New research has found that squid can delay gratification through the famous "marshmallow experiment".
Good things favor people who are willing to wait, and this principle also applies to cuttlefish who have experienced "waiting" with Alexandra Schnell. Schnell is a comparative psychologist at the University of Cambridge in the United Kingdom. For the past 10 years, she has been studying the behavior and cognitive abilities of cephalopods and testing these animals using traditional experiments that measure the brain power of primates and other vertebrates. Surprisingly, these wet and sticky creatures performed quite well.
In fact, a new study shows that squid has self-control. Squid is not a fish, but a close relative of octopus and squid. When faced with choices, some squids tend to give up instant gratification in exchange for more generous rewards. In humans and other species, this ability is called "delay maintenance" (delay maintenance), and is considered an important step in the evolutionary path towards complex decision-making capabilities.
Six sub-adult squid participated in the experiment-the famous marshmallow test conducted by researchers at Stanford University 50 years ago became the basis of this new experiment. Each squid will be placed in front of two cubicles. A small piece of delicious king prawn (king prawn) is placed in a compartment, which can be enjoyed immediately, but the portion looks like an appetizer to the squid. The next compartment is a more tempting choice-a lively grass shrimp (grass shrimp), but it takes a while to eat this shrimp. If the squid chooses to wait for more delicious prey, it will wait longer in the next round of experiments.
Squid's marshmallow experiment
"The most surprising thing is that they can tolerate a waiting time of 50 to 130 seconds." Schnell said, "This ability is comparable to animals with large brain capacities, such as chimpanzees, crows and parrots. "
In addition, the most patient cuttlefish waiting for their beloved food also performed better in the learning test. This connection has only been seen in humans and chimpanzees. In the future, Schnell and his team plan to expand the scope of the test and investigate the connections in depth.
However, like humans, not every squid is a star student. "There are indeed some impatient guys." Schnell continued, "There is a squid that will not stop using its siphon to spray me until I go to feed. Their personality differences are quite big."
In order to ensure the animals. Indeed, using information to make trade-offs between choices, the researchers introduced a different set of experiments. In the new experimental setting, large prawns are placed in one compartment, but grass prawns in the other compartment cannot be touched.
"I have not trained them to wait under any conditions. If their self-control is flexible, you would expect squid to eat it immediately even if they are not your favorite food." Shi Nai Er said. And the test result is indeed the case, the squid found that they could only eat the prawns and ate it without hesitation. In addition, this also shows that the squid did not delete the prawns from their food list.
"When you use different quality foods to study self-control, you have to test these." Schneier emphasized, "If I give a kid an apple and tell him:'If you wait 15 minutes, you can still have a chocolate Great. "Most kids might say: "No problem, I want chocolate."" Schnell added. The research team needs to confirm that in the squid experiment, if the "apple" is the only choice, will the squid eat the "apple".
There is another sign that may also indicate that the squid did deliberately wait. In some experiments, the squid appeared to be keeping themselves away from instant rewards. "We have also seen this coping mechanism in other animals, trying to resist temptation and waiting for more generous returns." Schnell said. The parrot would close his eyes, the crow and the dog would turn around, and the chimpanzee would try to distract himself. However, Schnell does not know whether the squid will take similar actions, but this possibility is worth looking forward to.
Jennifer Vonk is a comparative cognitive psychologist at Oakland University in Michigan, USA. She was not involved in the study, but she was very happy to see scientists using squid to carry out these tests. Testing more types of species can help us reveal which factors drive cognitive abilities.
As early as more than 550 million years ago, the ancestors of squids and their close relatives embarked on two completely different evolutionary paths from the ancestors of vertebrates. The closest common ancestor of the two is a worm-like creature with a very simple nervous system, but they do not have these abilities. This shows that any cognitive traits shared by humans and squids today have evolved independently.
"Animal brains are very different in structure." Schnell said, "The mammalian brain is divided into two hemispheres and consists of five cerebral lobes. The brains of cephalopods are like donuts. When it comes to squid or Octopus, their brain contains 30 to 40 brain lobes, and does not have a hemisphere like humans.”
And the donut-shaped brain is not the only criterion to distinguish squids from vertebrates with larger brains. A major hypothesis that life develops advanced cognitive abilities believes that this driving force can help animals deal with the challenges of complex social life. However, squids are not social animals that cooperate with each other. Both parents will not raise offspring together, and their life span is only two years, so there will be no overlapping generations. This means that the squid will not establish strong intimacy with their close relatives and partners. Some species even have to work hard to identify whether the mating partner is of the opposite sex. During mating, males attach their sperm to any individuals they encounter.
"We don't know whether social group life is essential to complex cognitive abilities, unless we can also prove that animals that are not very social do not have this ability." Funk said, "There is still a lot of room for deepening understanding. "
