Charisma is a trait found in persons whose are characterized by a personal charm and magnetism, along with innate and powerfully sophisticated abilities of interpersonal communication. One who is charismatic is said to be capable of using their personal being to interface with other human beings in a direct manner to effectively communicate.

The term was introduced in scholarly usage by German sociologist Max Weber as charismatic authority. He defined it as one of three forms of authority, the other two being traditional authority and rational authority. According to Weber, charisma is defined as a certain quality of an individual personality, by virtue of which one is set apart from ordinary people and endowed with specifically exceptional powers or qualities.

Charisma almost always evolves in the context of boundaries set by traditional or rational authority, but by its nature tends to challenge this authority and is thus often seen as revolutionary. However, the constant challenge that charismatic authority presents to a particular society will eventually subside as it is incorporated into that society. The way in which this happens is called routinization.

Routinization is the process by which charismatic authority is succeeded by a bureaucracy controlled rationally established authority or by a combination of traditional and bureaucratic authority. For example, Muhammad, who had charismatic authority as The Prophet among his followers, was succeeded by the traditional authority and structure of Islam, a clear example of routinization.

Some leaders may employ various tools to create and extend their charismatic authority by utilizing the science of public relations, for example. As in the example of Christianity, a religion which evolves its own priesthood and establishes a set of laws and rules is likely to lose its charismatic character and move towards another type of authority upon the removal of that leader.


Comfort noise is artificial background noise used in radio and wireless communications to fill the silence in a transmission resulting from voice activity detection or from the audio clarity of modern digital lines.

Some modern telephone systems such as wireless and VoIP use voice activity detection, a form of squelching where low volume levels are ignored by the transmitting device. In digital audio transmissions, this saves bandwidth of the communications channel by transmitting nothing when the source volume is under a certain threshold, leaving only louder sounds such as a speaker’s voice to be sent. However, improvements in background noise reduction technologies can occasionally result in the complete removal of all noise.

The result of receiving total silence, especially for a prolonged period, has a number of unwanted effects on the listener, including the following:

  • The listener may believe that the transmission has been lost, and therefore hang up prematurely.
  • The speech may sound choppy and difficult to understand.
  • The sudden change in sound level can be jarring to the listener.

To counteract these effects, comfort noise is added, usually on the receiving end in wireless or VoIP systems, to fill in the silent portions of transmissions with artificial noise. The noise generated is at a low but audible volume level, and can vary based on the average volume level of received signals to minimize jarring transitions.

In modern VoIP products, users may control whether they want comfort noise enabled or disabled. During the siege of Leningrad in 1942, the beat of a metronome was used as comfort noise on the Leningrad radio network, indicating that the network was still functioning.


A whistled language is a system of whistled communication which allows fluent whistlers to transmit and comprehend a potentially unlimited number of messages over long distances. Whistled languages are different in this respect from the restricted codes sometimes used by herders or animal trainers to transmit simple messages or instructions. Generally, whistled languages emulate the tones or vowel formants of a natural spoken language, as well as aspects of its intonation and prosody, so that trained listeners who speak that language can understand the encoded message.

Whistled languages are normally found in locations with difficult mountainous terrain, slow or difficult communication, low population density and/or scattered settlements, and other isolating features such as shepherding and cultivation of hillsides. Thery have been more recently found in dense forests like the Amazon where they may replace spoken dialogues in the villages, while hunting or fishing to overcome the pressure of the acoustic environment.

The main advantage of whistling speech is that it allows the speaker to cover much larger distances than ordinary speech, without the strain (and lesser range) of shouting. The long range of whistling is enhanced by the mountainous terrain found in areas where whistled languages are used. Many areas with such languages work hard to preserve their ancient traditions, in the face of rapidly advancing telecommunications systems in many areas.

Whistled speech may be very central and highly valued in a culture. Shouting is very rare in Sochiapam, Oaxaca. Men in that culture are subject to being fined if they do not handle whistle-speech well enough to perform certain town jobs. They may whistle for fun in situations where spoken speech could easily be heard.

In Sochiapam, Oaxaca, and other places in Mexico, and reportedly in West Africa as well, whistled speech is men’s language: although women may understand it, they do not use it. Though whistled languages are not secret codes or secret languages, they may be used for secretive communication among outsiders or others who do not know or understand the whistled language though they may understand its spoken origin.


Idioglossia refers to an idiosyncratic language, one invented and spoken by only one or a very few people. Most often, idioglossia refers to the “private languages” of young children, especially twins. It is also known as cryptophasia, and commonly referred to as twin talk or twin speech. Children who are exposed to multiple languages from birth are inclined to create idioglossias, but these languages usually disappear at a relatively early age.

Poto and Cabengo are a pair of identical twin girls (real names Grace and Virginia Kennedy, respectively), who used a secret language up to the age of about 8. Poto and Cabengo is also the name of a documentary film about the girls made by Jean-Pierre Gorin and released in 1979.

They were apparently of normal intelligence and developed their own communication because they had little exposure to spoken language in their early years. They were left in the care of a grandmother, who met their physical needs but did not play or interact with them. The grandmother spoke only German, while the parents spoke English. They had no contact with other children, seldom played outdoors, and were not sent to school.

Their father later stated in interviews that he realized the girls had invented a language of their own, but since their use of English remained extremely rudimentary, he had decided that they were in fact retarded and that it would do no good to send them to school. When he lost his job, he told a caseworker at the unemployment office about his family, and the caseworker advised him to put the girls in speech therapy. At Children’s Hospital of San Diego, speech therapist Alexa Kratze quickly discovered that Virginia and Grace, far from being retarded, had at least normal intelligence, and had invented a complex idioglossia.

Their language was spoken extremely quickly and had a staccato rhythm. These characteristics transferred themselves to the girls’ English, which they began to speak following speech therapy. Linguistic analysis of their language revealed that it was a mixture of English and German with some neologisms and several idiosyncratic grammatical features.

Many speech and hearing experts, as well as psychiatrists, offered speculation as to why the girls had not picked up English, as most idioglossic twins do as they go along whether or not they retain their personal language. Kratze pointed out that the girls had had very little contact with anyone outside their family, and that contact within the family had been minimal at best. These factors contributed to the girls’ developmental disability, even if they had been born with normal intelligence.

Once it was established that the girls could be educated, their father apparently forbade them to speak their personal language. He was quoted in Time magazine as saying “They don’t want to be associated as dummies. You live in a society, you got to speak the language.” Asked if they remembered their language, the girls confirmed that they did, but their father quickly stepped in to chide them for “lying”. They were mainstreamed and placed in separate classes in elementary school. However, they were still affected by their family’s emotional neglect.


Guy Warren Ballard was an American mining engineer who became, with his wife Edna Anne, the founder of the I AM Activity. Ballard visited Mt. Shasta, California in 1930, where he met another hiker who identified himself as Saint Germain. Mr. Ballard’s experiences take place within the larger North American mountain ranges. Guy Ballard, his wife Edna, and later his son Donald became the sole Accredited Messengers of Saint Germain. Their teachings form the original nucleus for what are today called the Ascended Master Teachings.

The doctrine of the I AM Activity has its roots in theosophy. Its teachings were not new, but the publicity the Ballards achieved spread their teachings into the developing New Age movements in the United States. Many New Age movements now involve the Ascended Master Teachings.

The movement believes in the existence of a group called the Ascended Masters, a hierarchy of supernatural beings that includes Saint Germain, Jesus, Gautama Buddha, Maitreya, and thousands more. These are believed to be humans who have lived in physical bodies, become immortal, and attained their ascension. The Ascended Masters are believed to communicate to humanity through certain humans, including Guy and Edna Ballard. Because Jesus is believed to be one of the Ascended Masters, making the Christ Light available to seekers who wish to move out of darkness, many of the members of the I AM Activity consider it to be a Christian religion.

The movement teaches that the omnipotent, omniscient and omnipresent creator God is in all of us as a spark from the Divine Flame, and that we can experience this presence, love, power and light through quiet contemplation and by repeating affirmations and decrees. By affirming something one desires, one can cause it to happen.

According to Los Angeles Magazine article, in August 1935, the Ballards hosted a gathering at the Shrine Auditorium in Los Angeles that drew a crowd of 6,000. Guy Ballard spoke under the pseudonym he used in authoring his books, Godfre Ray King, and his wife used the pseudonym Lotus. Their meetings included teachings they described as being received directly from the Ascended Masters. They led the audiences in prayers and affirmations including adorations to God and invocations for abundance of every good thing, including love, money, peace, and happiness.

The Ballards founded a publishing house, Saint Germain Press, to publish their books and began training people to spread their messages across the United States. Meetings became limited to members after hecklers began disrupting their open meetings. Over their lifetimes, the Ballards recorded nearly 4,000 messages which they said were from the Ascended Masters. Guy Ballard, his wife Edna, and later his son Donald became the sole Accredited Messengers of the Ascended Masters.

Ballard died in 1939. In 1942 his wife and son were convicted of fraud after a government audit found that they had stored up $3 million from donations and what it called a retail racket by false statements of their religious experiences which had not in fact occurred, based on their claims of miraculous communication with the spirit world and supernatural power to heal the sick. A landmark Supreme Court decision overturned the conviction, ruling that the question of whether the Ballards believed their religious claims should not have been submitted to a jury.


Culture industry is a term coined by Theodor Adorno and Max Horkheimer, who argued that popular culture is akin to a factory producing standardized cultural goods to manipulate the masses into passivity; the easy pleasures available through consumption of popular culture make people docile and content, no matter how difficult their economic circumstances. Adorno and Horkheimer saw this mass-produced culture as a danger to the more difficult high arts. Culture industries may cultivate false needs; that is, needs created and satisfied by capitalism. True needs, in contrast, are freedom, creativity, or genuine happiness.

Adorno and Horkheimer were key members of the Frankfurt School. They were much influenced by the dialectical materialism and historical materialism of Karl Marx, as well the revisitation of the dialectical idealism of Hegel, in both of which where events are studied not in isolation but as part of the process of change. As a group later joined by Jurgen Habermas, they were responsible for the formulation of Critical Theory.

In works such as Dialectic of Enlightenment and Negative Dialectics, Adorno and Horkheimer theorised that the phenomenon of mass culture has a political implication, namely that all the many forms of popular culture are a single culture industry whose purpose is to ensure the continued obedience of the masses to market interests. In The Dialectic of Enlightenment, they postulated a modern form of bread and circuses, the method used by the rulers of Ancient Rome to maintain their power and control over the people. This new system filled leisure time with amusements to distract the consumers from the boredom of their increasingly automated work. They were never left alone long enough to recognise the reality of their exploitation and to consider resisting the economic and social system. This pessimistic view of prevailing culture as an anti-enlightenment opiate for the masses draws strongly on Marxism for its condemnation of what is characterised as being continuing capitalist oppression.

Although Western culture used to be divided into national markets and then into highbrow, middlebrow and lowbrow, the modern view of mass culture is that there is a single marketplace in which the best or most popular works succeed. This recognizes that the consolidation of media companies has centralized power in the hands of the few remaining multinational corporations now controlling production and distribution. The theory proposes that culture not only mirrors society, but also takes an important role in shaping society through the processes of standardization and commodification, creating objects rather than subjects. The culture industry claims to serve the consumers’ needs for entertainment, but conceals the way that it standardizes these needs, manipulating the consumers to desire what it produces.

The outcome is that mass production feeds a mass market that minimizes the identity and tastes of the individual consumers who are as interchangeable as the products they consume. The rationale of the theory is to promote the emancipation of the consumer from the tyranny of the producers by inducing the consumer to question beliefs and ideologies. Adorno claimed that enlightenment would bring pluralism and demystification. Unfortunately, society is said to have suffered another fall, corrupted by capitalist industry with exploitative motives.

Anything made by a person is a materialisation of their labour and an expression of their intentions. There will also be a use value: the benefit to the consumer will be derived from its utility. The exchange value will reflect its utility and the conditions of the market: the prices paid by the television broadcaster or at the box office. Yet, the modern soap operas with their interchangeable plots and formulaic narrative conventions reflect standardised production techniques and the falling value of a mass produced cultural product. Only rarely is a film released that makes a more positive impression on the general discourse and achieves a higher exchange value.

Critics of the theory say that the products of mass culture would not be popular if people did not enjoy them, and that culture is self-determining in its administration. This would deny Adorno contemporary political significance, arguing that politics in a prosperous society is more concerned with action than with thought. Adorno is also accused of a lack of consistency in his claims to be implementing Marxism. Whereas he accepted the classical Marxist analysis of society showing how one class exercises domination over another, he deviated from Marx in his failure to use dialectic as a method to propose ways to change.

Marx’s theory depended on the willingness of the working class to overthrow the ruling class, but Adorno and Horkheimer postulated that the culture industry has undermined the revolutionary movement. Adorno’s idea that the mass of the people are only objects of the culture industry is linked to his feeling that the time when the working class could be the tool of overthrowing capitalism is over.

However, despite these problems, the concept has influenced intellectual discourse on popular culture, popular culture studies, and Cultural Institutions Studies.


Memory is the brains’s ability to store, retain, and subsequently retrieve information. Traditional studies of memory began in the realms of philosophy, including techniques of artificially enhancing the memory. The late nineteenth and early twentieth century put memory within the paradigms of cognitive psychology. In recent decades, it has become one of the principal pillars of a branch of science called cognitive neuroscience, an interdisciplinary link between cognitive psychology and neuroscience.

Sensory memory corresponds approximately to the initial period after an item is perceived. The ability to look at an item and remember what it looked like with just a second of observation is an example of sensory memory. With very short presentations, participants often report that they seem to observe more than they can actually report. In early experiments, subjects were presented with a grid of letters arranged into three rows. After a the brief presentation, subjects were then played a tone, cuing them for which of the rows to report. Based on these experiments, it was shown that the capacity of sensory memory was approximately 12 items, but that it degraded within a few hundred milliseconds. Because this form of memory degrades so quickly, participants would see the display but be unable to report all of the items. This type of memory cannot be prolonged via rehearsal.

Short term memory is believed to rely mostly on an acoustic code for storing information, and to a lesser extent a visual code. I has been found that test subjects have more difficulty recalling collections of words that are acoustically similar, such as dog, hog, fog, bog, log, etc. However, short term memory has been an unexplainable phenomenon with certain individuals gifted to remember large amounts of information quickly, and to be able to recall that information in seconds.

Long term memory can store much larger quantities of information for potentially unlimited duration, sometimes a whole life span. For example, given a random seven digit number, we may remember it for only a few seconds before forgetting, suggesting it was stored in our short term memory. On the other hand, we can remember telephone numbers for many years through repetition. This information is said to be stored in long term memory. While short term memory encodes information acoustically, long term memory encodes it semantically. It has been discovered that after 20 minutes, test subjects had the least difficulty recalling a collection of words that had similar meanings such as big, large, great, huge, etc.

Short term memory is supported by patterns of brain communication, dependent on regions of the frontal lobe. Long term memories are maintained by more stable and permanent changes in neural connections widely spread throughout the brain. The hippocampus is essential to the consolidation of information from short term to long term memory, although it does not seem to store information itself. Rather, it may be involved in changing neural connections for a period of three months or more after the initial learning.

One of the primary functions of sleep is improving consolidation of information, as it can be shown that memory depends on getting sufficient sleep between training and test, and that the hippocampus replays activity from the current day while sleeping.

The best way to improve memory seems to be to increase the supply of oxygen to the brain, which may be accomplished with exercise. Walking for three hours each week suffices, as does swimming or bicycle riding. One study found that frequent eating, such as five small meals a day, promotes a healthy memory by preventing dips in blood glucose, the primary energy source for the brain.


Radio frequency is the frequency or rate of oscillation within a range of about 3 cycles per second to 300 billion cycles per second. This range corresponds to the frequency of alternating current electrical signals used to produce and detect radio waves. Since most of this range is beyond the vibration rate that most mechanical systems can respond to, radio frequency usually refers to oscillations in electrical circuits or electromagnetic transmission.

Electromagnetic waves occur in the radio frequency portion of the electromagnetic spectrum. A common use is to transport information through the atmosphere or outer space without wires. Radio waves are distinguished from other kinds of electromagnetic waves by their wavelength, a relatively long wavelength in the electromagnetic spectrum.

Radio waves were first predicted by mathematical work done in 1865 by James Clerk Maxwell. Maxwell noticed wave like properties of light and similarities in electrical and magnetic observations and proposed equations that described light waves and radio waves as waves of electromagnetism that travel in space. In 1887 Heinrich Hertz demonstrated the reality of Maxwell’s electromagnetic waves by experimentally generating radio waves in his laboratory. Many inventions followed, making practical use of radio waves to transfer information through space.

The transmission of radio waves is affected by many variables. Atmospheric moisture, the stream of particles from the sun called solar wind, and time of day will all have an effect on the signal. All radio waves are partially absorbed by atmospheric moisture. Atmospheric absorption reduces the strength of radio signals over long distances.

Ultra high frequency signals of 30 to 300 million cycles per second are used for radio and television broadcasting. They are generally more degraded by moisture than lower bands of transmission. The layer of the Earth’s atmosphere called the ionosphere is filled with charged particles that can reflect radio waves. The reflection of radio waves can be helpful in transmitting a radio signal over long distances as the wave repeatedly bounces from the sky to the ground.

Microwaves are electromagnetic waves with wavelengths ranging from 300 to 3000 million cycles per second, and are used for cell phone transmissions. Microwaves contain insufficient energy to chemically change substances by ionization and so are an example of nonionizing radiation. Due to this fact, it has not yet conclusively been shown that microwaves have any biological effects.

During World War II, it was observed that individuals in the radiation path of microwave radar installations observed clicks and buzzing sounds in response to the transmissions. It was through this observation that it became known that microwaves could cause the perception of sounds in the human brain by inducing an electric current in the body’s hearing centers.

Research by NASA in the 1970s showed that this effect occurs as a result of thermal expansion of parts of the human ear around the cochlea, even at low power density. Later, signal modulation was found to produce sounds or words that appeared to originate intracranially. It was studied for its possible use in communications but has not been developed due to the possible hazardous biological effects of microwave radiation.

The first American to publish on microwave effects was Allan H. Frey, in 1961. In his experiments, the subjects were discovered to be able to hear appropriately pulsed microwave radiation from a distance of over 300 feet from the transmitter. This was accompanied by side effects such as dizziness, headaches, and a pins and needles sensation.

Extremely low frequency 3–300 Hz Power grids, communication with submarines
Ultra low frequency 300–3000 Hz Communication within mines
Very low frequency 3–30 kHz Submarines, avalanche beacons, heart rate monitors, geophysics
Low frequency 30–300 kHz Navigation, time signals, AM longwave broadcasts
Medium frequency 300–3000 kHz AM broadcasts
High frequency 3–30 MHz Shortwave broadcasts, amateur radio and aviation communications
Very high frequency 30–300 MHz FM, television broadcasts, aircraft communications
Ultra high frequency 300–3000 MHz Television, microwave ovens, cell phones, LAN, Bluetooth, GPS
Super high frequency 3–30 GHz Microwave devices, wireless LAN, most modern Radars
Extremely high frequency 30–300 GHz Radio astronomy, high-speed microwave radio relay


The term mediumship denotes the ability of a person (the medium) to apparently experience contact with spirits. The medium generally attempts to facilitate communication between people and spirits who may have messages to share.

A medium may appear to listen to and relate conversations with spirit voices, go into a trance and speak without knowledge of what is being said, allow a spirit to enter their body and speak through it, and relay messages from the spirits those who wish to contact them with the help of a physical tool, such as a writing implement.

Mediumship is also part of the belief system of some New Age groups. In this context, and under the name channeling, it refers to a medium who receive messages from a teaching spirit.

Channeling became quite popular in the United States after the rise of Spiritualism as a religious movement. Modern Spiritualism is said to date to the mediumistic activities of the Fox sisters in New York state during 1848. The trance mediums Paschal Beverly Randolph and Emma Hardinge Britten were among the most celebrated lecturers and authors on the subject in the mid 1800s. Mediumship was also described by Allan Kardec, who coined the term Spiritism, around 1860.

After the exposure of the fraudulent use of stage magic tricks by mediums such as the Davenport Brothers, mediumship fell into disrepute, although it never ceased being used by people who believed that the dead can be contacted.

From the 1930s through the 1990s, as psychical mediumship became less practiced in Spiritualist churches, the technique of channeling gained in popularity, and books by channellers who related the wisdom of non corporeal and non terrestrial teacher spirits became best sellers amongst believers.

For some mediums, a spirit guide is a highly evolved spirit with the sole purpose of helping the medium develop and use their skills. They assist mediums in following their spiritual path. For other mediums, a spirit guide is one who brings other spirits to a medium’s attention or carries communications between a medium and the spirits of the dead.

Many mediums claim to have specific guides who regularly work with them and bring in spirits. Some mediums believe that spirits will communicate with them directly without the use of a spirit guide.

In old line Spiritualism, a portion of the service, generally toward the end, is given over to the pastor or another medium who receives messages from the spirit world for the congregants. This may be referred to as a demonstration of mediumship. Today, demonstration of mediumship is part of the church service at all churches affiliated with the National Spiritualist Association of Churches.

Some mediums remain conscious during this communication period, while others go into a trance where a spirit uses the medium’s body to communicate. Trance mediumship is defined as a spirit taking over the body of the medium, sometimes to such a degree that the medium is unconscious.

In the 1860s and 1870s, trance mediums were very popular. Spiritualism had attracted adherents who had strong interests in social justice, and many trance mediums delivered passionate speeches on abolitionism, temperance, and women’s suffrage.

Because the typical trance medium has no clear memory of the messages conveyed while in a trance, a medium of this type generally works with an assistant who writes down or otherwise records his or her words.

There are two main techniques mediumship developed in the latter half of the 20th century. One type involves psychics or sensitives who can speak to spirits and then relay what they hear to their clients. One of the most noted channels of this type is clairvoyant Danielle Egnew, known for her communication with angelic entities.

The other incarnation of non physical mediumship is a form of channeling in which the channeler goes into a trance, or leaves their body and then becomes possessed by a specific spirit, who then talks through them. In the trance, the medium enters a cataleptic state marked by extreme rigidity. The control spirit then takes over, the voice may change completely and the spirit answers the questions of those in its presence or giving spiritual knowledge.

The most successful and widely known channeler of this variety is JZ Knight, who claims to channel the spirit of Ramtha, a 30 thousand year old man. Others claim to channel spirits from future dimensional ascended masters or in the case of the trance mediums of the Brahma Kumaris, God himself. Hossca Harrison is medium for a non physical entity named Jonah. There is video of Jonah taking over Hossca’s body and giving a message on YouTube.

While advocates of mediumship claim that their experiences are genuine, the Encyclopedia Britannica article on spiritualism notes that many Spiritualist mediums were discovered to be engaged in fraud, sometimes employing the techniques of stage magicians in their attempts to convince people of their clairvoyant powers. The article also notes that the exposure of widespread fraud within the spiritualist movement severely damaged its reputation and pushed it to the fringes of society in the United States.

Skeptics include atheists, agnostics who do not believe in the existence of spirits, and those who do not think contact with spirits through mediums is possible. Some skeptics say the phenomena of mediumship are the result of self delusion, unconscious influence, or magician’s techniques such as cold reading, hot reading, and conjuring.


Ants are social insects that evolved from ancestors in the Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. Today, more than 12,000 species are classified with upper estimates of about 14,000 species.

Ants form colonies that range in size from a few tens of predatory individuals living in small natural cavities to highly organized colonies which may occupy large territories and consist of millions of individuals that are mostly sterile females forming castes of workers, soldiers, or other specialised groups. The colonies are sometimes described as superorganisms because ants appear to operate as a unified entity, collectively working together to support the colony.

Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study. Many human cultures make use of ants in cuisine, medication, and rituals. Some species are valued in their role as biological pest control agents. However, their ability to exploit resources brings ants into conflict with humans as they can damage crops and invade buildings. Some species, such as the red fire ant, are regarded as invasive species, since they can spread rapidly into new areas.

Ants communicate with each other using pheromones. These chemical signals are more developed in ants than in other insect groups. They perceive smells with their long, thin and mobile antennae. The paired antennae provide information about the direction and intensity of scents. Since most ants live on the ground, they use the soil surface to leave pheromone trails that can be followed by other ants.

In species that forage in groups, a forager that finds food marks a trail on the way back to the colony. This trail is followed by other ants, and these ants then reinforce the trail when they head back with food to the colony. When the food source is exhausted, no new trails are marked by returning ants and the scent slowly dissipates. This behaviour helps ants deal with changes in their environment. For instance, when an established path to a food source is blocked by an obstacle, the foragers leave the path to explore new routes. If an ant is successful, it leaves a new trail marking the shortest route on its return. Successful trails are followed by more ants, reinforcing better routes and gradually finding the best path. But ants use pheromones for more than just making trails. A crushed ant emits an alarm pheromone that sends nearby ants into an attack frenzy and attracts more ants from further away. Several ant species even use propaganda pheromones to confuse enemy ants and make them fight among themselves.

Pheromones are also exchanged mixed with food and passed among members of the community, transferring information within the colony. This allows other ants to detect what task group other colony members belong to. In ant species with queen castes, workers begin to raise new queens in the colony when the dominant queen stops producing a specific pheromone.

Many animals can learn behaviours by imitation but ants may be the only group apart from mammals where interactive teaching has been observed. One species of ant leads a nest mate to newly discovered food by the excruciatingly slow process of tandem running. The follower obtains knowledge through its leading tutor. Both leader and follower are acutely sensitive to the progress of their partner with the leader slowing down when the follower lags, and speeding up when the follower gets too close. Controlled experiments with some colonies suggest that individuals may choose nest roles based on their previous experience.

An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. One group was continually rewarded with prey, while it was made certain that the other failed. As a result, members of the successful group intensified their foraging attempts while the unsuccessful group ventured out less and less. A month later, the successful foragers continued in their role while the others moved to specialise in brood care.

Ants perform many ecological roles that are beneficial to humans, including the suppression of pest populations and aeration of the soil. The use of weaver ants in citrus cultivation in southern China is considered one of the oldest known applications of biological control. On the other hand, ants can become nuisances when they invade buildings or cause economic losses.

In some parts of the world, large ants are used as surgical sutures. The wound is pressed together and ants are applied along it. The ant seizes the edges of the wound in its mandibles and locks in place. The body is then cut off and the head and mandibles remain in place to close the wound. Some ants have toxic venom and are of medical importance.

In South Africa, ants are used to help harvest rooibos, which are small seeds used to make an herbal tea. The plant disperses its seeds widely, making manual collection difficult. Black ants collect and store these and other seeds in their nest, where humans can gather them. Up to half a pound of seeds can be collected from one ant mound.