Perception Flashcards
What is perception
- stimuli acquired from environment through our 5 sense organs get stores in our sensory memory ( 1 sec for sight, 5 sec for sound)
2.once sense, stimuli goes through filtering:
Selective attention (you choose to focus on one stimuli and ignore others)
or divided stimuli (you subconsciously focus on multiple stimuli)
- Once filtered, the stimuli is perceived (organized and interpreted)
this perception process and decision making is based on our experiences which are stored in our memory.
what is divided and selective filtering
Selective attention (you choose to focus on one stimuli and ignore others)
or divided stimuli (you subconsciously focus on multiple stimuli)
Which kind of filtering must a pilot have
divided filtering - must be able to interpret mutliple stimuli at same time (instruments, radio, visual cueues, etc)
what are the 2 types of perception processing
Bottom - up: use the info gained from sensors to build a mental model
Top-down: use experiences and past knowledge to modify a mental model
How is perception subjective
perception is based on memory and experience and every experiences something differenlty..
Ex:
A pilot may have insufficient experience or experienced something differently which can lead to the formation of an incorrect model.
A pilot with experience landing on narrow runways doesn’t have sufficient experience to land on wide runways. His perception will be different
What do mental models do:
- allow the brain to interpret confilicting perceptual info received at the senses
- allows us to sort through the info in an understandable form
3.are a very efficient way of meeting the sensory processing challenge
What’s an illusion
Misinterpretation of stimuli / sensory inputs against the mental model
means what we are seeing is faulty event though it is 100% right
what happens during an illusion
when the brain experiences a new scene, it will construct a model and compare it to the reality it knows.
Ex:
if you look at a black and white image and the black spots make up a dog. Whilst there is no outline in the shape of a dog, your brain ‘constructed the reality’
if they are similiar, it will bounce between the two without deciding
Ex: X drawn one side of the cube, looks like it’s draw on a different side because the cube sides are equal. The brain goes back and forth between the two models and can’t decide/fix the reality.
2 sources of illusions
visual and vestibular
what is visual illusion
when the brain uses visual cuest to make inferences about what it sees.
**Visual perception of depth
**
what is the perception of hazy unclear objects vs clear
Ex: we perceive objects that are hazy or have indistinct color as far, and clear objects as close.
But during a foggy day, an object may appear because its hazy and indistinct even though the object is close.
Ex: if you are making an approach on a runway in a hazy conditions in a valley. The mist will make
Things appear as far and a pilot may assume he has adequate horizontal clearance
**Texture perception
**
What happens if a surface doesn’t have texture
Texture cueus give an idea of height
Without it, making height judgement is difficult
Ie. Sea plane has difficulty landing on glossy lake
Movement perception
we judge the rate of objects moving in our peripheral vision
A Cessna pilot will misjudge his taxing speed on a Boeing 747 because of the greater distance from the group reduces the relative motion of the external objects.
what’s a ponzo illusion
When 2 vertical lines are of the same length placed between 2 vertical lines converging at one end
It makes the 2 vertical lines appear of different length
What’s the muller lyre illusion
Two arrows of same length but one with tips inwards vs outwards make arrows appear of different length
what’s the flicker effect
when light (like strobe lights) flickers at 4 to 20 Hz giving you a feeling of **flicker vertigo **and a tumbling sensation
Contextual illusion example
The room with 3 guys
Brain makes assumptions about familiar objects and the assumptions are very strong
3 men of same height are in a room but look like they are of different height
The room looks the same to us.
But it’s the room that distorted but we can’t see that because that assumption is strong.
List of examples of illusions that happen during TAXIING
1) snow blowing ‘pace’ from tailwind
-If you see it blowing at a certain pace, you might use it as cueu for taxi speed
2) low to high deck change
Going for low to high deck might make you taxi faster
3)Habituation - fast to slow speed
Going from fast landing roll into a slow turn to exit the runway - wrong perception of speed
List an example of illusion at take off
head movement back and forward during take off could cause Somatogravic illusion - may over estimate the take off pitch
Illusions during cruising.
1)Rapid Deacceleration after a constant speed
can cause pitching down
2)False horizon
Like useing faint lines as horizong when it is something else
Or if you follow a rising valley floor, you assume the flat surface is horizone but you don’t realize you are climbing
3) Leans -
a sense of pitching or rolling from somatogryal illusion)
Distance perception
after 60m stereoscopic we can’t see details in depth so we try to use visual cueus. Distant objects lose color and contrast.
But in a clear polar region where an object looks clear, can appear close but it’s actually far.
Relative altitude
Perception of wrong altitude You may think clouds at a distance are higher than you but they are lower when you pass them
or 2 aircrafts at 1000ft apart could look like their are on the same altitude.
**Auokinetic effects
**
causes movements in the aircraft, so feels like the aircraft is moving from one spot to another in the horizong
Illusions during landing
**1)lack of texture or colour **on runway can distort height and distance from the runway
**2)vanishing point - **
when on flat surface, we see converging ends of a runway vertical lines. But in bad weather those lines aren’t visible so the brains assumes the location of hte lines
In upslope runway
Might seem that you are high on the appraoch, so you tend to make a shallow appraoch.
In a downslope
Might seem that you are low on the appraoch, so you tend to make a high appraoch.
TExture flow (visual aiming point)
the point where your eye point meets the runway.
Usually the flow is outwards in all directions.
If the weather isn’t clear, it will affect the visual aiming point - you might touch down in the wrong position, or do a ‘late round out’
what is going around mean
when you go from **slow flight approach into a fast powerful climb **
can trigger ‘samotogravic illusion’ due to linear acceleration
How to combat illusions
1) trust your instruments
2) Ensure ‘**large visual segment’ **- by adjusting height of your seat
3) adjust the ‘Attitude’ of the aircraft - increase the approach speed by nose down and add more flops to see better.
4) aside from looking out, move your body and head and take mor input and visuals into your perfipheral view
5)** look at distant objects **to avoid empthy vield myopia
an aircraft at converging / collision course may look like it is moving at constant angle.
what is visual segment
when approaching, its the horizontal distance you see and get most visual inputs from.
situational awareness
perception of elements in the environment within a volumen of space and time, their meaning and their projection of status in the near future.
it’s a complete understanding of the situation (perception should match reality)
it requires correct analysis of the situation with all available info sources provided to you and constant montio the situation and make adjustment to decisions regularly.
