Stephen van Vlack

Sookmyung Women`s University

Graduate School of TESOL

Human Learning and Cognition

Fall 2003

Answers - Week 4 Terry, Chapter 2

1. What is an orienting response and why is this important?

An orienting response is a reflex or a reaction to a particular stimulus. It can take the form of a particular and observable behavior like a blink or a startle in response to, for example, a bus driving by too close or it can be something that is less perceivable such as a advanced heart rate or breathing. An orienting response in which a person or animate object reacts to seek out the source of a stimulus, and as such is often though of as being evolutionary in general because it is this response which may keep a person or animal alive in a dangerous situation. So, for example, if a person hears a huge boom they will turn in the direction of the noise to try to ascertain what might have caused it.

2. What is habituation? Give your own example.

Habituation is a process by which the orienting response to a certain stimulus will gradually diminish and possibly disappear. Of course this type of reaction depends on the stimulus. In order for the orienting response to diminish the stimulus needs to b a rather innocuous one. Following this habituation is seen as a very basic type of learning in which a person or animate object comes to know something about a stimulus. In the case of an innocuous stimulus the creature learns that the stimulus is not harmful and they therefore are able to ignore it. If the stimulus is not harmful then the orienting repose becomes a conditioned response as the creature learns what they need to do to save themselves. A simple example of a habituation would be a certain smell. At first the smell might grab your attention, but the more you smell the same thing the more you will simply cease to notice it provided, of course, the smell does not harm you or mean danger is present.

3. How is habituation studied?

Habituation is studied as simply as possible. The basic idea is that habituation is the simplest kind of learning, which means by studying habituation we can try to determine the basic tenets of learning. This means that researchers try to study habituation in as controlled an environment as possible. Simple tests and highly controlled laboratory experiments with often very simple organisms are conducted to try to glean the most basic facts about learning. In such experiments control is the most important factor.

4. What are some different ways of explaining habituation?

There are two basic ways of explaining habituation. They are learning and nonlearning. The learning explanation was discussed above and should be fairly clear. Nonlearning explanations include theory about sensory adaption or fatigue. In a situation in which a stimulus is constant, it has been argued, the sensory will simply cease to notice the stimulus over time. Sensory adaption has been used to explain why people cease to notice an incessant noise or smell over a range of time. In a similar, but different, vein sensory fatigue is when the sensors are overloaded and therefore temporarily weaken. As a result the response system is weakened and something resembling habituation is seen to occur. It is a sensory fatigue situation which is said to occur in the habituation of people to things like spicy food. Evidence from experiments where dishabituators are used, however, invalidate both of these explanations. When a dishabituator is introduced into a habituation experiment, the sensors are clearly able to pick it up and focus attention on the new stimulus so long as the new stimulus (dishabituator) is sufficiently different from the habituated stimulus. Therefore, such nonlearning explanations are not able to fully explain habituation.

A physiological-based theory of habituation contains the idea of a dual processors in habituation. Studies have shown that there seem to be two types of neurons in the spinal column, one for suppression (H neurons) and the other for arousal (S neurons). Such a proposal follows closely in the wake of experiments which revealed that an opposite effect to habituation, sensitization, also occurs in response to certain stimulus. In sensitization the stimulus causes a stronger reaction each time it is presented. What seems to determine whether the H or the S neurons are activated is the intensity of the stimulus. Neutral or less intense stimulus will activate H neurons and a habituation will result. Highly intense stimulus will cause S neurons to be activated and sensitization will result.

Cognitive theories of habituation invoke differences in the proposed workings of short-term and long-term memory to explain why habituation effects seem to diminish over a time interval. An enduring habituation of an orienting response will necessarily be the result of the stimulus having entered the long-term memory. For this to happen the organism will have to have been exposed to the stimulus several times in short intervals. The basic idea is that if the intervals between stimulus exposure are too great there will be residual information held in the short-term memory and he stimulus will not be recognized and if the stimulus is not recognized there can be no habituation. An interesting aspect of these cognitive explanations is the inclusion of context in the model. Following this, the context in which the stimulus has and does occur must also play an important role in the habituation process. In studies where a stimulus always occurred in a particular context am orienting response occurs in the context even when the stimulus itself is not present. This shows that organisms use context to actually expect a certain stimulus and react whether the stimulus occurs of not.

5. How does frequency affect stimulus?

As mentioned briefly above, frequency is necessary for knowledge of a stimulus to be encoded in long-term memory. Thus frequency allows an organism to learn things a both a stimulus.

6. What are some other effects of stimulus. List and explain using your own examples.

Familiarity with a certain stimulus has been shown to cause changes in the affective relationship the organism has for the stimulus. Basically this means that organisms have a strong tendency to prefer the things they are familiar with and tend to shun or possibly even dislike things they are not familiar. This preference for familiar stimulus encourages the organism to seek out that stimulus when possible and as a result they will have much more exposure and be able to process and integrate more contextual information about that stimulus, thus allowing for perceptual learning.

Perceptual learning is linked to what we discussed above in that once we have learned soe basic information about a stimulus it si easier to learn more peripheral things about it. The fact that we are drawn to this stimulus gives us opportunities to learn perceptually.

Latent inhibition is the opposite of perceptual learning. It basically says that once an organism has habituated a certain stimulus they will learn less about that stimulus because they simply don not care about it. This is in accordance with what we know about the nature of habituation. It seems then that there is a fine line between getting perceptual learning or latent inhibition to occur.

Priming is a phenomenon by which exposure to a stimulus will prime the stimulus for easier activation and processing later. This makes orienting to a certain stimulus easier in relation to time.