Priming (psychology)
Encyclopedia
Priming is an implicit memory
effect in which exposure to a stimulus
influences a response to a later stimulus. It can occur following perceptual, semantic, or conceptual stimulus repetition. For example, if a person reads a list of words including the word table, and is later asked to complete a word starting with tab, the probability that he or she will answer table is greater than if not so primed. Another example is if people see an incomplete sketch that they are unable to identify and they are shown more of the sketch until they recognize the picture, later they will identify the sketch at an earlier stage than was possible for them the first time.
The effects of priming can be very salient
and long lasting, even more so than simple recognition memory
. Unconscious priming effects can affect word choice on a word-stem completion test long after the words have been consciously forgotten.
Priming works best when the two stimuli are in the same modality
. For example visual priming works best with visual cues and verbal priming works best with verbal cues. But priming also occurs between modalities, or between semantically
related words such as "doctor" and "nurse".
readings.
Positive priming is thought to be caused by spreading activation. This means that the first stimulus activates parts of a particular representation or association
in memory
just before carrying out an action or task. The representation is already partially activated when the second stimulus is encountered, so less additional activation is needed for one to become consciously aware of it.
Negative priming is more difficult to explain. Many models have been hypothesized, but currently the most widely accepted are the distractor inhibition and episodic retrieval models. In the distractor inhibition model, the activation of ignored stimuli is inhibited by the brain. The episodic retrieval model hypothesizes that ignored items are flagged 'do-not-respond' by the brain. Later, when the brain acts to retrieve this information, the tag causes a conflict. The time taken to resolve this conflict causes negative priming.
Perceptual priming is based on the form of the stimulus and is enhanced by the match between the early and later stimuli. Perceptual priming is sensitive to the modality and exact format of the stimulus. An example of perceptual priming is the identification of an incomplete word in a word-stem completion test. The presentation of the visual prime does not have to be perfectly consistent with later testing presentations in order to work. Studies have shown that, for example, the absolute size of the stimuli can vary and still provide significant evidence of priming
Conceptual priming is based on the meaning of a stimulus and is enhanced by semantic tasks. For example, table, will show priming effects on chair, because table and chair belong to the same category.
s can prime for complete words that include them. An example of this would be that the morpheme 'psych' can prime for the word 'psychology'.
denotes a special form of visuomotor priming effect. The distinctive feature of response priming is that prime and target are presented in quick succession (typically, less than 100 milliseconds apart) and are coupled to identical or alternative motor responses. When a speeded motor response is performed to classify the target stimulus, a prime immediately preceding the target can thus induce response conflicts when assigned to a different response as the target. These response conflicts have observable effects on motor behavior, leading to priming effects, e.g., in response times and error rates. A special property of response priming is its independence from visual awareness of the prime: For example, response priming effects can increase under conditions where visual awareness of the prime is decreasing.
and phonological activations during visual word recognition.
The term "masked" refers to the fact that the prime word or pseudoword is masked by symbols such as ###### that can be presented in a forward manner (before the prime) or a backward manner (after the prime). These masks enable to diminish the visibility of the prime. The prime is usually presented less than 80 ms in this paradigm.
In all, the short SOA (duration of prime presentation) associated with the masking make the masked priming paradigm a good tool to investigate automatic and irrepressive activations during visual word recognition.
. Tests such as the word-stem completion task, and the word fragment completion task measure perceptual priming. In the word-stem completion task, participants are given a list of study words, and then asked to complete word "stems" consisting of 3 letters with the first word that comes to mind. A priming effect is observed when participants complete stems with words on the study list more often than with novel words. The word fragment completion task is similar, but instead of being given the stem of a word, participants are given a word with some letters missing. The lexical decision task can be used to demonstrate conceptual priming. In this task, participants are asked to determine if a given string is a word or a nonword. Priming is demonstrated when participants are quicker to respond to words that have been primed with semantically-related words, e.g., faster to confirm "nurse" as a word when it is preceded by "doctor" than when it is preceded by "butter". Other evidence has been found through brain imaging and studies from brain injured patients.
patients are described as those who have suffered damage to their medial temporal lobe
, resulting in the impairment of explicit recollection of everyday facts and events. Priming studies on amnesic patients have varying results, depending on both the type of priming test done, as well as the phrasing of the instructions.
Amnesic patients do as well on perceptual priming tasks as healthy patients, however they show some difficulties completing conceptual priming tasks, depending on the specific test. For example, they perform normally on category instance production tasks, but show impaired priming on any task that involves answering general knowledge questions.
Phrasing of the instructions associated with the test has a dramatic impact on an amnesic's ability to complete the task successfully. When performing a word-stem completion test, patients were able to successfully complete the task when asked to complete the stem using the first word that came to mind, but when explicitly asked to recall a word to complete the stem that was on the study list, patients performed at below-average levels.
Overall, studies from amnesic patients indicate that priming is controlled by a brain system separate from the medial temporal system that supports explicit memory
.
. In one study, patients with Wernicke's aphasia who were unable to make semantic judgments showed evidence of semantic priming, while patient with Broca's aphasia who were able to make semantic judgments showed less consistent priming than Wernicke's aphasics or normal controls (Milberg and Blumstein 1981). This dissociation was extended to other linguistic categories such phonology and syntactic processing by Blumstein, Milberg and their colleagues.
tasks, while retaining normal performance on lexical decision tasks. These results suggest that AD patients are impaired in any sort of priming task that requires semantic processing of the stimuli, while priming tasks that require visuoperceptual interpretation of stimuli are unaffected by Alzheimers.
- the inability to comprehend spoken words, but maintaining the ability to read and write, and with no effects to hearing ability. J.P. showed normal perceptual priming, but his conceptual priming ability for spoken words was, expectedly, impaired. Another patient, N.G., who suffered from prosopanomia (the inability to retrieve proper names) following damage the his left temporal lobe, was unable to spontaneously provide names of persons or cities, but was able to successfully complete a word-fragment completion exercise following priming with these names. This demonstrated intact perceptual priming abilities.
Priming while improving performance decreases neural processing in the cerebral cortex
of sensory stimuli with stimulus repetition. This has been found in single-cell recordings and in electroencephalography
(EEG) upon gamma wave
s, with PET
and functional MRI. This reduction is due to representational sharpening in the early sensory areas which reduces the number of neurons representing the stimulus. This leads to a more selective activation of neurons representing objects in higher cognitive areas.
. The left prefrontal cortex is believed to be involved in the semantic processing of words, among other tasks.
The view that perceptual priming is controlled by the extrastriate cortex while conceptual priming is controlled by the left prefrontal cortex is undoubtedly an oversimplified view of the process, and current work is focused on elucidating the brain regions involved in priming in more detail.
This can occur even if the subject is not conscious of the priming stimulus. An example of this was done by Bargh
et al. in 1996. Subjects were implicitly primed with words related to the stereotype of elderly people (example: Florida, forgetful, wrinkle). While the words did not explicitly mention speed or slowness, those who were primed with these words walked more slowly upon exiting the testing booth than those who were primed with neutral stimuli. Similar effects were found with rude and polite stimuli: those primed with rude words were more likely to interrupt an investigator than those primed with neutral words, and those primed with polite words were the least likely to interrupt. A Harvard study showed that something as simple as holding a hot or cold beverage before an interview could result in pleasant or negative opinion of the interviewer.
Implicit memory
Implicit memory is a type of memory in which previous experiences aid in the performance of a task without conscious awareness of these previous experiences. Evidence for implicit memory arises in priming, a process whereby subjects show improved performance on tasks for which they have been...
effect in which exposure to a stimulus
Stimulus (psychology)
In psychology, stimuli are energy patterns which are registered by the senses. In behaviorism and related stimulus–response theories, stimuli constitute the basis for behavior, whereas in perceptual psychology they constitute the basis for perception.In the second half of the 19th century, the...
influences a response to a later stimulus. It can occur following perceptual, semantic, or conceptual stimulus repetition. For example, if a person reads a list of words including the word table, and is later asked to complete a word starting with tab, the probability that he or she will answer table is greater than if not so primed. Another example is if people see an incomplete sketch that they are unable to identify and they are shown more of the sketch until they recognize the picture, later they will identify the sketch at an earlier stage than was possible for them the first time.
The effects of priming can be very salient
Salience (neuroscience)
The salience of an item – be it an object, a person, a pixel, etc – is the state or quality by which it stands out relative to its neighbours...
and long lasting, even more so than simple recognition memory
Recognition memory
Recognition memory is a subcategory of declarative memory Essentially, recognition memory is the ability to recognize previously encountered events, objects, or people...
. Unconscious priming effects can affect word choice on a word-stem completion test long after the words have been consciously forgotten.
Priming works best when the two stimuli are in the same modality
Modality (semiotics)
In semiotics, a modality is a particular way in which the information is to be encoded for presentation to humans, i.e. to the type of sign and to the status of reality ascribed to or claimed by a sign, text or genre. It is more closely associated with the semiotics of Charles Peirce than Saussure...
. For example visual priming works best with visual cues and verbal priming works best with verbal cues. But priming also occurs between modalities, or between semantically
Semantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
related words such as "doctor" and "nurse".
Positive and negative priming
The terms positive and negative priming refer to when priming affects the speed of processing. A positive prime speeds up processing, while a negative prime lowers the speed to slower than un-primed levels. Positive priming is caused by simply experiencing the stimulus, while negative priming is caused by experiencing the stimulus, and then ignoring it. Positive priming effects happen even if the prime is not consciously seen. The effects of positive and negative priming are visible in event-related potential (ERP)Event-related potential
An event-related potential is any measured brain response that is directly the result of a thought or perception. More formally, it is any stereotyped electrophysiological response to an internal or external stimulus....
readings.
Positive priming is thought to be caused by spreading activation. This means that the first stimulus activates parts of a particular representation or association
Association (psychology)
In psychology and marketing, two concepts or stimuli are associated when the experience of one leads to the effects of another, due to repeated pairing. This is sometimes called Pavlovian association for Ivan Pavlov's pioneering of classical conditioning....
in memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
just before carrying out an action or task. The representation is already partially activated when the second stimulus is encountered, so less additional activation is needed for one to become consciously aware of it.
Negative priming is more difficult to explain. Many models have been hypothesized, but currently the most widely accepted are the distractor inhibition and episodic retrieval models. In the distractor inhibition model, the activation of ignored stimuli is inhibited by the brain. The episodic retrieval model hypothesizes that ignored items are flagged 'do-not-respond' by the brain. Later, when the brain acts to retrieve this information, the tag causes a conflict. The time taken to resolve this conflict causes negative priming.
Perceptual and conceptual priming
The difference between perceptual and conceptual primes is whether items with a similar form or items with a similar meaning are primed.Perceptual priming is based on the form of the stimulus and is enhanced by the match between the early and later stimuli. Perceptual priming is sensitive to the modality and exact format of the stimulus. An example of perceptual priming is the identification of an incomplete word in a word-stem completion test. The presentation of the visual prime does not have to be perfectly consistent with later testing presentations in order to work. Studies have shown that, for example, the absolute size of the stimuli can vary and still provide significant evidence of priming
Conceptual priming is based on the meaning of a stimulus and is enhanced by semantic tasks. For example, table, will show priming effects on chair, because table and chair belong to the same category.
Repetition
Repetition, also called direct priming is a form of positive priming. When a stimulus is experienced, it is also primed. This means that later experiences of the stimulus will be processed more quickly by the brain. This effect has been found on words in the lexical decision task.Semantic
In semantic priming, the prime and the target are from the same semantic category and share features. For example, the word dog is a semantic prime for wolf, because the two are both similar animals. Semantic priming is theorized to work because of spreading neural networks. When a person thinks of one item in a category, similar items are stimulated by the brain. Even if they are not words, morphemeMorpheme
In linguistics, a morpheme is the smallest semantically meaningful unit in a language. The field of study dedicated to morphemes is called morphology. A morpheme is not identical to a word, and the principal difference between the two is that a morpheme may or may not stand alone, whereas a word,...
s can prime for complete words that include them. An example of this would be that the morpheme 'psych' can prime for the word 'psychology'.
Associative
In associative priming, the target is a word that has a high probability of appearing with the prime, and is "associated" with it but not necessarily related in semantic features. dog is an associative prime for cat, since the words are closely associated and frequently appear together (in phrases like "raining cats and dogs"). A similar effect is known as context priming. Context priming works by using a context to speed up processing for stimuli that are likely to occur in that context. A useful application of this effect is reading written text. The grammar and vocabulary of the sentence provide contextual clues for words that will occur later in the sentence. These later words are processed more quickly than if they had been read alone, and the effect is greater for more difficult or uncommon words.Response Priming
In the psychology of visual perception and motor control, the term Response PrimingResponse priming
In the psychology of perception and motor control, the term response priming denotes a special form of Priming. Generally, priming effects take place whenever a response to a target stimulus is influenced by a prime stimulus presented at an earlier time...
denotes a special form of visuomotor priming effect. The distinctive feature of response priming is that prime and target are presented in quick succession (typically, less than 100 milliseconds apart) and are coupled to identical or alternative motor responses. When a speeded motor response is performed to classify the target stimulus, a prime immediately preceding the target can thus induce response conflicts when assigned to a different response as the target. These response conflicts have observable effects on motor behavior, leading to priming effects, e.g., in response times and error rates. A special property of response priming is its independence from visual awareness of the prime: For example, response priming effects can increase under conditions where visual awareness of the prime is decreasing.
Masked priming: Examining orthographic and phonological activation during word recognition
The masked priming paradigm has been widely used in the last two decades in order to investigate both orthographicOrthographic
Orthographic may refer to:* Orthographic projection** Orthographic projection ** Orthographic projection * Orthography...
and phonological activations during visual word recognition.
The term "masked" refers to the fact that the prime word or pseudoword is masked by symbols such as ###### that can be presented in a forward manner (before the prime) or a backward manner (after the prime). These masks enable to diminish the visibility of the prime. The prime is usually presented less than 80 ms in this paradigm.
In all, the short SOA (duration of prime presentation) associated with the masking make the masked priming paradigm a good tool to investigate automatic and irrepressive activations during visual word recognition.
Measuring the effects of priming
Priming effects can be found with many of the tests of implicit memoryIndirect tests of memory
Indirect memory tests assess the retention of information without direct reference to the source of information. Participants are given tasks designed to elicit knowledge that was acquired incidentally or unconsciously and is evident when performance shows greater inclination towards items...
. Tests such as the word-stem completion task, and the word fragment completion task measure perceptual priming. In the word-stem completion task, participants are given a list of study words, and then asked to complete word "stems" consisting of 3 letters with the first word that comes to mind. A priming effect is observed when participants complete stems with words on the study list more often than with novel words. The word fragment completion task is similar, but instead of being given the stem of a word, participants are given a word with some letters missing. The lexical decision task can be used to demonstrate conceptual priming. In this task, participants are asked to determine if a given string is a word or a nonword. Priming is demonstrated when participants are quicker to respond to words that have been primed with semantically-related words, e.g., faster to confirm "nurse" as a word when it is preceded by "doctor" than when it is preceded by "butter". Other evidence has been found through brain imaging and studies from brain injured patients.
Amnesia
AmnesicAmnesia
Amnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...
patients are described as those who have suffered damage to their medial temporal lobe
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
, resulting in the impairment of explicit recollection of everyday facts and events. Priming studies on amnesic patients have varying results, depending on both the type of priming test done, as well as the phrasing of the instructions.
Amnesic patients do as well on perceptual priming tasks as healthy patients, however they show some difficulties completing conceptual priming tasks, depending on the specific test. For example, they perform normally on category instance production tasks, but show impaired priming on any task that involves answering general knowledge questions.
Phrasing of the instructions associated with the test has a dramatic impact on an amnesic's ability to complete the task successfully. When performing a word-stem completion test, patients were able to successfully complete the task when asked to complete the stem using the first word that came to mind, but when explicitly asked to recall a word to complete the stem that was on the study list, patients performed at below-average levels.
Overall, studies from amnesic patients indicate that priming is controlled by a brain system separate from the medial temporal system that supports explicit memory
Explicit memory
Explicit memory is the conscious, intentional recollection of previous experiences and information. People use explicit memory throughout the day, such as remembering the time of an appointment or recollecting an event from years ago....
.
Aphasia
Perhaps the first use of semantic priming in neurological patients was with stroke patients with aphasiaAphasia
Aphasia is an impairment of language ability. This class of language disorder ranges from having difficulty remembering words to being completely unable to speak, read, or write....
. In one study, patients with Wernicke's aphasia who were unable to make semantic judgments showed evidence of semantic priming, while patient with Broca's aphasia who were able to make semantic judgments showed less consistent priming than Wernicke's aphasics or normal controls (Milberg and Blumstein 1981). This dissociation was extended to other linguistic categories such phonology and syntactic processing by Blumstein, Milberg and their colleagues.
Dementia
Patients with Alzheimer's disease (AD), the most common form of dementia, have been studied extensively as far as priming goes. Results are conflicting in some cases, but overall, AD patients show decreased priming effects on word-stem completion and free associationFree association (psychology)
Free association is a technique used in psychoanalysis which was originally devised by Sigmund Freud out of the hypnotic method of his mentor and coworker, Josef Breuer....
tasks, while retaining normal performance on lexical decision tasks. These results suggest that AD patients are impaired in any sort of priming task that requires semantic processing of the stimuli, while priming tasks that require visuoperceptual interpretation of stimuli are unaffected by Alzheimers.
Focal cortical lesions
Patient J.P., who suffered a stroke in the left medial/temporal gyrus, resulting in word meaning deafnessPure word deafness
Pure Word Deafness is caused by bilateral damage to the posterior superior temporal lobes or disruption of connections between these areas. It exhibits itself as inability to comprehend the meaning of speech, but still being able to hear, speak, read, and write.-Presentation:The underlying...
- the inability to comprehend spoken words, but maintaining the ability to read and write, and with no effects to hearing ability. J.P. showed normal perceptual priming, but his conceptual priming ability for spoken words was, expectedly, impaired. Another patient, N.G., who suffered from prosopanomia (the inability to retrieve proper names) following damage the his left temporal lobe, was unable to spontaneously provide names of persons or cities, but was able to successfully complete a word-fragment completion exercise following priming with these names. This demonstrated intact perceptual priming abilities.
Perceptual priming
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
of sensory stimuli with stimulus repetition. This has been found in single-cell recordings and in electroencephalography
Electroencephalography
Electroencephalography is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain...
(EEG) upon gamma wave
Gamma wave
A gamma wave is a pattern of neural oscillation in humans with a frequency between 25 to 100 Hz, though 40 Hz is prototypical.According to a popular theory, gamma waves may be implicated in creating the unity of conscious perception...
s, with PET
Positron emission tomography
Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
and functional MRI. This reduction is due to representational sharpening in the early sensory areas which reduces the number of neurons representing the stimulus. This leads to a more selective activation of neurons representing objects in higher cognitive areas.
Conceptual priming
Conceptual priming has been linked to reduced blood flow in the left prefrontal cortexPrefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...
. The left prefrontal cortex is believed to be involved in the semantic processing of words, among other tasks.
The view that perceptual priming is controlled by the extrastriate cortex while conceptual priming is controlled by the left prefrontal cortex is undoubtedly an oversimplified view of the process, and current work is focused on elucidating the brain regions involved in priming in more detail.
In daily life
Priming is thought to play a large part in the systems of stereotyping. This is because attention to a response increases the frequency of that response, even if the attended response is undesired. The attention given to these response or behaviours primes them for later activation.This can occur even if the subject is not conscious of the priming stimulus. An example of this was done by Bargh
John Bargh
John A. Bargh is a distinguished social psychologist currently working at Yale University, where he has formed the Automaticity in Cognition, Motivation, and Evaluation Laboratory...
et al. in 1996. Subjects were implicitly primed with words related to the stereotype of elderly people (example: Florida, forgetful, wrinkle). While the words did not explicitly mention speed or slowness, those who were primed with these words walked more slowly upon exiting the testing booth than those who were primed with neutral stimuli. Similar effects were found with rude and polite stimuli: those primed with rude words were more likely to interrupt an investigator than those primed with neutral words, and those primed with polite words were the least likely to interrupt. A Harvard study showed that something as simple as holding a hot or cold beverage before an interview could result in pleasant or negative opinion of the interviewer.