consciousness and attention are not fully dissociable in all circumstances

Posted comment on ´Against the view that consciousness and attention are fully dissociable` by G. Marchetti and published in Front. Psychol. 15th February 2012, doi / 10.3389/fpsyg.2012.00036


Marchetti in his review article provides argument against the view that consciousness and attention are fully dissociable. He states that there are various forms of consciousness and attention and not all the forms of attention produce the same kind of consciousness. In the case of low level attention, this form can exist with or without consciousness, but in the case of top-down attention this form can only exist with. This view goes against the opinion of Koch and Tsuchiya (2006) for example who describe four possibilities of top-down attention and consciousness including top-down attention with and without consciousness. According to Marchetti, the high-level top-down attention without consciousness form of Koch and Tsuchiya occurs because of a failure to recognize the different types of top-down attention and consciousness that exist. Therefore, attention cannot be considered the same as consciousness, and attention in some form is always required, hence consciousness and attention is not in all situations fully dissociable.

Marchetti begins his article by reviewing evidence of the close correlation between attention and consciousness. Selection means that something can be attended to and can be isolated from the other features of the event with conscious awareness completely on the attended feature whilst the other features are ignored. Also, both visual and temporal perception can be modulated by attention, eg. attention alters phenomenal appearance by boosting the stimulus contrast (Liu, 2009). Marchetti goes on to describe inattentional blindness which was originally explained by the presence of unconscious processing, but with no conscious perception and no attentional processing. However, alternative explanations have been put forward with memory lapse being one of them. In this case, the individual is assumed to forget about the distracting stimulus due to the delay between its presentation and the individual being questioned. Another alternative explanation is perceptual load. In their experiment with the development of a change detection flicker task, Rensink et al. (1997) found  that the identification of changes was extremely difficult not due to the disruption of perceived information or stored information, but due to the level of attention applied.  Change detection appears to be dependent on the level of perceptual load, eg. low load is linked to awareness of irrelevant stimuli, but with high load there is no such awareness. This confirms the view that attention is needed for the detection of change.

Having shown that inattentional blindness is linked to the lack of conscious awareness of stimuli that may or may not be attended to, Marchetti goes on in his review article to investigate more thoroughly the view of Koch and Tsuchiya that consciousness can be dissociated from top-down attention. Marchetti believes that their view is only partly true since there are cases of consciousness in the absence of a certain form of top-down attention, but in the presence of another form of attention such as bottom-up and there are no cases of conscious awareness in the complete absence of some form of attention. Marchetti explains this by saying that Koch and Tsuchiya failed to take into account the different forms of attention and consciousness that exist. For example, there are least 2 different forms of top-down attention, eg. focused and diffuse (or distributed attention), each with different characteristics. There are also different forms of consciousness such as ambient awareness where there is a general awareness of the environment and focal awareness where there is a detailed awareness of a scene, but not necessarily with access to the Self. Just like with attention, characteristics of the consciousness forms differ.

Koch and Tsuchiya (2006) gave several examples as evidence for their view of dissociable attention and consciousness, eg. attentional blink and gist and these examples were given alternative explanations by Marchetti in his review article. In the case of attentional blink, performance at detecting the second stimulus (T2) improves with a longer delay between its presentation and the presentation of the main stimulus (T1). This is thought to be because processing of T1 takes up the limited attentional resources so that either access to these resources is denied for T2, or the representation of T2 is so vulnerable that it easily suffers from the interference of simultaneous distracting features surrounding it. However, less than optimal focusing on T1 actually led to improved T2 detection (Olivers and Nieuwenhuis, 2005) and although Koch and Tsuchiya said this was due to top-down attention and consciousness opposing one another, a more accepted explanation was given by Srinivasan in 2008. Srinivasan described a diffused (distributed) attentional strategy that under certain conditions appears more appropriate than focused attention. One such condition is when subjects know that they need to consider a large number of items in order to report a second target stimulus. As attention widens to incorporate the extra task, it may also widen temporally and hence, includes T2 in the series of stimuli. However, Marchetti explains that this explanation does not take into account the overall improvement in T1 performance so it is probably not just diffused attention, but also a temporary increase of the allocated attentional resources owing to the difficulty of the task. This temporary increase may be related to arousal since it was found that decreased or increased arousal makes the attentional system more susceptible to other input, including T2. Another explanation was given in that the task itself may induce a positive emotional state, which has been shown to improve performance with some cognitive tasks.

These explanations were also given for Koch and Tsuchiya`s other evidence for fully dissociable consciousness and attention that of animal and gender detection in a dual task and gist. In the case of gist, Marchetti describes the use of diffused attention and states that gist is evidence of another form of consciousness (ie. primary consciousness) where there is awareness, but not the language capability to perceive it or describe it. Diffused attention was also given as an explanation for the pop-out and cocktail party effect.  Top-down attention was found to be necessary for the subliminal pop-out effect whereas the cocktail party effect required some form of attention, either top-down or bottom-up for consciousness to occur.  Although the cocktail party effect was interpreted by Umilta (1994) as having attention and consciousness as independent systems with the object being perceived consciously in a direct manner without attention, Mack and Rock (1998) disputed this by showing that increasing the inhibition of attention to an object led to a decrease in probability that the object would be perceived. Hence, Marchetti concluded in his article that some kind of attention is always involved in conscious perception even in situations where high emotional values such as one`s own name are applied. In the absence of attention, there is no conscious awareness.

In the case of iconic memory, Marchetti quotes in his review article the work of Lamme (2003) who proposes that there can be consciousness without attention since the attentive selection process operates at a later stage than consciousness and that attention does not determine whether stimuli reach a conscious state, but determines whether a conscious report about stimuli is possible. Lamme`s model supports Block`s 1996 view of the existence of two distinct kinds of awareness: phenomenal and access awareness and the distinction in sensory memory between iconic memory and working memory. Lamme quotes work on change detection experiments saying that attention is a selection process that determines if the stimulus goes from phenomenal consciousness to access awareness. The model is based on observations that there are different levels of processing that stimuli can reach and that these different levels of processing rely on an early distinction between conscious and unconscious stimuli. According to Marchetti, the Lamme model overlooks the fact that both attention and consciousness can assume a variety of different forms. For example, if Lamme says that non-attentional selection mechanisms lead to unconscious processing of stimuli then preliminary attention means that information might be processed even if not consciously experienced. Marchetti`s explanation is based on attention being necessary for consciousness, but various levels and types of attention are possible. In the case of change detection, Marchetti explains the finding that a change in location cued during the blank ISI leads to improved performance is not proof of consciousness without attention, but instead confirms that there is an early component of attention (an exogenous one) that can capture a specific item in the iconic memory. Lamme also stated in 2003 that a view of a visual scene is experienced with a ´richness of content` that goes beyond what can be reported when questioned. Marchetti explains this ´richness of content` as occurring when the participant`s initial application of attention to a presented array of items triggers a ´primary` (non-verbalized), rich form of consciousness of the visual scene. Subsequently, the content of the primary consciousness can be verbalized because of the use of an additional amount of attention due to the cue.

Having investigated the view that there can be no consciousness without some form of attention, Marchetti goes on in his review article to look at whether there can be top-down attention without consciousness. Some researchers affirm the view because attention can generate or modulate unconscious phenomena. Naccache et al. (2002) state that it is possible to elicit unconscious priming in a number-comparison task, but only if the subject’s temporal attention is allocated to the time window in which the prime target pair is presented. Unconscious priming vanishes when temporal attention is focused away from this time window. Sumner et al. (2006) state that attention modulates neural sensorimotor processes that are entirely separate from those supporting conscious perception and Bahrami et al. (2008) affirm that in tasks of low perceptual load any spare capacity from the processing of the relevant stimulus spills over to the processing of irrelevant stimuli regardless of whether or not subjects are conscious of the representations. However, Marchetti`s view is that attention can also generate unconscious phenomena, but is not per se evidence that there can be top-down attention without consciousness. Consciousness only occurs when top-down attention is at a lower level that it has not reached threshold consciousness. Observations of top-down attention without consciousness comes from, according to Marchetti, the confusion of the perception of consciousness absence with the absence of perception, or by overlooking the existence of the many forms of attention and consciousness.

    In the case of confusing the perception of consciousness absence with the absence of perception, Marchetti explains that a person can be aware of something without being aware of something else, or even that a person can be aware of not being aware of something. Mole (2008) said that cases, in which the subjects are on the lookout for something that does not appear, are not cases of attention without perception. They are rather, cases where the subject perceives that nothing has yet occurred. Overlooking this means that a mistake is made between perception of absence and absence of perception. Therefore, some experiments provide evidence of top-down attention in the absence of conscious awareness of something, but in the presence of conscious awareness of something else. In the case of motion-induced blindness (MIB), paying more attention to the MIB target increases the probability of its disappearance from consciousness, ie. the more the participant looks at something, the more he sees. However, in this case the MIB target is an illusion and hence, this demonstrates that top-down attention with consciousness can occur in the absence of something.

Another explanation for misinterpreting top-down attention without consciousness is that the existence of various forms of attention and consciousness are overlooked. Marchetti uses the example of blindsight and a subject named GY to refute the claim that there is top-down attention in the absence of any form of consciousness. He explains that although GY may have verbally reported no awareness of any cues, it might not have meant that he had no conscious experience of anything. Verbal reporting requires a higher order reflective form of consciousness, but GY could have been experiencing primary consciousness and therefore, there would be endogenous attention without reflective (autonoetic) consciousness, but with direct, primary (anoetic) consciousness.

Marchetti continues his review article with a look at whether any kind of attention can be dissociated from consciousness and concluded that it is possible with low level attention (preliminary attention), but not with high level top-down attention. Marchetti quoted Velman`s 1991 work where the aim was to confute the conventional assumption that preconscious processing is identical to pre-attentive processing and conscious processing is identical to focal-attentive processing. Velman based his view on evidence that preconscious processing is not inflexible, not limited to simple, well-learned stimuli, not non-attended or pre-attentive since preconsciously processed stimuli are subjected to sophisticated and elaborate analysis. In this way, preconscious cues may receive attentional resources even though they may not enter consciousness. Therefore, Marchetti concludes that preliminary attention and consciousness can be dissociated. This is confirmed by other studies, eg. dichotic listening tasks, shadowing tasks and Stroop effect which show that stimuli can be preconsciously processed if given at least a minimal level of attention. Subjects pay a certain although low level of attention to the to-be-ignored stimuli even if instructed not to and this is possible through distributing the focus of attention and allocating a small level of attentional resources to them as described above.  This supports Damasio`s view (1999) and provided him with an acceptable explanation of some diseases such as akinetic mutism, epileptic automatism and advanced stages of Alzheimer’s disease. According to Damasio (1999), there is evidence of dissociation between low-level attention and consciousness because the sufferer exhibits some basic signs of attention (eg. the ability to form sensory images of objects and execute accurate movements relative to those images), but it is not related to the sense of Self, to thoughts relating to wishing, considering or, future time. Therefore, this form of attention is distinguished from high-level attention, which extends in time and whose focus on appropriate objects is indicative of consciousness. Therefore, Marchetti concludes that consciousness can be dissociated only from low-level attention (preliminary attention), whether of an endogenous or exogenous kind, but it cannot from high-level top-down attention.

In summary, Marchetti`s review article provides argument against the view that consciousness and attention are fully dissociable in all situations. By giving alternative explanations to common attention/consciousness experiments he gives evidence that there cannot be consciousness without some form of attention, but there can be different forms of both with different characteristics. The experimental results obtained explore these various forms of both consciousness and attention. From these experiments and conditions he states that there cannot be high-level top-down attention without consciousness and arguments put forward against this view come about by the failure of researchers to take into account the differing forms that top-down attention and consciousness can assume. However, Marchetti also recognizes that there can be low-level attention (preliminary attention) with or without consciousness. Therefore, Koch and Tsuchiya`s view of dissociable consciousness and attention is only correct to a certain point.


Marchetti in his review article dismissed the idea of a fully dissociable consciousness and attention for every situation – a view that we all can understand if we look at our daily lives. We know that in our experienced activities conscious awareness is not always the same as what is being attended to. For example, I know I can talk and drive at the same time and my attention is split between watching the road, automatically changing gear and talking about something. Or, if I think deeply about something and try and solve a problem, I may have full conscious awareness and full concentration on the task, but I still may be jogging or doing the washing up. Or, if I accidentally drop a glass I`m already moving trying to catch it before I consciously realise it`s falling and tell myself I need to move. Therefore, Marchetti`s conclusions were correct about non-dissociating attention and consciousness and also about the different forms of consciousness and awareness that exist. I know that in certain circumstances I need full attention on a task and conscious awareness is at the highest level, eg. playing a piece of music for the first time. In this case, higher order top-down attention then exists with conscious awareness. However, as described in Marchetti`s review, there may be occasions when all is required is low level preliminary attention, but with no awareness. What makes this topic interesting is the balance of conscious, unconscious, and even preconscious events, the shifts of consciousness and the link between conscious awareness and top-down and bottom-up attention. If we understand why something is attended to, or conversely what is ignored and how this is linked to conscious awareness, we can possibly manipulate the situation to our advantage. This type of knowledge is already being applied to daily life. For example, vast amounts of money are spent on things like advertising or educational methods – money spent to increase conscious awareness and attention to increase product buying or learning for example. It can also be important in situations where individuals suffer cognitive deficiencies – if we can improve the quality or quantity of the event attended to then maybe increases in memory or information processing will occur.

Therefore, in order to improve the quality or quantity of attended information, we have to investigate what determines what is attended to and how the relevant neurochemical mechanism works. What we attend to or not attend to depends on the physical functioning of two types of attentional system – the top-down attentional system and the bottom-up. These may have common cell types and common cell neurochemical mechanisms, but they differ in the activity and connectivity of the various brain areas involved. High level attention involves the dorsal brain areas, frontal and parietal areas, and the prefrontal cortex plus known sensory orienting systems such as the frontal eye fields and intraparietal sulcus. In this case, there is top-down voluntary recollection of information and selection and processing of material requires activity in the central executive, working memory and cortical memory areas. In contrast, bottom-up attention requires activity in ventral and parietal areas and is linked to involuntary memory recollection. There is also a difference between attention that is focused and a diffuse (or distributed) type described by Marchetti in his article in that with the former, attention is focused on one event whereas, in the latter,  attention is distributed over the general event, a bit like a ´group` impression. Although not mentioned by Marchetti in his review article, there is a third attentional state which exists when the emotional state of the individual is fear. In this situation, differences in quality and quantity of incoming and processing of information are observed in comparison to the individual`s normal emotional status.

The idea that physiological systems give rise to mental representations is not new. In 1890, James hypothesized that his experience was what he agreed to attend to and in this case, ´experience` means awareness and ´attend` means attention and here, the only form of attention meant is that of top-down. For either high or low level forms of attention, the first 270 milliseconds of a visual event are the same independent of whether the feature is attended or not. Bundesen`s Neural Theory of Visual Attention of 1990 described two waves of processing of this incoming information. The first wave involves attention distributed non-selectively over the visual field leading to a saliency map since perception, memories and values are applied to the objects. This leads on to the second wave where there is selective competition to populate the short-term memory store by allocating attentional resources according to the ´weight` of the stimulus taken from the saliency map. Therefore, in every sensory event, some features are attended to whereas others are not and preconscious events may slip to conscious events or may die out. This is equivalent to the fading out of one of the ´multiple drafts` of conscious experienced events.

Attended features are assumed to be fully processed and how much attentional resources are allocated is dependent on difficulty, novelty etc. Features preferred for attendance can depend on the stimuli`s colours, intensities, sizes, the memories and/or the values they evoke and even non-visual factors such as task difficulty and timing. In Marchetti`s review, he states that attention can change the perception of the stimulus. Event characteristics such as greater contrast lead to focus on the attended and longer and earlier timing of focus. This applies to both top-down and bottom-up attention. Features coming from bottom-up attention are accepted as sensory, but still critique, memories, emotions and values and recency and adaptation rules are applied. With conscious recollection in the absence of relevant sensory stimulus, the attention is internal and reflects individual choices, can be relatively automatic (sometimes need to focus on material to retrieve it), and does not require the allocation of sensory bottom-up attentional resources since there is an automatic memory recall process. In this case, the areas required for conscious awareness of successfully retrieved memories are the prefrontal cortex (initiation vs monitoring and maintenance; the ventrolateral regions – items and maintenance), dorsolateral areas (updating and manipulation), medial temporal areas (binding), and the parietal cortex (filtering and selection of material). The interconnectivity of the areas is demonstrated by the shared gamma 40HZ brain waves observed which are initiated by the prefrontal cortex and hippocampal areas and spread out across the relevant areas.

The attentional mechanism for attended and unattended features is said to show three properties at a computational level: a filtering process, which has limited capacity; selectivity, with some features attended and others not depending on stimulus characteristics; and a modulated ease of processing of the selected events. This view was extended by Knudson in 2007 who added the involvement of working memory to Bundesen`s  Neural Theory of Visual Attention. Therefore, the attentional mechanism was said to consist of four components: working memory, competitive selection based on biased competition (eg. stimulus, colour, size), top-down sensitive control (based on memory and value recall and association) and automatic saliency bottom-up filtering (based on stimulus features and automatic recall of associated memories and values). That attention acts as a selecting mechanism for conscious contents and working memory as the specific store supports Dehaene and Changeux`s 2011 Neuronal Global Workspace Theory for consciousness. The involvement of working memory in attention is also supported by the observations that working memory tasks are disrupted by shifts in attention. The working memory buffer in the parietal area is for gating stored information with cortical binding of relational activity. This is likely since working memory is responsible for the manipulation of information, fitting it to recalled memory, perception etc.  and the more informational processing that is carried out the better the memories formed. However, my own view is that working memory is a state where information is malleable and not a process. It provides the condition in which processing can occur, and where processing may mean just the selection of information based on strength of firing and binding.

However, not everything of an event is attended to. Non-attended features means the individual is not aware of them and cannot report them. However, this does not mean that the features are not processed and the level of processing, as Marchetti described in his article in relation to inattentional blindness, is dependent on perceptual load (feature characteristics and value/desire dependent) and the level of resources allocated which is monitored by the prefrontal cortex and cingulate cortex areas. Non-attended features can also be due to diffuse attention where there is no focus,  instead where it is distributed like looking at a big scene, as in the case of gist. Again, processing is possible of the scene and depends on perceptual load and allocation of resources. In the case of non-attended features load may be higher for the focused features or may be non-changing or long-lasting so that resources are allocated to more immediate demands.

Therefore, there may be several scenarios possible regarding attentional system source, level and conscious awareness and functional experimentation and neuroimaging can determine the characteristics of each. The highest attentional level is top-down attention focused on a specific event or activity. In this case, since focus is elsewhere in the simultaneous event, unconscious features are likely to be either from the stimulus (bottom-up based, when the speed of event presentation is quicker than the eye, or when the feature is not as sensory stimulating as the main feature on which the focus is centred) or internally generated (ie. from associations, when the features lead to memory recall without processing or emotional memory recall dependent on stored values). Neuronal firing representing the unconscious features is likely to fade if other features or events take priority, hence perceptual load of the conscious feature is increased, or there could be a shift towards the feature becoming conscious (ie. preconscious features) if for example, the memories or values recalled spontaneously deem the feature more important than the conscious ones. Conscious features of an event with top-down attention can be considered the highest level of cognitive processing. In this case, the features can evoke recall of memories with or without additional processing of the information since recall can be directed by the individual thinking or by the attended feature itself. Recall of emotional values, an active working memory with information processing, adaptation, categorising and problem solving can all occur with conscious information. However, the quantity of information that an individual is consciously aware of is limited. Just like with features being processed unconsciously, the neuronal firing can fade due to for example the task being completed, the individual losing interest or being distracted, other features of the event taking priority, or even that there is shift due to timing out of the neuronal trace from the refractory periods of the neurons themselves.

Top-down attention does not have to be focused on one single event, it can, as Marchetti in his article described, also be diffuse or distributed. This was described in Salt (2012) as normal, waking attention, where attention flits between features, taking in the gist of the event as a whole. Unconscious features are likely to be processed dependent on perceptual load limit and again, recall of memories and values associated with the features would be automatic and without processing or adaptation. The firing would naturally fade out, but interest due to the recall of associated memories or values could be enough to shift the attention to the focused top-down, higher attentional form. Even conscious awareness of features in this diffuse attentional state does not reach the same level of conscious processing of the focused attentional state since there is fast moving, fast changing flitting of attention without a full, in-depth representation of the event being realized. It is the state where a group impression is formed and memories and values are unconsciously and consciously steered.

A state not described in Marchetti`s article is the top-down attentional fear state. In this emotional state with this level of attention, lots of material is automatically processed unconsciously with subsequent memory and value recall because the limit of perceptual load in this state is bigger even though there is a loss of representation quality. Less detail is probably more significant at the conscious level rather than the unconscious one because it is more likely that an unconscious feature would be ignored completely. Again, neuronal firing of the unconscious feature representation would fade if the feature is not seen as a threat. Past experiences associated with the unconscious feature and the value attributed to it could however, shift the feature from unconscious to conscious. As stated above, with conscious awareness in the fear attentional state there is a perceptual load increase even if quality is sacrificed. Memories associated with the features can be recalled with or without  processing (recall may be directed by individual thinking or by features) and values, an active working memory with information processing, adaptation, associations and even problem solving if necessary are linked to this status. There also appears to be a ´slowing` of time which is attributed to the increased perceptual load and level of informational input.

However, top-down attentional state is not the only human attentional system – bottom-up attention also exists and this is probably Marchetti`s exogenous system with physiological and functional equivalents existing in other living things. In the bottom-up attentional state there can also be a focus on certain features. This means, just like with the top-down system, that these features have been in some way selected. Whereas, selection in the dominating top-down system is linked to memory and value recall, selection in the bottom-up system relates to the features` characteristics themselves, eg. colours, size, movement for visual features and this is determined by the sensory physiological system itself. Conscious input of such features themselves lead to memory and value recall, and can lead to a shift to top-down attention if thinking and processing is involved requiring the working memory system. The neuronal firing representation of the conscious feature can fade if, for example recognition occurs, or interest shifts to another feature, or naturally with time if the refractory period of the firing cells is reached. In this latter case, saccades occur which is where attention is drawn to other neighbouring event features giving the appropriate neuronal cells time to neurochemically recover. There can also be a shift up to top-down attention if the working memory becomes involved to process the information, or there is stimulation of internal thinking, eg. about future intentions. Just like with the top-down attentional system some features, however, undergo unconscious processing and these features may be peripheral to the main focus or less physiologically demanding. The unconscious features are automatically processed and memories and values recalled if perceptual load allows. Neuronal firing representing these non-conscious features will also fade if timed out by the non-firing refractory period of the neurons involved or may shift to other features if interest is lost or the other feature is competitively superior with regards to the physiological system in use. A shift up to conscious awareness is also possible, eg. if interest is awakened through the automatic recall of a stimulating memory linked to the feature.

The second bottom-up attentional state is where there is no focused attention, but instead attention is diffused or distributed. In this case, attention ´flits` and it is stimulus driven by the feature characteristics themselves and the physiological system involved, but attention is distributed so that the event is seen as a ´whole` with no single feature grabbing the focus. With unconscious processing, features can be individually processed according to perceptual load limits and the recall of memories and values are initiated automatically, but it is unlikely that processing is to any great depth. An exception to this would be the recall of distressing associations prompted by a stimulus which would immediately shift the feature to conscious processing and probably top-down attention. Under normal emotional conditions, in the case of any conscious awareness, the features would be processed, but only to a degree where there is automatic perception since the diffuse attention means that no single feature dominates. The event is treated as a ´group experience` and the features are bound together even if individually received and perceived. Neuronal firing of any feature fades as another takes over, but there can be a shift to bottom-up conscious processing if one feature dominates physiologically or even top-down attention and awareness if the automatic processing of one feature stimulates to such a degree that it becomes the centre of the event.

The final attentional state is the bottom-up fear attentional state which is probably one of the most important attentional states for survival and is likely to be seen in many living species. In this case, features which the individual is consciously aware of are fully processed according to the system`s perceptual load limits relating to quality and quantity (eg. higher quantity, lower quality). In this case, event features are inputted and the firing patterns occurring result in automatic recognition, recall of memories and values that induce the emotional fear state in the individual. Fading only occurs if the stimulus is not seen as a threat anymore, otherwise the firing continues buoyed by shifts of attention to other event stimuli (eg. eyes flitting around). Instigation of the working memory system to process the incoming information, eg. to find an escape route, assess the danger, engages the brain areas linked to top-down attention and therefore, shifts attention from the bottom-up level. In the fear attentional state, bottom-up unconscious processing can occur if the perceptual load limit in this state is not reached. If it does occur, features are unlikely to be processed fully unless perceived as a threat from the automatic memory recall instigated from the feature perception. Fading occurs if the stimulus is not deemed a threat, or if other features of the event take the focus and perceptual load allocation of resources is applied to the other feature.

By understanding when and where each form of attentional system comes into play and therefore, what information is likely to be attended to and what is non-attended to, we can manipulate conscious awareness and attention to our cognitive advantage. For example, fading in focused top-down attention, could occur through boredom, other events taking priority, or the natural timing out of the firing. Therefore, in this case fading can be prevented by for example pointing out other features of the same event, or introducing novelty, or providing a question to be answered. This will stop the focus and conscious awareness from being shifted to alternatives. The same methods could be applied to prevent fading of focused bottom-up attention. In the case of unconscious processing, for example fading will occur naturally since the individual is unaware of the input and processing being carried out. Natural fading can be prevented by shifting the event from being unconsciously processed to being consciously processed, eg. by evoking memories or values associated with features of the event, or by drawing the attention to particular features. These types of ´tricks` can be and are applied to daily life. For example, advertising uses flashing images, moving images, bright colours, centre-stage placing to bring focused bottom-up attention to their product and content is included that appeals to their market customers to elicit top-down attention eg. cute puppies, fast cars.

On a more important note, the knowledge about shifts to conscious and unconscious awareness can be applied to aid individuals suffering from memory or attention problems, eg. ADHD and Alzheimer`s disease. In the case of Alzheimer`s disease, Damasio in 1999 said that in its advanced stages, sufferers exhibited a dissociation between low-level attention and consciousness. In this state, the sufferers exhibited some basic signs of attention such as being capable of forming sensory images of objects and performing accurate movements relative to those images. However, they were incapable of employing any sense of Self by wishing, expressing past experiences and future intentions for example which is indicative of the higher-level attentional system and consciousness. Therefore, in this case, the presentation of objects from the individual`s past, or of the individual`s peer group`s past that are of value to the individual could stimulate unconscious processing and stimulate the recall of unconscious memories and values. Binding of new information to this recalled information may aid memory formation even if there is no conscious awareness of it. Other possibilities would be the use of peripheral vision and distributed attention to increase the volume of unconscious processing, the use of distracting stimuli requiring more eye movement, fleeting bright colour presentation and, although prohibited by ethical concerns the binding of new information to objects of fear such as fire or spiders. The difficulty comes for researchers in determining how much conscious awareness there is when reliable reporting by the sufferer is not possible. In this case, advanced neuroimaging techniques over a long period may help demonstrate the success or failure of the information intake.

Therefore, the interrelationship of attention and conscious awareness and the different physiology and mechanisms involved is an important topic and one that, no doubt, will keep our attention for many more years.

Since we`re talking about the topic …………………………..

…..can we assume that learning during sleep employs the same top-down and bottom up attentional processes as whilst awake, but quantity and quality may have different limits?

……is it possible that drugs that reduce focus or favour the diffused attentional state can be used to explore the limits of attention (ie. measurement of phi), the effects on peripheral vision, and inattentional blindness?

……could neuroimaging of the brain areas of minimally conscious individuals be carried out when they are presented with a range of smells (visual and sounds are also possible, but are likely to produce less specific images) so that knowledge about the basic attentional systems focused on single events can be expanded?


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