Sensation And Perception Ch. 1 Study Questions

Front 1

Describe the idea of "The Allegory of the Cave" in Plato's Republic.

Back 1

The Allegory of The Cave" in Plato's Republic depicts our ordinary sense of reality as beings like prisoners in a cave. The prisoners are tethered together since childhood, bound to face only the wall in front of them, and all they are able to see are the shadows on the wall in front of them. This is their reality, and this depiction is meant to show how much of our conception of reality depends on what we can learn about the world through our senses.

Front 2

Explain the mechanism of adaptation and provide an example.

Back 2

Adaptation is a reduction in response caused by prior or continuing stimulation. For instance, upon arrival at a loud stadium, one might notice the increase in noise level, but soon after, the observer adapts to it, not noticing it anymore.

Front 3

What are sensory transducers and how are they related to perception?

Back 3

Sensory transducers are receptors that convert physical energy from the environment into neural activity. According to Democritus, our perception is based on information passed through these receptors from the outside world.

Front 4

What is nativism?

Back 4

Nativism is the idea that the mind produces ideas that are not derived from external sources. Rather, all our abilities are innate and not learned through experience.

Front 5

Explain how Descartes is known as a dualist.

Back 5

Descartes is known as a dualist because he believed in the idea that both mind and body exist. In fact, he considered the mind to be quite separate from the body. For instance, the mind is unextended (takes up no space), and has no substance. It is distinct from the body and survives the death of the body, like a soul.

Front 6

Describe empiricism and provide an example of one empiricist.

Back 6

Empiricism is the idea that experience from the senses is the only source of knowledge. Hobbes was an empiricist who believed that everything that could ever be known or even imagined had to be learned through the senses.

Front 7

Explain the notion of "tabula rasa."

Back 7

"Tabula rasa," or "blank slate" is the famous concept formulated by John Locke, who proposed that the newborn's mind is blank, waiting to be filled with information. This is done through experience, which is the essence of empiricism.

Front 8

What is psychophysics?

Back 8

Psychophysics is the science of defining quantitative relationships between physical and psychological (subjective) events.

Front 9

What is the "just noticeable difference" (JND) and why is it important in psychophysics?

Back 9

The JND is the smallest detectable difference between two stimuli, or the minimum change in a stimulus that can be correctly judged as different from a reference stimulus. It is also known as the "difference threshold." It is a key tool for investigating psychophysiological phenomena.

Front 10

Describe two psychophysical methods used to measure people's sensations.

Back 10

1) The method of constant stimuli involves the presentation of many stimuli, ranging from rarely to almost always perceivable. They are presented one at a time and participants respond to each presentation: "yes/no," "same/different," and so on. 2) The method of limits involves presenting stimuli that vary incrementally in one dimension until the participant responds differently.

Front 11

What is the method of adjustment?

Back 11

The method of adjustment is a psychophysical method, which uses the method of limits idea, but in which the participant controls the change in the stimulus.

Front 12

Explain Fechner's law.

Back 12

Fechner's law is a principle describing the relationship between stimulus magnitude and resulting sensation magnitude such that the magnitude of subjective sensation increases proportionally to the logarithm of the stimulus intensity. As the stimulus grows larger, larger changes are required for the changes to be detected by a perceiver.

Front 13

Why is the JND important in psychophysics?

Back 13

The JND, or "just noticeable difference" is the smallest detectable difference between two stimuli, or the minimum change in a stimulus that can be correctly judged as different from a reference stimulus. It is important in psychophysics because psychophysics involves measuring people's perception, and the JND is an important landmark in understanding their perception. Using this landmark experimenters are able to make conclusions about the way in which we perceive stimuli. In fact, the JND is a constant fraction of the comparison stimulus (Weber's Law).

Front 14

What are the signal and noise in the signal detection theory?

Back 14

The signal detection theory is a psychophysical theory that quantifies the response of an observer to the presentation of a signal in the presence of noise. The signal is the target stimulus and the noise is the interference that occurs, and is sometimes confused with the signal.

Front 15

What is magnitude estimation?

Back 15

Magnitude estimation is a psychophysical method in which the participant assigns values according to perceived magnitudes of stimuli.

Front 16

What is the central idea of Müller's doctrine of specific nerve energies?

Back 16

The central idea of Müller's doctrine of specific nerve energies is that we are aware only of the activity in our nerves, and we cannot be aware of the world itself. In addition, what is most important is which nerves are stimulated, and not how they are stimulated.

Front 17

What are cranial nerves?

Back 17

Cranial nerves are twelve pairs of nerves that originate in the brain stem and reach the periphery through openings in the skull. They are dedicated mainly to sensory and motor systems.

Front 18

What is Helmholtz's ophthalmoscope used for?

Back 18

Helmholtz's ophthalmoscope is a device used to look directly at the retina, the sheet of blood vessels, receptors, and neurons across the back of one's eye. It assists with the diagnosis of eye problems, and allows the observer to see the only part of the central nervous system that is visible from outside the skull.

Front 19

Explain how neurons communicate with one another.

Back 19

Neurons have axon terminals (presynaptic) as well as dendrites (postsynaptic). The axon terminal of the presynaptic neuron binds to the dendrite of the postsynaptic neuron. Neurotransmitters are now released by synaptic vesicles in the axon and fit into receptors on the dendrite on the other side of the synapse, thus communicating from the axon of the first neuron to the dendrite of the second neuron.

Front 20

What are neurotransmitters?

Back 20

Neurotransmitters are chemical substances used in neuronal communication at synapses.

Front 21

When is an action potential created?

Back 21

An action potential, or firing of a neuron is created when the membrane of the neuron permits sodium ions to rush into the cell, thus increasing the voltage. Very quickly afterward, potassium flows out of the cell, bringing the voltage back to resting voltage.