sensation and perception. transformation of stimulus energy into a meaningful understanding each...
DESCRIPTION
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 : _________&_________TRANSCRIPT
Sensation and Perception
Sensation and Perception
• Transformation of stimulus energy into a meaningful understanding– Each sense converts energy into awareness
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 : _________&_________
Perception
• Organization of sensory information into cognitive awareness environmental stimuli– Occurs in the cerebral cortex
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
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
Subliminal sensations
• Sensations not strong enough to be perceived– May be processed sometimes– May result in understanding without conscious
awareness• Blindsight
• Useful persuasion method?
Sensory adaptation
• Diminished sensitivity to a continuous stimulus– Allows for focus on relevant stimuli
Vision
• Stimulus: visible light– Wavelength– Intensity
Vision
• Receptive organ: the eye
Photoreceptors
• Rods• Cones
Visual pathway
• Optic nerve– Exits retina
• Optic chiasm• Thalamus• Primary visual
cortex
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
Perception of visual stimuli
• Perception occurs in visual association areas in the occipital, parietal and temporal lobes
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”
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!