The evolution of cognition is the process by which

life Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from that which does not, and is defined by the capacity for growth, reaction to stimuli, metabolism, energ ...

on Earth has gone from organisms with little to no cognitive function to a greatly varying display of cognitive function that we see in organisms today. Animal cognition is largely studied by observing

behavior Behavior (American English) or behaviour (British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as wel ...

, which makes studying extinct species difficult. The definition of cognition varies by discipline; psychologists tend define cognition by human behaviors, while ethologists have widely varying definitions.

Ethological Ethology is the scientific study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism as a term also describes the scientific and objective ...

definitions of cognition range from only considering cognition in animals to be behaviors exhibited in humans, while others consider anything action involving a

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...

to be cognitive.

Methods of study

Studying the evolution of cognition is accomplished through a comparative cognitive approach where a cognitive ability and comparing it between closely related species and distantly related species. For example, a researcher may want to analyze the connection between spatial memory and food caching behavior. By examining two closely related animals (chickadees and jays) and/or two distantly related animals (jays and chipmunks), hypotheses could be generated about when and how this cognitive ability evolved.

Animals with high levels of cognition

Higher cognitive processes have evolved in many closely and distantly related animals. Some of these examples are considered

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

, while others most likely shared a common ancestor that possessed higher cognitive function. For example, apes humans, and cetaceans most likely had a common ancestor with high levels of cognition, and as these species diverged they all possessed this trait. Corvids (the crow family) and apes show similar cognitive abilities in some areas such as tool use. This ability is most likely an example of convergent evolution, due to their distant relatedness. * Mammals **

Humans Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

possess possibly the highest level of cognitive function on earth. Some examples of their cognitive function include: high levels of motivation,

self awareness In philosophy of self, self-awareness is the experience of one's own personality or individuality. It is not to be confused with consciousness in the sense of qualia. While consciousness is being aware of one's environment and body and lifesty ...

problem solving Problem solving is the process of achieving a goal by overcoming obstacles, a frequent part of most activities. Problems in need of solutions range from simple personal tasks (e.g. how to turn on an appliance) to complex issues in business an ...

language Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of met ...

, culture, and many more. **

Cetaceans Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

(dolphins and orcas) have shown higher levels of cognition including: problem solving, tool use, and self recognition. ** Hyenas live in highly cognitive social groups. Hyenas have also demonstrated the behavior of feigning death to avoid conflicts with predators. **

Apes Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...

have shown cognitive abilities such as: problem solving, tool use, communication, language, theory of mind, culture, and many more. ** Canids have shown high level cognitive abilities such as: object permanence, social learning, and

episodic memory Episodic memory is the memory of everyday events (such as times, location geography, associated emotions, and other contextual information) that can be explicitly stated or conjured. It is the collection of past personal experiences that occurred ...

. **

Elephants Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae and ...

display many high cognitive behaviors, including those associated with grief, learning, mimicry, play, altruism, tool use, compassion, cooperation, *

Birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

Corvids Corvidae is a cosmopolitan family of oscine passerine birds that contains the crows, ravens, rooks, jackdaws, jays, magpies, treepies, choughs, and nutcrackers. In colloquial English, they are known as the crow family or corvids. Currently, 133 ...

demonstrates many high functioning cognitive abilities such as: problem solving, spatial temporal memory, mental time travel, and a particularly wide variety of tool usage. ** Parrots have displayed cognitive functions such as: tool use, problem solving, and mimicry of human speech.

Selection favoring cognition

Social living

Social living Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...

is thought to have co-evolved with higher cognitive processes. It is hypothesized that higher cognitive function evolved to mitigate the negative effects of living in social groups. For example, the ability to recognize individual groups members could solve the problem of cheating behavior. If individuals within the group can keep track of the cheaters, then they can punish or exclude them from the group. There is also a positive correlation between relative brain size and aspects of sociality in some species There are many benefits to living in social groups such as division of labor and protection, but in order to reap these benefits the animals tend to possess high levels of cognition.

Sex, mating, and relationships

Many animals have complex mating rituals require higher levels of cognition to evaluate. Birds are well known for their intense mating displays including

swan dance Swans are birds of the family Anatidae within the genus ''Cygnus''. The swans' closest relatives include the geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometim ...

s that can last hours or even days. Higher levels of cognition may have evolved to facilitate the formation of longer lasting relationships. Animals that form pair bonds and share parental responsibilities produce offspring that are more likely to survive and reproduce, which increases the fitness of these individuals. The cognitive requirements for this type of mating include the ability the differentiate individuals from their group and resolve social conflicts.

Finding, extracting, and protecting food

Another hypothesis for the evolution of cognition is that cognition allowed individuals access to food and resources that were previously unavailable. For example, the

genetic mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitos ...

for

color vision Color vision, a feature of visual perception, is an ability to perceive differences between light composed of different wavelengths (i.e., different spectral power distributions) independently of light intensity. Color perception is a part of ...

allowed for a greatly increased efficiency in finding and foraging fruit. Food caching behavior displayed in some birds and mammals is an example of a behavior that may have co-evolved with higher cognitive processes. This ability to store food for later consumption allows these animals to take advantage of temporary surpluses in

food availability Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingest ...

. Corvids have displayed incredible abilities to create and remember the locations of up to hundreds of caches. In addition, there is evidence that this is not just an instinctual behavior, but an example of future planning. Jays have been found to diversify the types of food they cache, possible indicating they understand the need to eat a variety of food. Some supporters of this hypothesis suggest that higher cognitive processes require a large brain to body ratio. This higher brain to body size ratio in turn requires a large metabolic input to function. The idea is that the two processes (greater access to food and the brain's growing need for energy) may have snowballed the evolution of these two features.

Technology, tools, innovation, and culture

The cognitive ability to use

tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task. Although many animals use simple tools, only human beings, whose use of stone tools dates ba ...

s and pass information from one generation to the next is thought to have been a driving force of the evolution of cognition. Many animals use tools including:

primates Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

elephants Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae and ...

cetaceans Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

, and some

invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

. Tool use varies widely depending on the species. For example,

sea otter The sea otter (''Enhydra lutris'') is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of the weasel family, but among the small ...

s have been observed using a rock to break open snail shells, while primates and New Caledonian crows have demonstrated an ability to fashion a new tool for a specific use. The ability to use tools seems to provide animals with a fitness advantage, usually in the form of access to food previously unavailable, which allows a competitive advantage for these individuals. Some animals have demonstrated the ability to pass information from one generation to the next (culture) including: primates, cetaceans, and birds. Primates and birds can pass information of specific tool use strategies on to their offspring who can, in turn, pass it on to their offspring. In this way, the information can remain in a group on individuals even after the original users are gone. One famous example of this is in a group of macaque monkeys in Japan. Researchers studying this species observed these monkeys feeding behavior in a population in Japan. The researchers witnessed one female, named Imo, realize that by washing potatoes in the nearby river you could remove much more sand and dirt then by simply wiping it off. Over the next few generations the researcher saw this behavior begin to appear in other individuals throughout the group.

References

{{reflist Cognition