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Sensory Receptors and Thresholds

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Psychology & Sociology

A sensation is any stimulus that sensory receptors in the body pick up and turn into electrical signals, such as action potentials. Meanwhile, perception begins when the central nervous system becomes aware of a sensation and interprets that information to figure out its meaning and how to respond. Sensory thresholds include the absolute threshold, the threshold of conscious perception, and the difference threshold.

The concept of psychophysics is introduced as the study of how physical stimuli interact with a person's psychology, with two important concepts in psychophysics being signal detection theory and sensory adaptation. Signal detection theory suggests that whether or not people are able to detect a stimulus depends on its intensity and each person's mental state. Sensory adaptation is the idea that a person's perception of a stimulus can change situationally or over time, either due to psychological or physiological changes in their body.

Lesson Outline

<ul> <li>Introduction to sensation, perception, and sensory thresholds</li> <ul> <li>Sensation</li> <ul> <li>Stimuli activating sensory receptors</li> <li>Examples of sensory receptors</li> </ul> <li>Perception</li> <ul> <li>Begins when the central nervous system becomes aware of a sensation</li> <li>Processing and interpreting information</li> </ul> <li>Sensory thresholds</li> <ul> <li>Absolute threshold</li> <li>Threshold of conscious perception</li> <li>Difference threshold (just noticeable difference)</li> <ul> <li>Weber's Law</li> <ul> <li>Proportional difference threshold</li> <li>Equation and explanation</li> </ul></ul></ul> <li>Psychophysics</li> <ul><li>Signal detection theory</li> <li>Sensory adaptation</li></ul> </ul>

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What are sensory receptors, and how do they generate action potentials?

Sensory receptors are specialized cells or structures found in sense organs throughout the body. They are responsible for detecting and responding to external stimuli, such as light, sound, and touch. For example, when they receive a particular stimulus, they undergo a process called transduction, converting the stimulus into an electrochemical signal called an action potential. Action potentials travel along nerve fibers and are eventually transmitted to the brain for interpretation and perception.

What are sensory thresholds and how do they relate to perception?

Sensory thresholds refer to the minimum level of stimulus intensity required for a sensory receptor to be activated and initiate an action potential. The three main types of sensory thresholds include the absolute threshold, the threshold of conscious perception, and the difference threshold. Absolute threshold refers to the lowest level of intensity at which a sensory receptor can detect a stimulus. The threshold of conscious perception refers to the minimum level of stimulus intensity required to be consciously aware of a stimulus. Lastly, the difference threshold refers to the minimum difference in the intensity of two stimuli that a person can consciously notice that the two are different. The relationship between sensory thresholds and perception is that sensory receptors need to receive signals above the sensory thresholds so that the stimili can be perceived. The threshold of conscious perception is often higher than the absolute threshold because, although sensory receptors may detect the stimuli below the threshold of conscious perception, the brain does not interpret these signals as a perceptible sensation. The threshold of conscious perception varies from person to person and can be influenced by factors such as attention, motivation, and previous experiences.

How does Weber's Law relate to the difference threshold?

Weber's Law states that the difference threshold, or the smallest detectable change in stimulus intensity, is directly proportional to the initial stimulus intensity. In other words, as the initial stimulus intensity increases, a larger change in the intensity is needed for an individual to notice the difference. Weber's Law demonstrates that the difference threshold is not a constant value but rather depends on the baseline level of the stimulus being measured.

What is sensory adaptation, and how does it relate to psychophysics?

Sensory adaptation is the process by which the sensitivity of sensory receptors decreases over time when exposed to a constant stimulus. This phenomenon makes us less aware of constant or repetitive stimuli, allowing us to focus on new or changing stimuli in our environment. Sensory adaptation is a crucial aspect of psychophysics, which is the study of the relationship between physical stimuli and the perceptions they evoke. By understanding sensory adaptation, researchers can gain insight into how our sensory systems work and how they might be affected or manipulated to improve overall sensory experiences and perception.