Attention

Cognitive psychology
Perception
Visual Object recognition Face recognition Pattern recognition
Attention
Memory
Aging Emotional Learning Long-term
Metacognition
Language
Metalanguage
Thinking
Cognition Concept Reasoning Decision making Problem solving
Numerical cognition
Number sense in animals Numerosity adaptation effect Approximate number system Parallel individuation system
v t e

Attention or focus, is the concentration of awareness on some phenomenon to the exclusion of other stimuli.^[1] 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."^[2] Attention has also been described as the allocation of limited cognitive processing resources.^[3] 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,^[4][5] 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 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, is investigating the diagnostic symptoms associated with traumatic brain injury and its effects on attention. Attention also varies across cultures.^[6] For example, people from cultures that center around collectivism pay greater attention to the big picture in the image given to them, rather than specific elements of the image. On the other hand, those involved in more individualistic cultures tend to pay greater attention to the most noticeable portion of the image.^[7]

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 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 was the first to recognize the importance of empirical investigation.^[8] 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 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.^[9] Their results soon sparked interest from the neuroscience community, which until then had been focused on monkey brains. With 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, 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.^[10]

A definition of a psychological construct forms a research approach to its study. In scientific works, attention often coincides and substitutes 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".^[11] Although these two psychological constructs (attention and intentionality) appear to be defined by similar terms, they are different notions. To clarify 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.^[12] Wundt interpreted 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."^[13] These experiments showed the physical limits of attention threshold, which were 3-6 letters observing the matrix during 1/10 s of their exposition.^[12] "We shall call the entrance into the large region of consciousness - apprehension, and the elevation into the focus of attention - apperception."^[14] 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.^[12] 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).^[15][16] Therefore, while intentionality 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 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 the limits of a human ability to concentrate awareness on a task.^{[17][18][19][20][21]} 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.^[22] As the mind grasps more details about an event, it also increases the number of reasonable combinations within that event, enhancing the probability of better understanding its features and particularity.^[22] 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).^[22] Empirical evidence suggests that 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.^[22] 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 the information he requires and on the process of choosing an algorithm for response actions, which involves the intensification of sensory and intellectual activities”.^[23]

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 is thought to operate as a two-stage process.^[24] 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 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.^[25] 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 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.^[26] 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 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.^[27] 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 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,^[25][28] 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).^{[29]: 5–7} 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 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.

1. Preattentive Stage: The unconscious detection and separation of features of an item (color, shape, size). Treisman suggests that this happens early in cognitive  processing and that individuals are not aware of the occurrence due to the counter intuitiveness of separating a whole into its part. Evidence shows that preattentive focuses are accurate due to illusory conjunctions.^[30]
2. Focused Attention Stage: The combining of all feature identifiers to perceive all parts as one whole. This is possible through prior knowledge and cognitive mapping. When an item is seen within a known location and has features that people have knowledge of, then prior knowledge will help bring features all together to make sense of what is perceived. The case of R.M's damage to his parietal lobe, also known as Balint's syndrome, shows the incorporation of focused attention and combination of features in the role of attention.^[31]

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^[32] 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 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."^{[29]: 5–7} The contrast of 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 the objects that result from this initial grouping."^[29]: 8

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 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."^[33] The product of 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.^[34] Attention must be divided among all of 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.^[35]

Older research involved looking at the limits of people performing simultaneous tasks like reading stories, while listening and writing something else,^[36] or listening to two separate messages through different ears (i.e., dichotic listening). Generally, classical research into attention investigated the ability of people to learn new information when there were multiple tasks to be performed, or to probe the limits of our perception (cf. 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^[37] or driving while being on the phone.^[38]

The vast majority of current research on human multitasking is based on performance of doing two tasks simultaneously,^[34] 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 the previously discussed tasks.^[39][40][41]

There has been little difference found between speaking on a hands-free cell phone or a hand-held cell phone,^[42][43] 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,^[44] passengers are able to change 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,^[45] explains that there 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.^[46] 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 was theorized by cognitive psychologists David Navon [he] and Daniel Gopher in 1979. However, more recent research using well controlled dual-task paradigms points at the importance of tasks.^[47]

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 the individual's limited-capacity attentional resources.^[46] 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.^[46]

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.^[48] Simultaneous attention 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 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.^[6][49] Research concludes that children with close ties to Indigenous American roots have a high tendency to be especially wide, keen observers.^[50] This points to a strong cultural difference in attention management.

Attention may be differentiated into "overt" versus "covert" orienting.^[51]

Overt orienting is the act of selectively attending to an item or location over others by moving the eyes to point in that direction.^[52] Overt orienting can be directly observed in the form of eye movements. Although overt eye movements are quite common, there 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 is the act of mentally shifting one's focus without moving one's eyes.^[25][52][53] 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)^[54] but does not influence 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 is linked to eye movement circuitry that sets up a slower saccade to that location.^[55]

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.^[52] In support of this, general theories of attention actively assume bottom-up (reflexive) processes and top-down (voluntary) processes converge on a common neural architecture, in that they control both covert and overt attentional systems.^[56] 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".^[57] However, this has been questioned on the grounds that N2, "a neural measure of covert attentional allocation—does not always precede eye movements".^[58] However, 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".^[58]

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 the subject.^[52]

Exogenous (from Greek exo, meaning "outside", and genein, meaning "to produce") orienting is frequently described as being under control of a stimulus.^[59] 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 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.^[60]

Several studies have investigated the influence of valid and invalid cues.^{[52][61][62][63]} They concluded that valid peripheral cues benefit performance, for instance when 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.^[64] 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 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 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.^[65]

When examining differences between exogenous and endogenous orienting, some researchers suggest that there are four differences between the two kinds of cues:

• exogenous orienting is less affected by cognitive load than endogenous orienting;
• observers are able to ignore endogenous cues but not exogenous cues;
• exogenous cues have bigger effects than endogenous cues; and
• expectancies about cue validity and predictive value affects endogenous orienting more than exogenous orienting.^[66]

There exist both overlaps and differences in the areas of the brain that are responsible for endogenous and exogenous orientating.^[67] 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 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.^[68] These aspects of attention are thought to involve parietal and temporal cortices, as well as the brainstem.^[69] More recent experimental evidence^[70][71][72] support the idea that the primary visual cortex creates a bottom-up saliency map,^[73][4] 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 the frontal cortex and basal ganglia^[69][74] as one of the executive functions.^[52][69] Research has shown that it is related to other aspects of the executive functions, such as working memory,^[75] and conflict resolution and inhibition.^[76]

A "hugely influential"^[77] 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 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 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.^[78]

Some people can process multiple stimuli, e.g. trained Morse code operators have been able to copy 100% of 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.^[79]

Based on 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.^[80] 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 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.^[81]

Attention is best described as the sustained focus of cognitive resources on information while filtering or ignoring extraneous information. Attention 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.^[82] 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 the model; connecting with the activities those patients could do as their recovering process advanced.

• Focused attention: The ability to respond discretely to specific sensory stimuli.
• Sustained attention (vigilance and concentration): The ability to maintain a consistent behavioral response during continuous and repetitive activity.
• Selective attention: The ability to maintain a behavioral or cognitive set in the face of distracting or competing stimuli. Therefore, it incorporates the notion of "freedom from distractibility."
• Alternating attention: The ability of mental flexibility that allows individuals to shift their focus of attention and move between tasks having different cognitive requirements.
• Divided attention: This refers to the ability to respond simultaneously to multiple tasks or multiple task demands.

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.

• Mindfulness: Mindfulness has been conceptualized as a clinical model of attention.^[83] Mindfulness practices are clinical interventions that emphasize training attention functions.^[84]
• Vigilant attention: Remaining focused on a non-arousing stimulus or uninteresting task for a sustained period is far more difficult than attending to arousing stimuli and interesting tasks, and requires a specific type of attention called 'vigilant attention'.^[85] Thereby, vigilant attention is the ability to give sustained attention to a stimulus or task that might ordinarily be insufficiently engaging to prevent our attention being distracted by other stimuli or tasks.^[86]

Most experiments show that one neural correlate of attention 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^[87] describes a more general model which identifies four core processes of attention, with working memory at the center:

• Working memory temporarily stores information for detailed analysis.
• Competitive selection is the process that determines which information gains access to working memory.
• Through top-down sensitivity control, higher cognitive processes can regulate signal intensity in information channels that compete for access to working memory, and thus give them an advantage in the process of competitive selection. Through top-down sensitivity control, the momentary content of working memory can influence the selection of new information, and thus mediate voluntary control of attention in a recurrent loop (endogenous attention).^[88]
• Bottom-up saliency filters automatically enhance the response to infrequent stimuli, or stimuli of instinctive or learned biological relevance (exogenous attention).^[88]

Neurally, at different hierarchical levels spatial maps can enhance or inhibit activity in sensory areas, and induce orienting behaviors like eye movement.

• At the top of the hierarchy, the frontal eye fields (FEF) and the dorsolateral prefrontal cortex contain a retinocentric spatial map. Microstimulation in the FEF induces monkeys to make a saccade to the relevant location. Stimulation at levels too low to induce a saccade will nonetheless enhance cortical responses to stimuli located in the relevant area.
• At the next lower level, a variety of spatial maps are found in the parietal cortex. In particular, the lateral intraparietal area (LIP) contains a saliency map and is interconnected both with the FEF and with sensory areas.
• Exogenous attentional guidance in humans and monkeys is by a bottom-up saliency map in the primary visual cortex.^[73][4] In lower vertebrates, this saliency map is more likely in the superior colliculus (optic tectum).^[89]
• Certain automatic responses that influence attention, like orienting to a highly salient stimulus, are mediated subcortically by the superior colliculi.
• At the neural network level, it is thought that processes like lateral inhibition mediate the process of competitive selection.

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.^{[90][91][54][92]}

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^[69][93] that can also interact and influence each other.