Sensation and Perception By: Mike Hervey

Thresholds Absolute Thresholds: the level of stimulation that is right on our perceptual borderline Absolute Thresholds: the level of stimulation that is right on our perceptual borderline Just Noticeable Difference: or JND is the minimum amount of distance between two stimuli that can be detected as distinct Just Noticeable Difference: or JND is the minimum amount of distance between two stimuli that can be detected as distinct Weber’s Law: An observation that the JND is a proportion of stimulus intensity. In other words, the greater the magnitude of the stimulus, the larger the differences must be to be noticed. Weber’s Law: An observation that the JND is a proportion of stimulus intensity. In other words, the greater the magnitude of the stimulus, the larger the differences must be to be noticed.

Sensory Mechanisms Sensory Coding: the process by which receptors convey such a range of info to the brain. When the sensation is converted to the brain Sensory Coding: the process by which receptors convey such a range of info to the brain. When the sensation is converted to the brain Visual Sensation: Occurs when the eye receives light input from the outside world. The object as it appears in nature is distal stimulus. The the image of that object on the retina is known as proximal stimulus. Visual Sensation: Occurs when the eye receives light input from the outside world. The object as it appears in nature is distal stimulus. The the image of that object on the retina is known as proximal stimulus.

Visual Sensation

Auditory Sensation

Sensory Adaptation Adaptation: an unconscious, temporary change in response to environmental stimuli. Adaptation: an unconscious, temporary change in response to environmental stimuli. Habituation: the process by which we become accustomed to a stimulus and notice it less and less over time. An example is being exposed to a bad smell for a long period of time. Habituation: the process by which we become accustomed to a stimulus and notice it less and less over time. An example is being exposed to a bad smell for a long period of time. Dishabituation: occurs when a change in the stimulus, even a small change, causes us to notice the stimulus again. Dishabituation: occurs when a change in the stimulus, even a small change, causes us to notice the stimulus again.

Attention Attention: refers to the processing through cognition of a select portion of the massive amount of information incoming from the senses and contained in memory. Attention: refers to the processing through cognition of a select portion of the massive amount of information incoming from the senses and contained in memory. Selective Attention: an example is when we try to attend a movie while trying to ignore people having an conversation behind you. Our ability to focus on a single thing in an environment full of stimuli. Selective Attention: an example is when we try to attend a movie while trying to ignore people having an conversation behind you. Our ability to focus on a single thing in an environment full of stimuli.

Attention 2 Filter Theories: they propose that stimuli must pass through some form of screen or filter to enter into our attention. Filter Theories: they propose that stimuli must pass through some form of screen or filter to enter into our attention. Attentional Resource Theories: they say we have only a fixed amount of attention and that this resource can be divided up as is required in a given situation. Attentional Resource Theories: they say we have only a fixed amount of attention and that this resource can be divided up as is required in a given situation. Divided Attention: Trying to focus on more that one task at a time. The most difficult when attending to two or more stimuli that activate the same sense. Divided Attention: Trying to focus on more that one task at a time. The most difficult when attending to two or more stimuli that activate the same sense.

Perceptual Processes How our mind interprets stimuli How our mind interprets stimuli Bottom Up processing is by recognizing an object by breaking it down into its component parts Bottom Up processing is by recognizing an object by breaking it down into its component parts Top down processing relies of prior experience with an object Top down processing relies of prior experience with an object Direct Perception takes the view that our sensations and sensory context are all we need for perception. Direct Perception takes the view that our sensations and sensory context are all we need for perception.

Perceptual Processes 2 Visual perception Visual perception -Monocular depth cues are those that we need only one eye to see -Linear perspective is a monocular cue based on the perception that parallel lines seen to draw closer together as the lines recede into the distance. -Binocular depth cues rely on both eyes viewing an image. Results in stereopsis, or the world we perceive in 3-D