Mid Sem Flashcards
Psychology is the what?
Scientific investigation of mental processes and behaviour
Scientific inquiry involves
Testing Hypotheses
The 3 factors to understand a person’s thoughts, feelings and actions
Biology, Psychological Experience and Cultural Context
Biology determines:
Capacity and limits of experience
Culture refers to:
Group values, beliefs and norms that give MEANING to a person’s behaviour
Psychological experience is:
How a person interprets their experience. Is influenced by biology and culture but not reducible to them
Micro/Macro
iology represents the micro-level, and culture represents the macro-level, of factors that influence psychological experience
Info:
• Psychobiologists focus their study on the biological factors that influence psychological experience; cross-cultural psychologists focus their study on the cultural factors that influence psychological experience (and thus whether psychological phenomena and processes are specific to particular cultures or whether they occur universally in all cultural groups); and cognitive psychologists focus their study on how people give meaning to (or interpret) their thoughts and feelings
Job Variances
- Counselling psychologists provide therapy to help people deal with issues that naturally arise during the course of life; clinical psychologists provide therapy to people with mental illnesses or disorders; both counseling and clinical psychologists administer and interpret psychological tests; and diagnose disorders and both clinical and counseling psychologists need at least six years of tertiary education and must meet the requirements of their state’s registration board; registered psychologists usually have a specific specialisation in a sub-discipline
- Academic psychologists need a PhD and usually do research and teaching
- Applied psychologists need at least three years of tertiary education and typically improve products or procedures
- Psychologists are not the same as psychiatrists, social workers, psychiatric nurses, or counselors; psychiatrists are medical doctors that can prescribe medication; psychologists, social workers, psychiatric nurses and counselors cannot prescribe medication, and all have different accreditation and registration boards
The historical roots of psychology stem from?
Philosophy
both psychology and philosophy address similar questions but differ in their method for answering them – philosophers use logic, reasoning and argument, whereas psychologists use scientific inquiry (or systemic experimentation)
Questions psychologists address: (answer with ___ vs ___)
a) to what extent do psychological processes reflect biological or environmental influences?
b) to what extent does knowledge about the world come from logic and reasoning or from observation and experience?
c) to what extent are people guided by their knowledge or by their feelings (and to what extent should they be)?
d) to what extent is human psychology similar to the psychology of other animals?
e) to what extent are humans fundamentally self-interested or oriented towards relating to and helping other people?
f) to what extent are people conscious of the contents of their mind and the causes of their behaviour?
g) to what extent can we understand psychological events without understanding biological functioning?
a) nature vs nurture
b) rationalism vs empiricism
c) reason vs emotion
d) continuity vs discontinuity with other animals
e) individualism vs collectivism
f) conscious vs unconscious
g) mind-body problem
Who is considered to be the ‘father of psychology’ and why?
Wilhelm Wundt because he designed the first psychology lab
What methods did Wilhelm Wundt use?
Controlled introspection
Who is Edward Titchener?
Wilhelm Wundt’s student and founder of Structuralism
he placed emphasis on experimentation to uncover the basic elements of consciousness; rigorous experimentation allows researchers to verify the output of introspection
Structuralism is:
a school of thought that argues that human consciousness can be reduced to smaller parts or elements, and that there are identifiable structures in the brain responsible for those elements or units of consciousness
Functionalism is:
a school of thought that emerged as a reaction to structuralism, and argues that consciousness cannot be reduced to smaller parts because the parts themselves have not function on their own
Although structuralism and functionalism are opposing schools of thought they are both useful because:
structuralism helps identify what structures in the brain are responsible for different parts of the human experience, and functionalism helps identify the purpose of different parts of the human experience
What are the 5 theoretical perspectives commonly used in psychology?
(i) psychodynamics, (ii) behaviourism, (iii) humanism, (iv) cognitive psychology, and (v) evolutionary psychology; each has strengths and weaknesses and so are best used in conjunction with one another
Key figures in psychodynamic theory
Freud and Jung
Psychodynamic perspective argues that:
people’s actions are influenced by their thoughts, feelings and wishes, but that because these may conflict with one another, they are often outside our conscious awareness of them
Psychodynamic theory asserts that unconscious thoughts, feelings and wishes can be uncovered using :
psychoanalysis because they are inferable from verbalised thoughts and feelings, and observable behaviours
main weakness of psychoanalysis
it is subjective – there is no way to verify if the inferences a psychoanalyst has made about a person’s unconscious thoughts, feelings and wishes are accurate
Key Figures in behaviourism:
Watson, Pavlov and Skinner
Behaviourism is
a school of thought in psychology which advocates for the sole study of observable behaviours rather than unobservable mental processes because mental processes cannot be verified by another person; as such, mental processes are said to live in a ‘black box’ that cannot be observed and should not be tested
Behaviourism argues that:
how people think, feel and act is determined by what they learn from their external environment; behaviour that is followed by a pleasant consequence increases in likelihood of occurring again and behaviour that is followed by an unpleasant consequence decreases in likelihood of occurring again
Behaviourism is significant because:
it draws attention to the fact that behaviour is (in part) shaped by learning experiences and because it is committed to scientific experimentation (thereby reducing subjectivity)
The main weakness of behaviourism
it overlooks the role of mental process in explaining human behaviour
Key Figures in Humanism:
Rogers and Maslow
Humanism developed as a reaction to:
psychoanalysis and behaviourism;
psychoanalysis is subjective – thus the analysts’ interpretation may be less accurate (or valid) and/or useful than the subjects’ interpretation of their own behaviour, and behaviourism ignores mental phenomena as if thoughts and feelings are not important for explaining human behaviour
Humanism emphasises the importance of treating each person:
s a unique individual (‘person-centred’ approach), who needs empathy, warmth and respect to fulfil their innate tendency to fulfil their potential (self-actualisation)
The main goal of humanism is:
self-actualisation
Humanism is criticised for:
being overly optimistic because it assumes that all people are innately good and strive to be their best self, however not all people act in ways that are ‘good’
• Humanism is also criticised for failing to take into account structural inequalities and disadvantages beyond the control of a person that affect their capacity to self-actualise
Key figures in cognitive psychology:
Descartes, Bandura, Chomsky and Tversky
Cognitive psychology explores mental phenomena (or the contents of the mind) such as:
thoughts, feelings, memories, perceptions, sensations, interpretations, language use and development, reasoning and logic, decision making etc.
Cognitive psychology treats the mind as if it were:
a computer or information processor; it receives input from the external environment, processes that information, and the output of that information processing is observable behaviour
Cognitive psychology is significant because:
unlike behaviourism that rejected the study of internal mental processes in favour of external environmental factors, it acknowledges the importance of thought in affecting our behaviour (not just experience)
Key Figures in evolutionary psychology:
Darwin
Evolutionary psychology argues that
human behaviour has evolved through the process of natural selection (where traits that are adaptive to the environment are passed on) to ensure the species survives and reproduces. Thus, much of our behaviour is innate (or instinctual/biologically prewired/part of our nature)
Evolutionary psychology is criticised most for:
use of deductive reasoning – using a specific event to make a generalisation; designing experiments that predict behaviour provide stronger evidence for a theory than post-hoc explanations
basic unit of the nervous system
Neurons
function of neurons
transmit information (i.e. electrical impulses) around the brain and body
Neuronal activity allows us to:
experience psychological phenomena
Estimated number of neurons in the brain
from 10 to 100 billion
Name the 3 types of neurons
(i) sensory, (ii) motor and (iii) inter
Sensory neurons job is to:
transmits information (i.e. electrical impulses) from the sensory receptors on the body to the brain for sensory processing
they may transmit information either directly to the brain or via the spinal cord
A sensory neuron is also called
an ‘afferent’ neuron because the ‘a’ indicates that it is going ‘toward’ something (here, the brain
After sensory information has been processed in the brain, what happens?
a motor neuron transmits information (i.e. electrical impulses) from the brain to the body or internal organs
Motor neurons carry
‘command’ from the brain to the body part or organ about what it should do
A motor neuron is also called
an ‘efferent’ neuron because the ‘e’ indicates that it is going ‘away’ from something (here, the brain)
A motor neuron transmits information to the body or organ via
the spinal cord
An interneuron:
connects neurons in the brain and spinal cord with each other
receives information from sensory neurons and passes information to motor neurons
A neuron has many parts including:
dendrite, cell body, nucleus, axon, axon hillock, collateral branches, myelin sheath, nodes of Ranvier and terminal buttons
The space between two neurons is called:
a synapse (or synaptic cleft)
Dendrites
look like branches at the top of the neuron; they receive information (i.e. electrical impulses) from nearby (or adjacent) neurons and pass it down to the cell body
The cell body
is a fluid sac in which the nucleus is seated
The nucleus
holds the chromosomes of the neuron (chromosomes are pairs of DNA that carry genetic information about the cell)
is like the ‘brain’ of the neuron and decides whether the electrical impulse it has received is strong enough to continue passing down to the axon
If a nucleus decides to pass the electrical impulse down, the neuron is said to have:
‘fired’; this is because once the impulse is passed down the axon, it will cause the terminal button to release neurotransmitters into the synapse – that is, the process cannot be stopped, the electrical impulse will not die down as it moves to the bottom of the neuron where the terminal buttons are
The longest part of the neuron is
the axon
The axon may have
‘collateral branches’
Info about axons
• The axon is simply an extension of the cell body; it starts at the axon hillock (where the cell body and axon join) and ends where the terminal buttons start
The axon is usually wrapped in:
a sheath of myelin
Myelin is material mostly made up of:
fatty cells (called ‘lipids’)
The function of the myelin sheath is:
to help pass the electrical impulse down to the terminal button as quickly as possible
The myelin sheath has spaces in it, called:
nodes of Ranvier; they also help transmit the electrical impulse as quickly as possible
The myelin sheath is also called:
‘white matter’ because lipids appear white in colour; thus, any axons that are unmyelinated are called ‘grey matter’
The more ‘white matter’ a person (i.e. more myelinated axons):
the quicker and smoother they tend to think and move (i.e. information to and from the brain is moving very quickly)
Damage to the myelin sheath leads to:
lower, jerky or uncoordinated movements (e.g. multiple sclerosis)
The terminal buttons
are at the bottom of the neuron
• Once terminal buttons are triggered by the electrical impulse it has received, it releases neurotransmitters into the synapse
Neurotransmitters (NTs) are:
chemicals stored in presynaptic vesicles
After NTs they are released into the synapse:
they bind to a receptor on the dendrite of the postsynaptic cell that is sensitive to that specific NT (i.e. not every NT can bind to every receptor; only particular NTs can ‘open’ particular receptors)
If a NT binds to a receptor, then the dendrite has just received an electrical impulse, and the process begins again
There are many different types of NTs, and depending on where they are released in the brain they have different effects
Some of the most common NTs, and their main functions, include:
(Question: what are they involved in?)
a) glutamate
b) GABA
c) dopamine
d) serotonin
e) acetylcholine
f) endorphins and enkaphalins
a) involved in excitation of neurons throughout the NS
b) involved in the inhibition of neurons in the brain
c) involved in emotional arousal, pleasure and reward, voluntary movement and attention
d) involved in sleep and emotional arousal, aggression, pain regulation and mood regulation
e) involved in learning and memory
f) involved in pain relief and elevation of mood
The nervous system (NS) is the biological basis (or ‘substrate’) for:
psychological experience; without a NS, we would not be able to think, feel, produce words or concepts, plan etc.
There are many nervous systems in our body
At the broadest level, there is the:
central nervous system (CNS) and the peripheral nervous system (PNS)
The CNS is made up of two parts:
the spinal cord and the brain
The spinal cord
receives information from sensory neurons to the brain, and transmits commands from the brain to parts of the body or organs via motor neurons
The brain
processes information received from the body or through the spinal cord to maintain basic life supports and processes as well as psychological activity; in doing these, it is able to responds to stimuli from the environment
The main function of the PNS is
to transmit information between the CNS and the rest of the body
The PNS can be broken down into other types of nervous systems;
specifically, the somatic (‘body’, voluntary) and autonomic (‘internal’, involuntary),
and within the autonomic,
the sympathetic (‘troubleshooter’, emergency or stress response) and the parasympathetic (‘housekeeping’, maintenance)
The somatic NS
conveys sensory messages from the body to the CNS and sends motor messages to muscles and organs
is responsible for voluntary (or intentional) movements, but it is involved in some unconscious activities (note: somatic means ‘bodily’)
The autonomic NS
is completely involuntary and is responsible for basic life functions (e.g. heartbeat, respiration); for example, we do not think about or choose whether we will breathe – we just do
The sympathetic NS is responsible for
getting the body ready to deal with stress or threat; it ‘activates’ us
The parasympathetic NS is responsible for
maintaining basic life functioning (e.g. heartbeat, respiration, digestion), and for bringing the body back down to normal functioning after it has been activated by the sympathetic NS; it ‘calms’ us
There are three parts to the brain:
the hindbrain, midbrain and forebrain
The forebrain is comprised of the: which whats?
(i) hypothalamus
(involved in maintain homeostasis of basic life functions such as eating, sleeping, sexual activity and emotional experiences, and it works closely with the endocrine (hormonal) system to maintain stability);
(ii) thalamus
(involved in ‘sensory regulation’; it receives sensory information from sensory neurons in the eyes, skin, nose, tongue etc, decides which part of the brain needs to receive that information to process it); and
(iii) cerebrum (involved in complex mental processing and is comprised of two parts: subcortical structures and the cortex)
The subcortical structures are comprised of two parts:
i) the basal ganglia (mostly involved in the control of movement); and
(ii) the limbic system (involved in emotionally-significant learning such as repeating pleasurable behaviours and reducing behaviours that have unpleasant consequences),
and (iii) septal area (involved in emotionally-significant learning and remembering such as remembering fear in other people (amygdala) and memory encoding and retrieval (hippocampus))
The cerebral cortex can be divided up in a number of ways, including:
areas (primary and association), lobes (occipital, parietal, temporal and frontal) and hemispheres (right and left)
primary areas
receive ‘raw’ sensory information from the eyes, skin, nose, etc. and conducts initial processing of this information
Association areas
form associations between different parts of the ‘raw’ material; thus, they are involved in more complex information processing, such as forming perceptions, having creative ideas, and making plans for the future
The occipital lobe
is at the back of the brain and is mainly involved with processing visual information
The parietal lobe
is above the occipital lobe and is mainly involved in processing information related to touch and spatial orientation (e.g. movement and relationship between objects in space)
The temporal lobe
is on each side of the head and is mainly involved in processing auditory information and language; these functions have evolved near each other because language was spoken before it was written and so communication required hearing
The frontal lobe
is at the front of the brain and is mainly involved in processing complex mental information such as complex sequences of movement, attention, planning, social skills, abstract thinking, memory and personality
The right hemisphere is mostly involved in
processing non-linguistic information (e.g. sounds) and is responsible for creativity and abstraction
The left hemisphere is mostly involved in
processing linguistic information (i.e. words) and is responsible for logic, reasoning and analysis
The hemispheres are joined by
the corpus callosum
The corpus callosum is involved in
the degree of cerebral lateralisation
The specialised functioning of the right and left hemispheres are more lateralised in:
males than females
If the corpus callosum is severed (cut):
the person appears as though they have ‘two minds’ because information in one hemisphere is not being shared with the other to produce an ‘integrated’ mind
The incident of Phineas Gage (a metal rod through his frontal lobe) is important in psychology because:
(i) it demonstrates that different parts of the brain are involved in different aspects of functioning (i.e. parts are specialised);
thus, frontal lobe damage affected his personality and not, for example, his ability to move;
and (ii) that we may be in less control of our personality (and other such complex psychological constructs) than we think
Phenotypic similiarity
• In adoption studies, researchers compare the phenotypic similarity between children and their birth families and the phenotypic similarity of the same children with their adoptive families
- If there is more phenotypic similarity between children and their birth families, then the role of genetic influence is highlighted (because the degree of relatedness = 0.5)
- If there is more phenotypic similarity between children and their adoptive families, then the role of environmental influence is highlighted (because the degree of relatedness = 0)
• The most effective way for exploring the extent to which human psychology is the result of genetic or environmental factors is to compare MZ twins that have been adopted out to separate homes; if they are phenotypically similar to each other, the role of genetic influence is highlighted, and if they are phenotypically dissimilar to each other, the role of environmental influence is highlighted
he extent to which genetic influence affects our psychology is quantified by
the heritability coefficient;
a number that varies between 0 and 1, where numbers close to 1 suggest that any variation in a characteristic is strongly due to genetic influence and scores near 0 suggest that any variation in a characteristic is strongly due to environmental influence
in the heritability coefficient;
numbers close to 1 suggest
that any variation in a characteristic is strongly due to genetic influence
in the heritability coefficient;
numbers close to 0 suggest
that any variation in a characteristic is strongly due to environmental influence
The incident of Phineas Gage provides support for
‘structuralism’ – a school of thought that sees psychological experience to be completely reducible to its components parts. However, this incident should be used to remember that the parts do not serve the same purpose as the ‘whole’. Thus, functionalism is also important. For example, ‘personality’ in the frontal lobe does not appear the same as ‘personality’ of the person Jane; Jane has some control over her personality and therefore the activity that occurs in her frontal lobe
Behavioural genetics is the study of
the extent to which human psychology is the result of genetic or environmental factors; twin and adoption studies may be used to help answer this (the nature-nurture debate)
• In twin studies,
researchers compare the phenotypic similarity between monozygotic (MZ; identical) twins and the phenotypic similarity between dizygotic (DZ; fraternal)
MZ
Identical
DZ
Fraternal
Phenotypic similarity refers to
how similar two people appear; in the context of psychology, we are interested in how similar they appear to each other on psychological constructs such as personality and mood
If MZ twins are more phenotypically similar to each other than DZ twins, then
the role of genetic influence is highlighted (because the degree of relatedness of MZ twins [or the chance of sharing the same gene with a relative] = 1.0)
If DZ twins are more phenotypically similar to each other than MZ twins, then
the role of environmental influence is highlighted (because the degree of relatedness of DZ twins is only 0.5)
Sensation is the process by which
sense organs gather information about the environment and transmit it to the brain for initial processing
perception is the process by which
the brain selects, organises and interprets the sensations
The difference between sensation and perception is
artificial because both work together to produce an integrated translation of physical reality into a psychological one
three principles underlying sensation and perception
(i) there is no one-to-one correspondence between physical and psychological reality,
(ii) they are active processes (i.e. information in the physical world is translated into psychological information) and
(iii) they are adaptive processes (i.e. they have evolved to enhance survival and reproduction)
Although we have different (or specialised) sensory systems, they have in common five features:
i) they transduce physical energy from the environment into neural impulses,
(ii) they are associated with estimates on the minimum amount of physical energy required for stimulus detection
(iii) psychological judgments are required in addition to minimum energy levels for stimulus detection,
(iv) psychological judgements are required about changes in levels of the stimulus and
(v) they are able to adapt or ‘tune out’ redundant information (i.e. physical stimulation where there is no change in the level)
During transduction
physical energy is received by sensory receptors in our sense organs and are converted into electrical (neural) impulses for the brain; the brain receives a ‘neural code’ – a pattern of firing based on the number, frequency and type of neurons firing – from which it interprets the quality (or nature) and intensity (or strength) of the sensation
We only notice or detect stimulation from our environment if it crosses
the absolute threshold
The absolute threshold refers to
the minimum amount of physical energy required to register or notice the stimulus; it is experimentally determined by measuring the amount of stimulation a person needs to detect the stimulus about 50% of the time
info
• Since there are individual differences in absolute thresholds and since they are sensitive to context (or situation), they are not really ‘absolute’ (or critical); they are only estimates
‘Signal detection theory’
was developed to address the limitations of the theory of absolute thresholds; it states that people make judgments about whether they have detected a stimulus. As such, it moves away from the external criterion of minimum levels of physical energy and move towards an internal/psychological decision
Judgements are influenced by
(i) stimulus sensitivity (i.e. how well a person sees, hears, feels etc.) and
(ii) response bias (i.e. a person’s readiness to report detecting a stimulus when uncertain)
Response bias is influenced by
expectations and motivation, and can affect four types of responses that integrate physical and psychological realities: (i) hits (reporting a present stimulus), (ii) misses (not reporting a present stimulus), (iii) false alarms (reporting an absent stimulus) and (iv) correct negatives (not reporting an absent stimulus)
A difference threshold refers to
he amount of physical energy required to notice a change in the level of a sensation; the amount required depends on the current intensity of the sensation – if it is high, more is required to notice a change
The psychological equivalent of the difference threshold is
the Just Noticeable Difference (JND)
Info
We can only see white light (400 – 700 nm), which is comprised of seven colours: red, orange, yellow, green, blue, indigo and violet (ROY G BIV)
Light particles travel in waves of different lengths;
they are seen as what?
long 700 are seen as red
short 400 wavelengths are seen as violet
What is the route that light takes through the eye?
light enters the eye through the cornea, passes through the aqueous humour (which supplies the eyes with nutrients), the pupil (a hole in the iris controlling the amount of light entering the eye), the lens (which focuses the eye based on the distance of objects), the vitreous humour and lands on the retina
Light is transduced into neural impulses in the retina and relayed to the brain via
the optic nerve
The central part of the retina is called
he fovea, which is sensitive to small detail; thus, we have sharpest vision for things in our line of sight (directly in front of the fovea)
The retina is
a thin multilayered tissue at the back of the eye; the inner layer contains two photoreceptors sensitive to light, rods and cones
We have many more
rods (120 million) than cones (8 million) which allow us to see in dim light
Rods v cones
- Rods produce the visual sensations of black, white and grey; cones produce the visual sensations of black, white and grey as well as colour
- Rods are mostly concentrated on the periphery of the retina, whereas cones are concentrated in the centre of the retina in the fovea
- Rods are more sensitive to light waves than cones – we need a lot more light to see colour
‘blind spot’
Where the optic nerve leaves the eye to go to the brain because there are no photoreceptors there
hearing
• The ability to hear is adaptively useful because then we can hear danger coming and we can communicate with one another
Sound
the physical energy transduced to produce the sensation of hearing
refers to rhythmic pulsations of acoustic energy, or air particles emitted outwards from the vibrating object
Sound is comprised of three properties:
(i) frequency, (ii) complexity and (iii) amplitude
Frequency refers to:
number of cycles per second; it is measured in hertz [Hz]; it produces the psychological sensation of pitch (i.e. the quality of a tone) – the higher the frequency, the higher the pitch; and the range of frequencies we can hear reduces with age
Complexity refers to
the extent to which a sound is composed of multiple frequencies; it produces the psychological sensation of timbre (i.e. the characteristic complexity of a sound)
Amplitude refers to
the height and depth of one oscillation; it is measured in decibels (dB); it produces the psychological sensation of loudness – the larger the amplitude, the louder the sound
The sense organ for hearing is the ear, comprised of three parts:
(i) outer ear, (ii) middle ear and (iii) inner ear
The outer ear is comprised of the:
pinna (collect and funnels sound waves into the ear) and (ii) auditory canal (amplifies and carries the sound waves to the middle ear)
The middle ear is comprised of:
(i) the eardrum (or ‘tympanic membrane’; which reproduces the sound waves on a microcosmic scale, causing movement in the ossicles) and
(ii) the ossicles (three tiny bones – hammer, anvil and stirrup) whose vibrations further amplify the sound waves)
The inner ear contains:
(i) the cochlea (which transduces the waves of its fluid into neural impulses),
(ii) hair cells (which carries the neural impulse to the auditory nerve) and
(iii) auditory nerve (which carries the neural impulse to the brain)
smell
Smell (or olfaction) is adaptively useful because it allows us to survive and reproduce: we can detect danger, discriminate between spoilt and unspoilt foods, recognise familiar others and choose mates based on pheromones
The physical energy transduced in smell are
molecules of gas emitted by various substances are inhaled from the air through the nose; they are transduced into neural impulses in olfactory receptors in the olfactory epithelium; the neural impulses travel to the brain via the olfactory nerve
Taste (or gustation)
is adaptively useful because we are protected from eating spoilt food and we are able to regulate the ingestion of nutrients (e.g. salt and sugar)
The physical energy transduced in taste are
the molecules soluble in saliva; they are transduced by receptors in our tastebuds on our tongues (which are sensitised to specific tastes – mainly sweet, sour, salty, and bitter); unlike receptors in our eyes and ears, the receptors in our mouth are replaced every 10 – 11 days – regeneration is important to avoid permanent loss of taste
Touch is adaptively useful because
it allows us to: protect the body from injury, identify objects, maintain body temperature and facilitate social interaction
• Skin is the sense organ that allows us to have the sensation of touch, and it is our largest organ
Phantom limbs
where people with missing limbs (e.g. amputees or those born without a limb) report sensations of touch even though there is no skin to receive the sensory stimulation – teach us about how the brain processes sensory information and how we experience the sensation of touc
Most importantly, they show that sensations are not wholly dependent on physical stimulation (or energy) from the environment; sensations are in part influenced by the function the neurons were ‘pre-wired’ to do (e.g. carry ‘touch’ information) and where they re-wire in the brain after the limb is missing
How many receptors on skin?
approx. 5 million
Receptors are sensitive to one of three types of properties of touch
i) pressure, (ii) temperature and (iii) pain
Pressure receptors transduce
mechanical energy by an external object that causes skin to displace; their activity gives us the psychological sensation or perception of texture; pressure receptors on the skin have different sensitivities so receptors on our hands and face are more sensitive than those on our legs or back
There are two types of temperature receptors
‘cold and warm’; they are activated by differences in temperature between the body and the environment
Pain receptors
do not transduce any physical energy; they are activated by extreme levels in the other senses
Pain
is an important source of information for us because it motivates us to behave in ways that will terminate the source of the pain and thus prevent damage to skin tissue
• Pain is strongly influenced by beliefs, expectations, emotional states and personality; thus, sensations of pain are linked with our perceptions (or interpretation) of pain
Proprioreceptive senses are responsible for:
and are made up of two parts:
giving us our sensation of body position and movement in space
(i) vestibular sense (provides information about body position in space by responding to gravity and movement) and
(ii) kinaesthesia (provides information about the movement and position of our limbs in relation to the other parts of the body)
Receptors for vestibular sense are
in the inner ear and transduce gravity (physical energy) into neural impulses; specifically, the semicircular canals sense acceleration/deceleration as the head moves and the vestibular sacs sense gravity and the position of the head in space
Receptors for kinesthesia are
in the joints and muscles
‘Gestaltism’
the whole (perception) is greater than the sum of its (sensory) parts
As perception is interpretative, it is not an accurate reflection of the physical world. Instead, what we ‘see’ depends on what we consider meaningful.
As perception is interpretative and can be inaccurate, it is subject to illusion
