Intro Perception & Chemical Senses Flashcards
What is sensation?
Ability to detect a stimulus. Physiological response to a stimulus
What is perception
Psychologically based. While processing it you are Giving meaning to a detected stimulus
Perception defines our experience of
Reality
We perceive signals in our environment which are important to our…
Survival
Perception is a product of…
Evolution
Psychophysics is
How ppl perceive different sensations
Most important motivation for development of psychophysics is…
Perception seems very subjective
How do we measure perception?
Absolute thresholds
Signal detection
Absolute threshold (psychophysics)
What is the outer limit of our perception? Smallest intensity of a stimulus that can be physically detected.
Standard measure of absolute threshold is:
50% of time person can detect a stimulus
Can see a candle flame a bit less than…
50km away
Can hear a ticking watch up to…
6 meters away with no other noise
Can detect a tilt less than
1/2 a minute on a clock face (vestibular)
Can taste ………. Of sugar in 8 litres of water
A teaspoon
Can smell ………….. Of perfume in 3 rooms
A drop
Can feel the wing of a fly falling on your cheek from a height of…..
10cms
How to separate sensitivity from a biased response?
Using signal detection
Just noticeable difference JND
Smallest difference before being noticed. Three lines.
Signal detection measurement
Lines that are the same in the testing… As well as different lines.
Signal detection. If a person is biased to saying “yes” a lot. They will have a lot of……..in their testing results
‘False alarms’
Signal detection. If a person is highly biased to saying ‘no’ they will be more………..in their test results.
Misses
Webers law
People’s perceptions may differ depending on what the object actually is. JND will be more for an object that is lighter as opposed to a heavy object. Sensitivity decreases when objects get heavier.
Fechners law (after webber)
Same as weber but he put it in a mathematical equation. JND btwn two objects that have smaller intensity will increase quickly as the weight increases.
Stevens power law
Intensity of Sensations measured in relation to a specific stimulus.
Stevens power law and pain
Electric shock. Rating it in terms of magnitude. Estimations of sensation increased hugely as small voltage increases happened.
Stevens power law and light detection
As the light brightness increased sensitivity (%) was reduced - couldn’t detect big changes.
Sensory stimuli depends on…
What is means for you/how it affects you.
Different reactions to different stimulus related to different sensory modalities that has an….
Evolutionary basis
Are people’s sensations the same?
No
Cross-modality matching
Used to determine whether people’s sensations of stimuli intensity is similar or not. Match sound to another modality (ie sound with corresponding with colour intensity)
The 2 chemical senses are
Taste
Smell
Smell is
Olfaction
Taste is called
Gustation
Taste and smell called chemical senses because…
Involve the detection of chemicals
Smell detects chemicals in the
Air
Chemicals in the air we detect are called
Odourants
Odourant Air chemicals need to be one of 3 things:
Volatile to float in air
Small enough to detect
Needs to be water repellent
We can’t detect:
Carbon dioxide
The centre of smell detection is at the…
Olfactory epithelium
Olfactory epithelium contains
Olfactory receptor cells or sensory neurons OSN
How many Olfactory Sensory neurons OSN do we have?
20 million
How many different types of Olfactory sensory neurons OSN do we have?
350-400
Each smell actives a few types of different…
OSNs
Once OSNs are activated the signals then go to the…
Glomeruli
What is glomeruli?
First stage of processing. Cells that coordinate info from OSNs. Pass info on to other cells and eventually to the olfactory cortex in the brain
Olfactory cortex is buried deep inside the
Temporal lobe
Unique characteristics of odour perception…
- OSN are very slow to reach the brain
- Depends on past experience with smell
- odour hedonics (preference) largely learnt
- smell disconnected from language
Reaction to smells can be in a very
Physical/primal level. Which past experience shaping our perception.
Smells can trigger
Memories
Smells produce more
Emotionally intense memories
Memories triggered by odours activate the …… More than memories cued by other senses
Amygdala
Amygdala
Emotional learning
Factors that affect our sense if smell
Genetics Experience Cultural norms Gender Age
Anosmia
Inability to smell
Specific anosmia
Maybe just one thing you can’t smell
Global anosmia
No smell
Pheromones
Chemicals emitted by one member of a species that triggers a physiological or behavioural response in another member of same species. Way of communicating.
Pigs use pheromones as
Sexual communication
Androsterone
A steroid found in both male and female sweat and urine
Humans cannot voluntarily secrete …… In order to communicate
Smells
Chemosignals are
Chemicals released by humans detectable by olfactory system. Effect behaviour, mood, hormonal status, sexual arousal of other ppl
Difference btwn pheromones and chemosigmals:
- do not secrete chemosignals for communication
- response caused by chemosignals to other ppl is not reliable
Pheromones in animal produce more…..responses in the other animal
Reliable
Flavour is a combination of
Taste and smell
2 kinds of ways we smell
Incoming air breathed through nostrils
Retro nasal olfactory sensations
Retronasal olfactory sensations
Chewing food releases chemicals that dissolve in air in mouth travel up the palate to olfactory bulb as backwards them forwards to bulb
Without smell ability to identify foods by taste is
Poor
The more the intense the food the (ie coffee, chocolate)
Less likely ppl could identify it without smell
Four basic tastes are:
Sour
Salty
Bitter
Sweet
Preferences for taste are
Quite innate
Umami
The fifth basic taste. Delicious savoury taste
Smells can trigger
Memories
Smells produce more
Emotionally intense memories
Memories triggered by odours activate the …… More than memories cued by other senses
Amygdala
Amygdala
Emotional learning
Factors that affect our sense if smell
Genetics Experience Cultural norms Gender Age
Anosmia
Inability to smell
Specific anosmia
Maybe just one thing you can’t smell
Global anosmia
No smell
Pheromones
Chemicals emitted by one member of a species that triggers a physiological or behavioural response in another member of same species. Way of communicating.
Pigs use pheromones as
Sexual communication
Androsterone
A steroid found in both male and female sweat and urine
Humans cannot voluntarily secrete …… In order to communicate
Smells
Chemosignals are
Chemicals released by humans detectable by olfactory system. Effect behaviour, mood, hormonal status, sexual arousal of other ppl
Difference btwn pheromones and chemosigmals:
- do not secrete chemosignals for communication
- response caused by chemosignals to other ppl is not reliable
Pheromones in animal produce more…..responses in the other animal
Reliable
Flavour is a combination of
Taste and smell
2 kinds of ways we smell
Incoming air breathed through nostrils
Retro nasal olfactory sensations
Retronasal olfactory sensations
Chewing food releases chemicals that dissolve in air in mouth travel up the palate to olfactory bulb as backwards them forwards to bulb
Without smell ability to identify foods by taste is
Poor
The more the intense the food the (ie coffee, chocolate)
Less likely ppl could identify it without smell
Four basic tastes are:
Sour
Salty
Bitter
Sweet
Preferences for taste are
Quite innate
Umami
The fifth basic taste. Delicious savoury taste
Smells can trigger
Memories
Smells produce more
Emotionally intense memories
Memories triggered by odours activate the …… More than memories cued by other senses
Amygdala
Amygdala
Emotional learning
Factors that affect our sense if smell
Genetics Experience Cultural norms Gender Age
Anosmia
Inability to smell
Specific anosmia
Maybe just one thing you can’t smell
Global anosmia
No smell
Pheromones
Chemicals emitted by one member of a species that triggers a physiological or behavioural response in another member of same species. Way of communicating.
Pigs use pheromones as
Sexual communication
Androsterone
A steroid found in both male and female sweat and urine
Humans cannot voluntarily secrete …… In order to communicate
Smells
Chemosignals are
Chemicals released by humans detectable by olfactory system. Effect behaviour, mood, hormonal status, sexual arousal of other ppl
Difference btwn pheromones and chemosigmals:
- do not secrete chemosignals for communication
- response caused by chemosignals to other ppl is not reliable
Pheromones in animal produce more…..responses in the other animal
Reliable
Flavour is a combination of
Taste and smell
2 kinds of ways we smell
Incoming air breathed through nostrils
Retro nasal olfactory sensations
Retronasal olfactory sensations
Chewing food releases chemicals that dissolve in air in mouth travel up the palate to olfactory bulb as backwards them forwards to bulb
Without smell ability to identify foods by taste is
Poor
The more the intense the food the (ie coffee, chocolate)
Less likely ppl could identify it without smell
Four basic tastes are:
Sour
Salty
Bitter
Sweet
Preferences for taste are
Quite innate
Umami
The fifth basic taste. Delicious savoury taste
Smells can trigger
Memories
Smells produce more
Emotionally intense memories
Memories triggered by odours activate the …… More than memories cued by other senses
Amygdala
Amygdala
Emotional learning
Factors that affect our sense if smell
Genetics Experience Cultural norms Gender Age
Anosmia
Inability to smell
Specific anosmia
Maybe just one thing you can’t smell
Global anosmia
No smell
Pheromones
Chemicals emitted by one member of a species that triggers a physiological or behavioural response in another member of same species. Way of communicating.
Pigs use pheromones as
Sexual communication
Androsterone
A steroid found in both male and female sweat and urine
Humans cannot voluntarily secrete …… In order to communicate
Smells
Chemosignals are
Chemicals released by humans detectable by olfactory system. Effect behaviour, mood, hormonal status, sexual arousal of other ppl
Difference btwn pheromones and chemosigmals:
- do not secrete chemosignals for communication
- response caused by chemosignals to other ppl is not reliable
Pheromones in animal produce more…..responses in the other animal
Reliable
Flavour is a combination of
Taste and smell
2 kinds of ways we smell
Incoming air breathed through nostrils
Retro nasal olfactory sensations
Retronasal olfactory sensations
Chewing food releases chemicals that dissolve in air in mouth travel up the palate to olfactory bulb as backwards them forwards to bulb
Without smell ability to identify foods by taste is
Poor
The more the intense the food the (ie coffee, chocolate)
Less likely ppl could identify it without smell
Four basic tastes are:
Sour
Salty
Bitter
Sweet
Preferences for taste are
Quite innate
Umami
The fifth basic taste. Delicious savoury taste
What three things can tell us where sound is coming from?
Interaural time difference
Interaural level difference
Head and Pinna cues
Our brain can calculate the difference how fast each ear is receiving the info…..this is called
Interaural time difference
Our brain can tell how loud each ear detects the stimulus…. This is called
Interaural level difference
For there to be maximum Interaural time difference the sound would need to be coming
Directly to the left or right
Where would the sound have to be located for there to be no Interaural time difference?
Directly in front or behind you
Interaural level difference is a better cue for sound localisation for which frequency sounds
High
Pinna is
The ear on the outside if your head
