financial markets In finance , the efficientmarkethypothesis EMH asserts that financial markets are informationally ... the market. The efficientmarkethypothesis was developed by Professor Eugene Fama at the University ... . ref name Fortune2002 Although the efficientmarkethypothesis has become controversial because substantial ... utility maximizing agents, the efficientmarkethypothesis requires that agents have rational ... have disputed the efficientmarkethypothesis both empirically and theoretically. Behavioral ... generally not supported strong forms of the efficientmarkethypothesis ref name ContraryEmpirical ... colend Notes Reflist colwidth 30em References Burton G. Malkiel 1987 . efficientmarkethypothesis, The New ... Handbook of Macroeconomics investment management stock market DEFAULTSORT EfficientMarketHypothesis ... it . Fortune . ref Empirical analyses have consistently found problems with the efficientmarket ... rdp2000 01.html The Efficient Markets Hypothesis A Survey . Reserve Bank of Australia. ref The efficientmarkethypothesis emerged as a prominent theory in the mid 1960s. Paul Samuelson had begun to circulate ... markethypothesis. ref cite journal last Samuelson first Paul title Proof That Properly Anticipated ... that the UK stock market is weak form efficient, other studies of capital markets have pointed toward their being semi strong form efficient. A study by Khan of the grain futures market indicated ... strong form efficient. However, the market s ability to efficiently respond to a short term, widely ... can be&mdash but the market as a whole is always right. There are three common forms in which the efficientmarkethypothesis is commonly stated&mdash weak form efficiency , semi strong form efficiency ... with an efficientmarket due to differences in interest rate s. ref Burton Malkiel Burton ... accepted by efficientmarket theorists as explaining the anomaly ref name ContrarianNextGen David Dreman ... hypothesis problem, where it is impossible to ever test for market efficiency, since to do so ... more details
The efficient coding hypothesis was proposed by Horace Barlow in 1961 as a theoretical model of sensory neuroscience sensory coding in the brain. ref Barlow, H. 1961 Possible principles underlying the transformation of sensory messages in Sensory Communication , MIT Press ref Within the brain, neurons often communicate with one another by sending electrical impulses referred to as action potentials or spikes. One goal of sensory neuroscience is to decipher the meaning of these spikes in order to understand how the brain represents and processes information about the outside world. Barlow hypothesized that the spikes in the sensory system formed a neural code for efficiently representing sensory information. By efficient Barlow meant that the code minimized the number of spikes needed to transmit a given signal. This is somewhat analogous to transmitting information across the internet, where different file formats can be used to transmit a given image. Different file formats require different number of bits for representing the same image at given distortion level, and some are better suited for representing certain classes of images than others. According to this model, the brain is thought to use a code which is suited for representing visual and audio information representative of an organism s natural environment. Efficient coding and information theory The development of the Barlow s hypothesis was influenced by information theory introduced by Claude Shannon only a decade before. Information theory provides the mathematical framework for analyzing communication systems. It formally defines concepts such as information, channel capacity, and redundancy. Barlow s model treats the sensory pathway as a communication channel where neuronal spiking is an efficient code for representing ... the redundancy between representational units. A key prediction of the efficient coding hypothesis ... in nature. ref Lewicki, M.S. 2002 Efficient coding of natural sounds . Nature Neuroscience , 5 4 ... more details
to Lo, the Adaptive Markets Hypothesis can be viewed as a new version of the efficientmarkethypothesis ...The Adaptive MarketHypothesis , as proposed by Andrew Lo 2004,2005 , is an attempt to reconcile theories that imply that the markets are efficient with behavioral alternatives, by applying the principles of evolution competition, adaptation, and natural selection to financial interactions. ref http www.investmentnews.com apps pbcs.dll article?AID 20050207 SUB 502070709 1008 TOC ref Under this approach the traditional models of modern financial economics can coexist alongside behavioral models. He argues that much of what behavioralists cite as counterexamples to economic rationality loss aversion ..., he means distinct groups of market participants, each behaving in a common manner i.e. pension funds, retail investors, market maker s, and hedge fund managers, etc. . If multiple members of a single group are competing for rather scarce resources within a single market, that market is likely to be highly efficient, e.g., the market for 10 Year US Treasury Notes, which reflects most relevant information ... abundant resources in a given market, that market will be less efficient, e.g., the market for oil paintings from the Italian Renaissance. Market efficiency cannot be evaluated in a vacuum, but is highly context dependent and dynamic. Shortly stated, the degree of market efficiency is related to environmental factors characterizing market ecology such as the number of competitors in the market, the magnitude of profit opportunities available, and the adaptability of the market participants ..., Andrew 2004 The Adaptive MarketHypothesismarket efficiency from an evolutionary perspective http papers.ssrn.com sol3 papers.cfm?abstract id 728864 Lo, Andrew 2005 Reconciling Efficient Markets with Behavioral Finance The Adaptive Markets Hypothesis Category Finance theories Category Financial economics ... a consistent level of expected return s is to adapt to changing market conditions. Survival is the only ... more details
financial markets In finance , Noisy MarketHypothesis contrasts the efficientmarkethypothesis in that it claims that the prices of securities are not always the best estimate of the true underlying value of the firm. It argues that prices can be influenced by speculators and momentum trader s, as well as by insiders and institutions that often buy and sell stocks for reasons unrelated to fundamental value, such as for diversification, liquidity and taxes. These temporary shocks referred to as noise can obscure the true value of securities and may result in mispricing of these securities for many years. ref http sec.online.wsj.com article SB115025119289879729.html The Noisy MarketHypothesis , Wall Street Journal , Jeremy Siegel , June 14, 2006 ref Quantitative methods may be used to identify speculative market activity, and so to separate noise from true value. The McKellar algorithm , used by various asset managers, analyzes the relationship between related variables, such as levels of Russian iron smelting activity and the Sharpe ratio of Swedish car manufacturers. The degree of correlation has significant predictive power as to the amount of noisiness in the securities markets, and the deviation from true value. References reflist econ theory stub investment management stock market Category Financial markets Category Economic efficiency Category Economic theories Category Financial economics Category Behavioral finance ... more details
nofootnotes date December 2009 The market timing hypothesis is a theory of how firms and corporation s in the Economics economy decide whether to finance their investment with Ownership equity equity or with debt instruments. It is one of many such corporate finance theories, and is often contrasted with the pecking order theory and the trade off theory , for example. The idea that firms pay attention to market conditions in an attempt to time the market is a very old hypothesis. Baker and Wurgler 2002 , claim that market timing is the first order determinant of a corporation s capital structure use of debt and equity. In other words, firms do not generally care whether they finance with debt or equity, they just choose the form of financing which, at that point in time, seems to be more valued by financial markets . ref Baker and Wurgler, Market Timing and Capital Structure , The Journal of Finance, 2002. http www.blackwellpublishing.com content BPL Images Journal Samples JOFI0022 1082 57 1 414 5C414.pdf ref Market timing is sometimes classified as part of the behavioral finance literature, because it does not explain why there would be any asset mis pricing , or why firms would be better ... problem within a market timing model. The typical version of the market timing hypothesis is thus ... makers are behavioral or rational. The empirical evidence for this hypothesis is at best, mixed ... events. He found that the effect of market timing disappears after only two years. ref AYDO AN ALTI. How Persistent Is the Impact of Market Timing on Capital Structure? , The Journal of Finance, 2006 ... are generally able to beat the market is not supportive. Even for the most active issuers it is hard to reject the hypothesis that the timing of the issuing decisions is random. ref Frank, M. and Nezafat, P. 2010, Credit Market Timing. Available at SSRN http ssrn.com abstract 1571798 ref Beyond such academic studies, a complete market timing theory ought to explain why at the same moment in time ... more details
Efficient can refer to Efficiency disambiguation Efficient horse , winner of the 2007 Melbourne Cup Efficient Networks , a modem manufacturer now called Gigaset Communications. Inefficiency , a term with a number of meanings in economics Efficient estimator , a type of statistical estimator. disambig ... more details
Infobox book name The Efficient Society Why Canada is as Close to Utopia as it Gets title orig translator image Image Efficientsocietycover.jpg thumb right The cover of the 2002 paperback edition image caption author Joseph Heath illustrator cover artist country language series subject genre publisher pub date english pub date media type pages isbn 0 67089149 5 oclc dewey congress preceded by followed by The Efficient Society Why Canada is as Close to Utopia as it Gets is a popular book by Canada Canadian philosopher and author Joseph Heath . First released in 2001, the book is Heath s attempt to explain why Canada works . He argues that Canada s successes as a nation are largely attributable to its commitment to Efficiency economics efficiency as a value. The book was released to positive reviews, and became a national best seller. Overview Drawing on rational choice and game theory , Heath argues that a vast of array of social problems are in fact the result of Prisoner s Dilemma prisoner s dilemmas and collective action problems. While capitalism as a means of production alleviates many of these such as Efficiency wages Shirking shirking , it creates many others. Government intervention in the economy can further help to relieve these collective action problems. Heath argues that the government should operate only in markets where a collective action problem occurs and not in markets where this problem is absent where it is a race to the bottom not a race to the top . This is one of the reasons, Heath argues, that the United Nations Annual Human Development Report consistently ranks Canada as the best place in the world to live. Canadians throughout their history have shown ... in welfare, not market based, economies. Heath also argues that by maintaining physicians on a fee schedule, as opposed to letting the market establish the price of services, the Canadian health ... about Canada DEFAULTSORT Efficient Society ... more details
You may be looking for Efficient Frontier company Image markowitz frontier.jpg right frame Efficient Frontier. The hyperbola is sometimes referred to as the Markowitz Bullet , and its upward sloped portion is the efficient frontier if no risk free asset is available. With a risk free asset, the straight line is the efficient frontier. The efficient frontier is a concept in Modern portfolio theory introduced by Harry Markowitz and others. A combination of assets, i.e. a portfolio finance portfolio , is referred to as efficient if it has the best possible expected value expected level of return finance return for its level of risk usually proxied by the standard deviation of the portfolio s return . Here, every possible combination of risky assets, without including any holdings of the Risk free interest rate risk free asset , can be plotted in risk expected return space, and the collection of all such possible portfolios defines a region in this space. The left boundary of this region, a hyperbola , is then called the Efficient Frontier . See Modern portfolio theory The efficient frontier with no risk free asset further under Modern portfolio theory . See also Modern portfolio theory External links http www.investopedia.com terms e efficientfrontier.asp Efficient Frontier , investopedia http www.riskglossary.com link efficient frontier.htm Efficient Frontier , riskglossary.com Econ theory stub Category Financial economics Category Finance theories Category Mathematical finance Category Portfolio theories ... more details
Thoroughbred racehorse infobox horsename Efficient image caption sire Zabeel grandsire Sir Tristram dam ... Horse.aspx?hid 884214 ASB Efficient NZ Retrieved on 2009 10 6 ref race Victoria Derby 2006 br Melbourne Cup 2007 br Turnbull Stakes 2009 awards honours updated October 6, 2009 Efficient foaled ... Cup result ref ref name TheAge07 cite news url http www.theage.com.au news sport efficient wins melb cup 2007 11 06 1194118018578.html title Efficient wins Melbourne Cup publisher The Age date 6 ... news author Andrew Eddy url http www.theage.com.au news horse racing hayes fears efficient 2006 11 04 1162340095970.html title Hayes fears Efficient publisher The Age date 5 November 2006 accessdate 2007 11 06 ref Efficient was by the outstanding sire Zabeel from the mare Refused The Dance by Defensive ... Derby win Efficient was entered into the Melbourne Cup field, run three days later. However, he did ... Efficient had a very light campaign of just two starts. In the 1,400 metre Group 3 Schweppervescence ... One Australian Guineas over 1,600 metres. As a four year old in the Spring of 2007 Efficient ... then ran unplaced in the 2,000 metre Group 1 Turnbull Stakes . Three weeks later Efficient lined up ... 6 lengths by the winner El Segundo. Efficient s next start was the Melbourne Cup, his first start ... Rodd for the first time since their 2006 Victoria Derby win, Efficient settled back in the field and travelled well. He was pulled to the outside to make a run and in the closing stages Efficient ... horse Subzero in 1992. Efficient has had an injury plagued career since his Melbourne Cup win, and was withdrawn ... Melbourne Cup, but is an unlikely starter. Efficient was trained by expatriate New Zealand trainer ... name TheAge07 In winning the Melbourne Cup, Efficient became the first horse since Phar Lap to win the Melbourne Cup the year after winning the Victoria Derby. Efficient has had twenty starts for seven ... last first title Efficient s racing record publisher 2KY.com date url http www.2ky.com.au horse results ... more details
Multiple issues cleanup May 2009 expert May 2009 Contract law Efficient breach is a concept within legal theory, particularly law and economics , referring to a voluntary breach of contract and payment of damages by a party who concludes that they would incur greater economic loss by performing under the contract. Development of the theory According to Black s Law Dictionary, efficient breach theory is the view that a party should be allowed to breach a contract and pay damages, if doing so would be more economically efficient than performing under the contract. The first statement of the theory of efficient breach appears to have been made in a law review article by Robert Birmingham in Breach of Contract, Damage Measures, and Economic Efficiency , 24 Rutgers L.Rev. 273, 284 1970 Repudiation of obligations should be encouraged where the promisor is able to profit from his default after placing his promisee in as good a position as he would have occupied had performance been rendered . The theory was named by Charles Goetz and Robert Scott, Liquidated Damages, Penalties, and the Just Compensation Principle A Theory of Efficient Breach , 77 Colum.L.Rev. 554 1977 . Efficient breach theory is associated with Richard Posner and the Law and Economics school of thought. It has been used to defend the traditional common law rule that a tort non tortious breach of contract cannot be remedy law remedied by punitive damages and penal damages unreasonably excessive liquidated damages that are seen as a punishment for breach rather than a means to fairly compensate the other party . Such penalties would discourage efficient breach, and therefore economic efficiency efficient behavior, which would be undesirable for society as a whole. Posner explains his views in his majority opinion in Lake River Corp. v. Carborundum Co. , 769 F.2d 1284 7th Cir. 1985 . Posner s illustration Judge Richard Posner gave this well known illustration of efficient breach in Economic Analysis of Law blockquote ... more details
Refimprove date May 2010 In statistics , an efficient estimator is an estimator that estimates the quantity of interest in some best possible manner. The notion of best possible relies upon the choice of a particular loss function the function which quantifies the relative degree of undesirability of estimation errors of different magnitudes. The most common choice of the loss function is quadratic loss function quadratic , resulting in the mean squared error criterion of optimality. ref harvtxt Everitt 2002 p 128 ref Finite sample efficiency Suppose nowrap P sub sub is a parametric model and nowrap 1 X X sub 1 sub , , X sub n sub is the data sampled from this model. Let nowrap 1 T T X be the estimator for the parameter . If this estimator is bias of an estimator unbiased that is, nowrap 1 E &thinsp T &thinsp , then the celebrated Cram r Rao inequality states the variance of this estimator is bounded from below math operatorname Var ,T , geq mathcal I theta 1 , math where math scriptstyle mathcal I theta math is the Fisher information matrix of the model at point . Generally, the variance measures the degree of dispersion of a random variable around its mean. Thus estimators ... that the estimator is finite sample efficient estimator in the class of unbiased estimators if it reaches the lower bound in the Cram r Rao inequality above, for all nowrap . Efficient estimators ... sample efficiency to maintain popularity Finite sample efficient estimators are extremely rare. In fact, it was proved that efficient estimation is possible only in an exponential family , and only ... sample efficiency can no longer be formulated. Example Among the models encountered in practice, efficient ... from the sample. Thus, the sample mean is a finite sample efficient estimator for the mean of the normal ... asymptotically and are thus called asymptotically efficient estimators. This can be the case for some ... Efficient Estimator Category Estimation theory Category Statistical theory Category Statistical terminology ... more details
. An alternative release of Hypothesis was titled Visions of the Future . In Germany Hypothesis and The Dragon were issued together as a double album titled Portrait . The cover artwork for Hypothesis .... Track listing Hypothesis, Part 1 16 00 Hypothesis, Part 2 16 10 References http www.vangelismovements.com ... 1978 albums Category Albums produced by Giorgio Gomelsky 1970s album stub electronic album stub it Hypothesis The Dragon pt Hypothesis ... more details
According to the Porter Hypothesis , strict environmental regulation s can induce efficiency and encourage innovations that help improve commercial competitiveness. The hypothesis was formulated by the economist Michael Porter . The hypothesis suggests that strict environmental regulation triggers the discovery and introduction of cleaner technologies and environmental improvements, the innovation effect , making production processes and products more efficient. sup 1 sup The cost savings that can be achieved are sufficient to overcompensate for both the compliance costs directly attributed to new regulations and the innovation costs. In the first mover advantage , a company is able to exploit innovation by learning curve effects or patent ing and attains a dominating competitive position compared to companies in countries where environmental regulations were enforced much later. The Porter hypothesis has been applied to Registration, Evaluation and Authorization of Chemicals REACH . In one conclusion sup 2 sup , companies that adopt a cost leadership business strategy and have a relatively small product portfolio will fare better than companies that compete by product differentiation and have a larger number of chemicals that require regulation. References sup 1 sup Wagner, M. The Porter Hypothesis Revisited. A Literatur Review of Theoretical Model and Empirical Test. L neburg Centre for Sustainability Management, 2003, p.2 http www2.leuphana.de umanagement csm content nama downloads download publikationen 38 2downloadversion.pdf CSM L neburg sup 2 sup Chemicals Regulation and the Porter Hypothesis A Critical Review of the New European Chemicals Regulation Torsten Frohwein, Bernd Hansj rgens Journal of Business Chemistry January 2005 http www.wirtschaftschemie.de journal 20051 19 36.pdf open access publishing open access publication Category Marketing Category Environmental economics es Hip tesis de Porter environment stub ... more details
main Statistical hypothesis testing In statistical hypothesis testing , the alternative hypothesis or maintained hypothesis or research hypothesis and the null hypothesis are the two rival hypotheses which are compared by a statistical hypothesis testing statistical hypothesis test . An example might be where water quality in a stream has been observed over many years and a test is made of the null hypothesis that there is no change in quality between the first and second halves of the data against the alternative hypothesis that the quality is poorer in the second half of the record. The concept of an alternative hypothesis in testing was devised by Jerzy Neyman and Egon Pearson , and it is used in the Neyman Pearson lemma . It forms a major component in modern statistical hypothesis testing . However it was not part of Ronald Fisher Ronald Fisher s formulation of statistical hypothesis testing, and he violently opposed its use. ref name Cohen Jacob Cohen statistician Cohen, J. 1990. Things I have learned so far . American Psychologist 45 1304&ndash 1312. ref In Fisher s approach to testing, the central idea is to assess whether the observed dataset could have resulted from chance if the null hypothesis were assumed to hold, notionally without preconceptions about what other model might hold. Modern statistical hypothesis testing accommodates this type of test since the alternative hypothesis can be just the negation of the null hypothesis. References reflist Statistics Category Hypothesis testing Category Statistical inference eo Alternativa hipotezo ko ... more details
and 25.011. Millennium Problems In mathematics, the Riemann hypothesis , proposed by harvs txt first ... hypothesis for curves over finite fields . The Riemann hypothesis implies results about the distribution ... harv Bombieri 2000 . The Riemann hypothesis is part of Hilbert s eighth problem Problem 8 ..., Pierre Deligne proved an analogue of the Riemann Hypothesis for zeta functions of varieties defined over finite fields. The full version of the hypothesis remains unsolved, although modern computer ... hypothesis is concerned with the non trivial zeros, and states that The real part of any non ... popular books on the Riemann hypothesis, such as harvtxt Derbyshire 2003 , harvtxt Rockmore ..., as none of the factors have zeros. The Riemann hypothesis discusses zeros outside the region of convergence ... Riemann s statement of the Riemann hypothesis, from harv Riemann 1859 . He was discussing a version ... hypothesis. Consequences of the Riemann hypothesis The practical uses of the Riemann hypothesis include many propositions which are known to be true under the Riemann hypothesis, and some which can be shown to be equivalent to the Riemann hypothesis. Distribution of prime numbers Riemann ... sup harv Ingham 1932 . CITEREFvon Koch1901 Von Koch 1901 proved that the Riemann hypothesis is equivalent ... s result, due to harvtxt Schoenfeld 1976 , says that the Riemann hypothesis is equivalent to math ... functions The Riemann hypothesis implies strong bounds on the growth of many other arithmetic ... to the Riemann hypothesis. From this we can also conclude that if the Mertens function ... positive is equivalent to the Riemann hypothesis harv Titchmarsh 1986 . For the meaning of these symbols ... n , so the Riemann hypothesis can also be stated as a condition on the growth of these determinants. The Riemann hypothesis puts a rather tight bound on the growth of M , since harvtxt Odlyzko te Riele 1985 disproved the slightly stronger Mertens conjecture math M x le sqrt x. math The Riemann hypothesis ... more details
The innateness hypothesis is a linguistic theory of language acquisition which holds that at least some linguistic knowledge exists in humans at birth. ref http dictionary.reference.com browse innateness hypothesis Based on the Random House Dictionary, Random House, Inc. 2009. ref Facts about the complexity of human language systems, the universality of language acquisition, the facility that children demonstrate in acquiring these systems, and the comparative performance of adults in attempting the same task are all commonly invoked in support. The idea that there may be an age by which this learning must be accomplished is known as the critical period hypothesis . Noam Chomsky is responsible for the innateness hypothesis. Hilary Putnam published a critique of the innateness hypothesis entitled The Innateness Hypothesis and Explanatory Models in Linguistics . ref http www.springerlink.com content w476u76126j58330 fulltext.pdf ref References references See also Language acquisition Category Linguistics Category Philosophy of language Category Hypotheses ... more details
Orphan date July 2008 Entrenchment Management is referred to as a hypothesis for anti takeover in corporate business. This idea emerged in the 1980s when several actions to hostile takeover companies occurred, and several companies started planning on how to protect themselves from being bought through such a takeover. Entrenchment Management in Corporate Governance Entrenchment management and corporate governance go hand in hand, where according to corporate governance thinking, is how the entrenchment management will take place. Nowadays, there are several articles and essays on how to accomplish a proper entrenched management exercise without hurting shareholders, yet not abuse them for example when a board of directives is given the power to take corporate decisions in certain matters, where the corporation will be protected against hostile takeovers. Nonetheless, this form of corporate governance may cause distinct reaction on shares prices, which is why entrenchment management is not an easy concept to accomplish. Along with corporate governance, entrenchment management requires a lot of research and good management from the corporates market. References div class references small references Management Entrenchment, Corporate Governance and Accounting Arbitrage by Allan Hodgson and Peta Stevenson Clarke http www.financeprofessor.com governance Corporate 20Governance.html div Category Management ... more details
For the periodical Null Hypothesis The Journal of Unlikely Science Main Statistical hypothesis testing The practice of science involves formulating and testing hypothesis hypotheses , assertions that are falsifiable using a test of observed data. The null hypothesis typically corresponds to a general or default position. For example, the null hypothesis might be that there is no relationship between ... title null hypothesis definition publisher Businessdictionary.com date accessdate 2010 07 29 ... proven guilty can be interpreted as saying that his or her innocence is the null hypothesis. Other legal systems may exist in which the null hypothesis is that the defendant is guilty. The term was originally ... statistics.berkeley.edu stark SticiGui Text gloss.htm null hypothesis title Glossary publisher Statistics.berkeley.edu ... hypothesis, the alternative hypothesis , which asserts a particular relationship between the phenomena ... negation of the null hypothesis and predicts the results from the experiment if the alternative hypothesis is true. The use of alternative hypotheses was not part of Fisher s formulation, but became standard. Principle Hypothesis testing works by Sampling statistics collecting data and measuring how probability probable the data are, assuming the null hypothesis is true. If the data ... that the null hypothesis is false. If the data do not contradict the null hypothesis, then no conclusion is made. In this case, the null hypothesis could be true or false the data give insufficient ... attack and this drug has no effect on the chances of having a heart attack . The test of the hypothesis ... hypothesis is rejected. Choice of H sub 0 The choice of null hypothesis H sub 0 and consideration ... i.e. that on average it lands heads up 50 of the time . A potential null hypothesis is this coin ... result of 5 tosses is 5 heads. Under this null hypothesis, the data are considered unlikely with a fair coin, the probability of this is 3 . The data refute the null hypothesis the coin is biased ... more details
Orphan date February 2009 otheruses comparator disambiguation The comparator hypothesis is a hypothesis in the field of the psychology of motivation and learning . ref http books.google.com books?hl en&lr &id k6ufhxSYXe8C&oi fnd&pg PA51&dq comparator&ots 0kZ3T3e4dw&sig ObK0QBEZCAeLsxDUjVsSafHIBWg PPA53,M1 ref Created by Ralph Miller, it established that responses are due to a comparison between the direct activation of the outcome and the indirect activation of the outcome. The comparator hypothesis was the first model which successfully accounts for retrospective reevaluation phenomena. However, after the publication of the comparator hypothesis, traditional models like Wagner s SOP and the Rescorla Wagner model were modified to be able to account for retrospective reevaluation phenomena. Today, the comparator hypothesis can successfully account for counteraction phenomena, a topic in which both the traditional models and their reformulation tends to fail. References reflist Category Learning psychology Category Motivation psych stub ... more details
Refimprove date October 2009 Notability date October 2009 A skeptical hypothesis is a hypothetical situation which can be used in an argument for skepticism about a particular claim or class of claims. Usually the hypothesis posits the existence of a deceptive power that deceives our senses and undermines the justification of knowledge otherwise accepted as justified. Skeptical hypotheses have received much attention in modern Western philosophy. Some of the prominent skeptical hypotheses in Western philosophy include evil demon evil d mon , brain in a vat , and the five minute hypothesis , a possible more modern one epiphenomenalism . With the spread of materialism as a school of thought, numerous ideas it encompasses, which explain the mind, can be as skeptical these include The Multiple Drafts Model and Eliminative Materialism Origins of skeptical hypotheses The first skeptical hypothesis in the modern Western philosophy appears in Ren Descartes Ren Descartes Meditations on First Philosophy . At the end of the first Meditation Descartes writes I will suppose... that some evil demon of the utmost power and cunning has employed all his energies to deceive me. See also Dream argument Null hypothesis , sometimes called the skeptical hypothesis . Philosophical skepticism External links http pantheon.yale.edu kd47 responding.htm Responding to skepticism skepticism Category Epistemology sv Skeptisk hypotes ... more details
The 2R hypothesis or Ohno s hypothesis , first proposed by Susumu Ohno in 1970, ref name Ohno70 Ohno S 1970 . Evolution by Gene Duplication. London Allen and Unwin, ISBN 0 04 575015 7. ref is a contested hypothesis in genomics and molecular evolution suggesting that the genomes of the early vertebrate lineage underwent one or more complete genome duplication s, and thus modern vertebrate genomes reflect ..., and the term 2R hypothesis was probably coined in 1999 variations in the number of duplications typically still are referred to as examples of the 2R hypothesis. ref name Hokamp cite journal last1 Hokamp first1 K last2 McLysaght first2 A last3 Wolfe first3 KH title The 2R hypothesis and the human ... Duplication , the 2R hypothesis has been the subject of much research, but even with recent data from .... 2003 , ref name Hokamp the version of the genome duplication hypothesis from which 2R hypothesis takes ... last1 Hughes first1 AL title Phylogenies of developmentally important proteins do not support the hypothesis ... Ohno presented the first version of the 2R hypothesis as part of his larger argument for the general ... first1 W title Are we polyploids? A brief history of one hypothesis journal Genome research ... hypothesis saw a resurgence of interest in the 1990s, with multiple suggestions for the time and number ... years ago to after 450 million years ago. One argument for the hypothesis relies on the number of genes ... have shown patterns that are not consistent with the 2R hypothesis. Parsimony analysis has produced some results that, while not supportive of the hypothesis, do not rule it out. According to a 2001 review of the subject by Wojciech Maka owski, the hypothesis of whole genome duplications in the early ... of extensive duplication and that the parsimony tests that cast doubt on the hypothesis are of questionable ... evidence supporting the 2R hypothesis and that a long standing debate on the 2R hypothesis is approaching the end . ref name Kasahara cite journal last1 Kasahara first1 M title The 2R hypothesis ... more details
Named after the Hindu god of destruction, the Shiva Hypothesis is a hypothesis that purports to explain an apparent pattern in mass extinctions caused by impact event s. The hypothesis, created by Michael Rampino of New York University , says that gravitational disturbances caused by the Solar System crossing the plane of the Milky Way galaxy are enough to disturb comets in the Oort cloud surrounding the Solar System. This sends comets in towards the inner Solar System, which raises the chance of an impact. According to the hypothesis, this results in the Earth experiencing large impact events about every 30 million years such as the Cretaceous Tertiary extinction event . However, mass extinctions do not show any statistically significant periodicity. ref doi 10.1073 pnas.0802597105 References reflist External links http abob.libs.uga.edu bobk ccc cc020298.html A description of the Shiva hypothesis by Michael Rampino http users.tpg.com.au users tps seti crater.html A brief See also Tyche hypothetical planet Nemesis hypothetical star Category Impact events astronomy stub geology stub disaster stub es Hip tesis Shiva it Ipotesi di Shiva ... more details
Orphan date November 2006 The synaptotropic hypothesis is a neurobiology neurobiological hypothesis of neuron al growth and synapse formation. The hypothesis was first formulated by Vaughn in 1988 ref cite journal title Dendritic development and preferential growth into synaptogenic fields a quantitative study of Golgi impregnated spinal motor neurons author Vaughn JE, Barber RP, Sims TJ journal Synapse volume 2 pages 69 78 year 1988 pmid 2458630 issue 1 doi 10.1002 syn.890020110 ref , and remains a focus of current research efforts. ref cite journal title The regulation of dendritic arbor development and plasticity by glutamatergic synaptic input a review of the synaptotrophic hypothesis author Hollis Cline, Kurt Haas journal J Physiol volume 586 pages 1509 17 year 2008 pmid 18202093 issue 6 doi 10.1113 jphysiol.2007.150029 pmc 2375708 ref The hypothesis proposes that the formation of new synapses Synaptogenesis can guide the growth of dendrite s. The dendrites that find a synapse that successfully activates it are encouraged to mature and stabilize. The reasons for this stabilization after the growth of a synapse are as yet undiscovered, but there are hints that the activation of a synapse, somehow changes the biochemistry of the Focus Mechanism, that reabsorbs unused dendritic fibrils as part of the preliminary stages of new fibril proliferation. References reflist Category Neurophysiology Category Cellular neuroscience Category Developmental neuroscience Neuroscience stub ... more details
In paleoanthropology , the hunting hypothesis is the hypothesis that human evolution was primarily influenced by the activity of hunting for relatively large and fast animals, and that the activity of hunting distinguished human ancestors from other primate s. While it is undisputed that early humans were hunters, the importance of this fact for the final steps in the emergence of the Homo genus Homo genus out of earlier Australopithecines , with its bipedalism and production of stone tool s from about 2.5 million years ago , and eventually also control of fire from about 1.5 million years ago , are emphasized in the hunting hypothesis , and de emphasized in scenarios that stress the omnivore status of humans as their recipe for success, and social interaction , including mating behaviour as essential in the emergence of language and culture. Advocates of the hunting hypothesis tend to believe that tool use and toolmaking essential to effective hunting were an extremely important part of human evolution, and trace the origin of language and prehistoric religion religion to a hunting context. See also Acheulean Behavioral modernity Homo ergaster Homo Necans , an award winning book whose title translates as Man the Killer Hunter gatherer Killer ape theory Oldowan References Robert Ardrey , The Hunting Hypothesis A Personal Inquiry into the Evolutionary Sources of Order and Disorder , Atheneum, New York 1970 External links http encarta.msn.com encyclopedia 761566394 12 Human Evolution.html Human Evolution MSN Encarta BOT GENERATED TITLE http www.webcitation.org 5kwr6JAob Archived 2009 10 31 and http www.mnh.si.edu anthro humanorigins faq Encarta culture.htm Discussion of the hunting hypothesis from Encarta http www.indiana.edu origins teach P380 P380hominid.html http www.goanimal.com newsletters 2005 man hunter man hunter.html An article critical of the hunting hypothesis anthropology stub Category Anthropology Category Human evolution ja ... more details
The Distributional Hypothesis in linguistics is that words that occur in the same contexts tend to have similar meanings. ref name Harris cite journal last1 Harris first1 Z. year 1954 title Distributional structure url journal Word volume 10 issue 23 pages 146 162 ref The underlying idea that a word is characterized by the company it keeps was popularized by J. R. Firth Firth . ref name Firth Firth, J.R. 1957 . A synopsis of linguistic theory 1930 1955. In Studies in Linguistic Analysis , pp. 1 32. Oxford Philological Society. Reprinted in F.R. Palmer ed. , Selected Papers of J.R. Firth 1952 1959 , London Longman 1968 . ref The Distributional Hypothesis is the basis for Statistical semantics Statistical Semantics . Although the Distributional Hypothesis originated in Linguistics, it is now receiving attention in Cognitive science Cognitive Science . ref name McDonald McDonald, S., and Ramscar, M. 2001 . http citeseerx.ist.psu.edu viewdoc download?doi 10.1.1.104.7535&rep rep1&type pdf Testing the distributional hypothesis The influence of context on judgements of semantic similarity . In Proceedings of the 23rd Annual Conference of the Cognitive Science Society , pages 611 616. ref The origin and theoretical basis of the Distributional Hypothesis is discussed by Sahlgren. ref name Sahlgren http soda.swedish ict.se 3941 1 sahlgren.distr hypo.pdf The Distributional Hypothesis. Rivista di Linguistica Italian Journal of Linguistics , 20 1 . pp. 33 53. ref In recent years, the distributional hypothesis has provided the basis for the theory of similarity based generalization in language learning the idea that children can figure out how to use words they ve rarely encountered before by generalizing about their use from distributions of similar words. ref name Yarlett Yarlett, D ... The distributional hypothesis suggests that the more semantically similar two words are, the more ... Hypothesis Category Linguistics Category Computational linguistics ling stub ... more details
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