Chapter 8 Study Questions Flashcards
- Describe the Bell-Magendie law of neural transmission and explain its significance.
The Bell-Magendie law of neural transmission, refers to the discovery made by Charles Bell and François Magendie, indicating that the nervous system operates according to a “law of forward direction.” The law states that the nerves on the spinal cord are split between two pathways, one pathway carries the sensory nerves sent from sense receptors to the brain, while the other carries motor nerves that transmit impulses from the brain to muscles and glands. It’s called the law of forward direction as the nerve impulses are carried in only one direction. This principle emphasizes the separate functions of sensory and motor nerves, providing a crucial understanding of the physiological basis of sensation and movement.
- Describe the Doctrine of Specific Nerve Energies and its significance.
The Doctrine of Specific Nerve Energies, developed by Johannes Müller, expanded upon the Bell-Magendie law. Müller proposed that different types of sensory nerves contain distinct energies, and when these nerves are stimulated, they produce characteristic sensations regardless of the type of stimulation. An eye produces only sensory nerves regardless of if it’s stimulated by light, pressure, wind or electricity. This principle highlighted how specialized nerves functions are and how sensory experiences are determined by the nature of the nerve itself. Müller’s doctrine laid the groundwork for understanding the physiological mechanisms underlying sensory perception, contributing significantly to the advancement of the field of neurophysiology.
- Briefly describe the work of Johannes Muller (1801–1858) with respect to adequate stimulation (or specific irritability)
Johannes Müller’s work on adequate stimulation (or specific irritability) elucidated that different sense organs have varying levels of sensitivity to particular types of stimulation. He demonstrated that each type of sense organ is maximally responsive to a specific kind of stimulus, such as the eye being most receptive to light waves and the ear being most responsive to sound waves. This concept emphasized the differential sensitivity of sensory systems, leading to a more nuanced understanding of how humans perceive their environment.
- Briefly describe the work of Johannes Muller (1801–1858) with respect to the relationship between consciousness and sensations and reality
Müller explored the relationship between consciousness, sensations, and reality. He posited that the nature of the central nervous system, rather than the physical stimulus, determines human sensations. According to Müller, our awareness is not of the physical world directly but of the sensory impulses in the brain that correspond to the external objects. His work underscored the role of the nervous system as an intermediary between external stimuli and conscious experience, highlighting the limitations of human knowledge concerning the physical world. Müller’s insights aligned with Kantian philosophy, emphasizing the modification of sensory information before conscious experience and acknowledging the presence of an active mind within his mechanistic framework.
- Describe Hermann von Helmholtz (1821-1894) positions and theories with respect to vitalism
Helmholtz opposed vitalism, advocating materialism and the application of physical and chemical laws to living organisms.
- Describe Hermann von Helmholtz (1821-1894) positions and theories with respect to the principle of conservation of energy
Helmholtz supported the principle of conservation of energy, demonstrating its applicability to living organisms through his research on metabolic processes in frogs.
- Describe Hermann von Helmholtz (1821-1894) positions and theories with respect to the rate of nerve conduction
Challenging the belief in instantaneous nerve conduction, Helmholtz determined that it was relatively slow and a result of physical-chemical processes.
- Describe Hermann von Helmholtz (1821-1894) positions and theories with respect to theory of perception (including his notion of unconscious inference)
Helmholtz emphasized the significance of past experience in shaping perceptions, proposing the idea of unconscious inference to explain how sensations are transformed into perceptions. He applied this concept to various perceptual phenomena, including depth
- Describe Hermann von Helmholtz (1821-1894) positions and theories with respect to theory of colour vision
Helmholtz’s theory of color vision, known as the Young-Helmholtz theory, posited the existence of three different types of color receptors, each corresponding to one of the primary colors. He explained how combinations of these receptors could account for the perception of a wide range of colors and provided insights into various forms of color blindness.
- Describe Hermann von Helmholtz (1821-1894) positions and theories with respect to theory of auditory perception
He developed the resonance place theory, proposing that the basilar membrane in the ear contains different fibers sensitive to various sound frequencies. He suggested that the vibration of specific fibers accounts for the perception of different auditory experiences.
- Summarize his contributions to psychology
Helmholtz emphasized the active role of the mind in interpreting sensory information, bridging the gap between physics, chemistry, physiology, and psychology. His empirical and scientific approach laid the groundwork for the emergence of experimental psychology
- Briefly describe the work of Ewald Hering (1834–1918)
Ewald Hering, a contemporary of Hermann von Helmholtz, held contrasting views on perception. He emphasized innate perceptual capabilities, standing in opposition to Helmholtz’s idea of learned perceptions. Hering proposed that each point on the retina automatically provided three types of information about stimuli: height, left-right position, and depth. This contrasted sharply with Helmholtz’s belief in the gradual development of spatial perception based on correlated physiological and psychological events. Hering’s ideas contributed to the ongoing debate known as the Helmholtz-Hering debate.
- Describe his views concerning spatial perception and his theory of colour vision
Hering challenged the Young-Helmholtz theory, noting phenomena incompatible with it. He posited the existence of three types of receptors on the retina, each capable of responding in two ways. These receptors could either undergo a “tearing down” or “building up” process depending on the colors perceived. His theory explained the occurrence of afterimages and phenomena such as the sensation of gray when certain color pairs were mixed. The debate between the Young-Helmholtz theory and Hering’s theory continues to influence contemporary research on color vision.
- Briefly describe the work of Christine Ladd-Franklin (1847–1930). Describe her theory of colour vision
Christine Ladd-Franklin, an accomplished psychologist, made significant contributions to the field, particularly in the realm of color vision. Her work was based on an evolutionary perspective, postulating that achromatic vision developed first in the course of evolution, followed by blue-yellow sensitivity and, finally, red-green sensitivity. Ladd-Franklin’s theory emphasized the idea that the anatomy of the eye and its visual abilities had evolved progressively. Though her theory initially garnered attention, it later fell into neglect, although some scholars still find validity in her analysis of color vision.
- Define phrenology and describe the development of this field including the work of Franz Joseph Gall
Phrenology was a pseudo-scientific theory that gained popularity in the 19th century. It was developed by Franz Joseph Gall, who proposed that mental faculties were localized in specific areas of the brain and that the size of these faculties could be determined by examining the bumps and depressions on the skull. Gall’s claims were not substantiated scientifically, and he often made speculative assertions based on incomplete evidence.
