Sensation and Perception SAC Revision Flashcards
Dependent variable (DV)
The aspect of a participant’s behaviour or experience that is assumed and expected to change as a result if the manipulation of the IV selected by the researcher.
Independent variable (IV)
Referred to as the ‘treatment’ variable to which participants may be exposed (or not exposed).
Population
Refers to the entire group of research interest from which a sample is drawn and to which the researcher will seek to generalise (apply) the results of their investigation.
Sample
A sample is a subset or part of the population that is selected for research purposes.
What are the three sampling procedures?
-Convenience Sampling
-Random Sampling
-Stratified Sampling
Convenience Sampling
Occurs when the researcher cannot obtain a complete list of the population, or divide it into subgroups, and therefore the sample becomes whoever is most accessible.
Random Sampling
Is a sampling technique that ensures every member of the population of research interest has an equal chance of being selected to be part of the sample.
Stratified Sampling
Is the process of selecting a sample from a population composed of various subgroups in such a way that each subgroup is represented.
What are the three experimental designs?
-Between Subjects Design
-Within Subjects Design
-Mixed design
Within Subjects Design
Also repeated measures and within groups, each participant (‘subject’) is in both the experimental and control groups or all the treatment conditions (if there is no control group).
Between Subjects Design
Also called independent groups and between groups, each participant (or ‘subject) is randomly allocated to one of two (or more) groups or conditions and provides one score for data analysis.
The order effect
Occurs when participants’ responses in the various conditions are affected by the order of conditions to which they were exposed.
Counterbalancing
A technique used to deal with order effects when using a repeated measures design. With counterbalancing, the participant sample is divided in half, with one half completing the two conditions in one order and the other half completing the conditions in the reverse order.
Attention
Refers to actively focusing on particular information while simultaneously ignoring other information.
What are the three types of attention?
-Sustained Attention
-Selective Attention
-Divided Attention
Sustained Attention
Allows us to fully process information or complete a task.
Example: Watching a movie without needing to pause or rewind to understand the plot.
Selective Attention
Acts as a filter that helps us to prioritise incoming information according to its performance.
Example: Focusing on what one person says and ignoring the sounds of other conversations or stimuli that may distract you.
Divided Attention
Allows us to process multiple sources of information or stimuli more efficiently.
Example: Driving while following directions from your navigation system.
Sensation
Involves receiving sensory information from the environment. This is done via sensory receptors (specialised cells in your sense organs).
3 steps of sensation
-Reception
-Transduction
-Transmission
Reception
The process of detecting incoming sensory information.
Transduction
The process by which the information is converted into a form which can travel along neural pathways to the brain as neural impulses.
Transmission
Involves sending the information to the brain.
Eg. Vision:
Optic nerve - thalamus - visual cortex
Perception
Refers to the process of selecting, organising, and interpreting sensory information.
3 stages of perception
-Selection
-Organisation
-Interpretation
Selection
The process of attending to certain sensory stimuli and excluding others (conscious and unconscious selection).
Organisation
The process of regrouping sensory stimuli to form meaningful understanding.
Interpretation
The process in which information is given meaning to that it can be understood. Bringing together incoming sensory information and existing knowledge.
Bottom-up processing
A stimulus driven process that entirely relies on raw sensory information and no past knowledge. Used when information is unfamiliar or highly complex.
Top-down processing
Begins with the whole picture. Relies on context, previous knowledge and your expectations. Used when what is being perceived is relatively familiar and less complex.
3 categories of perception principles:
-Gestalt
-Depth cues
-Perceptual constancies
4 Types of gestalt principles
-Figure-ground organisation
-Closure
-Similarity
-Proximity
Figure-ground organisation
We use this principle when we visually organise a scene so that we seperate an object (‘figure’) from the background.
Closure
The perceptual tendency to close-up, fill-in or ignore gaps in an image in order to view an object as a whole.
Similarity
The tendency to perceive parts of a visual image that have similar traits (colours, size, shape, texture) as belonging together as a group or whole.
Proximity
The tendency to perceive parts of a visual image which are positioned close together as belonging together in a group. We group items based on their nearness to each other, in order to create a meaningful whole.
Depth Perception
The ability to accurately estimate the distance of objects and therefore perceive the world in three dimensions.
Depth cues
Are sources of information from the environment, internal and external cues that help us perceive how far away objects are and therefore to perceive depth.
What are the two groups of depth cues?
Binocular and monocular.
Binocular depth cues
Require the use of both eyes working together in order to provide information to the brain about depth and distance.
Convergence
Involves the brain detecting distance from changes in tension in the eye muscles that occur when the two eyes turn inwards to focus on objects that are close.
Retinal disparity
Refers to the very slight difference in the location of the images on the retinas which enables us to make judgements about the depth or distance of an object.
Monocular depth cues
Require the use of only one eye to provide information to the brain about depth and distance, but they also operate with both eyes.
Accommodation
involves the automatic adjustment of the shape of the lens to focus an object in response to changes in how far away the object is.
What are the pictorial cues?
-Linear Perspective
-Interposition
-Relative Size
-Texture Gradient
-Height in the Visual Field
Linear Perspective
is the apparent convergence of actual or imagined parallel lines as they recede into the distance.
Interposition
Also called overlap, occurs when one object partially blocks or covers another, and the partially blocked object is perceived as further away than the object that obscures it.
Texture Gradient
refers to the gradual reduction of the detail that occurs in an object or surface as it recedes into the distance, compared with an object or surface that is close and perceived as fine detail.
Relative Size
refers to the tendency to visually perceive the object that produces the largest image on the retina as being closer, and the object that produces the smallest image on the retina as being further away.
Height in the Visual Field
refers to the location of objects in our field of vision, whereby objects that are located closer to the horizon are perceived as being more distant than objects located further from the horizon.
Perceptual set
is a temporary readiness to perceive something in accordance with what we expect it to be.
What are the factors that influence Perceptual Set in Vision?
-Context
-Motivation
-Past Experience
-Emotional State
-Culture
Context
Refers to the setting or environment in which a perception is made.
Motivation
refers to the processes which activate and sustain purposeful or goal directed behaviour.
Past Experience
refers to our personal experiences throughout our lives.
Emotional State
refers to how we are feeling and how it can influence the way in which we perceive visual information.
Gustation Perception
is our perception of taste.
What are the 4 stages of gustation perception?
-Reception
-Transduction
-Transmission
-Interpretation
What are the 5 tastes?
-Salty
-Sweet
-Sour
-Bitter
-Umami (Savoury)
Biological factors on taste
-Genetics
-Age
Age
The ability to taste many substances is already well-developed at birth. Young children contain more tastes buds than older people because we lose taste as we age.
Genetics
Different genes can change our sensitivity to specific tastants.
Supertasters
About 25% of the population are super-tasters.
Their genetic code causes them to have more papillae with taste buds at their base.
Papillae are smaller, and packed densely.
Non-tasters
About 25% of the population are non-tasters.
Their genetic code causes them to have less papillae with taste buds at their bases.
Papillae are wider, loosely arranged, so they are less sensitive to tastants.
What are the psycho-social factors on taste?
-Taste Aversion
-Flavour
-Perceptual Set in Gustation
Taste Aversion
Through classical conditioning, a bad experience with food can result in a negative association with it, leading to a phenomena known as taste aversion.
Flavour
Combination of Smell, Appearance, Texture, and Temperature with Taste
Perceptual Set in Gustation
Is our expectation of how a food will taste, based upon information from other senses.
-Direct experience
-Colour and Colour Intensity
-Texture
-Packaging and Labelling
Visual Illusions
is a misconception of external usual stimuli that occurs as a result of a distortion or mistake when interpreting the stimuli.
Perceptual Distortion
an inconsistency between a perceptual experience and physical reality.
Muller-Lyer Illusion (Why does it occur?)
Definition: The vertical lines of the illusion appear to be different lengths, but they are the same.
Reasoning: We incorrectly apply depth and distance cues when judging size in 2-dimensional objects (bottom-up processing, misapplying visual cues).
The illusion occurs because it is similar to a common architectural geometry, and that lines farther away are likely to be longer in reality than lines that are perceived to be closer (top down processing, due to our lived experiences and incorrect assumptions from memory).
Ames Room Illusion (Why does it occur?)
Definition: Apparent distance theory states that when two retinal images are the same size but one image appears to be at a greater distance, then the one that appears further away will be interpreted as bigger or larger.
Agnosia
is a brain disorder leading to the loss or impairment of the ability to recognise and identify objects, person, sounds, or other sensory stimuli.
Visual Agnosia
The loss or impairment of the ability to recognise visual stimuli.
Two types of visual agnosia
-Apperceptive visual agnosia
-Associative visual agnosia
Apperceptive visual agnosia
An inability to accurately perceive visually presented stimuli. What is seen cannot be recognised, People with this disorder cannot perceive the individual parts of a stimulus as a meaningful, unified whole.
Associative visual agnosia
An inability to associate a visual stimulus with stored information about object in memory despite having otherwise normal perceptual abilities. People with this disorder can describe an object or even draw it or copy a picture of it, thereby indicating that they can correctly perceive the physical characteristics of an object.
Synaesthesia
Synaesthesia is a perceptual experience in which stimulation of one sense produces additional sensations in another. The experience associated with the additional; sensations ‘adds’ to the overall perceptual experience without replacing the initial sense.
Synaesthesia characteristics
-It is real, not imagined, perception
-Involuntary occurrence, it is very difficult to suppress.
-Consistent and removable across time.
-Individual from one person to another.
-One-directional.
Spatial Neglect Definition
Is a neurological disorder whereby individuals are unable to notice anything either on their left or right side even though there may be no sensory loss.
How does spatial neglect relate to attention?
Spatial neglect relates to attention in which the individual loses spatial processing, orienting attention, spatial awareness, and perception.
random allocation is important to between subject design
Random allocation to the different conditions will help ensure groups are well matched on participant variables and therefore fairly equivalent. Is the process by which each member of the sample has an equal chance of being assigned to either the control or experimental condition.
Advantages of between subjects design
-There is not a need to spread out the time period between the different experimental conditions meaning a fast, one time, experiment.
-No order effects between conditions to control
-Quicker and easier data collection
Disadvantages of between subjects design
-Need for larger number of participants
-Less control over participant variables.
Advantages of within subjects design
-It can effectively control the unwanted influence of variables from individual differences.
-Requires relatively small number of participants
Disadvantages of within subjects design
-Participants guessing the experiment and therefore creating expectations and beliefs.
-Order effects
Mixed design
an investigation that combines features of both a between subjects design and within subjects design.
Extraneous Variables
Is any variable other than the IV that can cause a change in the DV.
Cofounding variables
A variable other than the IV that has an effect on the DV, but cannot be separated from the IV.
Placebo
A false treatment used so that none of the participants know whether they are being exposed to the experimental condition.
Placebo Effect
Occurs when there is a change in a participants behaviour due to their expectations about the treatment.
Hypothesis
Make sure to include, aim, IV & DV, population. A supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
Aim
The effect of IV on the DV. A purpose or intention; a desired outcome.
Primary data
Primary data refers to the first hand data gathered by the researcher.
Secondary data
Secondary data means data collected by someone else earlier
Quantitative data
Quantitative data is numbers-based, countable, or measurable.
Qualitative data
Qualitative data is interpretation-based, descriptive, and relating to language.
Objective data
Objective means verifiable information based on facts and evidence.
Subjective data
Subjective means information or perspectives based on feelings, opinions, or emotions.
Validity
The concept of validity is also applied to research studies and their findings.
Internal validity
Internal validity examines whether the study design, conduct, and analysis answer the research questions without bias.
External Validity
External validity examines whether the study findings can be generalised to other contexts.
Systematic errors
Is a consistent or proportional difference between the observed and true values of something. Systematic errors will reduce accuracy.
Random errors
Random error occurs due to chance.
Ethical guidelines are:
-Voluntary participation
-Informed consent
-Withdrawal rights
-Confidentiality
-Deception
-Debriefing
Voluntary participation
Ensures that a participant willingly decides to take part in an experiment.
Informed consent
Needs to be obtained before an experiment commences.
Withdrawal rights
refers to the right of the participant to cease their participation in a study at anytime without negative consequences or pressure to continue.
Confidentiality
Is a participant’s right to privacy with regard to access, storage and disposal of information collected about them that is related to research.
Deception
In research should not occur unless it is necessary. It is used in some cases where giving participants information about an experiment beforehand might influence their behaviour during the study and thus affect the accuracy of results.
Debriefing
involves participants being informed of the study’s true purpose once the experiment has ended.
What are the different parts of ethics?
-Beneficence
-Non-maleficence
-Respect
-Justice
-Integrity
Beneficence
Where research is considered through the scope of maximising the benefits to society while minimising harm to others.
Non-maleficence
In the medical profession, the principle of non-maleficence involves avoiding causing any kind of harm at all.
Respect
The research is shown through the consideration of an individuals welfare.
Justice
Ensures fair treatment for all, from selection through to result collection.
Integrity
Involves the researcher’s commitment to the honest conducting and reporting of research.
visual constancy
Our ability to perceive that an object remains the same, even when the object projects different images onto our retinas in our eyes.
What are the visual constancies?
-Shape
-Colour
-Size
-Brightness
-Location consistancy
What role do Rods and Cones have in our visual perception?
Rods are responsible for vision at low light levels, they do not mediate colour vision, and have a low spatial acuity. Cones are active at higher light levels, are capable of color vision and are responsible for high spatial acuity.
Prosopagnosia
The inability to recognise known and new faces.
Describe potential causes, treatments and strategies people with different types of agnosia use to navigate everyday life.
Organising and creating routines to help people find things by placing them in the same location every time.
How does miraculin influence taste
It can change the taste perception of a sour substance to sweet. Its modifying taste action results from binding sweet taste receptors when acids are simultaneously present.
