Sensation and Perception involves three main concepts: 1) Sensation is the activation of sense organs by a stimulus or source of physical energy. Perception is the interpretation and analysis of sensations by the sense organs and brain. 2) Psychophysics studies the relationship between the physical aspects of stimuli and our psychological experiences of them, such as absolute and difference thresholds. 3) Gestalt principles help us organize visual scenes into meaningful wholes, including principles of closure, similarity, and proximity which influence our perceptions of objects and groupings.

1. Sensation and Perception

2. • Sensation
The activation of sense organs by a source of physical energy (stimulus)
• Stimulus
Energy that produces a response in sense organs
• Perception
The sorting out, interpretation (explanation), and analysis (examination, investigation) of stimulus
by the sense organs and brain.

3. • Psychophysics
• The study of the relationship between physical aspect of stimuli and our psychological experience
of them.
• Absolute Threshold
The smallest intensity of a stimulus that must be present to detected. Absolute threshold is the
stimulus intensity that is detected 50%of the time.
• Difference thresholds (Just noticeable difference)
The smallest level of added or reduced stimulation required to sense that a change in stimulation
has occurred.

4. • Gestalt Principles
• Gestalt principle of visual perception refer to the ways in which we
organize features of a visual scene by grouping them to perceive as a
whole, complete form.
• Gestalt principles help us construct a meaningful whole object from
an assortment parts that, when considered bits, lack any real
meaning.

5. • Gestalt Principles
• Closure
• Similarity
• Proximity
• Closure
Closure is the perceptual tendency to mentally ‘close up’ fill in or ignore
gapss in a visual image and to perceive objects as complete (‘whole’).

6. • Similarity
The principle of similarity involves the tendency to perceive parts of visual
image that have similar features- such as size, shape, texture, or color- as
belonging together in a unit, group, or whole.
• Proximity
The principle of proximity is the tendency to perceive parts of visual image
which are positioned close, together as belonging together in a group. We
group the separate bits into a whole based on how close the are to each
other.