1. Sensation and Perception

2. Transformation of stimulus energy into a meaningful understanding –Each sense converts energy into awareness

3. Sensation Detection and encoding of physical stimuli into neural signals –Occurs at sensory receptors –External stimuli correspond to sensory modalities –Light waves: ___________ –Sound waves : ___________ –Pressure, warmth, cold, pain : ___________ –Chemical messengers : _________&__________ –Body position and movement : _________&_________

4. Perception Organization of sensory information into cognitive awareness environmental stimuli –Occurs in the cerebral cortex

5. Processing stimuli Bottom-up processing –Scientific explanation –Begins with receptors and works up to integration Top-down processing –Understanding stimuli based on prior experience and expectations –The brain will rapidly interpret stimuli based on their “most likely” explanation

6. Thresholds of sensation Absolute threshold –Minimum stimulation needed to detect a stimulus 50% of the time Difference threshold –Minimum difference between two stimuli that can be detected 50% of the time

7. Subliminal sensations Sensations not strong enough to be perceived –May be processed sometimes –May result in understanding without conscious awareness Blindsight Useful persuasion method?

8. Sensory adaptation Diminished sensitivity to a continuous stimulus –Allows for focus on relevant stimuli

9. Vision Stimulus: visible light –Wavelength –Intensity

10. Vision Receptive organ: the eye

11. Photoreceptors Rods Cones

12. Visual pathway Optic nerve –Exits retina Optic chiasm Thalamus Primary visual cortex

13. Processing visual stimuli Feature detectors in the primary visual cortex respond to specific features in parallel –Form –Movement –Depth –Color This information is passed to higher levels of cortical processing for integration

14. Perception of visual stimuli Perception occurs in visual association areas in the occipital, parietal and temporal lobes

15. Color vision Young-Helmholtz trichromatic theory –Red, green, blue color receptors in the retina –Stimulation of one or many results in color sensation Opponent-process theory –Colors are analyzed in terms of opponent colors Red vs. Green Yellow vs. Blue Black vs. White –One color turns some cells “on” and other cells “off”

16. Psychology of visual perception Top-down processing means that what we see is influenced by biological, psychological and socio-cultural factors Perceptions are the result of interpretations by an experienced brain!