Trial And Error
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Trial and error is a fundamental method of
problem-solving Problem solving is the process of achieving a goal by overcoming obstacles, a frequent part of most activities. Problems in need of solutions range from simple personal tasks (e.g. how to turn on an appliance) to complex issues in business an ...
characterized by repeated, varied attempts which are continued until success, or until the practicer stops trying. According to W.H. Thorpe, the term was devised by
C. Lloyd Morgan Conwy Lloyd Morgan, FRS (6 February 1852 – 6 March 1936) was a British ethologist and psychologist. He is remembered for his theory of emergent evolution, and for the experimental approach to animal psychology now known as Morgan's Canon, a pr ...
(1852–1936) after trying out similar phrases "trial and failure" and "trial and practice". Under
Morgan's Canon Morgan's Canon, also known as Lloyd Morgan's Canon, Morgan's Canon of Interpretation or the principle or law of parsimony, is a fundamental precept of comparative (animal) psychology, coined by 19th-century British psychologist C. Lloyd Morgan. In ...
,
animal behaviour Ethology is the scientific study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism as a term also describes the scientific and objectiv ...
should be explained in the simplest possible way. Where behavior seems to imply higher mental processes, it might be explained by trial-and-error learning. An example is a skillful way in which his terrier Tony opened the garden gate, easily misunderstood as an insightful act by someone seeing the final behavior. Lloyd Morgan, however, had watched and recorded the series of approximations by which the dog had gradually learned the response, and could demonstrate that no insight was required to explain it.
Edward Lee Thorndike Edward Lee Thorndike (August 31, 1874 – August 9, 1949) was an American psychologist who spent nearly his entire career at Teachers College, Columbia University. His work on comparative psychology and the learning process led to the theory o ...
was the initiator of the theory of trial and error learning based on the findings he showed how to manage a trial-and-error experiment in the laboratory. In his famous experiment, a cat was placed in a series of puzzle boxes in order to study the
law of effect The law of effect is a psychology principle advanced by Edward Thorndike in 1898 on the matter of behavioral conditioning (not then formulated as such) which states that "responses that produce a satisfying effect in a particular situation become ...
in learning. He plotted to learn curves which recorded the timing for each trial. Thorndike's key observation was that learning was promoted by positive results, which was later refined and extended by
B. F. Skinner Burrhus Frederic Skinner (March 20, 1904 – August 18, 1990) was an American psychologist, behaviorist, author, inventor, and social philosopher. He was a professor of psychology at Harvard University from 1958 until his retirement in 1974. ...
's
operant conditioning Operant conditioning, also called instrumental conditioning, is a learning process where behaviors are modified through the association of stimuli with reinforcement or punishment. In it, operants—behaviors that affect one's environment—are c ...
. Trial and error is also a method of problem solving,
repair The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installa ...
, tuning, or obtaining
knowledge Knowledge can be defined as awareness of facts or as practical skills, and may also refer to familiarity with objects or situations. Knowledge of facts, also called propositional knowledge, is often defined as true belief that is distinc ...
. In the field of
computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical discipli ...
, the method is called generate and test ( Brute force). In elementary algebra, when solving equations, it is guess and check. This approach can be seen as one of the two basic approaches to problem-solving, contrasted with an approach using
insight Insight is the understanding of a specific cause and effect within a particular context. The term insight can have several related meanings: *a piece of information *the act or result of understanding the inner nature of things or of seeing intu ...
and
theory A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be s ...
. However, there are intermediate methods which for example, use theory to guide the method, an approach known as ''guided empiricism''. This way of thinking has become a mainstay of
Karl Popper Sir Karl Raimund Popper (28 July 1902 – 17 September 1994) was an Austrian-British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the cl ...
's
critical rationalism Critical rationalism is an epistemological philosophy advanced by Karl Popper on the basis that, if a statement cannot be logically deduced (from what is known), it might nevertheless be possible to logically falsify it. Following Hume, Poppe ...
.


Methodology

The trial and error approach is used most successfully with simple problems and in games, and it is often the last resort when no apparent rule applies. This does not mean that the approach is inherently careless, for an individual can be methodical in manipulating the variables in an attempt to sort through possibilities that could result in success. Nevertheless, this method is often used by people who have little knowledge in the problem area. The trial-and-error approach has been studied from its natural computational point of view


Simplest applications

Ashby Ashby may refer to: People * Ashby (surname) * Alan la Zouche, 1st Baron la Zouche of Ashby (1267–1314), governor of Rockingham Castle and steward of Rockingham Forest, England * Walter Ashby Plecker (1861–1947), American physician and publi ...
(1960, section 11/5) offers three simple strategies for dealing with the same basic exercise-problem, which have very different efficiencies. Suppose a collection of 1000 on/off switches have to be set to a particular combination by random-based testing, where each test is expected to take one second. his is also discussed in Traill (1978–2006, section C1.2 The strategies are: *the perfectionist all-or-nothing method, with no attempt at holding partial successes. This would be expected to take more than 10^301 seconds, .e., 2^1000 seconds, or 3·5×(10^291) centuries*a serial-test of switches, holding on to the partial successes (assuming that these are manifest), which would take 500 seconds on average * parallel-but-individual testing of all switches simultaneously, which would take only one second Note the tacit assumption here that no intelligence or insight is brought to bear on the problem. However, the existence of different available strategies allows us to consider a separate ("superior") domain of processing — a ''"meta-level"'' above the mechanics of switch handling — where the various available strategies can be randomly chosen. Once again this is "trial and error", but of a different type.


Hierarchies

Ashby's book develops this "meta-level" idea, and extends it into a whole
recursive Recursion (adjective: ''recursive'') occurs when a thing is defined in terms of itself or of its type. Recursion is used in a variety of disciplines ranging from linguistics to logic. The most common application of recursion is in mathematics ...
sequence of levels, successively above each other in a systematic hierarchy. On this basis, he argues that human intelligence emerges from such organization: relying heavily on trial-and-error (at least initially at each new stage), but emerging with what we would call "intelligence" at the end of it all. Thus presumably the topmost level of the hierarchy (at any stage) will still depend on simple trial-and-error. Traill (1978–2006) suggests that this Ashby-hierarchy probably coincides with
Piaget Piaget () may refer to: People with the surname * Édouard Piaget (18171910), a Swiss entomologist * Jean Piaget (18961980), a Swiss developmental psychologist * Paul Piaget (disambiguation), several people * Solange Piaget Knowles (born 1986) ...
's well-known theory of developmental stages.
his work also discusses Ashby's 1000-switch example; see §C1.2 His or HIS may refer to: Computing * Hightech Information System, a Hong Kong graphics card company * Honeywell Information Systems * Hybrid intelligent system * Microsoft Host Integration Server Education * Hangzhou International School, in ...
After all, it is part of Piagetian doctrine that children learn first by ''actively doing'' in a more-or-less random way, and then hopefully learn from the consequences — which all has a certain resemblance to Ashby's random "trial-and-error".


Application

Traill (2008, ''espec. Table "S" on p.31'') follows Jerne and Popper in seeing this strategy as probably underlying ''all'' knowledge-gathering systems — ''at least in their initial phase''. Four such systems are identified: *
Natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charle ...
which "educates" the DNA of the species, *The brain of the individual (just discussed); *The "brain" of society-as-such (including the publicly held body of science); and *The
adaptive immune system The adaptive immune system, also known as the acquired immune system, is a subsystem of the immune system that is composed of specialized, systemic cells and processes that eliminate pathogens or prevent their growth. The acquired immune system ...
.


Features

Trial and error has a number of features: *solution-oriented: trial and error makes no attempt to discover ''why'' a solution works, merely that it ''is'' a solution. *problem-specific: trial and error makes no attempt to generalize a solution to other problems. *non-optimal: trial and error is generally an attempt to find ''a'' solution, not ''all'' solutions, and not the ''best'' solution. *needs little knowledge: trials and error can proceed where there is little or no knowledge of the subject. It is possible to use trial and error to find all solutions or the best solution, when a testably finite number of possible solutions exist. To find all solutions, one simply makes a note and continues, rather than ending the process, when a solution is found, until all solutions have been tried. To find the best solution, one finds all solutions by the method just described and then comparatively evaluates them based upon some predefined set of criteria, the existence of which is a condition for the possibility of finding a best solution. (Also, when only one solution can exist, as in assembling a jigsaw puzzle, then any solution found is the only solution and so is necessarily the best.)


Examples

Trial and error has traditionally been the main method of finding new drugs, such as
antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...
.
Chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...
s simply try chemicals at random until they find one with the desired effect. In a more sophisticated version, chemists select a narrow range of chemicals it is thought may have some effect using a technique called structure–activity relationship. (The latter case can be alternatively considered as a changing of the problem rather than of the solution strategy: instead of "What chemical will work well as an antibiotic?" the problem in the sophisticated approach is "Which, if any, of the chemicals in this narrow range will work well as an antibiotic?") The method is used widely in many disciplines, such as
polymer technology A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic an ...
to find new polymer types or families. Trial and error is also commonly seen in player responses to
video game Video games, also known as computer games, are electronic games that involves interaction with a user interface or input device such as a joystick, controller, keyboard, or motion sensing device to generate visual feedback. This fee ...
s - when faced with an obstacle or
boss Boss may refer to: Occupations * Supervisor, often referred to as boss * Air boss, more formally, air officer, the person in charge of aircraft operations on an aircraft carrier * Crime boss, the head of a criminal organization * Fire boss, ...
, players often form a number of strategies to surpass the obstacle or defeat the boss, with each strategy being carried out before the player either succeeds or quits the game.
Sports team A sports team is a group of individuals who play sports (sports player), usually team sports, on the same team. The number of players in the group depends on type of the sports requirements. Historically, sports teams and the people who play ...
s also make use of trial and error to qualify for and/or progress through the
playoffs The playoffs, play-offs, postseason or finals of a sports league are a competition played after the regular season by the top competitors to determine the league champion or a similar accolade. Depending on the league, the playoffs may be eithe ...
and win the
championship In sport, a championship is a competition in which the aim is to decide which individual or team is the champion. Championship systems Various forms of competition can be referred to by the term championship. Title match system In this system ...
, attempting different strategies, plays, lineups and formations in hopes of defeating each and every opponent along the way to victory. This is especially crucial in playoff series in which multiple wins are required to advance, where a team that loses a game will have the opportunity to try new tactics to find a way to win, if they are not eliminated yet. The
scientific method The scientific method is an empirical method for acquiring knowledge that has characterized the development of science since at least the 17th century (with notable practitioners in previous centuries; see the article history of scientific m ...
can be regarded as containing an element of trial and error in its formulation and testing of hypotheses. Also compare
genetic algorithm In computer science and operations research, a genetic algorithm (GA) is a metaheuristic inspired by the process of natural selection that belongs to the larger class of evolutionary algorithms (EA). Genetic algorithms are commonly used to gene ...
s,
simulated annealing Simulated annealing (SA) is a probabilistic technique for approximating the global optimum of a given function. Specifically, it is a metaheuristic to approximate global optimization in a large search space for an optimization problem. It ...
and
reinforcement learning Reinforcement learning (RL) is an area of machine learning concerned with how intelligent agents ought to take actions in an environment in order to maximize the notion of cumulative reward. Reinforcement learning is one of three basic machine ...
– all varieties for search which apply the basic idea of trial and error.
Biological evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...
can be considered as a form of trial and error. Random mutations and sexual genetic variations can be viewed as trials and poor reproductive fitness, or lack of improved fitness, as the error. Thus after a long time 'knowledge' of well-adapted genomes accumulates simply by virtue of them being ''able'' to reproduce.
Bogosort In computer science, bogosort (also known as permutation sort, stupid sort, slowsort or bozosort) is a sorting algorithm based on the generate and test paradigm. The function successively generates permutations of its input until it finds one t ...
, a conceptual sorting algorithm (that is extremely inefficient and impractical), can be viewed as a trial and error approach to sorting a list. However, typical simple examples of bogosort do not track which orders of the list have been tried and may try the same order any number of times, which violates one of the basic principles of trial and error. Trial and error is actually more efficient and practical than bogosort; unlike bogosort, it is guaranteed to halt in finite time on a finite list, and might even be a reasonable way to sort extremely short lists under some conditions.
Jumping spider Jumping spiders are a group of spiders that constitute the family (biology), family Salticidae. As of 2019, this family contained over 600 described genera and over 6,000 described species, making it the largest family of spiders at 13% of all sp ...
s of the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
'' Portia'' use trial and error to find new tactics against unfamiliar prey or in unusual situations, and remember the new tactics. Tests show that ''
Portia fimbriata ''Portia fimbriata'', sometimes called the fringed jumping spider, is a jumping spider (family Salticidae) found in Australia and Southeast Asia. Adult females have bodies 6.8 to 10.5 millimetres long, while those of adult males are 5.2 to ...
'' and ''
Portia labiata ''Portia labiata'' is a jumping spider (family Salticidae) found in Sri Lanka, India, southern China, Burma (Myanmar), Malaysia, Singapore, Java, Sumatra and the Philippines. In this medium-sized jumping spider, the front part is orange-brown ...
'' can use trial and error in an artificial environment, where the spider's objective is to cross a miniature
lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') a ...
that is too wide for a simple jump, and must either jump then swim or only swim.


See also

* Ariadne's thread (logic) *
Brute-force attack In cryptography, a brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the correc ...
* Brute-force search *
Dictionary attack In cryptanalysis and computer security, a dictionary attack is an attack using a restricted subset of a keyspace to defeat a cipher or authentication mechanism by trying to determine its decryption key or passphrase, sometimes trying thousands o ...
*
Empiricism In philosophy, empiricism is an epistemological theory that holds that knowledge or justification comes only or primarily from sensory experience. It is one of several views within epistemology, along with rationalism and skepticism. Empir ...
*
Genetic algorithm In computer science and operations research, a genetic algorithm (GA) is a metaheuristic inspired by the process of natural selection that belongs to the larger class of evolutionary algorithms (EA). Genetic algorithms are commonly used to gene ...
*
Learning curve A learning curve is a graphical representation of the relationship between how Skill, proficient people are at a task and the amount of experience they have. Proficiency (measured on the vertical axis) usually increases with increased experience ...
*
Margin of error The margin of error is a statistic expressing the amount of random sampling error in the results of a survey. The larger the margin of error, the less confidence one should have that a poll result would reflect the result of a census of the e ...
* Regula falsi *
Voodoo programming Voodoo may refer to: Religions * African or West African Vodun, practiced by Gbe-speaking ethnic groups * African diaspora religions, a list of related religions sometimes called Vodou/Voodoo ** Candomblé Jejé, also known as Brazilian Vod ...


References


Further reading

*Ashby, W. R. (1960: Second Edition). ''Design for a Brain''.
Chapman & Hall Chapman & Hall is an imprint owned by CRC Press, originally founded as a British publishing house in London in the first half of the 19th century by Edward Chapman and William Hall. Chapman & Hall were publishers for Charles Dickens (from 1840 ...
: London. *Traill, R.R. (1978–2006). ''Molecular explanation for intelligence…'', Brunel University Thesis
HDL.handle.net
*Traill, R.R. (2008). ''Thinking by Molecule, Synapse, or both? — From Piaget’s Schema, to the Selecting/Editing of ncRNA''. Ondwelle: Melbourne
Ondwelle.com
— or French versio
Ondwelle.com.
*Zippelius, R. (1991). ''Die experimentierende Methode im Recht'' (Trial and error in Jurisprudence), Academy of Science, Mainz, {{Authority control Error Heuristics Learning methods Problem solving methods Philosophy of science