Sensation and Perception Flashcards
Sensation
The process of receiving and detecting raw sensory information via our sensory organs and sending it to the brain. It occurs in three distinct stages: reception, transmission, and transduction.
Reception
The very first stage of sensation is reception. Reception is simply the process in which our sense organs first receive information about a stimulus from our internal or external environment.
Transduction
The conversion of raw sensory information detected by sensory receptors into the form of an electrochemical neural message or impulse (action potential), so that can be sent to the brain.
Transmission
The process of sending sensory information as a neural impulse to the part of the brain responsible for processing sensory information.
Perception
The process of selecting, organising, and interpreting sensory information to be able to understand and assign meaning to it. Perception can occur automatically and unconsciously.
Selection
The process of attending to certain features of sensory stimuli to the exclusion of others. Selection helps us to narrow down the information that has been sent to us, allowing our brain to attend to just a few features of sensory stimuli at a time. This process can occur consciously or unconsciously.
Organisation (perceptual)
The process of regrouping features of sensory stimuli together in order to form cohesive and meaningful information, making it easier to recognise patterns or categories in interpretation.
Interpretation
The process of understanding and assigning meaning to sensory information. This is the point where we can also become consciously aware of sensory stimuli.
Sensory receptors
The receptors on a neuron that specialise in detecting and receiving information about specific kinds of sensory stimuli.
Process of sensation
- Reception - Our sensory organs receive stimuli
- Transduction - The sensory data is converted into a form that can be sent as a neural impulse
- Transmission - The sensory message is sent to the brain.
Process of perception
- Selection - Our brain attends to certain features of sensory stimuli (consciously or unconsciously)
- Organisation - Our brain organises information into meaningful groups
- Interpretation - Our brain makes sense of the information using the present context and past experiences
Photoreceptors
The sensory receptors on the retina of the eye which receive light and are responsible for the process of transduction.
Rods
Photoreceptors that allow someone to see in low levels of light and do not allow us to see colour.
Cones
Photoreceptors that allow someone to see colour and fine details in well-lit conditions.
Optic nerve
The two nerves which extend from the back of the eye to the brain, along which visual information is transmitted to the brain.
Reception in vision
The sensory stimuli of light is received by visual sensory receptors. Light travels through the eye, before reaching an area at the back of the eye called the retina. Once at the retina, the light is then received by sensory receptors on the retina called photoreceptors (rods and cones).
Transduction in vision
The rods and cones are responsible for the transduction of electromagnetic light energy into electrochemical energy, which is a form which can later be sent to the brain for processing. They then send this electrochemical signal to another kind of neuron in the eye called the ganglion cells.
Transmission in vision
The ganglion cells create an action potential, which allows the visual sensory message to be sent to the brain via the optic nerve and then the thalamus for processing.
Gestalt principles
Guiding rules of perception that allow us to organise independent visual signals into meaningful wholes. We do this via processes of pattern and object recognition. (Gestalt - German word for shape or form).
Similarity principle
Reflects the way we group together parts of an image that are similar in some way. Elements of an image can be similar in their size, shape, colour, position, etc.
Figure ground principle
Involves a persons tendency to see some figures as being at the front of an image.
Closure principle
Refers to a persons ability to mentally complete images that are otherwise incomplete.
Visual constancy
A persons ability to perceive visual objects as staying the same even though the sensation of the objects may change. Three visual constancies that affect our interpretation of visual stimuli include: Shape, Size, and Brightness.
Depth cues
Visual clues that allow someone to judge the distance or depth of stimuli in their environment.
Monocular depth cues
Monocular depth cues rely on clues perceived by just one eye to be able to make these judgements, and binocular depth cues rely on clues from both eyes. There are three monocular depth cues: accommodation, motion parallax, and pictorial depth cues.
Accommodation
Eye muscles bulging and flattening according to how far away an object is. In this way, our eye is accommodating for distance. To focus on a close-up object our eye muscles need to bulge; In contrast to focus on a far-away object our eye muscles need to flatten.
Pictorial depth cues
Any information conveyed to the observer of a two-dimensional image that gives the impression of 3-dimensional image, a typical technique artists use.
Relative size
The relative size of objects to one another in our visual field helps us to judge distance.
Height in the visual field
In our visual field, the closer objects are to the horizon line, the further away they appear. This means that their height in the visual field helps us to determine their distance.
Linear perspective
Parallel lines within our visual field appear to meet in the distance, but are separated up close. In this way, our perspective of lines (linear perspective) allows us to gauge distance.
Interposition (AKA overlap)
When objects overlap one another, we perceive the object that is covered by another as being further away than the one obscuring it.
Texture gradient
We rely on the use of texture to judge how far away objects are. The closer we are, the greater the detail of texture we can see.
Binocular depth cues
Relies on the use of both eyes, the judgement of depth is dependent on the comparison between or combination of the images projected onto both the left and right eye.
Retinal disparity
Refers to the difference or disparity between the different retinal images received by either eye. The closer an object is, the greater the disparity.
Convergence
The process of our eyes turning inwards, and the strain that it produces signals to our brain that something is up close, due to objects being too close to our eyes.
Taste
The sensation and perception of flavour. As with all of our senses, this process starts with the three stages of sensation: reception, transduction and transmission.
Reception in taste
When chewing, our saliva breaks down food into chemical molecules which can be tasted, known as tastants (the sensory stimuli received during taste). Tastants are first received by our gustatory receptors, which are located within our taste buds (containing around 100 gustatory receptors each).
Transduction in taste
The chemical form of tastants is converted into electrochemical energy so that it can be transmitted to the brain.
Transmission in taste
Sent to the gustatory cortex
Taste bud
receptors on the tongue
5 basic flavours
Each tastant contains different information regarding its flavour. We can detect five basic flavours: salty, sweet, sour, bitter, and umami (also known as savoury).
Influences on taste perception
There are a range of factors that can influence the way we perceive flavours including, our age, genetics, perceptual set, and culture can all influence the way we perceive flavour.
Age influence on taste perception
As we age, our perception of flavours becomes less sensitive, thought to be due to a decline in the number of taste buds, as well as a general age-related decline in the sensitivity of our senses including both smell and taste.
Genetic influence on taste perception
Genes can determine whether we are more or less sensitive to certain flavours, as well as our sensitivity to flavour more generally.
Perceptual set
The appearance of our food can contribute to our expectations of its taste and, as a result, our enjoyment and perception of its flavour. Some influences from the appearance of food on flavour perception include: Colour and shape.
Appearance
The appearance of our food can contribute to our expectations of its taste and, as a result, our enjoyment and perception of its flavour. Some influences from the appearance of food on flavour perception include: Colour and shape.
Food packaging
As well as the colour of food packaging, other visual information on food packing such as brand names, brand logos, and images can all influence the way we perceive the flavour of food.
Culture
The foods we have grown up with and become accustomed to eating are likely to be tolerated and enjoyed more than foods which are foreign to us. If we have grown up in a culture that emphasises health and wellbeing, we may have a greater liking for the flavour of healthy foods like vegetables and legumes.
Fallibility
The quality of being prone to error or experiencing difficulties in judgement.
Visual illusions
A kind of perceptual distortion which occur when we misinterpret visual information and see stimuli in a way that conflicts with how it is in reality.
Muller-Lyer Illusion
A famous visual illusion, named after the man who first described it. The trick of the illusion has something to do with what is on either end of each line.
Ames room
A well-known visual illusion, that occurs when a person views two people in a special Ames Room through a peep hole that looks front on into the room. The illusion occurs because the shape of the room has been constructed in a specific way.
How perceptual set influences taste
Perceptual sets can cause perceptual distortions when they cause us to taste something that isn’t really there, or cause us to taste something more or less intensely than it truly is in our food. The appearance of food and its packaging.
How colour intensity influences taste
The intensity of the colour of the food we eat can lead to perceptual distortions in flavour judgement. As a general rule, the more intense the colour of food, the more flavour we perceive that we are tasting even when this is not the case.
How texture influences taste
How a food feels in our mouth, or its “texture”, can affect our experience and judgement of a food’s flavour. Texture can affect our judgement of flavour in a variety of ways: the intensity of, and how much we enjoy the flavour.
Synaesthesia
A perceptual phenomenon characterised by the experience of unusual perceptions in one sensory system after another sensory system has been activated. It is automatic and cannot be controlled, is usually consistent, and generally experienced one-way (see green as 4, but not 4 as green).
