SENSORY,ATTENTIAL AMD PERCEPTIONAL PROCESSES

Activity . Fig. . : Sound Waves Amplitude one cycle Sound waves are described in terms of their frequency, which is measured in terms of cycles per second.

Its unit is called Hertz (Hz). Frequency and wavelength have an inverse relationship. When the wavelength increases, the frequency decreases, and when the wavelength decreases, the frequency increases. Amplitude and frequency both are physical dimensions.

Besides these, there are three psychological dimensions of sound, namely loudness, pitch and timbre. Loudness of the sound is determined by its amplitude. Sound waves with large amplitude are perceived as loud; those with small amplitude are perceived as soft. Loudness is measured in decibels (db).

Pitch refers to highness or lowness of a sound. The seven notes used in Indian classical music represent a gradual increase in their pitch. Frequency determines the pitch of a sound wave. The higher the frequency, the higher will be the pitch.

The range of hearing is generally Hz- , Hz. Timbre refers to the nature or quality of a sound. For example, the sound of a car engine and a person talking differ with respect to quality or timbre. The timbre of a A TTENTIONAL P ROCESSES In the previous section we have discussed some sensory modalities that help us in collecting information from the external world and also from our internal system.

A large number of stimuli impinge upon our sense organs simultaneously, but we do not notice all of them at the same time. Only a selected few of them are noticed. For example, when you enter your classroom you encounter several things in it, such as doors, walls, windows, paintings on walls, tables, chairs, students, schoolbags, water bottles, and so on, but you selectively focus only on one or two of them at one time. The process through which certain stimuli are selected from a group of others is generally referred to as attention.

At this point it may be noted that besides selection, attention also refers to several other properties like alertness, concentration, and search. Alertness refers to an individual’s readiness to deal with stimuli that appear before her/him. While participating in a race in your school, you might have seen the participants on the starting line in an alert state waiting for the whistle to blow in order to run. Concentration refers to focusing of awareness on certain specific objects while excluding others for the moment.

For example, in the classroom, a student concentrates on the teacher’s lecture and ignores all sorts of noises coming from different corners of the school. In search an observer looks for some specified subset of objects among a set of objects. For example, when you go to fetch your younger sister and brother from the school, you just look for them among innumerable boys and girls. All these activities require some kind of effort on the part of people.

Attention in this sense refers to “effort allocation”. Attention has a focus as well as a fringe. When the field of awareness is centered on a particular object or event, it is called focus or the focal point of attention. On the contrary, when the objects or events are away from the center of awareness and one is only vaguely aware of them, they are said to be at the fringe of attention.

Attention has been classified in a number of ways. A process-oriented view divides it into two types, namely selective and sustained . We will briefly discuss the main features of these types of attention. Sometimes we can also attend to two different things at the same time.

When this happens, it is called divided attention . Box . describes when and how the division of attention is possible. Selective Attention Selective attention is concerned mainly with the selection of a limited number of stimuli or objects from a large number of stimuli.

We have already indicated that our perceptual system has a limited capacity to receive and process information. This means that it can deal only with a few stimuli at a given moment of time. The question is, which of those stimuli will get selected and processed? Psychologists have identified a number of factors that determine the selection of stimuli.

Factors Affecting Selective Attention Several factors influence selective attention. These generally relate to the characteristics of stimuli and the characteristics of individuals. They are generally classified as “external” and “internal” factors. External factors are related to the features of stimuli.

Other things held constant, the size, intensity, and motion of stimuli appear to be important determinants of attention. Large, bright, and moving stimuli easily catch our attention. Stimuli, which are novel and moderately complex, also easily get into our focus. Studies indicate that human photographs are more likely to be attended to than the photographs of inanimate objects.

Similarly, rhythmic auditory stimuli are more readily attended to than verbal narrations. Sudden and intense stimuli have a wonderful capacity to draw attention. Internal factors lie within the individual. These may be divided into two main categories, viz.

motivational factors and cognitive factors. Motivational factors relate to our biological In day-to-day life we attend to several things at the same time. You must have seen people driving a car and talking to a friend, or attending to phone calls on a mobile set, or putting on sunglasses, or listening to music. If we watch them closely, we will notice that they are still allocating more effort to driving than to other activities, even though some attention is given to other activities.

It indicates that on certain occasions attention can be allocated to more than one thing at the same .