Lecture 7 - Perception as a product of the brain

Question 1

What is the difference between sensation and perception?

Answer 1

sensation:
- the ability to detect sensory input, which can include many signals that may not reach conscious awareness
perception:
- the subjective experience of sensory input, such as the feeling of red or the experience of roughness of the skin

Question 2

What was Rene Descartes’ view on the mind and brain, and what is dualism?

Answer 2

Rene Descartes supported the concept of dualism, which posits that the mind and brain are separate entities. He believed the brain was material and measurable, while the mind was immaterial and communicated with the brain via the pineal gland

Question 3

How did Wundt and Helmholtz contribute to overthrowing dualism?

Answer 3

Wundt and Helmholtz applied the scientific method to study sensation and perception, showing that these could be measured and were products of brain activity, thereby challenging the idea that the mind was separate and mysterious

Question 4

How do we ‘see’ according to visual perception theory?

Answer 4

To see, the visual system must detect electromagnetic radiation (light) and convert it into neural events through a process called transduction. This involves photoreceptors in the retina absorbing photons and generating action potentials that are interpreted by the brain

Question 5

What is the physiological blind spot, and why don’t we usually notice it?

Answer 5

The physiological blind spot is the point where the optic nerve leaves the eye, called the optic disc, which lacks photoreceptors, making us blind to images projected there. We don’t typically notice it because the brain uses perceptual filling-in to infer and complete the missing information based on surrounding areas

Question 6

What is the Opponent Process Theory, and what phenomenon does it explain?

Answer 6

The Opponent Process Theory explains that the human visual system contains, mechanisms tuned to opposite colors. After protracted viewing of certain colors, you can see oppositely colored after images, demonstrating competitive mechanisms in color vision.

Question 7

What is color constancy, and how does the brain achieve it?

Answer 7

Color constancy is the perception of consistent colors in varying lighting conditions.
The brain achieves this by estimating the prevailing light source and subtracting its influence from the perceived color of objects, helping maintain a stable perception of object colors.

Question 8

How does sensory adaptation affect perception of complex visual features like gender in faces?

Answer 8

sensory adaptation can impact the perception of complex visual features.
For example, adapting to faces of a specific gender can cause androgynous faces to appear as the opposite gender, showing that even well-known complex forms are subject to change through visual adaptation.

Question 9

What is the difference between dichromat and trichromat vision, and how does it affect color perception?

Answer 9

Dichromat:
- An individual with two types of photoreceptors, which limits their ability to distinguish between certain colors
Trichromat:
- an individual with three types of photoreceptors, allowing for a broader range of color perception.
- for example, humans are typically trichromats, while many animals are dichromats.