Briefly explain Freud's theory of dreams.
Explain Gestalt theory, and cite an example.
Explain the difference between absolute threshold and difference threshold.
Explain, in detail, the process of vision.
Describe the Gestalt principles of proximity, similarity, continuity, and closure.
Freud's theory of dreams posits that dreams are the disguised expression of repressed and unconscious desires. According to Freud, the content of dreams is symbolic and represents the fulfillment of unconscious wishes that are too threatening to express openly. He believed that dreams are a way for the unconscious mind to express forbidden or suppressed thoughts or desires in a disguised or symbolic form.
Gestalt theory, developed by Max Wertheimer, Wolfgang Köhler, and Kurt Koffka, emphasizes that humans perceive and comprehend things as a whole rather than as separate parts. It suggests that the mind organizes sensory information into meaningful patterns and wholes. An example of Gestalt theory is the perception of a melody. When we hear a series of individual notes played in a particular order, our brain organizes them into a coherent melody rather than perceiving them as separate, disconnected tones.
Absolute threshold refers to the lowest level of stimulus intensity that an individual can detect. It is the level at which a stimulus is just barely perceptible to a person. On the other hand, the difference threshold (also known as the just noticeable difference) is the minimum difference in stimulus intensity that can be detected 50% of the time. Absolute threshold is concerned with whether a stimulus is detectable at all, while difference threshold is concerned with the ability to detect a difference between two stimuli.
The process of vision involves several steps. It begins with the cornea and the lens focusing incoming light onto the retina at the back of the eye. The retina contains specialized cells called photoreceptors, which are responsible for converting light into electrical signals. There are two types of photoreceptors: rods, which detect black, white, and gray and are responsible for peripheral vision, and cones, which are responsible for color vision and are most densely packed in the fovea.
When light stimulates the photoreceptors, they transduce the light energy into electrical signals, which are then transmitted to the bipolar cells and then to the ganglion cells. The ganglion cells' axons bundle together to form the optic nerve, which carries visual information from the retina to the brain.
From the optic nerve, visual information is processed in different areas of the brain, including the thalamus and the primary visual cortex in the occipital lobe. In the primary visual cortex, the brain begins to interpret and make sense of the visual information received.
The Gestalt principles of proximity, similarity, continuity, and closure are principles that describe how humans perceive and organize visual information.
Proximity refers to our tendency to perceive objects that are close to each other as belonging to a group. For example, if there are three circles placed close together, we perceive them as a group rather than as separate circles.
Similarity suggests that we tend to group objects that are similar to each other based on their shape, color, size, or other attributes. For instance, if we see a group of squares and triangles, we tend to perceive them as two separate groups based on their shape.
Continuity suggests that we prefer to see continuous lines or patterns rather than disjointed or fragmented ones. So, if there's a broken line, we perceive it as a smooth, continuous line.
Closure refers to our tendency to mentally complete unfinished or incomplete figures or patterns. For example, if we see a circle with one small section missing, we tend to perceive it as a complete circle.