Eye Structure and Vision Defects Quiz

Sensation & Perception: Key Concepts

• Sensory activation is strongest when a stimulus is initially detected, followed by sensory adaptation to conserve energy and attentional resources.
• Psychophysics, pioneered by Gustav Fechner in 1860, is the study of how we perceive sensory stimuli based on their physical characteristics.
• Absolute threshold refers to the lowest level of a stimulus that can be detected when no other similar stimuli are present, such as a single candle 48 kilometers away or 50 odorant molecules.
• Just Noticeable Difference (JND) represents the smallest amount of stimulus change that can be detected, following Weber's Law which states that the stronger the stimulus, the greater change needed to detect.
• Signal detection theory, introduced by Green & Swets in 1966, explains how stimuli are detected under uncertain conditions, with the signal-to-noise ratio affecting detection.
• Phosphenes, vivid sense of light caused by pressure on the eye's receptor cells, are examples of cross-modal senses.
• The McGurk effect illustrates the integration of visual and auditory information, while the rubber-hand illusion demonstrates the interaction between touch and sight to create false experiences.
• Our brains do not rely solely on current sensory input but also consider past information and engage in parallel processing to attend to multiple senses at once.
• Top-Down Processing involves analyzing whole stimuli and then processing smaller parts, while Perceptual constancy allows us to perceive stimuli consistently across varied conditions.
• Attention plays a crucial role in selective attention, as demonstrated by the Cocktail Party Effect and change-blindness.
• The visual system involves the perception of light, visible light wavelengths, and the reflection and absorption of light by objects.
• The structure of the eye, including the sclera, iris, pupil, cornea, and lens, affects the way light is focused onto the retina for visual perception.

Structure and Functions of the Eye, Motion Perception, Gestalt Principles, Depth Perception, and Visual Illusions

• The lens of the eye changes shape to bend light and adapt to different distances, accommodating for near or distant objects.
• Myopia (nearsightedness) is the inability to see distant objects, while hyperopia (far-sightedness) is the inability to see near objects due to the focusing of images in front of or behind the retina.
• The retina contains rods for vision in dim light and cones for color vision and detail in brighter conditions.
• The optic nerve carries visual information from the retina to the brain, with most axons going to the thalamus and then the visual cortex.
• The brain processes motion perception by comparing visual frames of what is to what was, and the Phi phenomenon is the perception of continuous motion between separate objects viewed rapidly.
• Gestalt principles are rules that govern how we perceive objects as unified figures or forms, formulated in the early 20th century.
• Depth perception is the ability to see spatial relations in three dimensions, with monocular and binocular depth cues providing information about the closeness and farness of objects.
• Monocular depth cues include relative size, texture gradient, interposition, linear perspective, height in plane, and light and shadow.
• Binocular depth cues, such as binocular disparity and convergence, allow the brain to judge the depth and position of objects by comparing information from both eyes.
• Visual illusions like the moon illusion, Ames Room illusion, Muller-Lyer illusion, Ponzo illusion, horizontal-vertical illusions, and Ebbinghaus-Titchner illusions demonstrate how perception can deceive us.
• Blindness can lead to a heightened sense of touch, and color blindness results from the absence or reduced number of certain types of cones.
• Hearing, or audition, involves the perception of sound as vibrations traveling through a medium, with sound waves having pitch (wave frequency) and loudness (amplitude).