Sensation & Perception

Sensation & Perception

1. Vision

   • Lens- functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing an image of the object to be formed on the retina.
     • Pupil- is the black circle in the center of your iris that allows light to pass through
   • Retina- receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition.
     • Rods and Cones- Cones are responsible for color vision and function best in relatively bright light, as opposed to rod cells, which work better in dim light.
   • The Brain and the Eye- Light > rods and cones > neural signals > bipolar cells > ganglion cells > optic nerve > optic chiasm > opposite half brain >

2. Hearing

   • Hearing Capacities- Humans are capable of estimating a sound's origin through a process called sound localization, which relies on timing and intensity differences in sound waves collected by each of our two ears
   • Properties of sound-The ear can be divided into the outer, middle, and inner ear
     • Auditory Perception-The outer ear is responsible for collection and amplification of sound.The air-filled middle ear transforms sound waves into vibrations, protecting the inner ear from damage.The fluid-filled inner ear transduces sound vibrations into neural signals that are sent to the brain for processing.

3. Smell

   • Stimuli- chemical signals
     • Receptors- receptor cells in nasal cavity
   • Pheromones-chemical messages that can be sent by one member of a species to another and usually linked to sexual attraction.

4. Taste

   • Stimuli-chemical substances dissolved in water or other fluids.
     • Receptors- taste buds
   • Sensitivity-There are five main types of taste sensations: bitter, salty, sweet, sour, and umami

5. Pressure on the Skin-The receptor cells in the skin can be broken down into three functional categories: mechanoreceptors sense pressure and texture, thermoreceptors sense temperature, and nociceptors sense pain. sensation travels from recpetor to brain to be procesed.

6. Webers Law-size of Just Noticeable Difference (JND) is proportional to size of initial stimulus

7. Absolute Thresholds-absolute threshold or minimum amount of stimulation that the organism can detect for a specific type of sensory input. (50% of time)

8. Top-Down Processing-brain uses this also like reversible figures or when we perceive a word before we know all the individual letters.

   • Bottom-Up Processing-used in feature analysis. Start at parts and build toward the whole.

9. sensaton vs perception- sensation is the input about the physical world that is registered by our sensory receptors. Perception is the process by which the brain selects, organizes, and interprets sensations

   • psychophysics-the scientific study of the relationship between stimuli and the sensations and perceptions
   • Sensory adaptation- involves the gradual decrease in behavioral response with repeated application of a particular stimulus over time.