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127-413: Research on the visual P2 is at an early stage compared to other more established ERP components and there is much that we still do not know about it. Part of the difficulty of clearly characterizing this component is that it appears to be modulated by a large and diverse number of cognitive tasks. Functionally, there seems to be partial agreement amongst researchers in the field of cognitive neuroscience that

254-410: A periodic variable is a measure of its change in a single period (such as time or spatial period ). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values . In older texts, the phase of a periodic function

381-406: A bottom-up saliency map, which is received by the superior colliculus in the midbrain area to guide attention or gaze shifts. The second aspect is called top-down processing, also known as goal-driven, endogenous attention, attentional control or executive attention. This aspect of our attentional orienting is under the control of the person who is attending. It is mediated primarily by

508-410: A central point on a screen. It is then that participants are given a cue indicating the identity of a target stimulus. Following a delay, participants are then presented with a set of items. Instructed to identify the location of the target stimulus, participants respond by button-pressing or some other method. Trials are classified as either "efficient" or "inefficient" based upon the relationship between

635-520: A common neural architecture, in that they control both covert and overt attentional systems. For example, if individuals attend to the right hand corner field of view, movement of the eyes in that direction may have to be actively suppressed. Covert attention has been argued to reflect the existence of processes "programming explicit ocular movement". However, this has been questioned on the grounds that N2 , "a neural measure of covert attentional allocation—does not always precede eye movements". However,

762-624: A complex social community with multiple relationships. Many Indigenous children in the Americas predominantly learn by observing and pitching in. There are several studies to support that the use of keen attention towards learning is much more common in Indigenous Communities of North and Central America than in a middle-class European-American setting. This is a direct result of the Learning by Observing and Pitching In model. Keen attention

889-615: A delay, and a subsequent stimulus upon which participants must make a classification. Researchers have used the visual search paradigm with stimulus arrays and found that target stimuli elicited larger anterior P2 components compared with standards. This evidence suggests that top-down information processing about feature classification affected processing at the visual perception stage. Thus, the P2 may index mechanisms for selective attention, feature detection (including color, orientation, shape, etc.) and other early stages of item encoding. With regard to

1016-452: A drum, slamming a door, etc. where the amplitude is transient and must be represented as either a continuous function or a discrete vector. Percussive amplitude envelopes model many common sounds that have a transient loudness attack, decay, sustain, and release. With waveforms containing many overtones, complex transient timbres can be achieved by assigning each overtone to its own distinct transient amplitude envelope. Unfortunately, this has

1143-461: A given word. Researchers found that the P2 component varied with the level of expectancy for a particular item in a sentence for right but not left visual field presentations, suggesting that the left hemisphere of the brain may use contextual information to prepare for the visual analysis of upcoming stimuli. For presentation biased to the left hemisphere, the P2 is larger (more positive) for strongly constrained sentence endings, independent of whether

1270-494: A high tendency to be especially keen observers. This learning by observing and pitching-in model requires active levels of attention management. The child is present while caretakers engage in daily activities and responsibilities such as: weaving, farming, and other skills necessary for survival. Being present allows the child to focus their attention on the actions being performed by their parents, elders, and/or older siblings. In order to learn in this way, keen attention and focus

1397-462: A high tendency to be especially wide, keen observers. This points to a strong cultural difference in attention management. Attention may be differentiated into "overt" versus "covert" orienting. Overt orienting is the act of selectively attending to an item or location over others by moving the eyes to point in that direction. Overt orienting can be directly observed in the form of eye movements. Although overt eye movements are quite common, there

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1524-468: A message while carrying on a meaningful conversation. This relies on the reflexive response due to "overlearning" the skill of morse code reception/detection/transcription so that it is an autonomous function requiring no specific attention to perform. This overtraining of the brain comes as the "practice of a skill [surpasses] 100% accuracy," allowing the activity to become autonomic, while your mind has room to process other actions simultaneously. Based on

1651-399: A much more crude fashion (i.e., low-resolution). This fringe extends out to a specified area, and the cut-off is called the margin. The second model is called the zoom-lens model and was first introduced in 1986. This model inherits all properties of the spotlight model (i.e., the focus, the fringe, and the margin), but it has the added property of changing in size. This size-change mechanism

1778-507: A repetition effect for words that had been studied in the left visual field, (encoded in the right hemisphere ), but not in the right visual field. The P2 amplitude was bigger for words that had been seen before. This indicates that P2 amplitude is modulated by aspects of recognition and that there is a hemispheric difference (which may be important for language processing, see below). The P2 has also been found to be involved in language processes including sentential constraint and expectancy for

1905-404: A sinusoidal waveform. One property of root mean square voltages and currents is that they produce the same heating effect as a direct current in a given resistance. The peak-to-peak value is used, for example, when choosing rectifiers for power supplies, or when estimating the maximum voltage that insulation must withstand. Some common voltmeters are calibrated for RMS amplitude, but respond to

2032-430: A specified reference and therefore should be modified by qualifiers, such as average , instantaneous , peak , or root-mean-square . Pulse amplitude also applies to the amplitude of frequency - and phase -modulated waveform envelopes . In this simple wave equation The units of the amplitude depend on the type of wave, but are always in the same units as the oscillating variable. A more general representation of

2159-435: A visual search. The amplitude of the P2 is greater when the visual search is more efficient (selective attention), but this does not affect the latency. Research using the visual search paradigm has shown that features such as color, size, and orientation of the stimulus have a necessary role in eliciting the P2 effect seen during trials of efficient search. Other characteristics, such as attention, repetition and probability of

2286-468: A visual semantic priming paradigm, P2 amplitude differences are associated with phase-locked theta brain wave oscillations. Among the complex of the P1 , N1 and P2, the P2 shows the strongest task-related modulation of theta wave oscillations between congruent and incongruent tasks. Source analyses in this study and others showed that local generators of the P2 may originate in parieto-occipital regions. Also, it

2413-401: Is a distinction that can be made between two types of eye movements; reflexive and controlled. Reflexive movements are commanded by the superior colliculus of the midbrain . These movements are fast and are activated by the sudden appearance of stimuli. In contrast, controlled eye movements are commanded by areas in the frontal lobe . These movements are slow and voluntary. Covert orienting

2540-480: Is a lack of measurement surrounding distributions of temporal and spatial attention. Only a concentrated amount of attention on how effective one is completing the task and how long they take is being analyzed making a more redundant analysis on overall cognition of being able to process multiple stimuli through perception. Attention is best described as the sustained focus of cognitive resources on information while filtering or ignoring extraneous information. Attention

2667-440: Is a mental state (“the power of the mind to be about something”, arising even unconsciously), the description of the construct of attention should be understood in the dynamical sense as the ability to elevate the clear perception of the narrow region of the content of consciousness and to keep in mind this state for a time. The attention threshold would be the period of minimum time needed for employing perception to clearly apprehend

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2794-467: Is a single pool of attentional resources that can be freely divided among multiple tasks. This model seems oversimplified, however, due to the different modalities (e.g., visual, auditory, verbal) that are perceived. When the two simultaneous tasks use the same modality, such as listening to a radio station and writing a paper, it is much more difficult to concentrate on both because the tasks are likely to interfere with each other. The specific modality model

2921-529: Is a very basic function that often is a precursor to all other neurological/cognitive functions. As is frequently the case, clinical models of attention differ from investigation models. One of the most used models for the evaluation of attention in patients with very different neurologic pathologies is the model of Sohlberg and Mateer. This hierarchic model is based in the recovering of attention processes of brain damage patients after coma . Five different kinds of activities of growing difficulty are described in

3048-472: Is an initial pre-attentive parallel phase of perceptual segmentation and analysis that encompasses all of the visual items present in a scene. At this phase, descriptions of the objects in a visual scene are generated into structural units; the outcome of this parallel phase is a multiple-spatial-scale structured representation. Selective attention intervenes after this stage to select information that will be entered into visual short-term memory." The contrast of

3175-539: Is based on performance of doing two tasks simultaneously, usually that involves driving while performing another task, such as texting, eating, or even speaking to passengers in the vehicle, or with a friend over a cellphone. This research reveals that the human attentional system has limits for what it can process: driving performance is worse while engaged in other tasks; drivers make more mistakes, brake harder and later, get into more accidents, veer into other lanes, and/or are less aware of their surroundings when engaged in

3302-440: Is because they are typically presented at the center of a display, where an observer's eyes are likely to be fixated. Central cues, such as an arrow or digit presented at fixation, tell observers to attend to a specific location. When examining differences between exogenous and endogenous orienting, some researchers suggest that there are four differences between the two kinds of cues: There exist both overlaps and differences in

3429-572: Is both a requirement and result of learning by observing and pitching-in. Incorporating the children in the community gives them the opportunity to keenly observe and contribute to activities that were not directed towards them. It can be seen from different Indigenous communities and cultures, such as the Mayans of San Pedro , that children can simultaneously attend to multiple events. Most Maya children have learned to pay attention to several events at once in order to make useful observations. One example

3556-434: Is driven by the properties of the objects themselves. Some processes, such as motion or a sudden loud noise, can attract our attention in a pre-conscious, or non-volitional way. We attend to them whether we want to or not. These aspects of attention are thought to involve parietal and temporal cortices, as well as the brainstem . More recent experimental evidence support the idea that the primary visual cortex creates

3683-436: Is enhanced firing. If a neuron has a different response to a stimulus when an animal is not attending to a stimulus, versus when the animal does attend to the stimulus, then the neuron's response will be enhanced even if the physical characteristics of the stimulus remain the same. In a 2007 review, Professor Eric Knudsen describes a more general model which identifies four core processes of attention, with working memory at

3810-409: Is evoked as part of the normal response to visual stimuli, but the amplitude and latency (delay between stimulus and response) may be affected by exogenous factors, such as repeated visual stimuli. This component has been linked with higher-order perceptual and attentional processes, including feature analysis of geometric figures and visually presented words . The exact function and neural source of

3937-400: Is important in the search for exoplanets (see Doppler spectroscopy ). In general, the use of peak amplitude is simple and unambiguous only for symmetric periodic waves, like a sine wave, a square wave, or a triangle wave. For an asymmetric wave (periodic pulses in one direction, for example), the peak amplitude becomes ambiguous. This is because the value is different depending on whether

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4064-403: Is investigating the diagnostic symptoms associated with traumatic brain injury and its effects on attention. Attention also varies across cultures. The relationships between attention and consciousness are complex enough that they have warranted philosophical exploration. Such exploration is both ancient and continually relevant, as it can have effects in fields ranging from mental health and

4191-449: Is known that the visual P2 in monkeys is generated by neurons in area V2 of extrastriate cortex . Researchers used a combination of ERP, current source density (CSD) and multiunit activity (MUA) methods to locate the source of the P2 in the V2 layer of the visual cortex between 100–300 ms. At present, the P2 has been well-characterized in studies that focus primarily on visual sensation, such as

4318-541: Is linked to eye movement circuitry that sets up a slower saccade to that location. There are studies that suggest the mechanisms of overt and covert orienting may not be controlled separately and independently as previously believed. Central mechanisms that may control covert orienting, such as the parietal lobe , also receive input from subcortical centres involved in overt orienting. In support of this, general theories of attention actively assume bottom-up (reflexive) processes and top-down (voluntary) processes converge on

4445-416: Is no longer amplitude since there is the possibility that a constant ( DC component ) is included in the measurement. Peak-to-peak amplitude (abbreviated p–p or PtP or PtoP ) is the change between peak (highest amplitude value) and trough (lowest amplitude value, which can be negative). With appropriate circuitry, peak-to-peak amplitudes of electric oscillations can be measured by meters or by viewing

4572-466: Is not yet understood whether the visual, auditory or other P2s reflect the same functional and neural activities. Like other evoked-response potentials, the presence of the P2 is revealed in the waveform of the EEG recorded by time-locking data from trials to the onset of the stimulus, in appropriate paradigms. As data from the recordings of multiple trials are averaged together, the persistent characteristics of

4699-488: Is present in the ways in which children of indigenous backgrounds interact both with their surroundings and with other individuals. Simultaneous attention requires focus on multiple simultaneous activities or occurrences. This differs from multitasking, which is characterized by alternating attention and focus between multiple activities, or halting one activity before switching to the next. Simultaneous attention involves uninterrupted attention to several activities occurring at

4826-458: Is required. Eventually the child is expected to be able to perform these skills themselves. In the domain of computer vision , efforts have been made to model the mechanism of human attention, especially the bottom-up intentional mechanism and its semantic significance in classification of video contents. Both spatial attention and temporal attention have been incorporated in such classification efforts. Amplitude The amplitude of

4953-464: Is sensitive to the difference between two and three-dimensional images, without using actual depth or information integrated across both eyes. Much in line with observations of traditional visual search paradigms, the application of P2 studies to language research has shown that the amplitude of the P2 is sensitive to both the orthographic combinability and phonological consistency (neighborhood sizes for similar appearing and similar sounding words) in

5080-471: Is simultaneous attention which involves uninterrupted attention to several activities occurring at the same time. Another cultural practice that may relate to simultaneous attention strategies is coordination within a group. San Pedro toddlers and caregivers frequently coordinated their activities with other members of a group in multiway engagements rather than in a dyadic fashion. Research concludes that children with close ties to Indigenous American roots have

5207-426: Is sometimes called the amplitude. For symmetric periodic waves, like sine waves or triangle waves , peak amplitude and semi amplitude are the same. In audio system measurements , telecommunications and others where the measurand is a signal that swings above and below a reference value but is not sinusoidal , peak amplitude is often used. If the reference is zero, this is the maximum absolute value of

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5334-509: Is that P2 amplitude changes are sometimes seen independent of N1 amplitude changes, again suggesting some degree of independence of N1, and P2 latencies and amplitudes appear to be affected by old age. In terms of modality, the visual P2 is similar to the auditory P2 and both have been studied in similar contexts. There are most likely multiple distinct P2s in different modalities, including both frontal and posterior visual P2s, which may or may not have similar origins or functional similarities. It

5461-448: Is the act of mentally shifting one's focus without moving one's eyes. Simply, it is changes in attention that are not attributable to overt eye movements. Covert orienting has the potential to affect the output of perceptual processes by governing attention to particular items or locations (for example, the activity of a V4 neuron whose receptive field lies on an attended stimuli will be enhanced by covert attention) but does not influence

5588-452: Is the intentional allocation of attentional resources to a predetermined location or space. Simply stated, endogenous orienting occurs when attention is oriented according to an observer's goals or desires, allowing the focus of attention to be manipulated by the demands of a task. In order to have an effect, endogenous cues must be processed by the observer and acted upon purposefully. These cues are frequently referred to as central cues . This

5715-402: Is the result of different angles of view integrated between the two eyes. In this study, P2 amplitude was significantly larger in the condition with three-dimensional convex and concave images, than in condition with two-dimensional images. These changes were found for electrodes placed over bilateral parieto-occipital regions. This study showed that the P2 generated around the visual cortex region

5842-402: Is the spotlight model. The term "spotlight" was inspired by the work of William James , who described attention as having a focus, a margin, and a fringe. The focus is an area that extracts information from the visual scene with a high-resolution, the geometric center of which being where visual attention is directed. Surrounding the focus is the fringe of attention, which extracts information in

5969-465: Is thought that the visual P2 encompasses both a frontal and a posterior source component; in particular some of the neural activity may originate from the visual cortex in the occipital region, while the similar auditory P2 is likely generated at least in part in the auditory cortex in the temporal region and the reticular activating system . Ross and Tremblay recently showed different source locations for auditory evoked N1 and P2 sources using MEG. In

6096-402: Is thought to operate as a two-stage process. In the first stage, attention is distributed uniformly over the external visual scene and processing of information is performed in parallel. In the second stage, attention is concentrated to a specific area of the visual scene (i.e., it is focused), and processing is performed in a serial fashion. The first of these models to appear in the literature

6223-542: The allocation of limited cognitive processing resources. Attention is manifested by an attentional bottleneck , in terms of the amount of data the brain can process each second; for example, in human vision , less than 1% of the visual input data stream of 1MByte/sec can enter the bottleneck, leading to inattentional blindness . Attention remains a crucial area of investigation within education , psychology , neuroscience , cognitive neuroscience , and neuropsychology . Areas of active investigation involve determining

6350-455: The frontal cortex and basal ganglia as one of the executive functions . Research has shown that it is related to other aspects of the executive functions, such as working memory , and conflict resolution and inhibition. A "hugely influential" theory regarding selective attention is the perceptual load theory , which states that there are two mechanisms that affect attention: cognitive and perceptual. The perceptual mechanism considers

6477-562: The square root of the mean over time of the square of the vertical distance of the graph from the rest state; i.e. the RMS of the AC waveform (with no DC component ). Mathematically the RMS can be defined as: R M S = E [ y 2 ] {\displaystyle RMS={\sqrt {\mathbb {E} [y^{2}]}}} Where y is the amplitude of the signal. For complicated waveforms, especially non-repeating signals like noise,

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6604-523: The P2 become apparent. The fact that this waveform appears stable across similar trials is what suggests that it is a meaningful response to a given stimulus. Using electrodes attached to the earlobes of participants as a reference the visual P2 can be found over anterior and central sites on the scalp, and is usually maximal over the frontal region. The more posterior P2 has been studied in relation to visual complexity in language processing, visual search tasks and memory and repetitions paradigms. The component

6731-500: The P2 is not yet known, but some evidence indicates that the P2 may reflect general neural processes that occur when a visual (or other sensory) input is compared with an internal representation or expectation in memory or language context. The P2 has traditionally been studied in the context of perception, with specific emphasis on how stimulus evaluation takes place. As such, multiple paradigms have been used in experiments seeking to understand how manipulations of sensory stimuli modulate

6858-446: The P2 is sensitive to short-term working memory and recognition as well. While these studies are not visual in nature, the relationship of the general waveform to memory capacity may have clinical applications (see below) that involve both visual and non-visual P2 components and points toward a consistent relationship between the two. In fact, researchers have found a similar memory effect for words that were presented visually. They found

6985-503: The P2 may be a part of cognitive matching system that compares sensory inputs with stored memory. The first mentions of an ERP component similar to that of the modern P2 were characterized in studies of basic visual and auditory evoked potentials . One of the first of such studies involved the presentation of flashing lights. Using this method, researchers found that a series of potential changes were consistently observed across repeated trials. These would later be classified as components of

7112-415: The P2 originates from. Specifically, this latency pattern has been found over posterior electrode sites. As such, the latency of flash evoked P2 waveform may be useful as an early diagnostic tool for Alzheimer's disease or Alzheimer's risk, particularly when seen over the characteristic posterior sites. Attention Attention or focus , is the concentration of awareness on some phenomenon to

7239-516: The P2 represents some aspect of higher-order perceptual processing, modulated by attention . It is known that the P2 is typically elicited as part of the normal response to visual stimuli and has been studied in relation to visual search and attention , language context information, and memory and repetition effects. The amplitude of the peak of the waveform may be modulated by many different aspects of visual stimuli, which allow it to be used for studies of visual cognition and disease. In general,

7366-754: The P2 separately from the N1 and have found that the amplitude of the P2 itself is larger for target stimuli that are less frequent. This is similar to the P3, though the P2 is usually seen for more simple features than the P3. In the auditory domain, there is evidence of enhanced P2 amplitudes even when a target stimuli is not embedded in a series of identical stimuli. In these instances, enhanced P2 amplitudes have been associated with auditory learning and repeated stimulus exposure. Enhanced P2 amplitudes have been reported in musicians with extensive listening experience as well as laboratory based auditory training experiments. A significant finding

7493-492: The P2 was characterized as a sub-component of a complex involving the N1, P1 and P2, which was known as the vertex potential and which was classically studied as a unitary phenomenon. In particular, the relationship between the N1 and P2 was thought to be important. The difference between the N1 and P2, known as the vertex amplitude, was found to be significantly larger for target than non-target stimuli and for rapid attention switching task. Further studies have subsequently examined

7620-420: The RMS amplitude is usually used because it is both unambiguous and has physical significance. For example, the average power transmitted by an acoustic or electromagnetic wave or by an electrical signal is proportional to the square of the RMS amplitude (and not, in general, to the square of the peak amplitude). For alternating current electric power , the universal practice is to specify RMS values of

7747-406: The ability of people to learn new information when there were multiple tasks to be performed, or to probe the limits of our perception (c.f. Donald Broadbent ). There is also older literature on people's performance on multiple tasks performed simultaneously, such as driving a car while tuning a radio or driving while being on the phone. The vast majority of current research on human multitasking

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7874-465: The ability of the newer techniques to measure precisely localized activity inside the brain generated renewed interest by a wider community of researchers. A growing body of such neuroimaging research has identified a frontoparietal attention network which appears to be responsible for control of attention. A definition of a psychological construct forms a research approach to its study. In scientific works, attention often coincides and substitutes

8001-457: The activity related to the P2 represents some sort of a top-down process in which prior associations is accessed in the presence of stimuli. It would appear that by incorporating relevant associations into working memory, presented stimuli can be evaluated as being either similar or dissimilar to mental representations. The visual P2 has been proposed to have clinical utility with regard to Alzheimer's disease diagnosis. Researchers have found that

8128-801: The actual word was the expected one or not. This has been interpreted as suggesting that the left hemisphere in particular uses top-down attentional mechanisms to prepare to process words that are likely to be expected. In some cases (for example, with pictures instead of words in sentences), it may also reflect matching of input with expectation. The P2 has also been found to be sensitive to other forms of visual cognitive processing. Researchers recorded visual evoked potentials in response to non-stereoscopic two-dimensional and three-dimensional images in order to study neurophysiological correlates of depth perception. These non-stereoscopic images depict depth using line drawings that can be perceived as three-dimensional by one eye as opposed to by binocular depth perception that

8255-401: The air or the diaphragm of a speaker ) is described. The logarithm of the amplitude squared is usually quoted in dB , so a null amplitude corresponds to − ∞  dB. Loudness is related to amplitude and intensity and is one of the most salient qualities of a sound, although in general sounds it can be recognized independently of amplitude . The square of the amplitude is proportional to

8382-517: The areas of the brain that are responsible for endogenous and exogenous orientating. Another approach to this discussion has been covered under the topic heading of "bottom-up" versus "top-down" orientations to attention. Researchers of this school have described two different aspects of how the mind focuses attention to items present in the environment. The first aspect is called bottom-up processing, also known as stimulus-driven attention or exogenous attention. These describe attentional processing which

8509-413: The attentiveness of the subject lead to decreased amplitude of the P2. Increased attention decreases the amount of search space, or number of associations that need to be made, and may facilitate feature classification in visual search at the stage of perceptual processing. More probable targets also lead to decreased amplitude of the P2, which is sensitive to the number of non-target (distracter) features in

8636-427: The auditory P2, the primary paradigm used to study manipulations of this type of sensory information is the auditory oddball task. In this procedure, participants are presented with a stream of auditory stimuli: including frequent, standard stimuli as well as infrequent, target stimuli. Participants of such studies are asked to ignore the frequent standards and respond to the infrequent targets. In general, increases in

8763-481: The average value of a rectified waveform. Many digital voltmeters and all moving coil meters are in this category. The RMS calibration is only correct for a sine wave input since the ratio between peak, average and RMS values is dependent on waveform . If the wave shape being measured is greatly different from a sine wave, the relationship between RMS and average value changes. True RMS-responding meters were used in radio frequency measurements, where instruments measured

8890-693: The center: Neurally, at different hierarchical levels spatial maps can enhance or inhibit activity in sensory areas, and induce orienting behaviors like eye movement. In many cases attention produces changes in the EEG . Many animals, including humans, produce gamma waves (40–60 Hz) when focusing attention on a particular object or activity. Another commonly used model for the attention system has been put forth by researchers such as Michael Posner . He divides attention into three functional components: alerting, orienting, and executive attention that can also interact and influence each other. Children appear to develop patterns of attention related to

9017-475: The characteristics of the P2. The visual P2 has been studied in the context of visual priming paradigms, oddball paradigms (where the amplitude is enhanced to targets), and studies of repetition in language. One of the more well-studied paradigms with regards to the visual P2 has classically been the visual search paradigm, which tests perception, attention, memory, and response selection. In this paradigm, participants are instructed to focus their attention at

9144-429: The combined research of Vygotsky and Luria have determined a large part of the contemporary understanding and definition of attention as it is understood at the start of the 21st-century. Multitasking can be defined as the attempt to perform two or more tasks simultaneously; however, research shows that when multitasking, people make more mistakes or perform their tasks more slowly. Attention must be divided among all of

9271-493: The component tasks to perform them. In divided attention, individuals attend or give attention to multiple sources of information at once or perform more than one task at the same time. Older research involved looking at the limits of people performing simultaneous tasks like reading stories, while listening and writing something else, or listening to two separate messages through different ears (i.e., dichotic listening ). Generally, classical research into attention investigated

9398-415: The conversation based upon the needs of the driver. For example, if traffic intensifies, a passenger may stop talking to allow the driver to navigate the increasingly difficult roadway; a conversation partner over a phone would not be aware of the change in environment. There have been multiple theories regarding divided attention. One, conceived by cognitive scientist Daniel Kahneman , explains that there

9525-416: The cue will not relay reliable, accurate information about where a target is going to occur. This means that the mere presence of an exogenous cue will affect the response to other stimuli that are subsequently presented in the cue's previous location. Several studies have investigated the influence of valid and invalid cues. They concluded that valid peripheral cues benefit performance, for instance when

9652-403: The cultural practices of their families, communities, and the institutions in which they participate. In 1955, Jules Henry suggested that there are societal differences in sensitivity to signals from many ongoing sources that call for the awareness of several levels of attention simultaneously. He tied his speculation to ethnographic observations of communities in which children are involved in

9779-412: The definition of attention, it would be correct to consider the origin of this notion to review the meaning of the term given to it when the experimental study on attention was initiated. It is thought that the experimental approach began with famous experiments with a 4 x 4 matrix of sixteen randomly chosen letters – the experimental paradigm that informed Wundt 's theory of attention. Wundt interpreted

9906-409: The development of these technological innovations, neuroscientists became interested in this type of research that combines sophisticated experimental paradigms from cognitive psychology with these new brain imaging techniques. Although the older technique of electroencephalography (EEG) had long been used to study the brain activity underlying selective attention by cognitive psychophysiologists ,

10033-526: The effect of modulating the loudness of the sound as well. It makes more sense to separate loudness and harmonic quality to be parameters controlled independently of each other. To do so, harmonic amplitude envelopes are frame-by-frame normalized to become amplitude proportion envelopes, where at each time frame all the harmonic amplitudes will add to 100% (or 1). This way, the main loudness-controlling envelope can be cleanly controlled. In Sound Recognition, max amplitude normalization can be used to help align

10160-496: The elevation into the focus of attention - apperception." Wundt's theory of attention postulated one of the main features of this notion that attention is an active, voluntary process realized during a certain time. In contrast, neuroscience research shows that intentionality may emerge instantly, even unconsciously; research reported to register neuronal correlates of an intentional act that preceded this conscious act (also see shared intentionality ). Therefore, while intentionality

10287-434: The exclusion of other stimuli. It is the selective concentration on discrete information, either subjectively or objectively . William James (1890) wrote that "Attention is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. Focalization, concentration, of consciousness are of its essence." Attention has also been described as

10414-424: The experimental outcome introducing the meaning of attention as "that psychical process, which is operative in the clear perception of the narrow region of the content of consciousness." These experiments showed the physical limits of attention threshold, which were 3-6 letters observing the matrix during 1/10 s of their exposition. "We shall call the entrance into the large region of consciousness - apprehension, and

10541-415: The heating effect in a resistor to measure a current. The advent of microprocessor -controlled meters capable of calculating RMS by sampling the waveform has made true RMS measurement commonplace. In telecommunications, pulse amplitude is the magnitude of a pulse parameter, such as the voltage level, current level, field intensity , or power level. Pulse amplitude is measured with respect to

10668-470: The increased P2 found during trials of efficient visual searches reflected the ability for the brain to reduce search space. Such a hypothesis appears intuitive, as in the efficient visual arrays the targets share no features with the distracters. Thus, the distinct features of the distracters can be ignored for the purposes of a particular trial. Meanwhile, in the inefficient trials, the presence of shared features complicates such suppression, which might explain

10795-577: The individual's limited-capacity attentional resources. Other variables play a part in our ability to pay attention to and concentrate on many tasks at once. These include, but are not limited to, anxiety, arousal, task difficulty, and skills. Simultaneous attention is a type of attention, classified by attending to multiple events at the same time. Simultaneous attention is demonstrated by children in Indigenous communities, who learn through this type of attention to their surroundings. Simultaneous attention

10922-449: The information he requires and on the process of choosing an algorithm for response actions, which involves the intensification of sensory and intellectual activities”. In cognitive psychology there are at least two models which describe how visual attention operates. These models may be considered metaphors which are used to describe internal processes and to generate hypotheses that are falsifiable . Generally speaking, visual attention

11049-410: The information that is processed by the senses. Researchers often use "filtering" tasks to study the role of covert attention of selecting information. These tasks often require participants to observe a number of stimuli, but attend to only one. The current view is that visual covert attention is a mechanism for quickly scanning the field of view for interesting locations. This shift in covert attention

11176-421: The intensity of the wave. For electromagnetic radiation , the amplitude of a photon corresponds to the changes in the electric field of the wave. However, radio signals may be carried by electromagnetic radiation; the intensity of the radiation ( amplitude modulation ) or the frequency of the radiation ( frequency modulation ) is oscillated and then the individual oscillations are varied (modulated) to produce

11303-471: The latency of a P2 elicited by flashes of light is significantly increased in patients with dementia and early onset of Alzheimer's disease. It is also significantly delayed and interval between the P1 and the P2 was found to be significantly longer in patients with Alzheimer's disease compared to controls. This may suggest a defect in the pathway between visual cortex and the visual association center, where some believe

11430-456: The limits of a human ability to concentrate awareness on a task. Latvian prof. Sandra Mihailova and prof. Igor Val Danilov drew an essential conclusion from the Wundtian approach to the study of attention: the scope of attention is related to cognitive development. As the mind grasps more details about an event, it also increases the number of reasonable combinations within that event, enhancing

11557-468: The maximum positive signal is measured relative to the mean, the maximum negative signal is measured relative to the mean, or the maximum positive signal is measured relative to the maximum negative signal (the peak-to-peak amplitude ) and then divided by two (the semi-amplitude ). In electrical engineering, the usual solution to this ambiguity is to measure the amplitude from a defined reference potential (such as ground or 0 V). Strictly speaking, this

11684-481: The model; connecting with the activities those patients could do as their recovering process advanced. This model has been shown to be very useful in evaluating attention in very different pathologies, correlates strongly with daily difficulties and is especially helpful in designing stimulation programs such as attention process training, a rehabilitation program for neurological patients of the same authors. Most experiments show that one neural correlate of attention

11811-446: The notion of intentionality due to the extent of semantic uncertainty in the linguistic explanations of these notions' definitions. Intentionality has in turn been defined as "the power of minds to be about something: to represent or to stand for things, properties and states of affairs". Although these two psychological constructs (attention and intentionality) appear to be defined by similar terms, they are different notions. To clarify

11938-581: The objects that result from this initial grouping." In the twentieth century, the pioneering research of Lev Vygotsky and Alexander Luria led to the three-part model of neuropsychology defining the working brain as being represented by three co-active processes listed as Attention, Memory, and Activation. A.R. Luria published his well-known book The Working Brain in 1973 as a concise adjunct volume to his previous 1962 book Higher Cortical Functions in Man . In this volume, Luria summarized his three-part global theory of

12065-544: The observation that the amplitude of the P2 is decreased for such conditions. Likewise, this rationale may apply to contexts beyond traditional visual search paradigms, including language. Some studies of the P2 have cited the presence of a repetition effect as evidence that the P2 in part represents some facet of a perceptual-matching process. Additionally, one could link previous observations in other studies such as those utilizing either visual search and visual priming paradigms to this perceptual-matching process, suggesting that

12192-497: The peripheral cues are brief flashes at the relevant location before the onset of a visual stimulus. Psychologists Michael Posner and Yoav Cohen (1984) noted a reversal of this benefit takes place when the interval between the onset of the cue and the onset of the target is longer than about 300 ms. The phenomenon of valid cues producing longer reaction times than invalid cues is called inhibition of return . Endogenous (from Greek endo , meaning "within" or "internally") orienting

12319-423: The previously discussed tasks. There has been little difference found between speaking on a hands-free cell phone or a hand-held cell phone, which suggests that it is the strain of attentional system that causes problems, rather than what the driver is doing with his or her hands. While speaking with a passenger is as cognitively demanding as speaking with a friend over the phone, passengers are able to change

12446-489: The primary role of the perceptual load theory, assumptions regarding its functionality surrounding that attentional resources are that of limited capacity which signify the need for all of the attentional resources to be used. This performance, however, is halted when put hand in hand with accuracy and reaction time (RT). This limitation arises through the measurement of literature when obtaining outcomes for scores. This affects both cognitive and perceptual attention because there

12573-414: The probability of better understanding its features and particularity. For example, three items in the focal point of consciousness have six possible combinations (3 factorial), and four items have 24 (4 factorial) combinations. This number of combinations becomes significantly prominent in the case of a focal point with six items with 720 possible combinations (6 factorial). Empirical evidence suggests that

12700-424: The reading of Chinese phonograms. High combinability and consistency Chinese characters elicited lower P2 amplitudes than low combinability and low consistency characters. The suggests that characters with high combinability or high consistency facilitated early stages of orthographic and phonological processing which lowered activation at the perceptual level and resulted in a less positive P2. The neural source of

12827-489: The researchers acknowledge, "it may be impossible to definitively rule out the possibility that some kind of shift of covert attention precedes every shift of overt attention". Orienting attention is vital and can be controlled through external (exogenous) or internal (endogenous) processes. However, comparing these two processes is challenging because external signals do not operate completely exogenously, but will only summon attention and eye movements if they are important to

12954-607: The same location into forming objects." Treismans's theory is based on a two-stage process to help solve the binding problem of attention. These two stages are the preattentive stage and the focused attention stage. Through sequencing these steps, parallel and serial search is better exhibited through the formation of conjunctions of objects. Conjunctive searches, according to Treismans, are done through both stages in order to create selective and focused attention on an object, though Duncan and Humphrey would disagree. Duncan and Humphrey's AET understanding of attention maintained that "there

13081-562: The same time. Another cultural practice that may relate to simultaneous attention strategies is coordination within a group. Indigenous heritage toddlers and caregivers in San Pedro were observed to frequently coordinate their activities with other members of a group in ways parallel to a model of simultaneous attention, whereas middle-class European-descent families in the U.S. would move back and forth between events. Research concludes that children with close ties to Indigenous American roots have

13208-407: The scope of attention in young children develops from two items in the focal point at age up to six months to five or more items in the focal point at age about five years. As follows from the most recent studies in relation to teaching activities in school , “attention” should be understood as “the state of concentration of an individual’s consciousness on the process of selecting by his own psyche

13335-436: The scope of intention. From this perspective, a scientific approach to attention is relevant when it considers the difference between these two concepts (first of all, between their statical and dynamical statuses). The growing body of literature shows empirical evidence that attention is conditioned by the number of elements and the duration of exposition. Decades of research on subitizing have supported Wundt's findings about

13462-519: The signal. Amplitude envelope refers to the changes in the amplitude of a sound over time, and is an influential property as it affects perception of timbre. A flat tone has a steady state amplitude that remains constant during time, which is represented by a scalar. Other sounds can have percussive amplitude envelopes featuring an abrupt onset followed by an immediate exponential decay. Percussive amplitude envelopes are characteristic of various impact sounds: two wine glasses clinking together, hitting

13589-473: The signal; if the reference is a mean value ( DC component ), the peak amplitude is the maximum absolute value of the difference from that reference. Semi-amplitude means half of the peak-to-peak amplitude. The majority of scientific literature employs the term amplitude or peak amplitude to mean semi-amplitude. It is the most widely used measure of orbital wobble in astronomy and the measurement of small radial velocity semi-amplitudes of nearby stars

13716-410: The source of the sensory cues and signals that generate attention, the effects of these sensory cues and signals on the tuning properties of sensory neurons , and the relationship between attention and other behavioral and cognitive processes, which may include working memory and psychological vigilance . A relatively new body of research, which expands upon earlier research within psychopathology,

13843-461: The stimuli. Studies regarding this showed that the ability to process stimuli decreased with age, meaning that younger people were able to perceive more stimuli and fully process them, but were likely to process both relevant and irrelevant information, while older people could process fewer stimuli, but usually processed only relevant information. Some people can process multiple stimuli, e.g. trained Morse code operators have been able to copy 100% of

13970-515: The stimulus also impact the amplitude of the P2. The diversity of these factors tends to suggest that the P2, as a response, is multidimensional with respect to its sensitivity to stimulus features. Researchers have found evidence that the P2 is involved in memory processes. Differences in P200 peak amplitude suggest that anterior and posterior distributional differences are elicited during encoding of words for rote and elaborative memory tasks. While encoding

14097-454: The study of disorders of consciousness to artificial intelligence and its domains of research. Prior to the founding of psychology as a scientific discipline, attention was studied in the field of philosophy . Thus, many of the discoveries in the field of attention were made by philosophers. Psychologist John B. Watson calls Juan Luis Vives the father of modern psychology because, in his book De Anima et Vita ( The Soul and Life ), he

14224-400: The subject's ability to perceive or ignore stimuli, both task-related and non task-related. Studies show that if there are many stimuli present (especially if they are task-related), it is much easier to ignore the non-task related stimuli, but if there are few stimuli the mind will perceive the irrelevant stimuli as well as the relevant. The cognitive mechanism refers to the actual processing of

14351-514: The subject. Exogenous (from Greek exo , meaning "outside", and genein , meaning "to produce") orienting is frequently described as being under control of a stimulus. Exogenous orienting is considered to be reflexive and automatic and is caused by a sudden change in the periphery. This often results in a reflexive saccade. Since exogenous cues are typically presented in the periphery, they are referred to as peripheral cues . Exogenous orienting can even be observed when individuals are aware that

14478-565: The target stimuli and non-target stimuli, known as "distracters". In the case of efficient search arrays, the target object or stimuli does not share any features in common with the distracters in the array. Likewise, in an inefficient array, the targets share one or more features with the "distracters". The visual P2 has also been studied in the context of the visual priming paradigm, which seeks to understand how prior information shapes future response. In this experimental design, participants are briefly presented with an image or word, followed by

14605-458: The two theories placed a new emphasis on the separation of visual attention tasks alone and those mediated by supplementary cognitive processes. As Rastophopoulos summarizes the debate: "Against Treisman's FIT, which posits spatial attention as a necessary condition for detection of objects, Humphreys argues that visual elements are encoded and bound together in an initial parallel phase without focal attention, and that attention serves to select among

14732-493: The visual P2 is difficult to ascertain given the limited spatial resolution of the ERP technique. Since the recordings obtained from the scalp reflect only the dipole moments created by post-synaptic potential changes, they are subject to several factors including orientation, magnitude, and number of generator dipoles. Thus, the observed topographies of the P2 observed in experimental conditions may not be indicative of their true source. It

14859-466: The visual evoked response (VER), part of which includes the P2. The P2 follows the visual N1 (or auditory N100 ) and P1 waveforms (negativity and positivity at 150 and 100ms respectively) and is followed by the N200 , P3 , and N400 waveforms. Other components may overlap with the P2 to some extent, making it difficult to distinguish clearly between them, depending on the location of measurement. Originally,

14986-631: The visual scene, since this fixed resource will be distributed over a larger area. It is thought that the focus of attention can subtend a minimum of 1° of visual angle , however the maximum size has not yet been determined. A significant debate emerged in the last decade of the 20th century in which Treisman's 1993 Feature Integration Theory (FIT) was compared to Duncan and Humphrey's 1989 attentional engagement theory (AET). FIT posits that "objects are retrieved from scenes by means of selective spatial attention that picks out objects' features, forms feature maps, and integrates those features that are found at

15113-411: The visual search paradigm. However, due to the wide range and diversity of factors that have been found to affect the characteristics of the P2, reaching a comprehensive theory of the underlying neural processes that the P2 reflects has been difficult. One theory is that the P2 indexes some form of selective attention which identifies meaningful stimuli through feature suppression. One study suggests that

15240-410: The wave equation is more complex, but the role of amplitude remains analogous to this simple case. For waves on a string , or in a medium such as water , the amplitude is a displacement . The amplitude of sound waves and audio signals (which relates to the volume) conventionally refers to the amplitude of the air pressure in the wave, but sometimes the amplitude of the displacement (movements of

15367-410: The waveform on an oscilloscope . Peak-to-peak is a straightforward measurement on an oscilloscope, the peaks of the waveform being easily identified and measured against the graticule . This remains a common way of specifying amplitude, but sometimes other measures of amplitude are more appropriate. Root mean square (RMS) amplitude is used especially in electrical engineering : the RMS is defined as

15494-447: The words across both memory tasks, participants who subsequently recalled less generated larger frontal amplitudes and smaller parietal/occipital amplitudes than those who recalled more. Also, researchers have found that the P200 (overlapping with the P300) was elicited in a digit span task when participants heard the reverse order of a digit series that they previously heard. This indicates that

15621-416: The working brain as being composed of three constantly co-active processes which he described as the; (1) Attention system, (2) Mnestic (memory) system, and (3) Cortical activation system. The two books together are considered by Homskaya's account as "among Luria's major works in neuropsychology, most fully reflecting all the aspects (theoretical, clinical, experimental) of this new discipline." The product of

15748-419: Was generally only available in hospitals, psychologists sought cooperation with neurologists. Psychologist Michael Posner (then already renowned for his influential work on visual selective attention) and neurologist Marcus Raichle pioneered brain imaging studies of selective attention. Their results soon sparked interest from the neuroscience community, which until then had been focused on monkey brains. With

15875-432: Was inspired by the zoom lens one might find on a camera, and any change in size can be described by a trade-off in the efficiency of processing. The zoom-lens of attention can be described in terms of an inverse trade-off between the size of focus and the efficiency of processing: because attention resources are assumed to be fixed, then it follows that the larger the focus is, the slower processing will be of that region of

16002-422: Was the first to recognize the importance of empirical investigation. In his work on memory, Vives found that the more closely one attends to stimuli, the better they will be retained. By the 1990s, psychologists began using positron emission tomography (PET) and later functional magnetic resonance imaging (fMRI) to image the brain while monitoring tasks involving attention. Considering this expensive equipment

16129-426: Was theorized by Cognitive Psychologists David Navon and Daniel Gopher in 1979. However, more recent research using well controlled dual-task paradigms points at the importance of tasks. As an alternative, resource theory has been proposed as a more accurate metaphor for explaining divided attention on complex tasks. Resource theory states that as each complex task is automatized, performing that task requires less of

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