Psychology Unit 2 AOS2

Attention: (+stimuli)

Attention: actively focusing on particular information while simultaneously ignoring other information. 

• Being able to focus on relevant info. allows individuals to direct energy and brain resources to important functions, sensations, and situations.

Two types of information sources that we pay attention to:

• Internal stimuli

• External stimuli

***There are 3 attention types (sustained, divided, selective)

Internal Simuli - Attention

Internal stimuli: Information or sensations that originate from within the body. → feeling hungry or tired, having a fever, being hot or cold, experiencing pain (eg: headache), or having an idea.

External Stimuli - Attention

External stimuli: Information or sensations that originate from outside the body. → conversations with others, completing tasks, reading, or other events one experiences with one of the five senses.

Attention Types: (list)

There are three types of attention: 

• Sustained attention

• Divided attention

• Selective attention

Sustained Attention - Attention

Sustained Attention: Focusing on one stimulus/task across a prolonged, continuous period of time. 

• Daily activities require sustained attention

• No set attention span - ability to sustain attention can be significantly impacted by distracting stimuli.

• Sustained attention involves maintenance of attention even in the presence of distractions → easier when the task is more engaging and the individual is less fatigued. 

Distractions - Attention

Distractions: Internal or external stimuli that draw attention away from the current task. 

*INTERNAL OR EXTERNAL SIMULI

Divided Attention - Attention

Divided Attention: Splitting attention across two or more stimuli at one time.

• Involves multitasking (act of working on multiple tasks at once)

• Individuals have a tendency to believe they are good at multitasking → BUT NO the brain can only process so many things at once.

• Switching tasks = individual prone to distraction, reduces understanding of task, decreases performance. 

Positives and Negatives of Multitasking:

Positives of Multitasking:	Negatives of Multitasking:
Enables individuals to perform two tasks at the same time.  Juggle a boring task with interesting task = feel more entertained.  Multitasking when we actively learn - process multiple tasks at once when 1+ task is automatic or easy.	Multitasking can have negative implications for our performance when: Stop a task not easy to resume. Tasks are less related, completed using different platforms = jumping between is disruptive. Tasks are more effortful and complex- require full attention complete.

Selective Attention:

Selective Attention: Involves exclusively focusing attention on a specific stimulus or task while ignoring all other stimuli or tasks

• Requires individual to filter out external stimuli (outside noise) AND filter internal stimuli (thoughts, emotions)

Eg: when driving, you may maintain your attention exclusively on the road, despite driving past shops and people on footpaths.

Attention Type + Role Table:

Type of Attention:	Role:
Sustained Attention:	Allow us to fully process information or complete a task.
Divided Attention:	Allows us to process multiple sources of information or stimuli more efficiently.
Selective Attention:	Acts as a filter that helps us to prioritise incoming information according to its importance.

Sensation and Perception: 

Most sensory information (stimuli) we receive is from our external environment:

• Through light (vision) — Chemical molecules (taste) — Temperature (touch)

Other stimuli comes from sensory receptor sites within our body, muscles and joints.

These systems have similarities - similar sequencing of info. processing for detecting and responding to stimuli. (Eg: Sensory systems including Vision and taste) 

Sensory systems are known as perceptual systems.

Sensations:

Sensation: The process of receiving and detecting raw sensory information via sensory organs - sending this information to the brain.

Involves senses detecting stimulus + sending the unprocessed sensory info. to brain.

• Sensation is the raw sensory info. the individual is NOT AWARE of what their senses have detected in sensation.

*Awareness of the detection happens at the stages of perception.

Process of sensation - the brain is not yet able to register sensory stimulus. We are unaware of what our senses have detected.

Process of Sensation:

Process of sensation - the brain is not yet able to register sensory stimulus. We are unaware of what our senses have detected.

• Sensory data is received + converted into a neural impulse

• Impulse is sent to the area of the brain responsible for processing that specific sensory info. _{^{(Three phases of reception, transduction and transmission)}}

• Sensation complete - raw sensory info. has been sent as neural impulse to brain

• Individual is STILL NOT AWARE of what their senses have detected.

*Awareness of the detection happens at the stages of perception.

Stages of Sensation: (list)

There are three distinct stages of sensation: (from what first occurs)

• Reception- where we receive the sensory information

• Transduction- where the information is converted into a neural impulse

• Transmission- where the information is sent for processing

Sensory Stimuli - Sensation

Sensory Stimuli: The raw pieces of information that are detected by the five senses

Perception:

Perception: The process of selecting, organising and interpreting sensory information

• Once sensation complete, the brain begins to process info it received - perception. 

• Perception occurs automatically/unconsciously however, it allows sensory info. to enter one’s conscious awareness so that it can be understood.

**3 stage process: selection, organisation, interpretation

Perception is an active process.

What we see, hear, smell, taste, touch = result of brain activity constructing personal understanding of reality from raw sensory info.

The process of perception - three stages:

• Selection -  attending to certain stimuli/features of stimuli and excluding others

• Organisation -  is the process of regrouping selected features of a stimuli in order for them to be arranged in a cohesive manner.

• Interpretation -  the process of assigning meaning to sensory information in order to understand it.

Sensation and Perception Flow Chart.

Sensation → Reception → Transduction → Transmission

*Still not aware for sensory stimuli

→ Perception → Selection → Organisation → Interpretation

*Individual is now aware

The visual sensory system:

The visual sensory system: A network that is involved in the sensation and perception of visual sensory stimuli, including the eyes, the brain and the neural pathways. 

Visual perception (Sensation in Vision)

Visual perception: The process of becoming consciously aware of visual stimuli as a result of interaction between the visual sensory system and the individual's internal + external environments. 

Sensation in Vision:

Sensation in Vision:

The organ for collecting visual sensory information is the eye. This is the process for visual sensation

• Sensory stimulus in the form of electromagnetic energy is received by visual sensory receptors in the eye.

• Light travels through eye to the retina (back of the eye) where sensory receptors are found.

• Here the light energy is converted (transduced) into neural energy and sent to the brain.

*3 Stages - selection, organisation, interpretation

VISUAL Perception stages:

Stages of Vision Perception:

• Selection

• Organisation

• Interpretation

Areas of the Human Eye - list.

• Cornea

• Pupil

• Iris

• Lense

• Retina

• Optic Nerve

The Cornea - Areas of the Human Eye

The cornea is the rounded, transparent covering over the front of your eye.

• Broad beam of light reflected from the object first passes through cornea.

• As the light passes through, its curved surface bends/focuses light waves into a narrower beam.

The Pupil - Areas of the Human Eye

The pupil is a round opening at the front of your eye that allows light waves to pass into the eye’s interior.

• After passing through the cornea, light waves next go through the pupil.

The Iris - Areas of the Human Eye

The iris is a circular muscle surrounding the pupil + controls amount of light entering the eye.

• The pupil is surrounded by the iris (coloured section).

• Dim light = the iris relaxes, allowing more light to enter.

• Bright light = it constricts, allowing less light to enter

The Lens - Areas of the Human Eye

The lens is a transparent, oval structure whose curved surface bends and focuses light waves into an even narrower beam.

• The shape of the lens is controlled by the ciliary muscles. *Binocular depth cues, accommodation

The Retina - Areas of the Human Eye

The image focused onto the retina is an inverted (upside-down) and reversed (back-to-front) image of the object being viewed. 

• The retina receives and absorbs light, and also processes images. 

• In the brain, it is rearranged so we can perceive what we are looking at as it is in reality.

The Optic Nerve - Areas of the Human Eye

Connects eyeball to brain. *Back of eye nerve.

Gustatory Perception: (general)

Gustatory perception: the process of becoming consciously aware of flavour.

The primary sensory organ for detecting gustatory information is the tongue. 

• Gustatory perception occurs in the Primary gustatory cortex - a sensory area in the parietal lobe that receives + processing taste.

Gustatory Perception PROCCESS:

• Before sensation -we break down food with saliva into tastants. 

• Tastants are then received by Gustatory receptors (sensory receptors for taste - located in taste buds).

• Tastants are converted into a form that is sent to the brain as a neural impulse and translated.

**Detecting flavour.

Taste Buds - Gustatory Perception

Taste buds: clusters of gustatory receptors (mostly located on our tongue, around the mouth, throat, nose, in a large number of papillae = small bumps).

Tastants - Gustatory Perception:

Tastants: The sensory stimuli received in the form of chemical molecules that are tasted. 

5 basic flavours detected during sensation - Gustatory Perception

Perception is about making sense of this pre-coded information: the brain detects the fundamental flavour and then processes it further - using info. from other senses.

5 Basic Flavours:

• Sweet - sugar, fruits

• Salty - chips, popcorn

• Sour - lemons, citrus

• Bitter - Coffee, rocket

• Unami - Meat, tomatoes, soy sauce.

Gustatory perception Occurs (other components)

• In the primary gustatory cortex - in parietal lobe that receives + processes taste.

• HOWEVER interpretation of food flavour involves other brain areas (that the gustatory cortex works with)

• Sensation of flavour relies on the sense of smell from the olfactory cortex (brain area processing smell).

• It is also influenced by our perception of food texture - perceived from info. from the somatosensory cortex.

Perception PROCESSES (not stages)

What we see, hear, smell, taste and touch = result of brain activity constructing personal understanding of reality from raw sensory info.

*3 stages of perception - but 2 PROCESSES of perception.

Two key processes of the perception of sensory stimuli:

• Bottom-up processing

• Top-down processing

*****These oppose each other.

Bottom-up processing - Perception Processes

Bottom-up processing: Incoming sensory information moves from stimulus information to general knowledge. **A stimulus driven processing that entirely relies on sensory information.

• We begin to perceive items with sensation, as opposed to ideas.

• Used when the information is unfamiliar or highly complex.

• Entry-level sensory data is processed in real-time and moves up to the brain to be perceived and understood.

Top-down processing - Perception Processes

Top-down processing: Moving from general knowledge to specific stimulus information. Driven by mental processes, prior knowledge + expectations.

• The brain forms an idea first from previous knowledge - then break it down into more specific information. 

• Used when what is being perceived is familiar and less complex.

• If something is expected to appear a specific way/mean something = more likely to be perceived in alignment with expectation.

Factors Affecting Visual Perception:

Our visual perception is influenced by biological, psychological and social factors.

• Biological factors = depth dues, monocular/binocular

• Psychological factors = visual perception principles (Gestalt principles and visual constancies) and perpetual set

• Social factors = cultural norms

Biological Factors - Visual Perception

Biological factors: internal genetic and/or physiologically based factors. 

• The eye - sensory organ responsible for receiving light to enable vision.

• Light enters eye through pupil, focused through lens onto retina. 

• Retina contains photoreceptors which receive light + convert sensory info. into something that can be sent to brain. 

• PHOTORECEPTORS INCLUDE Rods + Cones 

**BIOLOGICAL FACTORS AFFECTING VISUAL PERCEPTION = DEPTH PERCEPTION (monocular and binocular)

Photo Receptors - Biological factors affecting visual perception

• Photoreceptors = sensory receptors which receive light + convert sensory info. into something that can be sent to brain. 

• Rods- photoreceptors that allow someone to see in low levels of light.

• Cones- photoreceptors allowing someone to see colour + details in well-lit areas.  

**Defective photoreceptors (generally genetically caused) = COLOUR BLINDNESS. Affects 1/12 men and 1/200 women.

Photoreceptors rods vs cones table - biological factors visual perception

	Rods:	Cones:
Responds well in…	Low levels of light	Brightly lit conditions
Specialises in…	Night vision	Day vision
Process colour vision?	No	Yes
Do they process fine detail	No	Yes. responsible for visual acuity
Location in the eye	Outer edges of the retina	Concentrated in centre of the retina (fovea)
Allow peripheral vision?	Yes	No

Biological Factors affecting visual perception - Short Sightedness

Short-sightedness as a biological abnormality:

• The eye naturally refracts (bends) light onto the retina. 

• Abnormalities in the shape of the cornea/ lens can lead to refractive errors

• Causes the eye not to bend light as it is supposed to = reduced visual acuity.

****Myopia is short-sightedness

Biological Factors affecting visual perception - Myopia

Myopia as a type of refractory error: (biological abnormality)

Myopia: short-sightedness due to the focal point of one or both eyes being located in front of, instead of on, the retina.

• Causes far-away objects to appear blurry and close-range objects are viewed clearly. Can be corrected using prescription glasses/contacts.

Depth Perception: (biological factors affecting visual perception)

Depth perception: the ability to see the environment in three dimensions and estimate distances of objects from each other.

• Critical for survival, helps with effective navigation + function in life

• Without it = impossible for individuals to tell how far objects were from them + how much they needed to cover to reach them / avoid them.

• Depth perception includes ability to perceive distances of objects in space.

Depth perception -two classes of cues: monocular cues +binocular cues.

Depth Perception Cues: (biological factors affecting visual perception)

Depth perception can be perceived under two broad classes of cues:

• Monocular cues (using one eye)

• Binocular cues (using both eyes).

Binocular Depth Cues - Depth Perception (biological visual perception)

Binocular Depth Cues: The ability of both eyes to perceive an object in three-dimensional space.

Images seen with the two-eyes are perceived slightly differently with reference to view angle(s).

Factors that are accompanied by this phenomenon include: 

• Convergence

• Retinal disparity.

RETINAL DISPARITY Binocular Depth Cues - Depth Perception

Retinal disparity: Difference between the different retinal images received by either eye. Closer the object = greater disparity. 

• Explains how an object is looked at with either eyeball at different angles - so the brain can give slightly different perspectives.

• Occurs due to the horizontal separation of the eyes.

CONVERGENCE Binocular Depth Cues - Depth Perception

Convergence: A binocular oculomotor cue that deals with depth perception - When looking at something close to the eyes, the eyes turn inward (convergence) + eye muscles are strained. 

• This strain sends a signal to the brain, telling you something is very close + helps you gauge the distance of objects.

• Favoured when distance is closer than 10m.

Monocular Depth Cues - Depth Perception (biological visual perception)

Monocular Depth Cues: The cues that allow us to see depth using just one eye, or to detect how near or far an object is in relation to our position with one eye.

• Important for detecting depth. One eye = image is presented in 2D.

• Monocular cues are used in art -create illusion of depth in a 2D space. 

• Monocular depth cues help individuals see objects properly with 1 eye.

Monocular depth cues include: 

• Accommodation

• Motion parallax

• Pictorial depth cues.

ACCOMMODATION Monocular Depth Cues - Depth Perception

The lens bulges for close-up objects in our visual field + flattens for objects in the distance.

• To focus on close objects = ciliary muscles contract, altering lens shape.

• Looking at objects that are far away = ciliary muscles relax.

• Our brain receives this info. about our lens changing shape to infer the distance of an object from the eyes.

This is a monocular cue, even though we are often unaware of it.

MOTION PARALLAX Monocular Depth Cues - Depth Perception

Motion Parallax: A monocular depth cue that uses our perception of movement to gauge how far away something is. 

• Helps us to judge depth - The less objects in our visual field move, the further away they are from us.

• The objects in the distance seem to stay still - close objects that we are passing seem to move by quickly. 

PICTORIAL DEPTH CUES Monocular Depth Cues - Depth Perception (LIST)

Pictorial Depth Cues:

Monocular depth cues = pictorial cues. 

Artists use them to create depth + distance on 2D surfaces (paper/canvas)

Pictorial cues list:

• Linear perspective 

• Interposition

• Texture gradient

• Relative size

• Height in the Visual Field

LITHR - litter.

Linear Perspective - PICTORIAL DEPTH CUES Monocular Depth Cues

Linear Perspective: A depth cue utilising the fact that lines converge in the distance. Parallel lines will get closer together or narrower as they appear further from the viewer. e.g. Road/paths.

Interposition - PICTORIAL DEPTH CUES Monocular Depth Cues

Interposition: Objects that appeared to be becoming in between the viewer and another object. If an object interferes/overlaps the site of the second object, it is perceived closer to the viewer.

Texture Gradient - PICTORIAL DEPTH CUES Monocular Depth Cues

Texture Graditient: Details are too small to see when they are far away - known as texture gradient.  areas closer to the viewer will look coarser, areas further away have a finer texture.

Relative Size - PICTORIAL DEPTH CUES Monocular Depth Cues

Relative Size: Closer objects appear larger than objects further away. If two objects are expected to be the same size, the larger object will appear closer.

Height in the Visual Field - PICTORIAL DEPTH CUES Monocular Depth Cues

Height in the Visual Field: In a picture, objects that are further from the viewer appear higher in the visual field. Lower objects suggest they are closer to the viewer.

Psycological Factors - Visual Perception

Psychological factors: Internal factors pertaining to an individual’s mental processes, including their cognition, affect, thoughts, beliefs, and attitudes. 

Relevant to visual perception is the mental cognition, act of mentally processing incoming stimuli.
PSYCHOLOGICAL FACTORS AFFECTING VISUAL PERCEPTION - VISUAL PERCEPTION PRINCIPLES (gestalt principles and visual consistencies) AND PERPETUAL SET (historical experiences)

Visual Perception Principles - Psychological Factors affecting visual perception

Visual perception principles: Guiding rules that apply to incoming visual signals and determine how they are organised and interpreted.

• Help make sense of our reality by combining visual signals in a systematic way.

• Principles are applies automatically + unconsciously, but we can be conscious of them.

Two types of visual perception principles:

• Gestalt principles

• Visual constancies

GESTALT PRINCIPLES - Visual Perception Principles - Psychological factors affecting visual perception

Gestalt principles of visual perception: The ways in which we organise features of a visual scene by grouping them to perceive a whole, complete form - usually done in the simplest possible way.

• Help us construct a meaningful whole object from an assortment of parts. 

• *Movement of lights or pictures happens because our minds fill in the missing information.

*****The whole is greater than the sum of the individual parts

Gestalt principles used in visual perception:

• Figure–ground organisation

• Closure

• Similarity

• Proximity.

Figure-ground Organisation - GESTALT PRINCIPLES - Visual Perception Principles (Psychological factors)

Figure-ground organisation: The tendency of the visual system to simplify a scene into the main object that we are looking at  and everything else that forms the background.

• Illustrated in "faces or vases" illusion, also known as the Rubin vase. 

• Depending on if you see black or white as the figure - two faces or vase as profile 

• See white faces in profile = white colour is figure

• See black vase in profile = black colour is figure

Closure - GESTALT PRINCIPLES - Visual Perception Principles (Psychological factors)

Closure: Brain takes ambiguous visual information and organises it into something that makes sense to us—familiar, orderly, symmetrical - that we understand.

• Probably see a triangle. But in reality all there are are three “pac men.” 

• Cognitive process allow our minds to leap from comprehending elements as unrelated components → to entire shape as a whole.

• Perceive forms + objects where none were created.

Similarity - GESTALT PRINCIPLES - Visual Perception Principles (Psychological factors)

Similarity: Similar items tend to be grouped together. If a number of objects in a scene are similar to one another, you will naturally group them together and perceive them as a whole. 

• *Law of similarity

• Eg: Series of circles or squares stacked together will be viewed as a series of columns rather than just individual shapes.

Proximity - GESTALT PRINCIPLES - Visual Perception Principles (Psychological factors)

Proximity: Objects near each other tend to be viewed as a group.

• _{^{Eg:  See a number of people standing close together - immediately assume that they are all part of the same social group.}}

• _{^{Eg: At a restaurant the host or hostess might assume that people seated next to each other in the waiting area are together and ask if they are ready to be seated. In reality, they may only be sitting near each other because there is little room.}}

VISUAL CONSTANCIES - Visual Perception Principles - Psychological factors affecting visual perception

Visual Constancies (Perpetual Constancy):

Moving around in our daily lives, the images on our retinas constantly change yet, we perceive the world as stable - Recognise that objects don’t change shape the closer that we get to them, when we look at it from another angle or don't change colour quickly. 

These are recognised as: 

•  Shape Constancy

• Size Constancy

• Brightness Constancy

Shape Constancy - VISUAL CONSTANCIES - Visual Perception Principles - (Psychological factors)

Shape Constancy: The tendency to perceive objects as maintaining shape regardless of changes in the shape of the image on the retina. 

• When we move around, the angles at which we view objects change.

• Therefore the shape cast on the retina changes, HOWEVER we perceive objects as still maintaining their shape. 

*Automatically use the principle of shape constancy to recognise shape hasn’t changed.

Size Constancy - VISUAL CONSTANCIES - Visual Perception Principles - (Psychological factors)

Size Constancy: Recognising that an object’s size remains the same even when the size of the image cast on the retina changes.  

• Eg: On a station platform watching a train coming towards you, it looks smaller when it is further away and as it approaches the image on your retinas become larger.

• We understand that the train itself remains the same size.

Brightness Constancy - VISUAL CONSTANCIES - Visual Perception Principles - (Psychological factors)

Brightness Constancy: The tendency to perceive an object as maintaining its level of brightness in relation to its surroundings, despite changes in the light reflected from the object to the retina. 

• Eg: Turn off a light in your room, you understand that the colour of the walls hasn’t changed and you perceive their brightness as the same as before

Perpetual Set - Psychological factors affecting visual perception

Perceptual set: A predisposition to perceive certain features of sensory stimuli and ignore other features that are deemed irrelevant. 

The way individuals see the world is heavily influenced (and biased) by their past experiences, expectations, motivations, beliefs, emotions, and culture.

Schemas: A collection of basic knowledge about a concept or stimuli. 

*Our perceptual set is influenced by our schemas. 

Perceptual set- affect visual perception through - Selection and Interpretation and HISTORICAL EXPERIENCE

Perpetual Set FACTORS - Psychological factors affecting visual perception

Our perceptual set can affect our processes of visual perception through:

• Selection- feature detectors filtering in or out visual stimuli according to our predispositions

• Interpretation- we may interpret stimuli in a certain way when it is ambiguous.

Perpetual Set Historical Experience - psychological factors affecting visual perception

Historical experiences: Lived events from the past. An individual perceives what they expect to perceive - consciously or unconsciously. 

*Our perception can be influenced by our prior knowledge of related stimuli. 

Social Factors - Visual Perception:

Social factors: External factors relating to an individual’s interactions with others and their external environment, including their relationships and community involvement. 

***INFLUENCED BY CULTURAL NORMS

Cultural Norms - Social Factors Affecting Visual Perception

Cultural norms: A standard, value, or rule that outlines an appropriate behaviour or experience within a culture.

• Culture outlines customs, behaviour, and values of a particular group in society.

• Common cultural norms may involve language, food, style of education, religion, clothing, or social dynamics specific to a culture.

• Cultural background - shapes perceptual set, predisposing individuals to perceive visual stimuli in certain ways specific to cultural context. 

• People within the same culture share certain predispositions to perceive certain sensory stimuli similarly (through what is culturally normal).

Influences on Taste Perception:

• Gustatory perception is influenced by a range of factors.

• Taste preferences are determined by our perceptions - perceptions are influenced by biological, psychological and social factors 

Biological	Psychological	Social
Age and Genetics	Appearance and Food Packaging	Culture

Biological Factors - AGE - Taste perception (gustatory perception)

Biological Age: The ability to taste many substances is already well-developed at birth.  

• Infants start out with few taste buds - increase + develop during childhood.

• A persistent aversion to bitterness = helps protect children from eating poisonous foods during development.

• Children are much more responsive to taste than adults and have more taste receptors than adults - lose taste buds with age

• Taste perception fades with age = normal ageing process (60+)

Biological Factors - GENETICS - Taste perception (gustatory perception)

Biological Genetics: People vary in their ability to taste.

• Genetic differences make us more/less sensitive to chemical molecules in different foods. 

• Our genes can therefore influence how sensitive we are to bitterness, sweetness etc. 

Psychological Factors - Food Packaging - Taste perception (gustatory perception)

Psychological Food Packaging: Packaging, labelling and branding influence our perception of taste. 

• Individuals have a bias towards familiar brands as opposed to unlabelled food.

• Food arrangement + presentation affects taste perception. Presented neatly = more liked. Same food presented messily = less liked.

• Expectations about food sounds influence taste perception. Eg: expectations of texture and taste - of food fulfils these = more enjoyment.

Psychological Factors - Physical Appearance - Taste perception (gustatory perception)

Psychological Appearance: The appearance of food can contribute to how we taste and experience it. 

• Primary gustatory cortex integrates info. from visual cortex to perceive food.

• Past experiences predispose individuals to expect flavours

• Influences from the appearance of food on flavour perception include, colour and shape.

Social Factors - Cultural Differences - Taste perception (gustatory perception)

Cultural differences in food reflect our perceptual judgments of what we think tastes good and bad.

• Individuals prefer tastes they grow up with + try ‘new tastes’ with opportunity.

• Parents, siblings and relatives act as role models - encourage tasting of new foods or influence taste preferences through reactions to foods. 

• Cultural influences on taste are determined early in life.

Taste Perception. Gustatory Perception Image: