drop of sugar water. Insects in the second group saw a ball that moved “by itself” to the target (with help of a researcher-directed magnet under the platform). When the ball reached its destination, the watcher would get a reward. Insects in the third group simply found the ball already at the target with the reward next to it. Each demonstration/trial was conducted only three times.

Then the bumblebees were tested without further demonstration and only got a reward if they brought the ball to the target themselves. Virtually all bumblebees that had had a live demonstrator successfully dragged the ball to the target and did so faster than the other two groups. Those that had seen the ball moving by itself completed about 8 out of 10 trials. Finally, those bumblebees that had simply found the ball next to the reward were successful on average in only 3 or 4 of 10 trials and took the longest.

The student has become the master

Interestingly, the bumblebees did not simply copy what they observed early on. The bumblebee-demonstrator and magnet-using scientist always moved the farthest ball to the target. The student bumblebees usually moved the one closest to the target, even if it had a different colour than the one in the demonstration. And it was not a result of closest ball being pushed accidentally to the target, because the bumblebees usually dragged the ball actually being in-between the ball and the target.

To sum up: firstly, the bumblebees quickly learned a new task requiring the use of a tool (ball) and behaviour that has little to do with normal bumblebee foraging. And secondly, they did not blindly copy a previously observed behaviour, but used a more efficient method – moving the ball closest to the target.

Such unusual experiments show how great a capacity for learning and flexibility in problem solving these common insects have.

Did you know that dolphins know when they do not know?

When I was younger, I watched “Who wants to be a millionaire?” on TV sometimes. You probably know this program or one like it, in which a participant has to choose a correct answer to a question from among a couple of options. When they choose the right answer, they can continue to play for an increasing prize, but when they are wrong, they lose most or all they have won so for. But there is also a third option – the participant can decide not to choose any of the answers, but to finish the game and take with them what they won so far. Of course, the last option only makes sense if the participant doesn’t know the answer to the question.

Many animals were tested in set-ups similar to “Who wants to be a millionaire?” and like humans, they more often chose to evade “answering” when the task was too difficult.

In one experiment, scientists trained a buttlenosed dolphin to press one button when it heard a high-pitched tone (2100 Hz) and another when the tone was lower (between 1200 and 2099 Hz). At the beginning the choice was easy – the sound was definitely low or high – but with time difficulty increased (with the lower sound getting closer to the border between high and low – 2099Hz).

When the dolphin pressed the appropriate button, he got a reward (praise and a fish). However, when he chose wrong, he got nothing and had to wait a while for a new sound and another chance. Then a new button was added between the original two. When the dolphin pressed it, he didn’t get a reward, but after a short delay, a new, easy trial began. However, when the dolphin chose this option too often, the delay increased.

What did the dolphin do? Initially, when the high and low sounds clearly differed from each other, the dolphin had no problem choosing the correct button. However, when the sound was harder to determine, he often showed signs of uncertainty – he moved more slowly to the buttons, hesitated between them, and it took him more time to decide. In addition, he chose the middle button more often – that is, he did not try to win the reward right away, but rather preferred to wait for the next attempt.

The scientists who conducted this study did the same experiment on humans (not under water, but at a computer). The human choices were practically the same as those of the dolphin. Most people said they chose the middle option when they weren’t sure if the sound they heard was low or high. Although the dolphins could not explain their choices, their behavior indicates that they may similarly evaluate their uncertainty and respond accordingly.

Similar experiments have shown that different species of monkeys, rats, pigeons, or even honey bees also avoid difficult choices, if possible. They seem to “know that they do not know”.

Photo: Pixabay

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Did you know that wild mice that live near people are better at solving problems?

House mouse

Human activity is transforming the environment so much that many animal species are losing their place to live. But there are also a minority of species that can adapt to the new reality to some extent, or even prosper in it. Although life in the city means noise, pollution and less vegetation, there are also positive sides: an additional source of food all year round (in the form of leftovers from our tables) and fewer natural enemies (although cats are a big threat for many birds).

Living around people has an impact on animal behavior – for example, many birds in cities sing at higher frequencies to distinguish themselves from traffic. Research on birds also indicates that those living in urban areas are better problem solvers.

Coping with new problems seems to be one of the most important cognitive skills needed in the rapidly changing and unnatural environment created by humans. Recently, scientists have shown that mice that live close to humans are better problem solvers and, in at least one species, this is an innate ability that is a result of evolution, instead of something they learned during life.

Urban versus rural mice

In the first experiment, scientists caught striped field mice in the city and in rural areas. After treating all mice the same for a year in the laboratory, the tests began.

The mice were given various problem-solving set-ups (including a LEGO house – I’m not the only one who comes up with such ideas) which when opened – by pulling, pushing or moving various elements – gave them access to food.

Mice that were caught in the city were more likely to solve these problems. This couldn’t be explained by a fear of strange objects in the rural mice, because they actually approached the set-ups sooner and interacted with them longer.

As I wrote above, this experiment was carried out on mice that were born and grew up in the wild and it is possible that they could develop their cognitive abilities then – differently in rural and urban areas.

Long-term coexistence with humans

To find out the importance of long-term coexistence with humans, the same scientists conducted research on another species of mice – the house mouse. It is a synanthropic species that occurs almost exclusively near humans (this species also includes laboratory mice and various breeds of domestic pets).

There are several subspecies of domestic mice that have been associated with humans for different lengths of time: the Western European house mouse (Mus musculus domesticus) – about 11-13 thousand years, the Eastern European house mouse (Mus musculus musculus) – about 8,000 years, and the southeastern Asian house mouse (Mus musculus castaneus) – between 7,600 and 3,800 years. Thus, each of these subspecies had more or less time to adapt, through evolution, to humans’ changes to the environment (even if the living environment of people also changed a lot over these thousands of years). To eliminate the influence of individual mice’s life experience on the research, scientists did not study wild mice caught in the field, but studied their descendants, after several generations in the laboratory under constant conditions.

Adapting to life with humans

The descendants of the wild house mice were subjected to the same problem-solving tests as the field mice in the previous experiment. It turned out that the longer a mouse subspecies was associated with humans, the more likely it was to solve the problems. And this couldn’t be explained by the differences between subspecies in the time they took to approach the set-ups, or the differences in fear of a new environment.

Since all these experimental animals had lived under the same conditions throughout their lives, these studies show that different subspecies differ in their innate ability to deal with new problems. It seems that over the course of generations, coexistence with humans influenced the evolution of cognitive skills in wild animals.

Photo based on 4028mdk09, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11056096

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Did you know how smart chickens are?

When I was a child, I often went to visit my grandmother in the countryside. She had a small flock of chickens that freely roamed the front yard. At that time, I was mostly interested in exotic animals and paid little attention to the chickens. But now I regret that I didn’t observe their behaviour more, as chickens’ cognitive skills are more advanced than many people think.

Logical inference

Wild and free-range chickens live in groups with a hierarchical social structure. There is one dominant rooster and a dominant hen, subordinates of both sexes and chicks. The subordinates are not all equal, but form a so-called pecking order. Chickens can peck others who are lower in the hierarchy without fear of retaliation. If a new chicken is added to the group it has to find its place in the pecking order. But that does not mean that it has to fight each other chicken. Chickens watch each other’s fights and can draw conclusions from the results.

For example, if a new chicken beat a chicken that is dominant over the observer, the observer should avoid fights with the new chicken (if the new one is stronger than the dominant one, then the new one must be stronger than the observer). But if the new chicken lost to the dominant, then it might be worth it to attack the new chicken as there is a chance of winning. Chicken behaviour seems to indeed follow this logic. It is an example of self-assessment combined with transitive interference – a reasoning ability that humans develop only at the age of seven.

Numerical abilities

Even a few days old chicks can count, add and subtract (at least up to five). For example, in one experiment researchers showed chicks two sets of balls and then hid them behind two opaque screens. Afterwards they moved the balls between the screens, one ball at the time, while the chicks watched it. Afterwards chicks were able to indicate the screen behind which more balls were hidden.


When given the choice between two keys to peck, one of which gave brief access to food after a brief delay, and one of which gave much longer access to food after a longer delay, hens preferred the second option. Therefore, they were willing to wait a longer time for a greater reward.  In other words, chicken pass a kind of marshmallow test for self-control!

Communication and manipulation

I wrote some time ago about hens paying attention to great tit alarm calls. But chickens of course also listen to each other. They can adjust their calls to a specific situation and they can even cheat.

Roosters give one alarm call when they spot a bird of prey and a different one for a terrestrial predator (for example a raccoon). And hens react appropriately to each call and situation. When the rooster is in a safe place (for example under the cover of bushes), it will call longer. It seems to understand that it is safe from the predator.

Roosters also have a specific call and behavioural display they use to notify hens when they find tasty food, in order to increases their mating chances.  However, if a subordinate rooster finds food when a dominant rooster is nearby, it will only perform the display and omit the call, reducing the risk that the dominant rooster will notice him and chase him away. But when the dominant rooster is distracted by something else, subordinate roosters will also call.

Sometimes a rooster cheats and calls even if he doesn’t find food, but hens quickly learn not to trust this male.

Personality and its consequences

Like many other species that have been studied, chickens have personalities.

Some hens tend to be more nervous than others, which in turn affect their chicks’ stress level. Roosters’ personalities can affect result of a fight. If two roosters of the same size fight, the outcome can be predicted by studying their typical behaviour: usually the bolder, more active, more explorative and more vigilant individual wins.

These are just some examples of chickens’ cognitive abilities. Additionally, they have time perception, episodic memory, emotions and other skills often attributed to “more advanced” animals. They are much more than just “machines” for egg and meat production.

If you have a chance to observe (relatively) free-range chickens, take the opportunity to have a closer look at their behaviour. And if you want, let me know what you saw.

Photo: Quang Nguyen Vinh, Pexels.com

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Rats in action / Szczury w akcji

This time something different.

I decided to test my rats on puzzle box solving abilities.

Together with my daughters we made puzzle “boxes” from Lego and hid treats inside (dried coconut flakes). We gave the rats one or two chances to open the box without help or demonstration. That was not enough for them to figure it out. Then we left each puzzle half open. That was enough for Tokyo to get the treat and the next time she opened the “box” herself. The last puzzle we didn’t demonstrate. She got scared by the click of the door and was done for the day. Stripe was not successful this time. Partly because she missed our demonstrations.

The whole “experiment” lasted around 15 min.

Tym razem coś innego.

Postanowiłam sprawdzić, czy moje szczury poradzą sobie z otwieraniem pudełek-łamigłówek.

Razem z córkami zbudowałyśmy takie „pudełka” z klocków Lego. Do środka włożyłyśmy suszone płatki kokosa. Najpierw dałyśmy szczurom jedną czy dwie szanse samodzielnego otwarcia skrytek. To było za mało, żeby im się udało, więc częściowo otwarłyśmy skrytki. To wystarczyło Tokio, by dostać się do jedzenia i następnym razem już sama otworzyła „pudełka”. Ostatnia skrytka nie została zademonstrowana i Tokio przy próbie otwarcia przestraszyła się stuknięcia drzwiczek. Potem już wolała wejść do mojego rękawa niż zajmować się łamigłówkami. Kresce tym razem się nie udało. Częściowo dlatego, że przegapiła nasze demonstracje.

Całe to „doświadczenie” trwało ok. 15 minut.

Did you know that chickens listen to great tits?

Naked Neck hens and a great tit (small insert)

Maybe you are familiar with this situation: a group of crows is searching for food in a meadow. Suddenly one of them gives an alarm call and all birds fly off.

When animals live in groups often one of the group members will warn the others when it detects danger. Additionally, wild animals often react to alarm calls of other species, especially if they have common predators.

Domesticated animals also warn members of their group about danger. Free-range chickens behave appropriately when another chicken gives an alarm call. But do they react to alarm calls of wild birds? This is a valid question since, first of all, chickens were bred for hundreds of years for their meat or egg laying rather than survival skills. Secondly, most of the time humans provided at least some protection against predators. And lastly, unfortunately, in recent decades most of the chickens lived (and still live) indoors, completely isolated from nature and any predation besides humans.

Recently scientists decided to check if chickens respond to alarm call of wild birds, and specifically great tits. These bird species are both preyed upon by for example buzzards and goshawks. Researchers installed speakers on a free-range farm of Naked Neck chickens in France and played recordings of either great tits’ alarm calls or of their songs.

For the majority of the time hearing great tit alarm calls, the chickens were vigilant – they kept an erect posture and scanned their surroundings. When great tit songs were played the chickens spent less than half of the time vigilant.

At this moment it is unclear whether the response to alarm calls is instinctive or learned. However, if you plan to open a free-range chicken farm, it may be profitable to do it somewhere where many song birds live, even if they sometimes steal some chicken food.

Photos: Great tit – Petr Ganaj from Pexels.com; Naked Neck chickens – Simone Ramella from Rome, Italy – Corte Cecina, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=3830746

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Did you know that birds can plan their next day’s breakfast?

A western scrub-jay

Many people think that only humans know about and plan for the future. They see animal behaviour that is useful for the future, like squirrels hiding nuts in autumn, as innate (instinctive). However, experiments show that animals can plan also in situations they would never experience in the wild.

For example, the western scrub-jays (North American birds related to crows) can plan ahead as far as their next day’s breakfast.

The experiments (which I will explain below) may seem complicated, but that’s precisely the point, to force the birds to use their cognitive abilities and not act instinctively. And I invite you to imagine you are a scrub-jay and play along as though you were taking part in the experiment.

Each bird was housed in a room that was divided into three compartments (see illustration below). The middle part was available the whole time. Every morning only one of the side compartments (kitchens) was opened, with each kitchen available every second day. In kitchen 1 there was always breakfast waiting, but in kitchen 2 there was never anything to eat. Therefore, every second day, the jays were hungry in the morning. A few hours later the other kitchen was also opened. From then, the food was freely available until evening.

Scrub-jays are famous for caching (hiding) food for later, but during most of the experiment they only got powdered peanuts that there were not able to cache.

After six days, after the birds had gotten used to the situation, they were given whole nuts in the evening, which they could store in ice-cube trays filled with corn cob placed in both kitchens.

If you were a western scrub-jay, where would you hide the food?

The birds hid most of the nuts in the same place that I expect most people would   – in the breakfast-free kitchen.

So, maybe they cached the food because they just love doing so, and did it in the place in which they experienced hunger (some other animals are known to do that) and it was just an instinctive behaviour?

A second experiment gives a strong indication that the western scrub-jays actually planned their breakfast. The basic setup of the experiment was the same, but now one kitchen provided powdered nuts and the other powdered dry dog food (this may sound weird but these birds like both types of food). On the evening of the sixth day, they got whole nuts and dog kibble.

What did the birds do? They hid more nuts in the “dog-food kitchen” and more dog food in the “nuts kitchen”. This way they had a multiple breakfast options, no matter which kitchen was open.

Not only humans like a varied breakfast, and can plan ahead to ensure it!

Experimental cage

Western scrub-jay’s photo from Msulis at English Wikipedia. – Transferred from en.wikipedia to Commons by Common Good using CommonsHelper., CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=6658580


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