1. Sensation and Perception
Year 11 Psychology CCGS 2015.

2. Sensation v Perception example 1
Look at this image.
What do you SEE:
What do you PERCEIVE:
Sensation = Detecting stimuli input and sending it to the brain
Perception = Transferring sensory information into meaning
Everyone's sensation is the same, but perception can be different

3. (your brain thinks that it is in the shadow, so it interprets it as being lighter than it really is, your brain recognizes the checkerboard pattern and knows that it goes dark-light-dark, so it assumes that square B should be lighter than it really is).

4. Sensation – thresholds
For a stimulus to be sensed it must have sufficient energy to be detected. Absolute threshold Smallest amount of energy that can be detected half of the time. Only half of the time because the minimum energy strength varies between people and time. Difference Threshold. Smallest possible difference between two stimuli that can be detected half of the time.

5. Webers Law.
Ernst Weber noted that for people to really perceive a difference, the stimuli must differ by a constant "proportion" not a constant "amount".
POPCORN VIDEO.

6. Perception or sensation?
The body’s initial detection and conversion of stimulus energy is referred to as
sensation
The active process of organising and interpreting sensory stimuli to be a mental representation of the world is
perception

7. BOTTOM UP THEORIES
Emphasis the richness of the information entering the eye and the way that perception can occur from using all the information available.
Gibson believes perception occurs directly from sensation, feature detection theories examine the processes involved with assembling perception from sensations.

8. Top Down Theories
Stress the factors in the construction of reality that go beyond the information received from the senses. Gregorys theory and perceptual set theory regard perception as a very active process, whereby the individuals past knowledge, expectations and stereotypes seek out sensory data to “complete the picture”

9. Visual Perception – Illusions & Distortions
Visual illusion experienced when our perception of a stimulus is inconsistent with the reality of the object
Past experiences leads you to build up expectations about how you will perceive/respond to a certain stimuli = perceptual expectancy

15. Muller-Lyer Illusion
Consists of 2 lines of equal length, each with different shaped ends
One line has arrowheads at each end of the line
Other line has feathertails at end of each line
When we look at it
We think that the feathertail line looks longer than arrowhead line
Reality = both lines are exactly the same!

16. Muller-Lyer Illusion Explanation
Eye movement theories suggest illusion occurs because the eyes look in the wrong place
Eyes drawn past the line with feathertails to make the line look longer
Line with arrowheads – eyes are drawn within the lines  line smaller

19. Ames Room Illusion
Constructed to look like a rectangular room  dimensions aren’t normal
When viewer looks through a peephole with one eyes, they see a room consistent with their expectations of a normal rectangular room
Viewer observes a person as either shrinking or growing as they walk from one of side of room to other

21. Ames Room Illusion
Room is not actually rectangular in shape  trapezium!
Back wall is positioned on an oblique angle
2 back corners cast the same-sized image on the retina which is perceived to be the same distance away
Distorted windows and flooring