Sensation and Perception: Understanding the Human Senses

1. CHAPTER4 Sensation and perception form our world. Sensation is processed by physical receptors; perception is a psychological function of interpretation. Sensation and Perception EXIT

2. Sensory Processes Sensation Sensation is the process of receiving information from the environment through remarkable receptors in the human body. Perception Perception is the psychological process of organizing sensory information to make it meaningful. These two processes are intermixed. EXIT

3. The body receives information through the five main senses. Vision Taste The Five Human Senses Smell Hearing Touch EXIT

4. An absolute threshold is the minimal amount of sensory stimulation needed for a sensation to occur. EXIT

5. Vision is the dominant sense. Click on the arrows for more information. Retina Iris Pupil Blind Spot Cornea EXIT

6. The Iris The iris is a muscle that opens and closes in order to control the amount of light entering the eye. Iris Click for more information. Cornea Blind spot Iris Pupil Retina EXIT

7. The Cornea The cornea is the outer covering of the eye. Cornea Click for more information. Cornea Blind spot Iris Pupil Retina EXIT

8. The Pupil The pupil is the opening in the eye. Pupil Click for more information. Cornea Blind spot Iris Pupil Retina EXIT

9. The Retina The retina is the back of the eye that has receptors for light. Retina Click for more information. Cornea Blind spot Iris Pupil Retina EXIT

10. The Blind Spot The blind spot is where the optic nerve exits and there are no receptors for light waves. Blind Spot Click for more information. Cornea Blind spot Iris Pupil Retina EXIT

11. Blind Spot Demonstration Close your left eye and stare at the dot and move either forward or backward until the cube disappears. EXIT

12. Rods Rods are visual receptors that “see” only black and white and are most sensitive in low light. Cones Cones are visual receptors that receive color and are most sensitive in daylight. EXIT

13. Rods and Cones Rods Cones 7-8 million 120-125 million How many? Where concentrated? Sensitive to light? Sensitive to color? Center of retina Periphery of retina Low sensitivity Very sensitive Yes No EXIT

14. Color Vision Some people cannot tell the difference between certain colors. The most common form is the inability to see the colors of red or green. EXIT

15. The Structure of the Ear Cochlea This structure is a snail-shaped part of the ear that has tiny hairs and fluid that vibrate with incoming sound. Cochlea Eardrum Eardrum This is a piece of skin stretched over the entrance to the ear and vibrates to sound. EXIT

16. Sound Audition Sound is energy; it travels in waves like light, but much slower. Characteristics Pitch: how high or low a sound is Timbre: complexity of tone Intensity: loudness (measured in decibels) EXIT

17. Cutaneous Senses (Touch) There are 3 types of receptors: for pressure for temperature for injury or poison EXIT

18. The sense of smell performs a critical role in providing information about the food we eat. It is very closely related to the sense of taste. Animals also use smell (chemicals called pheromones) to communicate sexual interest. Smell (Olfaction) EXIT

19. Salty Sweet Sour Bitter Taste Taste receptors on the tongue are called taste buds. There are four types of taste receptors: salty, sweet, sour,andbitter. These receptors combine sensations to create subtle flavors. EXIT

20. Perception Perceptualconstancies use memory to maintain order in the world. Size constancy: ability to remember the size of an object no matter where it is located Color constancy: ability to perceive an object as the same color regardless of the environment Shape constancy: ability to perceive an object as having the same shape regardless of the angle Space constancy: ability to judge distance by perceiving either self or object movement EXIT

21. Perceptual Organization Gestalt: making incomplete organization whole (they way something should be rather than how it actually is) Similarity: grouping like things together Proximity: grouping things together that are near each other Closure: filling in the missing details EXIT

22. Perceptual Organization Proximity Closure Similarity EXIT

23. Perceptual Illusions Illusions are misperceptions. They illustrate how we organize objects into meaningful perceptions . Franz Müller-Lyer designed this illusion in 1889. Which line is longer? EXIT

24. The Vertical-Horizontal Illusion Are the two lines the same length? EXIT

25. Figure-Ground Illusion In the figure-ground illusion, the figure is in the front while the ground is in the back. Do you see the faces facing one another or do you see the vase? EXIT

26. Which cylinder is largest? Click the forward arrow to move the cylinder on the right forward to the middle cylinder. EXIT

27. Which cylinder is largest? Now click the forward arrow to move the cylinder forward to the front cylinder. EXIT

28. Which cylinder is largest? EXIT

29. Summary of Main Topics Covered Sensory Processes • Vision • Hearing • Touch • Smell • Taste Perception EXIT