State the determinants of selective attention. How does selective attention differ from sustained attention?

Selective attention is concerned mainly with the selection of a limited number of stimuli or objects from a large number of stimuli.

There are a number of factors that determine the selective attention. These factors generally relate to the characteristics of stimuli and the characteristics of individuals. All these factors are classified as external and internal factors.

(i) External factors are related to the features of stimuli. The size, intensity, and motion of stimuli are considered as important determinants of attention. Large, bright, and moving stimuli easily catch attention. Stimuli, which are novel and moderately complex, also easily get into ones focus. It has been observed 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.

(ii) Internal factors lie within the individual. These may be divided into two main categories-motivational factors and cognitive factors.. Motivational factors relate to our biological or social needs. When a person is hungry, he notices even a faint smell of food. A student taking an examination is likely to focus on a teacher’s instructions more than other students. Cognitive factors include factor's lik)e interest, attitude, and preparatory set. Objects or events, which appear interesting, are readily attended by individuals, similarly one pays quick attention to certain objects or events to which he is favourably disposed. Preparatory set generates mental state to act in a certain way and readiness of the individual to respond to one kind of stimuli and not to others.