Simple stimulus learning mechanisms and processes

¶ … Stimulus Learning

Habituation

Habituation is the process whereby a repetition of stimulus results in a decrease in reactions to such stimulus, because the recipient becomes accustomed to the effects of the presentation. Initially new, the stimulus in question becomes more familiar when presented repeatedly, and therefore elicits a response of less significance and intensity than the case was upon its initial presentation. This phenomenon is often used in education, as a simple form of learning. Students are presented with a single stimulus in order to promote habituation for the purpose of learning a new skill or gaining knowledge (Terry, 2006, p.27).

Studies in the manifestations of habituation have indicated physiological responses such as changes in heart rate and brain wave measurements to indicate stimulation, arousal, and attention. These all decreased with the repetitive presentation of a single stimulus. A method that is often used to measure habituation is eye fixations to novel visual stimuli. When presented with a new stimulus, it is the human tendency to explore it visually. As the item becomes familiar, the gaze is moved away and less attention is given to the stimulus. Hence, a decrease in eye fixations indicate an increase in habituation (Terry, 2006, p.29).

Habituation is however not an exclusively human manifestation. According to Terry (2006, p.29), experiments with rodents have for example shown that objects that are unfamiliar are more frequently and intensely explored than those that are familiar. In such cases, reduced attention indicates that habituation has taken place.

Habituation can also be measured by means of its parametric features. This means that a single stimulus is divided into dimensions or aspects, which are systematically varied. By measuring the time to habituation, the learning process can be explored and mapped for use by researchers and educators.

Perceptual Learning

Perceptual learning is a concept that concerns exposure frequency to a stimulus, and how this facilitates subsequent learning. On the basis of experiments in this regard, the conclusion is that it is easier to learn on the basis of a familiar stimulus than it is to use a new stimulus for new learning. Prior exposure to a stimulus helps the learner to perceive, recognize and identify it at a primary level of knowledge. This makes it easier to make further investigations and learn more about the stimulus (Terry, 2006, p.40). There are three main factors that affect perceptual learning. These include presenting contrasting stimuli; transfer from easy to difficult stimuli; and attention and feedback.

In terms of the first factor, the educator should not present only a single standard stimulus, as this is unlikely to promote the ability to distinguish the stimulus from others. It is therefore necessary to provide contrasting stimuli for the purpose of comparison and recognition.

The second factor implies that perceptual learning can be promoted by presenting more difficult stimuli that are based upon initially simple ones. Students can for example be presented with a simple set of patterns to distinguish, while more intricate stimuli are presented later.

The final factor considers the question of necessity in terms of feedback where stimuli are concerned. According to research, learning occurs by mere presentation, without the intention to learn. This is at least the case with simple stimuli. Where more complex discrimination is concerned, it appears that some feedback and intention are necessary.

In the classroom situation, it is therefore important to distinguish between the type of stimuli that requires little or no feedback and those that do. As the learning process progresses, so will the need for feedback.

The Effects of Stimulus Exposure

The effects of stimulus exposure extend far beyond habituation. In fact, habituation is but one behavioral effect of stimulus exposure, among many others. One such outcome is developing a preference for familiar stimuli. The mere exposure effect for example refers to an emotional change in preference when presented with a stimulus. "Mere" exposure means that the stimulus is presented without any external motivators such as rewards or difficulties connected to it (Terry, 2006, p.42). Interestingly, it has been found that the preference affect is not connected to a conscious memory of the stimulus (p.43).

It has also been found that brief exposure often produces a more positive response than long exposures. One of the reasons why mere exposure makes a stimulus more pleasing is that an excess of habituation may cause boredom, whereas its absence may produce a type of fear that is associated with the unfamiliar. Brief exposure then provides enough time for the recipient to become familiar with the stimulus without being bored by it and therefore losing interest.

On the other hand, it is difficult to quantify the effect of varied stimuli upon the mind. A given stimulus event can for example indicate multiple and conflicting results in different human beings. Some consistency occur in habituation, where a repeated stimulus becomes familiar in terms of easier learning and connecting it with new aspects of the same phenomenon.

However, it is also possible that habituation can prevent new learning. Overexposure to a stimulus could for example lead to its being ignored. Later learning about the stimulus is then difficult, as there is no attention on the object of learning.

There are several applications of stimulus exposure in the world today, despite the difficulties related to consistency. Areas that have benefited from this phenomenon include education, advertising, and psychology.

Application of Simple Stimulus Learning

Simple stimulus learning can be applied to various situations in life. In psychology, for example, a therapist may use it to help patients overcome fears or phobias (Terry, 2006, p.43). By providing the patient with controlled and repeated exposure to the feared item, it is projected that the habituation process will reduce attention to, and therefore fear of the object or situation. This is done in a very gradual way, with a mild form of the feared item presented initially. Gradually the stimulus is intensified, each time until habituation takes place. In this way, the patient becomes familiar with the feared item, and replaces the fear with a lack of attention. Some therapists combine the exposure with pleasant stimuli, such as relaxation exercises or soothing music. This is a form of counter-conditioning.