Attention is a limited resource that is deployed to facilitate the processing of critical information. One basic taxonomy of attention states that there are two types of attention:

1. Internal attention
   This refers to selecting control strategies and maintaining internally generated information, such as rules, responses, long-term and working memory. It involves regulating our internal mental life. Internal attention deals with our internally generated thoughts, desires and motivations.
2. External attention
   This refers to selecting and controlling incoming sensory information.

Posner stated that there is an attention system, that exists of three different systems:

1. Alerting (brain stem and frontal cortex)
   This is responsible for achieving a state of arousal. It uses the neurotransmitter norepinephrine.
2. Orienting (frontal and parietal cortex, including the frontal eye fields)
   This is responsible for directing our processing resources to incoming information. It can be described as external attention. It uses the neurotransmitter acetylcholine.
3. Executive function (medial frontal and parietal cortex)
   This is responsible for the supervision of attention. It decides where the attention should go. It can be described as internal attention. It uses the neurotransmitter dopamine.

The cocktail party problem refers to focusing on one speaker in a background of noise and other conversations. There are several theories of attention. There are filter theories, that describe when we process the incoming information:

1. Theory of early selection
   The sensory memory briefly maintains information from all perceptual systems and only the relevant information gets stored in the short-term memory. The irrelevant information gets sorted out early on in the information processing cycle.
2. Theory of late selection
   All sensory information is identified, but only attended information gets stored for further processing. The irrelevant information gets sorted out late in the early information processing cycle and is processed before it gets filtered out.
3. Theory of attenuation
   The intensity of the irrelevant information is diminished, but not eliminated. The irrelevant information is processed, but the intensity of this information is diminished so that only the relevant information makes it to the working memory.
4. Workload theory of attention
   This theory states that the amount of processing the unattended stimuli receive depends upon how difficult it is to process the attended target. If the workload is low, the selection is late, if the workload is high, the selection is early. If a distractor is used in experiments, then this distractor has a larger effect with a low workload.

The resource theory of attention uses the metaphor of the spotlight. This refers to the ‘spotlight of attention’ that illuminates locations of interest. The zoom lens theory uses this metaphor. The size of the spotlight depends on the size of the object that requires our attention. Evidence that attention is a resource comes from experiments by Egly, that show that attention can be bound to an object, instead of a spatial area. An explanation for this could be that the spatial location of objects changes constantly, so it would be more useful to focus our attention on the object, instead of the spatial location of the object. To test whether tasks compete for resources (such as attention), the dual-task paradigm can be used, where two tasks are measured both independently and dependently. Our ability to do multiple tasks simultaneously depends on how far apart they are on the relevant dimensions (e.g: speaking and listening tasks will be more difficult simultaneously than seeing and speaking tasks).

When an individual sees a stimulus, the first component of activity is known as feedforward sweep, which describes how incoming sensory information travels across the brain. Once an area is activated it can interact with both higher and lower brain areas in a mode of recurrent processing. This is processing within a network, that involves computations that occur in a cyclic fashion. The receptive field of a neuron indicates the physical space that stimulates the neuron. The normalization model of attention states that attention increases the neural response to a stimulus in the visual cortex. This model focusses on two functions of attention:

1. Increasing sensitivity to faint stimuli presented alone
2. Reducing the impact of task-irrelevant distractors when multiple stimuli are presented.

The stimulus drive is the presented image. The suppressive drive is the perception using attention to decrease the impact of a part of the image and the population response is what the individual sees. Taking attention away from a location in working memory causes a decrease in the memory performance.

The feature integration theory states that recognition of a target was modelled to be determined by two processes:

1. Preattentive visual processes
   These processes simultaneously analyse the entire scene and detect the presence of unique features (e.g: this searches for stand-out features and if the item alone could be recognized by a simple primary feature, such as shape, then this preattentive stage alone could lead to recognition).
2. Binding problem
   This is the use of attention to bind the different features together in order to recognize the object. This needs to happen if a single feature is not enough to recognize something because features are not processed together.

The non-selective pathway uses distributed attention. This is reminiscent of preattentive vision and allows rapid statistical analysis of the entire scene. If attention is attracted to an event in the visual field there will be a facilitation of processing around this location. After attention moves away, this location suffers from delayed responding to events. This is called the inhibition of return. The function of this is to make sure that searchers don’t return to the place they’ve just searched right away.

If people are looking at a rapid moving sequence and they are trying to detect two things that are close to each other, the second thing is not detected. This is called the attentional blink.

There are several failures of attention:

1. Change blindness
   The substantial differences between two nearly identical things are not noticed when presented sequentially.
2. Inattentional blindness
   This is the failure to notice a clearly visible target due to attention being diverted from the target.

An afterimage occurs when the vision of an object remains after the presentation has ceased (e.g: looking in bright light). Continuity editing describes a filmmaking technique to produce a smooth continuous experience across changes in camera shot.

Consciousness is being aware of one’s existence evidenced by thoughts and perceptions. Subliminal perception is perception where the stimulus is presented under a certain threshold (e.g: the stimulus is too dim or presented too quickly, but the effects on behaviour can still be measured. There are two distinct views on the functions of consciousness:

1. Inessentialism
   Consciousness is not necessary, because any action that can be performed by a conscious agent can also be performed by a non-conscious agent (e.g: philosophical zombies are not conscious, yet appear to be so).
2. Epiphenomenalism
   Consciousness has no function. It is merely a by-product of our brain processes (e.g: consciousness is equivalent to the whistle of a steam-train, unnecessary for the main mechanism).

Volition is our ability to make conscious choices. This includes a free will. There seems to be a causal relationship between our actions and our conscious thoughts, but Libet’s experiment seemed to provide evidence against this view. Our readiness potential, which indicates brain activity reflecting the initiation of preparing a movement, precedes our conscious awareness of a movement.

Another theory of consciousness states that the function of consciousness is to provide us with an executive summary of our current situation. The global workspace theory states that consciousness facilitates flexible, context-driven behaviour and that consciousness requires interactions between a broad range of brain areas (e.g: consciousness is needed to determine the mental state of others and this is highly context-driven).

Attention and consciousness share the property of involving the selection of particular information above other information. In attention, the selected information receives deeper processing and in consciousness, the selected information receives privileged access to the stage of our mental life. There are different types of consciousness:

1. Phenomenal consciousness
   This includes the experiential properties of sensations, feelings and perceptions. It is experience.
2. Access consciousness
   This includes representations that are broadcast for use in reasoning and control of action and can be reported. It is the mental life.

The left hemisphere of the brain is responsible for language. People with a split-brain cannot talk about what they see in their left visual field, but they will be able to use their hand to point at the object. They will not know the reason for this, as language is produced in the left hemisphere. Blindsight is a condition in which people have damage to the primary visual cortex which has the effect that people cannot see anymore, although their eyes are functioning properly. Although they cannot consciously report seeing anything, they do respond in various ways to stimuli presented in this damaged visual field.

The neural correlates of consciousness are used to differentiate the empirical approach of studying consciousness with the philosophical approach. Binocular rivalry arises when different images are presented simultaneously to the two eyes and results in experiencing seeing one image and then the other alternatively. The visible image dominates the invisible one in consciousness.