Quiz 9 Flashcards
Is the higher encephalization of primates compared to nonprimates due to more rapid brain growth? Explain.
This is likely not the cause, because mammal brains grow at about the same rate whether they are primates or not. The difference is in the rate of growth of body size.
What difference in functions distinguishes axons and dendrites?
Axons are responsible for output, while dendrites are responsible for input.
What makes white matter white?
White matter is called “white” because of its myelinated connections, distinguishing it from gray matter.
Why would you expect the brain of a monkey to be more affected by its encephalization than an equivalently encephalized dog, such as a chihuahua?
Differences in encephalization in dogs are not easily compared to encephalization in mammals, because dogs are often bred for larger or smaller body sizes (for instance, chihuahuas are bred for miniaturization).
Describe an example of a “sensitive period” effect during development in a nonhuman species.
There is evidence of a “sensitive period” for the development of birdsong in some species, in which they lose the ability to innately produce correct songs if they are isolated until adults.
Describe one example of “facilitated learning” in humans, and one example in a non-human species.
An example of facilitated learning in humans is language, in which the ability to speak a language is affected by how much a developing child hears language or speaks it themselves. An example in a non-human species would be oyster catchers, who have to follow their parents around as children to learn how to safely obtain food without hurting their beaks.
Give an example of a supernormal stimulus.
An example of a supernormal stimulus would be herring gull chicks and the way they identify the mothers who feed them. They would normally peck on a red spot on their mothers’ beaks, but can be easily picked by a substitute like a red pencil.
The old saying “You can’t teach an old dog new tricks,” suggests that the young may have more malleable brains. This common sense idea about human (and dog!) learning has recently been supported by discoveries about the way the nervous system develops. Briefly describe one example of developmental plasticity that shows how early experience can alter the wiring of the brain.
One example of developmental plasticity is the ability to learn language. It becomes more difficult at a certain age for someone to acquire language skills, as evidenced by “feral” children who did not learn to speak until they were much older.
Briefly outline the ways that the processes that shape neural circuits during brain development resemble Darwinian selection.
These processes can also be affected by mutation, which in turn alters brain function or the individual’s behavior. These changes can make the individual subject to selection for or against the mutation, which then affects inheritance. This is very close to the way other traits are naturally selected.
In fetal development, there is an over-production of motor neurons and nonspecific axon growth, which is followed by competition between the axons which eliminates the ones that are unable to compete. This process resembles natural selection.
In the middle of the last century a great many behavioral scientists were working on the assumption that the rate that associations were learned was solely a function of the complexity of the task and the relative strength of the reinforcer. This idea was undermined by a series of simple experiments by John Garcia. He showed that some associations can be learned in a single trial and retained for a lifetime, while others that were no more complicated, and were reinforced by equal or stronger reinforcers, could not be taught even with hundreds of trials. Both effects were due to innate learning predispositions. What were Garcia’s tasks that were easy and hard for rats to learn? Give an example of easy and hard to learn associations in humans?
The easy tasks for rats to learn were the association between light and shock and sweet and nausea, while the hard tasks were the association between light and nausea and shock and sweet.
How did Garcia’s results challenge the assumptions of behaviorism?
Behaviorism basically posited the idea of a “blank slate”, which said that what an individual experiences or is taught is what influences them completely. Garcia’s results suggested that nature plays as much a role as nurture or at least both are biased by the other.
How does the comparison between the ability to speak and the ability to read and write exemplify the difference between prepared learning and “normal” learning?
The ability to speak is prepared learning because children have an innate predisposition to acquire language. They begin to speak before they begin to read and write. Therefore, reading and writing are more likely to be “normal” learning because it requires the study of an entirely new skill.
