Psychology - Sensations

Sensory Adaptation

The diminishing sensitivity to a stimulus after prolonged exposure. It explains why we might stop noticing a constant smell or sound over time.

Example: When you first enter a room with a strong smell, you may notice it immediately, but after a while, you stop detecting it.

Vision in Low Light

The rods in the retina help us see better. Rods are more sensitive to light but do not detect color, unlike cones, which are responsible for color vision in bright light.

Peripheral Vision

Rods are concentrated in the outer parts of the retina, which is why you see better in dim light when looking to the side

Transduction

The process by which sensory stimuli (e.g., light, sound) are converted into neural impulses that the brain can interpret.

Example: In the ear, sound waves are converted into electrical signals that the brain can recognize as sound.

The Blind Spot

The area in the retina where the optic nerve connects. There are no photoreceptors (rods or cones) in this spot, leading to a lack of visual information.

How It Works: This results in a small part of our visual field where we cannot detect light, but our brain "fills in" the gap.

Signal Detection Theory

Explains how and when we detect the presence of a stimulus, taking into account not just the intensity of the stimulus but also psychological factors like expectations and experiences.

Example: After a scary movie, you're more likely to notice small, subtle noises because you're on alert.

Absolute Threshold

The minimum intensity of a stimulus that can be detected 50% of the time.

Example: The faintest sound you can hear in a quiet room is your absolute threshold for sound.

Color Deficiency

(often called color blindness) occurs when the eyes cannot perceive certain colors due to the absence or malfunction of certain cone types.

Most Common Type: Red-green color blindness is the most common form.

Sensorineural Deafness

Caused by damage to the inner ear or the auditory nerve, affecting the ability to process sound.

Common Causes: Exposure to loud noises, aging, or injury to the ear structures.

Phantom Pain

Occurs when someone experiences pain in a limb or part of the body that has been amputated. The brain still "feels" sensations in the missing body part.

 Kinesthesis

The sense of body movement and position, involving sensory receptors in the muscles, tendons, and joints.

Example: You can close your eyes and still know the position of your arms or legs.

Opponent-Process Theory and Afterimage Effect

_______ suggests that we perceive color through opposing pairs (red-green, blue-yellow). After staring at one color for a while, the opposing color may appear as an _____.

Example: After staring at a red image, you might see a green image when you look away.

Visual Information Pathway

Information travels from the retina to the optic nerve, then through the thalamus, and finally to the occipital lobe for processing.

Weber’s Law

States that the just noticeable difference (JND) between two stimuli is proportional to the size of the original stimulus.

Example: If you have a bag of marbles and it takes 5 marbles for you to notice a weight difference, it will take 10 marbles for a bigger bag to feel heavier.

Gustatory Receptors

Responsible for our sense of taste. There are five basic tastes: sweet, salty, sour, bitter, and umami. "Spicy" is not a taste but a sensation of pain.

Inner Ear Function

Responsible for both hearing (via the cochlea) and balance (via the vestibular system).

Example: The cochlea converts sound waves into neural signals, and the vestibular system helps maintain balance.

Conductive Deafness

Caused by damage to the outer or middle ear, such as the eardrum or ossicles, which prevents sound from being properly transmitted to the inner ear.

Example: A blocked ear canal or a damaged eardrum can cause conductive hearing loss.

Sensory Interaction

Occurs when one sense (e.g., smell) influences another (e.g., taste). This explains why you may not taste food properly when you have a cold and your nose is blocked.

Trichromatic Theory of Color Vision

Suggests that we have three types of cones (red, green, and blue) that work together to perceive all colors.

Transduction in Hearing

Occurs in the cochlea, where sound waves are converted into neural signals that are sent to the brain for interpretation.

Gate Control Theory

Proposes that pain signals can be blocked or enhanced by other sensory signals, such as touch. Rubbing an injury may "close the gate" and reduce pain perception.