This document discusses sensation and perception, specifically vision. It covers the basics of sensory reception and transduction, where stimuli are received by receptors and converted into action potentials that are sent to the brain. It describes concepts like absolute threshold, difference threshold, and signal detection theory. It provides details on the rods and cones in the eyes and their roles in bright, dark, and color vision. It also discusses visual perception concepts like figure-ground, grouping, proximity, and bottom-up and top-down processing.

1. Sensation and Perception
The Basics of Signal Perception
Vision

3. 1. Sensory Reception
1. Sensory Transduction
1. Action Potentials
2. Brain Processing

4. Sensory Reception

5. Sensory Transduction
Stimulus
Receptors
Translation
Cell Body
Ah Hah!

6. Resulting Action Potentials
Transduced signals are sent to the brain

7. Brain Processing

8. Absolute Threshold
The minimum stimulus needed for the receptor
to detect 50% of the time

9. Absolute Threshold
This is different for each individual

10. Absolute Threshold
Which helps explain things like pain tolerance

11. Difference Threshold
The minimum difference in stimulus intensity
required for us to feel a difference.

12. Difference Threshold
As the stimulus increases, so does the DT

13. Signal Detection Theory
The fly in the ointment
We judge stimulus in order to decide whether to
attend or not
We need to filter out all the craziness to focus

17. The Rods and Cones
are the Transducers

18. Cones:
Bright Vision
Many more
Packed in the center of the fovea

19. Rods
Dark Vision
Far fewer
Night vision
Shades of gray
Poor detail

20. Night Driving:
Mostly Rods
Reflectives
activate the
Cones

21. Color Perception
Color = Wavelengths
Brightness = Amplitude

22. Visual Perception
Figure and Ground

23. Grouping
Closure and
Contours

24. Grouping
Proximity

25. Bottom-Up Processing
From sensory input to processing:
We judge what we see based on processing
AFTER input

26. Top-Down Processing
Our pre-judgements affect what we really see

27. Some optical illusions
http://www.buzzfeed.com/jessicamisener/crazy-optical-illusions#2cpkulg