The differential outcomes effect (DOE) is a

theory A theory is a systematic and rational form of abstract thinking about a phenomenon, or the conclusions derived from such thinking. It involves contemplative and logical reasoning, often supported by processes such as observation, experimentation, ...

behaviorism Behaviorism is a systematic approach to understand the behavior of humans and other animals. It assumes that behavior is either a reflex elicited by the pairing of certain antecedent stimuli in the environment, or a consequence of that indivi ...

, a branch of

psychology Psychology is the scientific study of mind and behavior. Its subject matter includes the behavior of humans and nonhumans, both consciousness, conscious and Unconscious mind, unconscious phenomena, and mental processes such as thoughts, feel ...

, that shows that a positive effect on

accuracy Accuracy and precision are two measures of ''observational error''. ''Accuracy'' is how close a given set of measurements (observations or readings) are to their ''true value''. ''Precision'' is how close the measurements are to each other. The ...

occurs in

discrimination learning Discrimination learning is defined in psychology as the ability to respond differently to different stimuli. This type of learning is used in studies regarding operant and classical conditioning. Operant conditioning involves the modification of a ...

between different

stimuli A stimulus is something that causes a physiological response. It may refer to: *Stimulation **Stimulus (physiology), something external that influences an activity **Stimulus (psychology), a concept in behaviorism and perception *Stimulus (economi ...

when unique rewards are paired with each individual stimulus. The DOE was first demonstrated in 1970 by Milton Trapold on an experiment with

rats Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' (pack rats), '' Bandicota'' (bandicoot ...

. Rats were trained to discriminate between a clicker and a tone by pressing the left and right levers. Half of the rats were trained using the differential outcomes procedure (DOP), where the clicker was paired with sucrose and tone with food pellets. The remaining rats were trained with only sucrose or only food pellets. The rats trained with the DOP were significantly more accurate than those trained with only one type of

reinforcement In Behaviorism, behavioral psychology, reinforcement refers to consequences that increase the likelihood of an organism's future behavior, typically in the presence of a particular ''Antecedent (behavioral psychology), antecedent stimulus''. Fo ...

(common outcome). Since then it has been established through a myriad of

experiments An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into Causality, cause-and-effect by demonstrating what outcome o ...

that the DOE exists in most

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

capable of

learning Learning is the process of acquiring new understanding, knowledge, behaviors, skills, value (personal and cultural), values, Attitude (psychology), attitudes, and preferences. The ability to learn is possessed by humans, non-human animals, and ...

Definition

The DOE not only states that an

association Association may refer to: *Club (organization), an association of two or more people united by a common interest or goal *Trade association, an organization founded and funded by businesses that operate in a specific industry *Voluntary associatio ...

between a stimulus and a

response Response may refer to: *Call and response (music), musical structure *Reaction (disambiguation) *Request–response **Output or response, the result of telecommunications input *Response (liturgy), a line answering a versicle * Response (music) o ...

is formed as traditional

classical conditioning Classical conditioning (also respondent conditioning and Pavlovian conditioning) is a behavioral procedure in which a biologically potent Stimulus (physiology), stimulus (e.g. food, a puff of air on the eye, a potential rival) is paired with a n ...

states, but that a simultaneous association is formed between a stimulus and a reinforcer in the

subject Subject ( "lying beneath") may refer to: Philosophy *''Hypokeimenon'', or ''subiectum'', in metaphysics, the "internal", non-objective being of a thing **Subject (philosophy), a being that has subjective experiences, subjective consciousness, or ...

. If one were to pair a stimulus with a reinforcer, that is known as a differential condition. When this is employed, one can expect a higher accuracy in tests when discriminating between two stimuli, due to this increased amount of information available to the subject than in a non-differential condition.

History

In 1970 the DOE was discovered by Trapold when testing the reasoning behind the theory. He created an experiment where rats were taught to discriminate between a clicking noise and a tone. He associated the left bar with the clicking noise and the right bar with the

tone Tone may refer to: Visual arts and color-related * Tone (color theory), a mix of tint and shade, in painting and color theory * Tone (color), the lightness or brightness (as well as darkness) of a color * Toning (coin), color change in coins * ...

. The experimental group was given

sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...

for one response and

food Food is any substance consumed by an organism for Nutrient, nutritional support. Food is usually of plant, animal, or Fungus, fungal origin and contains essential nutrients such as carbohydrates, fats, protein (nutrient), proteins, vitamins, ...

for the other. The control group was randomly given either food or sucrose for each response. The rats in the

experimental group An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when ...

were able to discriminate between the two stimuli faster than the rats in the

control group In the design of experiments, hypotheses are applied to experimental units in a treatment group. In comparative experiments, members of a control group receive a standard treatment, a placebo, or no treatment at all. There may be more than one tr ...

. The DOE was then found to exist in various species including but not limited to

pigeons Columbidae is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with small heads, relatively short necks and slender bills that in some species feature fleshy ceres. ...

, and

horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 milli ...

over the years and was then finally explored in

humans Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

by Pauline Maki, J. Bruce Overmier, Sandra Delos, and Arlyne Gutmann in 1995. They tested

children A child () is a human being between the stages of childbirth, birth and puberty, or between the Development of the human body, developmental period of infancy and puberty. The term may also refer to an unborn human being. In English-speaking ...

who were from 4 to 7 years old to discriminate between two different

shapes A shape is a graphical representation of an object's form or its external boundary, outline, or external surface. It is distinct from other object properties, such as color, texture, or material type. In geometry, ''shape'' excludes informatio ...

. Children who were given either a reinforcer consisting of food for one response or given a verbal reinforcer for another response gave far more accurate answers than those who were given random reinforcers for different responses. Then in 2002, Odette Miller, Kevin Waugh, and Karen Chambers proved that the DOE exists in

adults An adult is an animal that has reached full growth. The biological definition of the word means an animal reaching sexual maturity and thus capable of reproduction. In the human context, the term ''adult'' has meanings associated with social and ...

. This

experiment An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs whe ...

was novel because it first used average adults (

college students A student is a person enrolled in a school or other educational institution, or more generally, a person who takes a special interest in a subject. In the United Kingdom and most commonwealth countries, a "student" attends a secondary school ...

) in the experiment, and had a complex discrimination task which required participants to be able to distinguish between 15 different

Kanji are logographic Chinese characters, adapted from Chinese family of scripts, Chinese script, used in the writing of Japanese language, Japanese. They were made a major part of the Japanese writing system during the time of Old Japanese and are ...

characters. In prior experiments, participants were only required to discriminate between two different stimuli. For the participants in the group given a differential condition, each Kanji character was given a unique

photo A photograph (also known as a photo, or more generically referred to as an ''image'' or ''picture'') is an image created by light falling on a photosensitive surface, usually photographic film or an electronic image sensor. The process and pra ...

and

prize A prize is an award to be given to a person or a group of people (such as sporting teams and organizations) to recognize and reward their actions and achievements.

for answering correctly. Participants in the group given a non-differential condition were given a random photo and prize for answering the question correctly. The group given a differential condition fared far better than those in the group with the non-differential condition, demonstrating that the DOE not only exists in adult humans but also can be applied to tasks requiring discrimination of more than two stimuli. A meta-analysis demonstrated that the DOP has a large effect on humans, demonstrating that effect in typically developing children and healthy adults. More recently several studies have looked at the applications of the differential outcomes effect for populations with

intellectual disabilities Intellectual disability (ID), also known as general learning disability (in the United Kingdom), and formerly mental retardation (in the United States), Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010).Archive is a generalized neurodevelopmental ...

and pervasive developmental disabilities. Scientists have theorised that this procedure may be useful in overcoming barriers to learning.

References

{{reflist Behaviorism Psychological theories Theory of mind