Attention and Perceptual Processes Notes 2024-25 PDF

SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES Attention: The process through which certain stimuli selected from a group of others is generally referred to as attention. Attention also ref...

SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES Attention: The process through which certain stimuli selected from a group of others is generally referred to as attention. 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 him or her. Concentration refers to focusing of awareness on certain specific objects while excluding others for the moment. Search is where an observer looks for some specified subset of objects among a set of objects. Attention has a focus where our maximum awareness is catered as well as a fringe where we are least aware of the stimuli. - When our awareness is centred on a particular object or event, it is called a focal point of attention. - When we have vague ideas about the stimulus and it is away from the centre of awareness, it is called a fringe of attention. Types of Attention: - Selective Attention, refers to the processes that allow an individual to select and focus on particular input for further processing while simultaneously suppressing irrelevant or distracting information. Theories of Selective Attention Filter Theory (Donald Broadbent, 1956) Filter – Attenuation Theory (Triesman, 1962)  SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES Multimode Theory (Johnston and Heinz, 1978) - Sustained Attention, a process that enables the maintenance of response persistence and continuous effort over extended periods of time. It is mainly concerned with concentration. - Divided Attention, occurs when mental focus is directed towards multiple ideas, or tasks, at once. Factors Affecting attention Selective Attention Sustained Attention 1. Sensory Modality External Factors Internal Factors 2. Clarity of Stimuli 3. Temporal Uncertainty 4. Spatial Uncertainity Motivational Cognitive Factors Factors  SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES Selective Attention: → External Factors: It is related to the features of stimuli, other things held constant size, intensity, and motion of stimuli appear to be important to determinants of attention. Large, bright, moving stimuli easily catch our attention. Stimuli which are novel and moderately complex also easily get into our focus. → Internal Factors: These live within the individual. These may be divided into 2 main categories. Motivational factors which relate to our biological all social needs. Whereas cognitive factors include factors like interest, attitude, and preparatory set. Sustained Attention: → Sensory Modality: Performances are found to be superior when stimuli or auditory than when they are visual. → Clarity of Stimuli: Intense in long lasting stimuli facilitates sustained attention and result in better performance. → Temporal Uncertainty: When stimuli appear at regular intervals of time, they are attended better than when they appear at irregular intervals. → Spatial Uncertainty: Similar that appear at a fixed place are readily attended, whereas those that appear at random locations are difficult to attend.  SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES PERCEPTUAL PROCESSES Perception is defined as the process by which we interpret the stimuli in our environment and give proper meaning to them. Two processing approaches are elucidated as follows- o The idea that the process of recognition begins from the parts, which serve as the basis for recognition of the whole is termed as Bottom-Up Processing. o The idea that the recognition process begins from the whole, which leads to the identification of its various components is termed Top-Down Processing. Human beings are creative and smart in nature who always attempt to give substantial meaning to the stimuli in their environment. Factors that play an important role in the perception process are described as follows- o Motivation- The needs and desires of a perceiver strongly influence his/her perception and people always aim to satisfy their needs and wants and for that people perceive objects in such a way that it will satisfy their needs and desires. o Expectations– The expectations about what we might perceive in a given situation also have a strong impact on our perception and it reflects a strong tendency to see what we expect to see even when the results are not in sync with the external reality. o Cognitive Styles- It is defined as the consistent way of dealing with our environment and it crucially affects the way we perceive our environment. o Cultural Background And Experiences- Different experiences and learning opportunities available to people available in different cultural settings also has a strong impact on the perception.  SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES The process of organising visual fields into meaningful wholes is defined as form perception. As per Gestalt Psychologists, we perceive different stimuli not as discrete elements but as an organised whole that has a definite form. For Example, a flower pot with a bunch of flowers is a whole and if the flowers are removed, the flower pot still remains a whole. The most primitive organisation takes place in the form of figure-ground segregation LAWS OF PERCEPTUAL ORGANISATION P → SSC → SSC The Principle Of Proximity: According to this principle, the objects that are close together in space or time are perceived together. The Principle Of Similarity: According to this principle, objects that are similar to one another and have similar characteristics are perceived as a group The Principle Of Smallness: As per this principle, smaller areas tend to be seen as figures against a larger background. The Principle Of Continuity: This principle states that we tend to perceive objects as belonging together if they appear to form a continuous pattern. The Principle Of Symmetry: This principle suggests that symmetrical areas tend to be seen as figures against asymmetrical backgrounds The Principle Of Surroundedness: This principle suggests that areas surrounded by others tend to be perceived as figures. The Principle Of Closure: We tend to fill gaps in stimulation and tend to perceive objects as a whole rather than their separate parts. SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES  SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES DEPTH PERCEPTION The process of viewing the world in three dimensions is termed distance or depth perception On perceiving depth, we mainly depend on two main sources of information termed cues. One is called Binocular cues as they require both eyes and another is called Monocular cues as they allow us to perceive depth with just one eye Monocular cues are explained below– o Relative Size: We tend to perceive an object farther away when it appears small, and closer when it appears bigger. o Overlapping: These cues occur when some portion of the object is covered by another object. The overlapped object is considered farther away, whereas the object that covers it appears nearer. o Linear perspective: Denotes the phenomenon by which distant objects appear to be closer together than nearer objects. o Aerial Perspective: The air comprises microscopic particles of dust and moisture that makes distant objects look hazy or blurry. This effect is called Aerial Perspective. o Light And Shade: In light, some parts of the object get highlighted, whereas some parts become darker. o Relative Height: Larger objects are perceived as being closer to the viewer and smaller objects as being farther away. o Texture Gradient: Denotes a phenomenon by which the visual field having more density of elements is seen farther away. o Motion Parallax: It is a kinetic monocular cue that occurs when objects at different distances move at a different relative speed. Binocular cues (Physiological Cues) are: o Retinal or Binocular Disparity: It occurs because the two eyes have different locations in our head. They are separated by each other horizontally by a distance of about 6.5 centimetres and due to the distance, the image formed on the retina of each eye of the same object is slightly different and this is known as retinal disparity. o Convergence: When we see a nearby object our eyes converge inward in order to bring the fovea of each eye. A group of muscles send messages to the brain regarding the degree to which eyes are turning inward and these messages are interpreted as cues to the perception of depth. The degree of convergence decreases as the object moved farther away from the observer o Accomodation: Accommodation refers to a process by which we focus the image on the retina with the help of ciliary muscle. PERCEPTUAL CONSTANCIES Perception of the objects is relatively stable in spite of changes in the stimulation of sensory receptors called perceptual constancy. We will now explore three types of Perceptual Constancies  SRI VENKATESHWAR INTERNATIONAL SCOOL CHAPTER 5 ATTENTIONAL AND PERCEPTUAL PROCESSES o Size Constancy: The tendency for the perceived size of objects to remain relatively unchanged with changes in their distance from the observer and the size of the retinal image is called Size Constancy. o Shape Constancy: In our perceptions, the shapes of familiar objects remain unchanged despite changes in the pattern of the retinal image resulting from the differences in their orientation. o Brightness Constancy: The tendency to maintain an apparent brightness constant under different amounts of illumination is termed brightness Constancy. ILLUSIONS They refer to misperceptions which are a consequence of misinterpretation of information received by our sensory organs. Some illusions are universal in nature whereas others are more personal and culture-specific. Some important visual illusions are as follows- o Geometric Illusion o Muller-Lyer Illusion o Vertical-Horizontal Illusion o Apparent Movement Illusion