Chapter 5: Empiricism, Sensationalism, and Positivism Flashcards
How did Bessel contribute to physiology and psychology with his reaction time study? How was is different form what Maskelynne and Kinnebrook’s conclusions?
Bessel (1784-1846), who speculated that the error had not been due to incompetence but to individual differences among observers. Bessel set out to compare his observations with those of his colleagues and indeed found systematic differences among them. This was the first reaction-time study, and it was used to correct differences among observers. This was done by calculating personal equations. For example, if 8/10ths of a second was added to Kinnebrook’s reaction time, his observations could reliably be equated with Maskelyne’s. Bessel found systematic differences among individuals and a way to compensate for those differences, but his findings did not have much impact on the early development of psychology.
Why did physiologists and scientists in the 17th and 18th century take to examining physical differences in lieu of Galileo’s primary and secondary qualities?
Because the most likely source of the discrepancy was the responding organism, physical scientists had reason to be interested in the biological processes by which organisms interact with the physical world. Physiologists studied the nature of nerves, neural conduction, reflexive behavior, sensory perception, brain functioning, and, eventually, the systematic relationship between sensory stimulation and sensation.
Bell-Magendie Law
There are two types of nerves: sensory nerves carrying impulses from the sense receptors to the brain and motor nerves carrying impulses from the brain to the muscles and glands of the body.
Charles Bell, the famous British physiologist, discovered the difference between sensory and motor neurons eleven years before Madendie did.
This clarified that sensation and movement, two things thought to be controlled by animals spirits or outside forces prior to this discovery, were actually mediated by the brain.
What was the ultimate contribution of the Bell-Magendie Law?
After Bell and Magendie, it was no longer possible to think of nerves as general conveyers of vibrations or spirits. Now a “law of forward direction” governed the nervous system. Sensory nerves carried impulses forward from the sense receptors to the brain, and motor nerves carried impulses forward from the brain to the muscles and glands.
Johannes Muller (1801-2858)
Expanded the Bell–Magendie law by demonstrating that each sense receptor, when stimulated, releases an energy specific to that particular receptor. This finding is called the doctrine of specific nerve energies.
Sensory receptors in the eye have a distinct reaction to light, just like mechanoreceptors in the ear respond in their own special way.
The Doctrine of Specific Nerve Energies
Each sensory nerve, no matter how it is stimulated, releases an energy specific to that nerve.
Theory of Adequate Stimulation
Although Müller claimed that various nerves contain their own specific energy, he did not think that all the sense organs are equally sensitive to the same type of stimulation. Rather, each of the types of sense organs is maximally sensitive to a certain type of stimulation. Müller called this “specific irritability,” and it was later referred to as adequate stimulation.
what was the most significant implication of Muller’s research?
The most significant implication of Müller’s doctrine for psychology was that the nature of the central nervous system, not the nature of the physical stimulus, determines our sensations.
Kant vs. Muller - similarities and differences
An ardent Kantian, Müller believed that he had found the physiological equivalent of Kant’s categories of thought. According to Kant, sensory information is transformed by the innate categories of thought before it is experienced consciously. For Müller, the nervous system is the intermediary between physical objects and consciousness. Kant’s nativism stressed mental categories, whereas Müller’s stressed physiological mechanisms. In both cases, sensory information is modified, and therefore, what we experience consciously is different from what is physically present.
Legacy of Muller
Müller was one of the greatest experimental physiologists ever. His Handbuch summarized what was known about human physiology at the time. Müller also established the world’s first Institute for Experimental Physiology at the University of Berlin. In addition, Müller understood the close relationship between physiology and psychology. He said, “Nobody can be a psychologist, unless he first becomes a physiologist” (Fitzek, 1997, p. 46).
Hermann von Helmholtz (1821-1894)
A monumental figure in the history of science who did pioneer work in the areas of nerve conduction, sensation, perception, color vision, and audition.
He was a student of Muller’s, and was an ardent materialist (anti-vitalist).
Helmholtz and Muller
Although Helmholtz accepted many of Müller’s conclusions, the two men still had basic disagreements, one of them over Müller’s belief in vitalism. In biology and physiology, the vitalism-materialism problem was much like the mind–body problem in philosophy. The vitalists maintained that life could not be explained by the interactions of physical and chemical processes alone. For the vitalists, life was more than a physical process and could not be reduced to such a process. Furthermore, because it was not physical, the “life force” was forever beyond the scope of scientific analysis. Müller was a vitalist.
Conversely, the materialists saw nothing mysterious about life and assumed that it could be explained in terms of physical and chemical processes. Therefore, there was no reason to exclude the study of life or of anything else from the realm of science. Helmholtz sided with the materialists, who believed that the same laws apply to living and nonliving things, as well as to mental and nonmental events.
Helmholtz and nerve conduction
He measured the speed of nerve conduction in the legs of frogs in a lab set up while he was doing his time in the army medical program. he found out that when he stimulated a nerve fiber attached to a muscle from a short and far distance, it took longer for the muscle to react when he stimulated from further away. He measured the speed of nerve conduction in humans to be about 165-330 ft/sec.
unconscious inference
According to Helmholtz, the process by which the remnants of past experience are added to sensations, thereby converting them into perceptions.
sensations + elements of past experience = perception
Helmholtz: sensation vs. perception
Although he believed that the physiological apparatus of the body provides the mechanisms for sensation, Helmholtz thought that the past experience of the observer is what converts a sensation into a perception. Sensations, then, are the raw elements of conscious experience, and perceptions are sensations after they are given meaning by one’s past experiences.
Helmholtz and Kant agreed on one important point: The perceiver transforms what the senses provide.
For Kant this transformation was accomplished when sensory information was structured by the innate faculties of the mind. For Helmholtz, the transformation occurred when sensory information was embellished by an individual’s past experience. With his notion of unconscious inference, Helmholtz came very close to what would later be considered part of psychology. That is, for unconscious inference to convert a sensation into a perception, memories of previous learning experiences must interact with current sensations.
Helmholtz: humans as energy systems
Applied law of conservation of energy to people by establishing the a human’s energy output was proportional to the amount of food and oxygen consumed but that person.
Helmholtzs’ legacy
Although Helmholtz was an empiricist in his explanations of sensation and perception, he did reflect the German Zeitgeist by postulating an active mind. According to Helmholtz, the mind’s task was to create a reasonably accurate conception of reality from the various “signs” that it receives from the body’s sensory systems. Helmholtz assumed that a dynamic relationship exists among volition, sensation, and reflection as the mind attempts to create a functional view of external reality. Helmholtz’s view of the mind differed from that of most of the British empiricists and French sensationalists because they saw the mind as largely passive. For Helmholtz the mind’s job was to construct a workable conception of reality given the incomplete and perhaps distorted information furnished by the senses (Turner, 1977).
Franz Joseph Gall (1758-1828)
Believed that the strengths of mental faculties varied from person to person and that they could be determined by examining the bumps and depressions on a person’s skull. Such an examination came to be called phrenology. (See also Phrenology.)
Gall accepted the widely held belief that faculties of the mind acted on and transformed sensory information, but he made three additional claims that changed the history of faculty psychology:
The mental faculties do not exist to the same extent in all humans.
The faculties are housed in specific areas of the brain.
If a faculty is well developed, a person would have a bump or protrusion on the corresponding part of the skull. Similarly, if a faculty is underdeveloped, a hollow or depression would be on the corresponding part of the skull.
phrenology
The examination of the bumps and depressions on the skull in order to determine the strengths and weaknesses of various mental faculties.
Mental faculties are different in different people, and faculties are housed in different areas of the brain.
German tradition
Rationalist: Kant, Leibniz, and Spinoza
Physiologists: Muller and Helmholtz
Psychophysics: Psychological perceptions in response to physical attributes of a stimulus
