Communication

==Other species==
{{See also|Biocommunication (science)|Biosemiotics}}
Besides human communication, there are many other forms of communication found in the animal kingdom and among plants. They are studied in fields like [[Biocommunication (science)|biocommunication]] and [[biosemiotics]].<ref>{{multiref | {{harvnb|Emmeche|2003|pp=[https://www.encyclopedia.com/education/encyclopedias-almanacs-transcripts-and-maps/biosemiotics 63–64]}} | {{harvnb|UMN staff|2016|loc=[https://open.lib.umn.edu/communication/chapter/1-1-communication-history-and-forms/ 1.1 Communication: History and Forms]}} | {{harvnb|Seckbach|Gordon|2016|pp=[https://books.google.com/books?id=ycOkDQAAQBAJ&pg=PR15 xv–xvi]}} }}</ref> There are additional obstacles in this area for judging whether communication has taken place between two individuals. Acoustic signals are often easy to notice and analyze for scientists, but it is more difficult to judge whether tactile or chemical changes should be understood as communicative signals rather than as other biological processes.<ref>{{harvnb|Håkansson|Westander|2013|p=45}}</ref>

For this reason, researchers often use slightly altered definitions of communication to facilitate their work. A common assumption in this regard comes from [[evolutionary biology]] and holds that communication should somehow benefit the communicators in terms of [[natural selection]].<ref>{{multiref | {{harvnb|Schenk|Seabloom|2010|pp=1, 3}} | {{harvnb|Håkansson|Westander|2013|p=7}} }}</ref> The biologists Rumsaïs Blatrix and Veronika Mayer define communication as "the exchange of information between individuals, wherein both the signaller and receiver may expect to benefit from the exchange".<ref>{{harvnb|Blatrix|Mayer|2010|p=128}}</ref> According to this view, the sender benefits by influencing the receiver's behavior and the receiver benefits by responding to the signal. These benefits should exist on average but not necessarily in every single case. This way, deceptive signaling can also be understood as a form of communication. One problem with the evolutionary approach is that it is often difficult to assess the impact of such behavior on natural selection.<ref>{{multiref | {{harvnb|Blatrix|Mayer|2010|p=128}} | {{harvnb|Schenk|Seabloom|2010|p=3}} }}</ref> Another common pragmatic constraint is to hold that it is necessary to observe a response by the receiver following the signal when judging whether communication has occurred.<ref>{{harvnb|Schenk|Seabloom|2010|p=6}}</ref>

===Animals===
{{main|Animal communication}}
Animal communication is the process of giving and taking information among animals.<ref>{{harvnb|Ruben|2002|pp=25–26}}</ref> The field studying animal communication is called [[zoosemiotics]].<ref>{{harvnb|Chandler|Munday|2011|p=15}}</ref> There are many parallels to human communication. One is that humans and many animals express sympathy by synchronizing their movements and postures.<ref>{{harvnb|Håkansson|Westander|2013|p=107}}</ref> Nonetheless, there are also significant differences, like the fact that humans also engage in verbal communication, which uses language, while animal communication is restricted to non-verbal (i.e. non-linguistic) communication.<ref>{{multiref | {{harvnb|Chandler|Munday|2011|p=15}} | {{harvnb|Håkansson|Westander|2013|p=1}} }}</ref> Some theorists have tried to distinguish human from animal communication based on the claim that animal communication lacks a [[Reference|referential function]] and is thus not able to refer to external phenomena. However, various observations seem to contradict this view, such as the warning signals in response to different types of predators used by [[vervet monkeys]], [[Gunnison's prairie dog]]s, and [[red squirrel]]s.<ref>{{multiref | {{harvnb|Håkansson|Westander|2013|p=13}} | {{harvnb|Hebb|Donderi|2013|p=[https://books.google.com/books?id=-65mAgAAQBAJ&pg=PT269 269]}} }}</ref> A further approach is to draw the distinction based on the complexity of [[human language]], especially its almost limitless ability to combine basic units of meaning into more complex meaning structures. One view states that [[recursion]] sets human language apart from all non-human communicative systems.<ref>{{multiref | {{harvnb|Håkansson|Westander|2013|p=14}} | {{harvnb|Luuk|Luuk|2008|p=[https://books.google.com/books?id=9S1pDQAAQBAJ&pg=PA206 206]}} }}</ref> Another difference is that human communication is frequently linked to the conscious intention to send information, which is often not discernable for animal communication.<ref>{{harvnb|Håkansson|Westander|2013|p=5}}</ref> Despite these differences, some theorists use the term "[[animal language]]" to refer to certain communicative patterns in animal behavior that have similarities with human language.<ref>{{multiref | {{harvnb|Houston|2019|pp=[https://books.google.com/books?id=-hiBDwAAQBAJ&pg=PA266 266, 279]}} | {{harvnb|Baker|Hengeveld|2012|p=[https://books.google.com/books?id=R8uWDVdRQlYC&pg=PA25 25]}} }}</ref>

[[File:Lampyris noctiluca.jpg|thumb|alt=Photo of a glowing firefly|Many species of fireflies, such as the ''[[Lampyris noctiluca]]'', communicate with light to attract mates.]]
Animal communication can take a variety of forms, including visual, auditory, tactile, [[olfactic communication|olfactory]], and gustatory communication. Visual communication happens in the form of movements, gestures, facial expressions, and colors. Examples are movements seen during [[Courtship display|mating rituals]], the colors of birds, and the rhythmic light of [[fireflies]]. Auditory communication takes place through vocalizations by species like birds, [[primates]], and dogs. Auditory signals are frequently used to alert and warn. Lower-order living systems often have simple response patterns to auditory messages, reacting either by approach or avoidance.<ref>{{multiref | {{harvnb|Ruben|2002|p=26}} | {{harvnb|Chandler|Munday|2011|p=15}} }}</ref> More complex response patterns are observed for higher animals, which may use different signals for different types of predators and responses. For example, some primates use one set of signals for airborne predators and another for land predators.<ref>{{multiref | {{harvnb|Danesi|2000|pp=58–59}} | {{harvnb|Hebb|Donderi|2013|p=[https://books.google.com/books?id=-65mAgAAQBAJ&pg=PT269 269]}} }}</ref> Tactile communication occurs through touch, [[vibrational communication|vibration]], stroking, rubbing, and pressure. It is especially relevant for parent-young relations, courtship, social greetings, and defense. Olfactory and gustatory communication happen chemically through smells and tastes, respectively.<ref>{{multiref | {{harvnb|Ruben|2002|p=26}} | {{harvnb|Chandler|Munday|2011|p=15}} }}</ref>

There are large differences between species concerning what functions communication plays, how much it is realized, and the behavior used to communicate.<ref>{{harvnb|Håkansson|Westander|2013|p=2}}</ref> Common functions include the fields of [[courtship]] and mating, parent-offspring relations, social relations, navigation, self-defense, and [[territoriality]].<ref>{{harvnb|Ruben|2002|pp=26–29}}</ref> One part of courtship and mating consists in identifying and attracting potential mates. This can happen through various means. [[Grasshoppers]] and [[crickets]] communicate acoustically by using songs, [[moths]] rely on chemical means by releasing [[pheromones]], and fireflies send visual messages by flashing light.<ref>{{multiref | {{harvnb|Ruben|2002|pp=26–27}} | {{harvnb|Håkansson|Westander|2013|p=2}} }}</ref> For some species, the offspring depends on the parent for its survival. One central function of parent-offspring communication is to recognize each other. In some cases, the parents are also able to guide the offspring's behavior.<ref>{{multiref | {{harvnb|Ruben|2002|p=27}} | {{harvnb|Håkansson|Westander|2013|pp=19–20}} }}</ref>

[[Social animal]]s, like [[chimpanzees]], [[bonobos]], wolves, and dogs, engage in various forms of communication to express their feelings and build relations.<ref>{{harvnb|Håkansson|Westander|2013|p=3}}</ref> Communication can aid navigation by helping animals move through their environment in a purposeful way, e.g. to locate food, avoid enemies, and follow other animals. In [[bats]], this happens through [[Animal echolocation|echolocation]], i.e. by sending auditory signals and processing the information from the echoes. [[Bees]] are another often-discussed case in this respect since they perform a type of [[Waggle dance|dance]] to indicate to other bees where flowers are located.<ref>{{harvnb|Ruben|2002|pp=27–28}}</ref> In regard to self-defense, communication is used to warn others and to assess whether a costly fight can be avoided.<ref>{{multiref | {{harvnb|Ruben|2002|p=28}} | {{harvnb|Schenk|Seabloom|2010|p=5}} }}</ref> Another function of communication is to mark and claim territories used for food and mating. For example, some male birds claim a hedge or part of a meadow by using [[Bird song|songs]] to keep other males away and attract females.<ref>{{harvnb|Ruben|2002|pp=28–29}}</ref>

Two competing theories in the study of animal communication are [[Nature versus nurture|nature theory and nurture theory]]. Their conflict concerns to what extent animal communication is programmed into the genes as a form of adaptation rather than learned from previous experience as a form of [[Classical conditioning|conditioning]].<ref>{{multiref | {{harvnb|Danesi|2000|pp=58–59}} | {{harvnb|Håkansson|Westander|2013|p=7}} }}</ref> To the degree that it is learned, it usually happens through [[Imprinting (psychology)|imprinting]], i.e. as a form of learning that only occurs in a certain phase and is then mostly irreversible.<ref>{{harvnb|Håkansson|Westander|2013|pp=14–15}}</ref>

===Plants, fungi, and bacteria===
[[Plant communication]] refers to plant processes involving the sending and receiving of information.<ref>{{harvnb|Karban|2015|pp=4–5}}</ref> The field studying plant communication is called [[phytosemiotics]].<ref>{{harvnb|Sebeok|1991|p=[https://books.google.com/books?id=Moc8XzWbT-QC&pg=PA111 111]}}</ref> This field poses additional difficulties for researchers since plants are different from humans and other animals in that they lack a [[central nervous system]] and have [[Cell wall#Plant cell walls|rigid cell walls]].<ref>{{multiref | {{harvnb|Karban|2015|pp=1–4}} | {{harvnb|Schenk|Seabloom|2010|pp=2, 7}} | {{harvnb|Blatrix|Mayer|2010|p=128}} }}</ref> These walls restrict movement and usually prevent plants from sending and receiving signals that depend on rapid movement.<ref>{{harvnb|Schenk|Seabloom|2010|p=6}}</ref> However, there are some similarities since plants face many of the same challenges as animals. For example, they need to find resources, avoid predators and [[pathogen]]s, find mates, and ensure that their offspring survive.<ref>{{harvnb|Karban|2015|pp=1–2}}</ref> Many of the evolutionary responses to these challenges are analogous to those in animals but are implemented using different means.<ref>{{harvnb|Karban|2015|p=2}}</ref> One crucial difference is that [[chemical communication]] is much more prominent in the plant kingdom in contrast to the importance of visual and auditory communication for animals.<ref>{{multiref | {{harvnb|Schenk|Seabloom|2010|p=7}} | {{harvnb|Blatrix|Mayer|2010|p=128}} }}</ref>

[[File:Stages of plant communication.svg|thumb|upright=1.5|alt=Diagram of the steps of plant communication: a cue is first emitted and later received, leading to a response|Steps of plant communication]]
In plants, the term ''behavior'' is usually not defined in terms of physical movement, as is the case for animals, but as a biochemical response to a [[Stimulus (physiology)|stimulus]]. This response has to be short relative to the plant's lifespan. Communication is a special form of behavior that involves conveying information from a sender to a receiver. It is distinguished from other types of behavior, like defensive reactions and mere sensing.<ref>{{harvnb|Karban|2015|pp=2–4}}</ref> Like in the field of animal communication, plant communication researchers often require as additional criteria that there is some form of response in the receiver and that the communicative behavior is beneficial to sender and receiver.<ref>{{multiref | {{harvnb|Karban|2015|p=5}} | {{harvnb|Schenk|Seabloom|2010|p=1}} | {{harvnb|Blatrix|Mayer|2010|p=128}} }}</ref> Biologist Richard Karban distinguishes three steps of plant communication: the emission of a cue by a sender, the perception of the cue by a receiver, and the receiver's response.<ref>{{harvnb|Karban|2015|p=7}}</ref> For plant communication, it is not relevant to what extent the emission of a cue is intentional. However, it should be possible for the receiver to ignore the signal. This criterion can be used to distinguish a response to a signal from a defense mechanism against an unwanted change like intense heat.<ref>{{harvnb|Karban|2015|p=45}}</ref>

Plant communication happens in various forms. It includes communication within plants, i.e. within [[plant cells]] and between plant cells, between plants of the same or related species, and between plants and non-plant organisms, especially in the [[rhizosphere|root zone]].<ref>{{harvnb|Baluska|Volkmann|Hlavacka|Mancuso|2006|loc=[https://books.google.com/books?id=IH9N4SKWTokC&pg=PA19 2. Neurobiological View of Plants and Their Body Plan]}}</ref> A prominent form of communication is airborne and happens through [[volatile organic compound]]s (VOCs). For example, [[maple]] trees release VOCs when they are attacked by a [[herbivore]] to warn neighboring plants, which then react accordingly by adjusting their defenses.<ref>{{multiref | {{harvnb|Arimura|Pearse|2017|pp=4–5}} | {{harvnb|Schenk|Seabloom|2010|p=1}} | {{harvnb|Baldwin|Schultz|1983|pp=277–279}} }}</ref> Another form of plant-to-plant communication happens through [[mycorrhizal fungi]]. These fungi form underground networks, colloquially referred to as the [[Wood-Wide Web]], and connect the roots of different plants. The plants use the network to send messages to each other, specifically to warn other plants of a pest attack and to help prepare their defenses.<ref>{{harvnb|Gilbert|Johnson|2017|pp=84, 94}}</ref>

Communication can also be observed for fungi and bacteria. Some fungal species communicate by releasing [[pheromone]]s into the external environment. For instance, they are used to promote sexual interaction in several aquatic fungal species.<ref>{{multiref | {{harvnb|O'Day|2012|pp=[https://books.google.com/books?id=kNB4u65WK6MC 8–9]|loc=1. Modes of cellular communication and sexual interactions in eukaryotic microbes}} | {{harvnb|Davey|1992|pp=951–960}} | {{harvnb|Akada|Minomi|Kai|Yamashita|1989|pp=3491–3498}} }}</ref> One form of communication between bacteria is called [[quorum sensing]]. It happens by releasing [[hormone]]-like molecules, which other bacteria detect and respond to. This process is used to monitor the environment for other bacteria and to coordinate population-wide responses, for example, by sensing the density of bacteria and regulating [[gene expression]] accordingly. Other possible responses include the induction of [[bioluminescence]] and the formation of [[biofilm]]s.<ref>{{multiref | {{harvnb|Waters|Bassler|2005|pp=319–320}} | {{harvnb|Demuth|Lamont|2006|p=xiii}} | {{harvnb|Berea|2017|p=59}} }}</ref>

=== Interspecies ===
{{main|Interspecies communication}}
Most communication happens between members within a species as intraspecies communication. This is because the purpose of communication is usually some form of cooperation. Cooperation happens mostly within a species while different species are often in conflict with each other by competing over resources.<ref>{{harvnb|Berea|2017|p=56}}</ref> However, there are also some forms of interspecies communication.<ref>{{multiref | {{harvnb|Danesi|2013|pp=167–168}} | {{harvnb|Berea|2017|p=56}} }}</ref> This occurs especially for [[symbiotic]] relations and significantly less for [[parasitic]] or predator-prey relations.<ref>{{multiref | {{harvnb|Blatrix|Mayer|2010|p=129}} | {{harvnb|Berea|2017|p=61}} }}</ref>

[[File:A honey bee on the Cosmos bipinnatus flower 2.jpg|thumb|alt=Photo of a honey bee on a flower|A honeybee on a [[Cosmos bipinnatus|''Cosmos bipinnatus'']]. Many flowers use vivid colors to signal to insects that they offer food like nectar.]]
Interspecies communication plays a key role for plants that depend on external agents for reproduction.<ref>{{harvnb|Karban|2015|p=109}}</ref> For example, flowers need insects for [[pollination]] and provide resources like [[nectar]] and other rewards in return.<ref>{{harvnb|Karban|2015|p=110}}</ref> They use communication to signal their benefits and attract visitors by using distinctive colors and symmetrical shapes to stand out from their surroundings.<ref>{{multiref | {{harvnb|Karban|2015|pp=110–112, 128}} | {{harvnb|Ketcham|2020|p=[https://books.google.com/books?id=IXznDwAAQBAJ&pg=PA100 100]}} }}</ref> This form of advertisement is necessary since flowers compete with each other for visitors.<ref>{{harvnb|Karban|2015|p=111}}</ref> Many fruit-bearing plants rely on plant-to-animal communication to disperse their seeds and move them to a favorable location.<ref>{{harvnb|Karban|2015|p=122}}</ref> This happens by providing nutritious fruits to animals. The seeds are eaten together with the fruit and are later excreted at a different location.<ref>{{harvnb|Karban|2015|pp=122–124}}</ref> Communication makes animals aware of where the fruits are and whether they are ripe. For many fruits, this happens through their color: they have an inconspicuous green color until they ripen and take on a new color that stands in visual contrast to the environment.<ref>{{harvnb|Karban|2015|pp=125–126, 128}}</ref> Another example of interspecies communication is found in the ant-plant relation.<ref>{{multiref | {{harvnb|Blatrix|Mayer|2010|p=129}} | {{harvnb|Berea|2017|p=56}} }}</ref> It concerns, for instance, the selection of seeds by [[ant]]s for their [[ant garden]]s and the pruning of exogenous vegetation as well as plant protection by ants.<ref>{{harvnb|Blatrix|Mayer|2010|p=127}}</ref>

Some animal species also engage in interspecies communication, like apes, whales, dolphins, elephants, and dogs.<ref>{{harvnb|Berea|2017|pp=56–57}}</ref> For example, different species of monkeys use common signals to cooperate when threatened by a common predator.<ref>{{harvnb|Berea|2017|p=61}}</ref> Humans engage in interspecies communication when interacting with [[pet]]s and [[working animals]].<ref>{{multiref | {{harvnb|Håkansson|Westander|2013|p=157}} | {{harvnb|Berea|2017|p=59}} | {{harvnb|Novak|Day|2018|pp=[https://books.google.com/books?id=bsBYDwAAQBAJ&pg=PA202 202–203]}} }}</ref> For instance, acoustic signals play a central role in [[dog communication|communication with dogs]]. Dogs can learn to react to various commands, like "sit" and "come". They can even be trained to respond to short syntactic combinations, like "bring X" or "put X in a box". They also react to the pitch and frequency of the human voice to detect emotions, dominance, and uncertainty. Dogs use a range of behavioral patterns to convey their emotions to humans, for example, in regard to aggressiveness, fearfulness, and playfulness.<ref>{{multiref | {{harvnb|Håkansson|Westander|2013|pp=157–158}} | {{harvnb|Coren|2012|p=[https://books.google.com/books?id=Yzb3K3PykREC&pg=PT42 42]}} }}</ref>