Theories of the Origin and Evolution of Human Language

Theories of the Origin and Evolution of Human Language The expression language origins refers to theories pertaining to the emergence and development of language in human societies. Over the centuries, many theories have been put forward- and almost all of them have been challenged, discounted, and ridiculed. (See Where Does Language Come From?) In 1866, the Linguistic Society of Paris banned any discussion of the topic: The Society will accept no communication concerning either the origin of language or the creation of a universal language. Contemporary linguist Robbins Burling says that anyone who has read widely in the literature on language origins cannot escape a sneaking sympathy with the Paris linguists. Reams of nonsense have been written about the subject (The Talking Ape, 2005). In recent decades, however, scholars from such diverse fields as genetics, anthropology, and cognitive science have been engaged, as Christine Kenneally says, in a cross-discipline, multidimensional treasure hunt to find out how language began. It is, she says, the hardest problem in science today (The First Word, 2007). Observations on the Origins of Language Divine origin [is the] conjecture that human language originated as a gift from God. No scholar takes this idea seriously today. (R.L. Trask, A Students Dictionary of Language and Linguistics, 1997; rpt. Routledge, 2014) Numerous and varied explanations have been put forth to explain how humans acquired language- many of which date back to the time of the Paris ban. Some of the more fanciful explanations have been given nicknames, mainly to the effect of dismissal by ridicule. The scenario by which language evolved in humans to assist the coordination of working together (as on the pre-historic equivalent of a loading dock) has been nicknamed the yo-heave-ho model. Theres the bow-wow model in which language originated as imitations of animal cries. In the poo-poo model, language started from emotional interjections. During the twentieth century, and particularly its last few decades, discussion of language origins has become respectable and even fashionable. One major problem remains, however; most models about language origins do not readily lend themselves to the formation of testable hypotheses, or rigorous testing of any sort. What data will allow us to conclude that one model or another best explains how language arose? (Norman A. Johnson, Darwinian Detectives: Revealing the Natural History of Genes and Genomes. Oxford University Press, 2007) Physical Adaptations - Instead of looking at types of sounds as the source of human speech, we can look at the types of physical features humans possess, especially those that are distinct from other creatures, which may have been able to support speech production. . . . Human teeth are upright, not slanting outwards like those of apes, and they are roughly even in height. Such characteristics are . . . very helpful in making sounds such as f or v. Human lips have much more intricate muscle lacing than is found in other primates and their resulting flexibility certainly helps in making sounds like p, b, and m. In fact, the b and m sounds are the most widely attested in the vocalizations made by human infants during their first year, no matter which language their parents are using. (George Yule, The Study of Language, 5th ed. Cambridge University Press, 2014) -   In the evolution of the human vocal tract since the split with other apes, the adult larynx descended to its lower position. Phonetician Philip Lieberman has persuasively argued that the ultimate cause of the human lowered larynx is its function in producing different vowels. This is a case of natural selection for more effective communication. . . . Babies are born with their larynxes in a high position, like monkeys. This is functional, as there is a reduced risk of choking, and babies are not yet talking. . . . By about the end of the first year, the human larynx descends to its near-adult lowered position. This is a case of ontogeny recapitulating phylogeny, the growth of the individual reflecting the evolution of the species. (James R. Hurford, The Origins of Language. Oxford University Press, 2014) From Words to Syntax Language-ready modern children learn vocabulary voraciously before they begin to make grammatical utterances several words long. So we presume that in the origins of language a one-word stage preceded our remote ancestors first steps into grammar. The term protolanguage has been widely used to describe this one-word stage, where there is vocabulary but no grammar. (James R. Hurford, The Origins of Language. Oxford University Press, 2014) The Gesture Theory of Language Origin - Speculation about how languages originate and evolve has had an important place in the history of ideas, and it has been intimately linked to questions about the nature of the signed languages of the deaf and human gestural behavior in general. It can be argued, from a phylogenetic perspective, the origin of human sign languages is coincident with the origin of human languages; sign languages, that is, are likely to have been the first true languages. This is not a new perspectiveit is perhaps as old as nonreligious speculation about the way human language may have begun. (David F. Armstrong and Sherman E. Wilcox, The Gestural Origin of Language. Oxford University Press, 2007) - [A]n analysis of the physical structure of visible gesture provides insights into the origins of syntax, perhaps the most difficult question facing students of the origin and evolution of language . . .. It is the origin of syntax that transforms naming into language, by enabling human beings to comment on and think about the relationships between things and events, that is, by enabling them to articulate complex thoughts and, most important, share them with others. . . . We are not the first to suggest a gestural origin of language. [Gordon] Hewes (1973; 1974; 1976) was one of the first modern proponents of a gestural origins theory. [Adam] Kendon (1991: 215) also suggests that the first kind of behaviour that could be said to be functioning in anything like a linguistic fashion would have had to have been gestural. For Kendon, as for most others who consider gestural origins of language, gestures are placed in opposition to speech and vocalization. . . . While we would agree with Kendons strategy of examining the relationships among spoken and signed languages, pantomime, graphic depiction, and other modes of human representation, we are not convinced that placing gesture in opposition to speech leads to a productive framework for understanding the emergence of cognition and language. For us, the answer to the question, If language began as gesture, why did it not stay that way? is that it did. . . . All language, in the words of Ulrich Neisser (1976), is articulatory gesturing. We are not proposing that language began as gesture and became vocal. Language has been and always will be gestural (at least until we evolve a reliable and universal capacity for mental telepathy). (David F. Armstrong, William C. Stokoe, and Sherman E. Wilcox, Gesture and the Nature of Language. Cambridge University Press, 1995) - If, with [Dwight] Whitney, we think of language as a complex of instrumentalities which serve in the expression of thought (as he would sayone might not wish to put it quite like this today), then gesture is part of language. For those of us with an interest in language conceived of in this way, our task must include working out all the intricate ways in which gesture is used in relation to speech and of showing the circumstances in which the organization of each is differentiated from the other as well as the ways in which they overlap. This can only enrich our understanding of how these instrumentalities function. If, on the other hand, we define language in structural terms, thus excluding from consideration most, if not all, of the kinds of gestural usages I have illustrated today, we may be in danger of missing important features of how language, so defined, actually succeeds as an instrument of communication. Such a structural definition is valuable as a matter of convenience , as a way of delimiting a field of concern. On the other hand, from the point of view of a comprehensive theory of how humans do all the things they do by means of utterances, it cannot be sufficient. (Adam Kendon, Language and Gesture: Unity or Duality? Language and Gesture, ed. by David McNeill. Cambridge University Press, 2000) Language as a Device for Bonding [T]he size of human social groups gives rise to a serious problem: grooming is the mechanism that is used to bond social groups among primates, but human groups are so large that it would be impossible to invest enough time in grooming to bond groups of this size effectively. The alternative suggestion, then, is that language evolved as a device for bonding large social groupsin other words, as a form of grooming-at-a-distance. The kind of information that language was designed to carry was not about the physical world, but rather about the social world. Note that the issue here is not the evolution of grammar as such, but the evolution of language. Grammar would have been equally useful whether language evolved to subserve a social or a technological function. (Robin I.A. Dunbar, The Origin and Subsequent Evolution of Language. Language Evolution, ed. by Morten H. Christiansen and Simon Kirby. Oxford University Press, 2003) Otto Jespersen on Language as Play (1922) - [P]rimitive speakers were not reticent and reserved beings, but youthful men and women babbling merrily on, without being so particular about the meaning of each word. . . . They chattered away for the mere pleasure of chattering . . ..   [P]rimitive speech . . . resembles the speech of little baby himself, before he begins to frame his own language after the pattern of the grownups; the language of our remote forefathers was like that ceaseless humming and crooning with which no thoughts are as yet connected, which merely amuses and delights the little one. Language originated as play, and the organs of speech were first trained in this singing sport of idle hours. (Otto Jespersen,Language: Its Nature, Development and Origin, 1922) - It is quite interesting to note that these modern views [on the commonality of language and music and of language and dance] were anticipated in great detail by Jespersen (1922: 392-442). In his speculations about the origin of language, he arrived at the view that referential language must have been preceded by singing, which in its turn was functional in fulfilling the need for sex (or love), on the one hand, and the need for coordinating collective work, on the other. These speculations have, in turn, their origins in [Charles] Darwins 1871 book The Descent of Man: we may conclude from a widely-spread analogy that this power would have been especially exerted during the courtship of the sexes, serving to express various emotions. . . . The imitation by articulate sounds of musical cries might have given rise to words expressive of various complex emotions. (quoted from Howard 1982: 70) The modern scholars mentioned above agree in rejecting the well-known scenario according to which language originated as a system of monosyllabic grunt-like sounds that had the (referential) function of pointing at things. Instead, they propose a scenario according to which referential meaning was slowly grafted upon nearly autonomous melodious sound. (Esa Itkonen, Analogy as Structure and Process: Approaches in Linguistics, Cognitive Psychology and Philosophy of Science. John Benjamins, 2005) Divided Views on the Origins of Language (2016) Today, opinion on the matter of language origins is still deeply divided. On the one hand, there are those who feel that language is so complex, and so deeply ingrained in the human condition, that it must have evolved slowly over immense periods of time. Indeed, some believe that its roots go all the way back to  Homo habilis, a tiny-brained hominid that lived in Africa not far short of two million years ago. On the other, there are those like [Robert] Berwick and [Noam] Chomsky who believe that humans acquired language quite recently, in an abrupt event. Nobody is in the middle on this one, except to the extent that different extinct hominid species are seen as the inaugurators of language’s slow evolutionary trajectory. That this deep dichotomy of viewpoint has been able to persist (not only among linguists, but among paleoanthropologists, archaeologists, cognitive scientists, and others) for as long as anyone can remember is due to one simple fact: at least until the very recent advent of writing systems, language has left no trace in any durable record. Whether any early humans possessed language, or didn’t, has had to be inferred from indirect proxy indicators. And views have diverged greatly on the matter of what is an acceptable proxy. (Ian Tattersall, At the Birth of Language.   The New York Review of Books, August 18, 2016) Also  See Where Does Language Come From?: Five Theories on the Origins of Language Cognitive Linguistics  and  Neurolinguistics

The benifits of nuclear medicine vs other forms of radiation exams Term Paper

The benifits of nuclear medicine vs other forms of radiation exams - Term Paper Example Today the stream of medical technologies has evolved to such an extent that almost all the medical specialists in medicine depend significantly on technology. In the following section this paper briefly describes the imaging modality called Nuclear Medicine. Although the imaging modalities like Nuclear Medicine, X-Rays, Computed Tomography, Magnetic Resonance Imaging, are categorized as modalities of medical imaging. Except for Nuclear Medicine which is also termed as Radionuclide Scanning, rest all belong to the field of radiology. The latter half of the paper presents a contrast between Nuclear Medicine and other above mentioned modalities of radiology. Nuclear Medicine: It is an old modality of medical imaging that was discovered accidently in middle of the twentieth century. Nuclear medicine is the conglomerate of physics, chemistry, mathematics, medicine, detectors and computer technology. It uses predetermined amounts of radioactive material to diagnose ailments pertaining to c ancer, heart etc. This noninvasive branch of medicine uses imaging modalities after a radioactive material also known as radiotracers is either injected into the subject through intravenous injection or the subject is made to swallow or it is inhaled by the subject. The radiotracer gets settled in the part of the body that is to be imaged or studied. These radioactive substances emit gamma rays – that is electromagnetic radiations consist of photons. These rays are detected by a gamma camera etc. These devices enable the specialist to understand the condition of the body part, on the basis on the level of radiation that is detected by the detector. Some of the imaging techniques used in nuclear medicine are Positron Emission Tomography (PET Scanner), Single Photon Emission Computed Tomography (SPECT), Bone Scanning and Cardiovascular imaging. Figure 1 shows a PET Scanner. Nuclear medicine is helpful in detecting cancers, inadequate flow of blood to various tissues in the body , improper functioning of organs. Figure 1. PET Scanner (Zwanger-Pesiri Radiology) Radiological Modalities: It is said that the invention of X-Rays by Roentgen in 1895 sparked off a trend of innovation in medicine. Clinical applications of X-Rays lead to the birth of radiology – one of the branches of medicine that has a significant role in other specialties like orthopedics and neurology. Computed Tomography (CT) scanning is an extension of use of X-Rays in medicine. Magnetic Resonance Imaging (MR) is another very important imaging modality that uses magnetic field and it was invented almost the same time as CT. Sideways radiology also saw the developments and use of ultrasounds in medicine. Nuclear Medicine vs. X-Rays, CT & MRI: Utility: Besides the anatomical (structural) information nuclear medicine (also called radionuclide scanning) also presents to the doctors the function of the body’s organ as well. This information enables the doctors to understand if the org an is functioning properly. In the case of other radiological modalities like X-Ray, CT etc, the information captured by them is purely anatomical. It is worth including here that the nuclear medicine images give lesser information about spatial resolution but the images obtained in nuclear medicine may help us to diagnose an ailment sooner than any other radiological

MOTION IN TWO OR THREE DIMENSIONS PowerPoint Presentation

MOTION IN TWO OR THREE DIMENSIONS - PowerPoint Presentation Example An example, the position vector of the particle gives the position of a particular time and this makes the velocity vector on the derivative of the position Positional vector also location or radius vector is the representation of a point in the relation to an origin. Positional vector in geometry is used in two or three-dimensional space but it can generalize to include space with given number of dimensions. The vector is used in different geometry to describe continuous and differentiable space curves. The vector is also used in mechanics in equation of motion (Chatterjee, 2009). The function defines the motion of a particle with its location in relation to the given coordinate system. Positional vector is a function of time and the three derivatives are computed with respect to time. The derivatives are used in kinematics, engineering, and control theory. Acceleration vector is the rate in which an object in motion changes its velocity the vector has no issue to deal with the going fast of an object in motion but it is concerned with the changing of how fast the object is moving (Davis and Porta, 1994). The consideration of acceleration vector is done in three dimensions. The acceleration vectors are even done to curved motions. The components of the vector is done to speed of traverse and also the curve in the direction of the velocity vector (Davis and Porta, 1994).Acceleration for the vector has also to do with centripetal components for the circular motions and is brought about done to the changes in direction and is always normal to the trajectory and also pointing towards the center of the curved path. The vector is so much related to specific relativity, which describes the behavior of the objects that are travelling relatively to other object and accelerations that are approaching that of light in a vacuum (Davis and Porta, 1994). Acceleration vector is used in

Late Adulthood Paper Essay Example for Free

Late Adulthood Paper Essay People over the age of 65 have gone through a life of changes. He or she starts off as a young baby. He or she then develops into a growing child. into a young individual, and finally into a full adult. Now however is the hardest stage of any older individual’s life, they start to realize that time is limited and their life is slowly starting to decline and come to an end. This experience can be very frightening to the individual because the elderly person is noticing different changes and the rise of different needs. Changes not only physically but socially are occurring, the need for proper living accommodations, and health care are their new worries. With this being said there are many challenges not only for the aging individual but for the whole family as well. One of the social changes that elderly have to deal with is the changes in role and social position. Individuals who have lived a long life tend to have a social status that is often taken away when they retire. This is due to the fact that the individual is no longer in the environment he or she is used to. To make this clearer one example would be someone who has worked for a company for thirty plus years. In these years the individual most likely has made countless friends, on top of that the individual might have been in position of authority. When the individual retires he or she loses the environment that made him the individual he or she was. Some adults go into a shock because they no longer have a purpose. Some feel like they are no longer needed, and often many older people tend to feel neglected or left out of society (Zastrow, H. C., Oren, D.2009). It is a difficult time for the elderly. Because before they were needed, they had a purpose. Raised children, had a purpose in their career, and often had friends and peers that made their social life exciting. With these last remaining years this all starts to fade away, friends, family, a loved one, and even their own health. This i s why living in a nursing home can be so beneficial. It is expected by the year 2050, that there will be just over one hundred million adults over the age of  sixty five (‘Administration of Aging’, 2014). Currently there are just over twenty million adults of the age of sixty five years of age. What this means is that the need for facilities such as hospices and nursing homes, as well as other health care related facilities will be on a rise as the years continue. Living accommodations in a nursing home may not be a farfetched idea for an elderly individual. This is because nursing homes have individuals just like their own. One reason most senior citizens get depressed is because they are often left alone, let us say their partner had passed away, most senior citizens withdraw from the world too. (2009). Nursing homes may allow new friendships and bonds to be formed with people in their own age group. A nursing home or hospice is the perfect environment for an aging individual not only for the social aspect, but the health aspects as well. When an elderly adult lives alone his or her health will often be highly neglected. In a nursing or hospice home however, there are many great hea lth benefits to take into consideration. According to Dependableathome (2009) the benefits of having an elderly adult in a nursing home is because of the environment is made for retired individuals. For one the nurses are all skilled, and highly equipped to handle aged individuals. These facilities allow for individuals to get services such as occupational therapy, physical therapy, speech and language services, as well as many other medical and social services that can ensure that the individual’s needs are met as best as possible. These are all benefits to an individual that went through adjustment in both retirement and their relationship in marriage, family and peer relationships. Adjustments into retirement can be difficult to overcome; retirement is one of the hardest situations to adjust to. When a person retires, he or she realizes that their life is starting to come down. Often most individuals do not know what to do with their self. Often for most people it takes a while for them to adjust to being home all day Zastrow, H. C., Oren, D. (2009). They often try to find projects to do around the house but after a while a form of depression kicks in. Another transition they must face is their changes in marriage, their family, and their peer relationships. Often sooner or later a spouse will die, peers will start to die, and family starts to drift off. This is an inevitable process. When a spouse dies the individual usually withdraws from society. When peers start to die it is a bittersweet  remembrance that their time is limited and the people they connected with in the past are no longer here. Family like children are full grown and living their own lives, this often neglects the older adult and is usually left alone to spend his or her remaining years by him or herself. Senior citizens not only deal with these types of hardships but social political hardships as well. Adults who are retired have a tough task at hand indeed. Individuals who once were working no longer have near the income that they once had. Most retired adults made poor choices as into how to set an up a retirement plan. Thus most retired adults only have so cial security income. Surviving on social security income alone is nearly impossible.Thus there are many social policies, laws and programs aimed into trying to help our retired population. Proper health care is one of the policies trying to be ensured to each retired adult. Proper health care will allow for one’s parent to be ensured into a proper nursing home. According to Administration of Aging. (2014), political issues that surround retired adults, include equipped and ensuring the proper resources are available to retired adults. These resources include proper medical care. Proper institutions such as nursing homes are available in the right areas and environment, and to make sure the low income retired adults are getting the nutrition he or she needs. There are also plenty of organizations aimed to ensure and to fight potential cuts to the older population to ensure that these populations get what they rightfully deserve.(2014). On a final note, in our growing population the need for facilities such as hospices, and nursing homes are on all time rises. With this growing population many families have to deal with the inevitable loss of a loved one. This inevitable lose can be a very tough, and challenging time for any family. For families a nursing home may be a perfect solution to help a family member in his or her last phase, or journey if one may in life. For with this growing population there are many different needs and factors that contribute in the later adulthood stage. Well obvious needs and changes are biological some needs are not so obvious; such changing needs both occur in social needs, and personality needs as well. Whatever the need may be it is important to take into consideration of each and every one of these retired individual are needs. Each one of these people have helped contribute in some sort of way into the growth of our country and we as a country need to  ensure that these people are getting the proper care they deserve. References Administration of Aging. (2014). Retrieved from http://www.aoa.gov/Aging_Statistics/future_growth/future_growth.aspx Dependableathome. (2009). Retrieved from http://www.dependableathome.com/ Zastrow, H. C., Oren, D. (2009). Understanding Human Behavior and the Social environment (8th Ed.). Retrieved from the University of Phoenix EBook Collection Database

Infectious Mononucleosis :: essays research papers

CauseInfectious mononucleosis is caused by the Ebstein-Barr virus, which is a member of the herpes family. This family also includes the viruses that cause cold sores, chicken pox, genital herpes, and birth defects. The Ebstein-Barr virus has a lengthy incubation period and symptoms usually take about 4-10 weeks to develop.Once a person is infected with a herpes virus, it never really goes away. The viruses are able to lie dormant in our bodies and become active at any time. The only way mono can be spread is through direct contact with infected saliva. That explains why it is known as the "kissing disease". Drinking from each- others glasses, sharing silverware, and coughing can also spread the virus. In rare cases it can be transmitted from person to person through blood transfusions.A person can only be infected when someone who has the virus passes it to someone who has never been exposed. But less than 5% of people w/ mono can recall being in contact w/ someone who had mono. That is b/c some people are strictly carriers. They carry the virus and pass it along to someone else without ever getting any symptoms themselves.Population AffectedAnyone can get mono. About 70-80% of all cases occur in people btw/ the ages of 15-30. Mono is most common among high school and college students who immune systems are usually run down from stress and fatigue. Although mono peaks earlier in females, it occurs more often in males. Females are usually 15-16 when they contract mono and males tend to be around 18-23. It is estimated that by the age of 40, 95% of the population has already had mono. That might be hard to believe, but most people who had mono didn't even know it. They had such mild cases that they thought it was just a cold or flu and their bodies were able to produce antibodies against ever having mono again.SymptomsIf symptoms do appear, they don't develop immediately. The incubation period lasts anywhere from 2 to 7 weeks. The 1st symptoms are commonly mistaken for a cold. They are headache, fatigue, loss of appetite, and chills. The symptoms become more severe as the body's lymphatic system is affected. These include extreme exhaustion, sore throat, fever and swollen glands.

Hunter-gatherer: Food and Limited Personal Possessions Essay

My people are what you call Hunter-Gatherers. We survive by hunting and gathering our food. We live in what are called â€Å"Bands.† These usually consist of 15-20 people, all of which are usually related either by blood or marriage. We don’t have any type of government or hierarchy like other civilizations. Instead we believe we are all created equal, and we treat each other in that manner. We are nomadic, which means that we do not stay in the same place year around. We move in order to take advantage of the abundance of different foods in different areas. I’m getting ahead of myself. Let me take you through a day in my life. Our breakfast is pretty simple. The outcome of the hunting and gathering of yesterday decides what food we will eat for breakfast today. On a good day we will eat grapefruit, or a mixture of fruits and nuts along with some elk jerky, and of course accompanied by spring water. After breakfast the men will leave for their daily hunt.There is a great skill to their hunting, for they must know where and when to look for the foods. The men use various tools in hunting for animals. The most common of these tools is the bow. This is the most powerful weapon available. Arrows made of wood with flint blades set in their ends are also used for hunting. Our men hunt for game such as deer, elk, bear, birds, etc. They also fish. The results of the hunt are very important, mostly because we must eat, but also because we need to utilize every part of the animal in order to survive. We have various uses for the animal after it has been killed. First and foremost it is our source for food. It also provides us with the shelter and the clothing we need.I guess now would be a good time to tell you about the types of homes we live in. We cannot build permanent homes because we move around. Our houses are temporary, and because we move around we have limited personal possessions. Our shelters are lightweight huts and wind-breaks that are built out of branches. We also use the skins of animals to create tents.Our clothing is also made of animal skins. We make our clothes by stitching together hides using bone needles and animal sinew. The teeth of the animal are often used to create necklaces or pendants.After the men arrive home from their hunt, the women work together to process the food that was collected that day. The nuts and shellfish need to be removed from their shells, and the birds that were killed need to be plucked of their feathers. We also need to skin the animals and prepare the meat for cooking. For dinner we will have duck, served with nuts and fruit. If anyone is still hungry afterward they can eat jerky or grapefruit. The meat will be cooked over a simple fire, roasted on a spit. Dinner will be delicious tonight, and a great reward for a successful day’s hunt.After dinner we sometimes gather around the fire and tell stories, or dance in celebration of the hunt. We must not take life for granted, for our lives are filled with hard work and the struggle to survive.Hope you enjoyed accompanying me in the journey through my day to day life!

Three Propositions Of The Arbitrage Pricing Theory Finance Essay - Free Essay Example

Sample details Pages: 3 Words: 932 Downloads: 6 Date added: 2017/06/26 Category Finance Essay Type Argumentative essay Did you like this example? Arbitrage opportunity arises if an investor can construct a zero investment portfolio with a zero profit, in other words, ability to make profit without any risk. Arbitrage Pricing Theory based on three main propositions. First, Security returns can be described by a factor model. Second, idiosyncratic risk can be diversified away. Third, Arbitrage opportunities are eventually diversified away.   This theory predicts a relationship between the returns of a  portfolio and the returns of a single asset through a linear combination of many independent macro-economic variables.1 In order to define how good the APT is, we need to look at how it work and how useful can it be. Roll and Ross (1995) stated that the actual return of a stock must follow the APT formula: R=E + ÃÆ'Ã… ½Ãƒâ€šÃ‚ ²f + e where E is equal to the expected return on the asset, ÃÆ'Ã… ½Ãƒâ€šÃ‚ ² is equal to the assets sensitivity to a change in the systematic factor, f is the actual r eturn on the systematic factor, and e is the return on the unsystematic, idiosyncratic factors.2 The expected return = rf + ÃÆ'Ã… ½Ãƒâ€šÃ‚ ²1*f1 + ÃÆ'Ã… ½Ãƒâ€šÃ‚ ²2*f2 +ÃÆ' ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ãƒâ€šÃ‚ ¦+ ÃÆ'Ã… ½Ãƒâ€šÃ‚ ²n*fn which rf is the risk free rate, ÃÆ'Ã… ½Ãƒâ€šÃ‚ ² is the sensitivity of the stock and f is the risk premium associated with each factor. ÃÆ'Ã… ½Ãƒâ€šÃ‚ ² is the measure of the relationship between the sensitivity of returns and the unanticipated movements in the factors. The unanticipated returns are what determine the ÃÆ'Ã… ½Ãƒâ€šÃ‚ ²s and their measurement is one of the important components of the APT approach. There are four main economic factors that are related to unanticipated returns on large portfolios, which are unanticipated changes in inflation, industrial production, risk premiums and the slope of the term structure of interest rate. Capital Asset Pricing Model is a model that describes the relationship between risk and expected return  and  which has been used in the pricing of risky securities.3 The risk premium on individual securities is E(ri) = rf + ÃÆ'Ã… ½Ãƒâ€šÃ‚ ²i[ E(rm)-rf] which rf is the risk free rate, ÃÆ'Ã… ½Ãƒâ€šÃ‚ ²i is the coefficient of the security relative to the market portfolio and rm is the market return. The APT and the CAPM are two of the most important theories on stock and asset pricing. CAPM is a dominant pricing model compare to APT. The APT and CAPM are similar as both of them gives us a standard criterion for rate of return that can be used in capital budgeting, security valuation, or investment performance evaluation. However, they are different in some point as APT is less restrictive in the assumptions. It allows the investor to develop their model of expected return for an asset. In the CAPM theory, the expected return on a stock is described by the movement of that stock relative to the stock market4 and the only factor that should be considered is the risk of the stock relative to the entire stock market. Test of the single-index model that account for human capital and cyclical variations in asset betas are far more consistent with the single-index APT. These tests suggest that macroeconomic variables are not necessary to explain expected returns. Moreover, anomalies such as effects of size and book-to-market ratios disappear once these variables are accounted for. According to Fama and French 1996, the multifactor APT is refined theories of how exposure to systematic risk factors would have influence expected returns, but it provide little guidance regarding which factors such as sources of risk, ought to result in risk premiums.5 According to the APT, only a few systematic factors will affect the long term average returns of financial assets and it focuses on the main forces that move aggregates of assets in large portfolio. In Chen, Roll and Ross (1986), the paper is about economic forces and the stock market which has explored a set of systematic economic state variables that has influences on stock market returns and has examined their influence on asset pricing.6 Asset prices that describe the economy should depend on how visible they are to the state variables. Stock returns are visible to regular economic news in which they are priced according to their visibility, and that the news can be measured as innovations in state variables which the proofing can be done through simple financial theory. The APT highlights the crucial distinction between non-diversifiable risk also as known as factor risk, that requires a reward in the form of a risk premium and diversifiable risk that does not. It is an extremely appealing model as it depends on the assumption that a rational equilibrium in capital markets precludes arbitrage opportunities. A violation of the APTs pricing relationships will cause extremely strong pressure to restore them even if only a limited number of investors become aware of the disequilibrium. Moreover, the APT yields an expected return-beta relationship using a well-diversified portfolio, in other words, it choose an appropriate degree of exposure to the major economic risks that influence both asset returns and organizations which practically can be constructed from a large number of securities.5 For these stated reasons, APT can somehow be defined as a good asset pricing model. However, the APT implies that the expected return-beta relationship holds for all but perhaps a small number of securities. Because it focuses on the no-arbitrage condition, without the further assumptions of the market or index model, the APT cannot rule out a violation of the expected return-beta relationship for any particular asset. For this reason, CAPM has a dominant role in todays financial market rather than the APT, which shows APT, is a good model but not a perfect model for asset pricing as it is not as good as the CAPM. Don’t waste time! Our writers will create an original "Three Propositions Of The Arbitrage Pricing Theory Finance Essay" essay for you Create order