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: vision, taste, touch

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

Systems have similarities - similar sequencing of information 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 happens at 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: (4)

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

1. Sensory data is received + converted into a neural impulse

2. Impulse is sent to the area of the brain responsible for processing that specific sensory info. 

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

4. 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- receive sensory information

• Transduction- information is converted intoneural impulse

• Transmission- 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 process info received. 

• Perception occurs automatically/unconsciously BUT, it allows sensory info. to enter conscious awareness so 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 understanding of reality from raw sensory info. SIO.

The process of perception - three stages:

• Selection -  attending to certain stimuli and excluding others

• Organisation - 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. Process for visual sensation:

• Sensory stimulus received by visual receptors in eye.

• Light travels through eye to the retina where sensory receptors are found.

• Light energy is converted (transduced) into neural energy - sent to 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 the inverted and reversed image of the object being viewed. 

• The retina receives + absorbs light + 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:

1. Before sensation -break down food with saliva into tastants. 

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

3. 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)

See, hear, smell, taste and touch = result of brain constructing 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.

• Begin to perceive items with sensation instead of ideas.

• Used when the information is unfamiliar/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. 

• What is being perceived is familiar + 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, physiologically based factors. 

• The eye - sensory organ that receives light, enables vision.

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

• _{^{Light enters eye through pupil, focused by lens on retina.}} 

• _{^{Retina (containing photoreceptors) - receives light + convert sensory info. into something that can be sent to brain.}} 

• _{^{PHOTORECEPTORS INCLUDE Rods + Cones}} 

Photo Receptors - Biological factors affecting visual perception

• Photoreceptors = sensory receptors - receive light + convert sensory info. into to be able to 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.

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, 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.

• 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) + factors

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 objects = greater disparity. 

• Explains how an object is looked at with either eye at different angles - brain gives slightly different perspective.

• Occurs from horizontal separation of eyes.

CONVERGENCE Binocular Depth Cues - Depth Perception

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

• Strain sends a signal to the brain = something is very close + helps 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.

• One eye = image is presented in 2D.

• 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.

unconscience monocular cue.

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) (5)

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 relating to individual’s mental processes - cognition, thoughts, beliefs, attitudes. 

Mental cognition- 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 reality - combine visual signals systematically.

• Principles applied automatically + unconsciously.

Two types of visual perception principles:

• Gestalt principles

• Visual constancies

GESTALT PRINCIPLES - Visual Perception Principles - Psychological factors affecting visual perception (+4)

Gestalt principles of visual perception: How we organise features of a visual scene - group them to perceive a whole, complete form (done in the simplest way).

• Constructs meaningful whole object from assorted parts. 

• *Movement of lights/pictures = minds fill in missing info.

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

Gestalt principles used in visual perception:

• Figure–ground organisation

• Closure

• Similarity

• Proximity.

FCSP

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

Figure-ground organisation: Tendency to simplify scene into the main object and everything else forming background.

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

• See white faces = white colour is figure

• See black vase = black colour is figure

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

Closure: Brain cognitive process takes ambiguous visual info. and organises it into something that makes sense -familiar, orderly, symmetrical.

• Allow our minds to leap from comprehending unrelated components → to entire shape as whole.

• Perceive objects where none were created.

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

Similarity: Similar items tend to be grouped together.

• *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.

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

Visual Constancies (Perpetual Constancy):

Moving around in daily lives, images on retinas constantly change yet, we perceive world as stable - Recognise that objects don’t change shape when getting closer, looking at then 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. 

• Move around = angles at which we view objects change - shape cast on the retina changes

• HOWEVER - perceive objects as maintaining 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 if 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 surroundings, despite changes in the light from object to 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 deemed irrelevant. 

Individuals see the world - influenced by experiences, expectations, motivations, beliefs, emotions, 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.

• Customs, behaviour, and values of a group in society.

• Cultural norms may involve language, food, education, religion, clothing, social dynamics.

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

• People with same culture = share predispositions to perceive sensory stimuli similarly

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 = more responsive to taste than adults, have more taste receptors than adults

• 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 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:

Fallibility:

Fallibility: The quality of being prone to error or experiencing difficulties in judgement. 

• Errors in the judgement / interpretation of sensory stimuli = perceptual distortions. 

• Normally functioning brains are susceptible to error.

• Errors in brain processing sensory information + perception info.

Visual Illusions:

Visual illusions: Perception of a visual stimulus that conflicts with how it is in physical reality. 

Not entirely understood how all visual illusions occur - result from variety of sources

• External environment

• Something physiological

• Something psychological

Müller-Lyer Illusion:

• Psychological explanations emphasise the role of our personal learning and memory.

• Misapplication of linear perspective to the lines of the arrowheads and where individuals would normally perceive lines.

Ames Room:

• Trapezoidal prism shape, no right angles - slanted floor slopes upwards towards the shorter back wall + Ceiling slopes upwards towards the further + taller back wall.

• Distortions of distance = maintain shape constancy. **only viewed from one eye

• Prevents accurate depth cues that binocular vision enable (would normally use to judge depth) 

• Object/person appears to change size moving across floor, (one corner to another). Brain misinterprets actual distances + sizes based on faulty depth cues AND anticipated familiarity of a room shape.

Fallibility of gustatory perception:

Sense of taste has an impact in many areas of our lives - eg: helps determine foods we eat, protect us from poisonous/contaminated food.

Taste is central to our lives - but (like all senses) gustatory perception is prone to error =  fallible.

Factors including fallibility in gustatory perception:

• Supertasters

• Exposure to miraculin

• Factors that influence the judgement of flavours

** Remember: Human taste facilitated through receptors in taste buds within the papillae = in mouth and tongue. 

Supertasters - fallibillity in gustatry perception

Supertasters: individuals who have significantly low thresholds for taste stimuli and an unusually high number of taste buds.

• Aspects of taste perception are genetically determined 

• Bartoshuck (1994) researched genetic differences in taste perception. 

• Found people who were extremely sensitive to PROP had many more taste buds + more taste receptors than the average person. 

Miraculin - fallibility in gustatory perception

Miraculin: A type of protein extracted from the ‘miracle berry’, native to West Africa, which alters taste perception in humans.

• Sour food (eg. lemon/ lime) - Acidity activates gustatory receptors on tongue responsible for detecting sour flavours. 

• Miraculin does not cause physiological changes to the functioning of sour taste buds.

• Binds to taste buds responsible for detecting sweet flavours and activates them when an acidic environment is created in mouth.

The judgement of flavours:

The judgement of flavours: Perception of flavour involves information integrated from other sensory systems (vision, touch, smell). 

• Perceptual distortions judging flavour occur due to external + internal influences on taste from other sensory systems. 

• Info. from other senses/ or memory, helps to judge flavours = ‘fool’ us into believing we taste something different from reality. 

The judgement of flavours factors:

• Influence of perceptual set

• Influence of colour intensity

• Influence of texture

The judgement of flavours: Influence of perceptual set:

Perceptual set: predisposition to perceive certain sensory stimulus features and ignore other features of stimulus deemed irrelevant. 

• Cause perceptual distortions = cause us to interpret flavours differently/ taste something more/less intensely.

• Eg. Appearance of food + packaging → expectation influencing flavour we perceive. 

• Popular brand → expect a high-quality taste, believe we taste better food.

The judgement of flavours: Influence of colour intensity:

• General rule: food more intensely coloured = leads to perception of stronger flavour, even when this is false.

• Determined by past experience - expect brighter colour =more ripe/intensely flavoured. 

• Encourages food brands to artificially dye products.

The judgement of flavours: Influence of texture

How food feels in the mouth - ‘texture’, can affect our experience and judgement of a food’s flavour. 

1. Intensity of the flavour we experience.

• The texture of food = determines how much is received by gustatory receptors + how long it stays in the mouth. 

Not a perceptual distortion - we are physically able to taste more/less of the food depending on its form.

2. It can also change how much we enjoy the flavour we perceive.

• Whether we judge food to be tasty depends on its texture. 

• Informed by expectations of how a food should feel + past experiences with specific food.

Not a perceptual distortion.

Distortions of taste and visual perceptions:

Perceptual distortions occur in healthy brains and provide no indication of something being ‘wrong’. 

Examples of otherwise normally functioning brains may experience perceptual distortions:

• Synaesthesia 

• Spatial Neglect

Synathesia:

Synaesthesia: A perceptual phenomenon characterised by the experience of unusual perceptions in one sensory system after another sensory system has been activated. 

• People see sounds, taste images, associate concepts with colour

• A person with Synesthesia is known as a synesthete.

• Involves perceptual distortions

• It is not a mental health disorder = occurs in healthy, intact brains.

*5 Characteristics of Synaesthesia:

Characteristics	Description
Synaesthesia is automatic and cannot be controlled	The perceptual experiences of secondary sense feel vivid and real, cannot be prevented.
Synaesthesia is generally experienced as a one-way process	E.G. A person who sees green when looking at  ‘4’, will not see ‘4’ when looking at green.
Synaesthesia is usually consistent	E.G. A person who sees ‘4’ as green, will always see it as green and not as another colour.
The experience pf synaesthesia is unique to the individual	If one person sees  ‘4’ as green, a person with the same kind of synaesthesia will NOT also see a 4 as green.
Synaesthesia is relatively common	Some forms are more common than others: High:1 in 100 people, Low: 1 in 2000 people

Forms of synaesthesia

• Grapheme-colour: sees colours when looking at symbols

• Sound-colour synaesthesia: sounds cause secondary perception of colours. 

• Lexical-gustatory: sees a word, a taste is triggered. 

Two distinct steps of Synaesthesia:

1. A sensory stimulus is detected by one sensory system.

2. During perception, info. from another secondary area of the brain is integrated + combined within the cerebral cortex as though it belongs to the same true sensory experience.

• Brain is in charge of perception + responsible for unique perceptual distortions. 

• Sensation and perception = distinct processes. Perception is subjective. 

Spatial Neglect:

Spatial neglect: A perceptual distortion affecting visual perception - an individual’s inability to perceive, report + orient sensory information located within one side of space.

Do not have malfunctioning senses - distortion occurs during perception process. 

• Attentional disorder - ignore one side of  visual field.

• Attributed to a brain lesion from neurodegenerative diseases, trauma, or a hemispheric stroke. 

• The hemisphere with the lesion dictates which side the individual is unable to attend to. 

  • Lesion right hemisphere → left visual field impacted 

  • Lesion left hemisphere → right visual field impacted

****Don’t realise their different perceptions - very obvious to others  due to the way it affects behaviour

Manifestations of spatial neglect:

• Gaze ‘drifts’ toward side of the brain the lesion occurred. 

• Display difficulties in dressing/grooming = unintentionally fail to attend to one side of their body. 

• Fail to attend to stimuli on one side of their visual field = eg: only eating food off of one side of a plate.