1. Sensation Myers’ PSYCHOLOGY Taken from: James A. McCubbin, PhD
Clemson University
Worth Publishers

2. Sensation & Perception
a process by which our sensory receptors and nervous system receive and represent stimulus energy
Perception
a process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

3. Sensation & Perception
Bottom-Up Processing
analysis that begins with the sense receptors and works up to the brain’s integration of sensory information
Top-Down Processing
information processing guided by higher-level mental processes
as when we construct perceptions drawing on our experience and expectations

4. Prosopagnosia 
Sensation 
Perception
a.k.a. “Face Blindness”

5. Sensation- Basic Principles
Psychophysics
study of the relationship between physical characteristics of stimuli and our psychological experience of them
Light- brightness
Sound- volume
Pressure- weight
Taste- sweetness

6. Sensation- Thresholds
Absolute Threshold
minimum stimulation needed to detect a particular stimulus 50% of the time
50%

7. Thresholds
Do I taste it or not? When stimuli are detectable less than 50 percent of the time, they are "subliminal." Absolute threshold is the intensity at which we can detect a stimulus half the time.

8. Sensation- Thresholds
Some info added from Essentials Psychology I
Difference Threshold or Just Noticeable Difference (JND)
Measures how much a stimulus must change before it becomes noticeably different
The study of difference threshold or JND led to Weber’s law

9. Sensation- Thresholds
Some info added from Essentials Psychology I
Weber’s Law
to perceive as different, two stimuli must differ by a constant minimum percentage
light intensity- 8%
weight- 2%
tone frequency- 0.3%
Law indicated that the more intense the stimulus, the more the stimulus intensity must be increased before a change is noticed
i.e. if music was being played softly, a small increase in sound would be noticeable… if music were being played loudly, it would require a much greater increase in sound to perceive as different

10. Sensation- Thresholds
Sensory adaptation
diminished sensitivity as a consequence of constant stimulation

11. Vision- Stabilized Images on the Retina
Sensory adaptation: Now you see it, now you don't! (a) A projector mounted on a contact lens makes the projected image move with the eye. (b) Initially the person sees the stabilized image, but soon she sees fragments fading and reappearing.

12. Sensation- Thresholds
Signal Detection Theory
predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise)
detection depends partly on person’s
experience
expectations
motivation
level of fatigue