NCERT BOOK QUESTIONS SOLVED
Question 1. Explain the functional limitations of the sense organs.
Responder:The sensory organs function with certain limitations. For example, our eyes cannot see things that are too dark or too bright. Likewise, our ears cannot hear sounds that are too quiet or too loud. The same applies to other organs. As humans, we function within a limited range of stimulation. In order to be perceived by a sensory receptor, a stimulus must be of optimal intensity or magnitude.
Question 2. What does light and dark adaptation mean? how do they happen
Responder:Brightness adjustment refers to the process of adjusting to bright light after exposure to dim light. This process takes about one to two minutes.
Dark adaptation refers to the process of adapting to a dimly lit environment after exposure to bright light. This can take half an hour or longer depending on the previous light exposure of the eye. The dark-adapted eye is about 100,000 times more sensitive to light than the light-adapted eye.
Question 3. What is color vision and what are the dimensions of color?
- A person's ability to distinguish different shades of color is called color vision.
- A person with normal color vision can distinguish over seven million different shades of color.
- There are three basic dimensions of hue, saturation, and lightness.
- Hue is a property of chromatic colors. Refers to the name of the color, e.g. B. Red, Blue and Green. Hue varies with wavelength and each color is identified with a specific wavelength. For example, blue has a wavelength of around 465 nm and green from around 500 nm. Achromatic colors such as black, white or gray are not characterized by hues. .
- Saturation is a psychological attribute that refers to the relative amount of hue in a surface or object.
- Light with a single wavelength (monochromatic light) appears to be highly saturated.
- When we mix different wavelengths, the saturation decreases. The gray color is fully unsaturated.
- Brightness is the perceived light intensity. It varies between bright and achromatic colors.
- White and black represent the top and bottom of the lightness dimension.
- White has the highest level of brightness while black has the lowest level.
Question 4. How does the auditory sensation arise?
Responder:Sound serves as a stimulus for the auditory sensation. Loudness, pitch and timbre are the properties of sound. Located on the basilar membrane, the organ of Corti is the main organ of hearing.
The hearing sensation begins when sound enters our ear and stimulates the main auditory organs.
The auricle collects sound vibrations and distributes them to the eardrum via the auditory flesh.
From the tympanic cavity, the vibrations are transmitted to the three ossicles, which increase their strength and transmit them to the inner ear. The cochlea receives sound waves in the inner ear.
Vibrations activate the endolymph, which also causes the organ of Corti to oscillate. Finally, the impulses are sent to the auditory nerve, which exits at the base of the cochlea and reaches the auditory cortex, where the impulse is interpreted.
Question 5. Define attention. Explain its properties.
Responder:The process of selecting certain stimuli from a group of others is commonly referred to as attention.
The qualities of attention are choice, attention, concentration, and seeking.
- Selection-Many stimuli reach our sense organs at the same time, but we do not perceive them all at the same time.Only a select few are noticed,For example. When you enter the classroom you will find multiple things like doors, walls, windows etc. but focus selectively on just one or two of them at a time.
- standby— Alert relates to aindividual readinessdeal with the stimuli that appear in front of him. For example. If you participate in a race at your school, you must have seen participants on the starting line in a state of alert, waiting for the whistle to run.
- concentration— Concentration refers tofocus on consciousnesson certain specific objects, others excluded for the time being, e.g. In the classroom, a student is concentrating on the teacher's lecture, ignoring all sorts of noises coming from different corners of the school.
- Search for— When searching, a viewer searches for a fewspecified subset of objectsbetween a set of objects, e.g. When we go to school to pick up our younger brothers and sisters from school, we simply look for them among countless boys and girls.
Question 6. What are the determinants of selective attention? How is selective attention different from sustained attention?
Responder:Selective attention refers to focusing conscious attention on a specific stimulus. Is primarily concerned with selecting a limited number of stimuli or objects from a larger number of stimuli. Factors affecting selective attention:
These relate to the properties of the stimuli. Other factors remained constant.
- The size, intensity, and movement of stimuli are important determinants.
- Large, shiny, moving objects easily attract our attention.
- Auditory narratives are more easily noticed than visual narratives.
- Stimuli that are novel and slightly complex attract our attention.
- Human figures are more likely to be observed than inanimate objects.
There are two types of internal factors:
(1) Cognitive Factors (2) Motivational Factors
- Cognitive factors include factors such as interests, attitudes, and preparation sets.
- Stimuli that appear interesting are gladly taken into account.
- Stimuli that are favorable to us also attract our attention.
- Preparation sets a state of mind to act in a certain way, responding to some stimuli and not others in that moment.
- motivating factors
- These relate, for example, to our biological and social needs. Hungry person gets food first. During exam days, students focus more on the teacher's instructions.
- Selective attention is primarily concerned with choosing a limited number of stimuli from a large number of stimuli, while sustained attention refers to focusing awareness on certain objects while excluding others for movement.
- It is the ability to focus attention on an object or event for an extended period of time.
Question 7. What is the main thesis of gestalt psychologists regarding the perception of the visual field?
Responder:Gestalt psychologists (Wertheimer, Koffka, and Kohler) outline several principles that describe how basic sensory input is organized into complete patterns.
- According to gestalt psychologists, humans perceive different stimuli as discrete elements but as an organized "whole" bearing a definite form.
- They believe that an object's form resides in its whole, which is distinct from the sum of its parts.
- For example, a vase with a bouquet of flowers is a whole. When the flowers are removed, the vase still remains in one piece. It is the configuration of the flower-
pot that has changed. Vase with flower is one configuration, without flowers is another configuration.
- Gestalt psychologists also point out that human brain processes are always geared towards the perception of a good figure. That's why people perceive everything in an organized way.
Some of these principles are discussed below:
- figure relation to the ground— We tend to divide the world around us into two parts: the figure, which has a specific shape and location in spaces; and the background, which has no form, seems to continue behind the figure and has no specific location. The figure-ground relationship helps clarify the distinction between sensation and perception.
- contours—Contours are formed whenever there is a clear difference in brightness or background color. Contours shape objects in our visual world because they distinguish one object from another or differentiate one object from general terrain. The contours determine the form, but are formless in themselves.
- grouping— Grouping rules describe basic ways we group elements perceptually. These are simple principles by which we perceive the world around us. Grouping principles includeSimilarity, closeness, unity and continuity.
- The principle ofsimilaritystates that objects of similar shape, size, or color tend to be grouped together. In the auditory sense, sounds of similar pitch and intensity are grouped together.
- of lions ofVicinitystates that objects that are close together in space or time tend to be perceived as belonging together or forming an organized group
- principle ofcontinuationdescribes the tendency to perceive a line that starts in one direction as continuing in the same way.
- lei fromcloserefers to perceptual processes that organize the perceived world by filling gaps in stimulation.
- In the case of the continuity principle, when the breaks are too strong or too long, continuity disappears and a unified whole is not perceived.
- Camouflage:When contours are visually broken, it is difficult to distinguish objects from the background. This is camouflage. It works because it breaks up contours, e.g. the uniform of soldiers in the forest.
Question 8. How does spatial perception arise?
Responder:The room is perceived three-dimensionally. This is due to our ability to transform a two-dimensional retinal view into a three-dimensional perception. Spatial attributes of objects such as size, shape, and distance between objects also contribute to spatial perception.
Question 9. What are the depth perception monocular signals? Explain the role of binocular cues in depth perception.
Responder:Monocular cues are psychological cues.
- These cues are often used by artists to add depth to two-dimensional paintings.
- For this reason, they are also referred to as picture hints.
- They help us judge distance and depth on two-dimensional surfaces.
- Some important monocular clues for judging distance and depth on two-dimensional surfaces are as follows:
- Relative size:The size of retinal images allows you to judge the distance based on post and current experiences with similar objects. As objects move away, the retinal image gets smaller and smaller. We tend to perceive an object as further away when it appears small and closer when it appears larger.
- Interposition or overlap:These clues occur when part of the object is covered by another object. The overlapping object is considered farther away, while the object covering it appears closer.
- Straight line perspective:This reflects a phenomenon where distant objects appear to be closer than the closest object. For example, parallel lines, like train tracks, appear to converge with distance.
- Aerial Perspektive:The air contains dust and moisture particles that make distant objects appear blurry or blurry. This effect is called aerial perspective.
- light and shadow:With light, some parts of the object are highlighted while others are darker. Lights and shadows give us information about the distance of an object.
- Relative Height:Larger objects are perceived as closer to the viewer and smaller objects as further away.
- Texture gradient:It represents a phenomenon in which the field of view is seen farther away with greater element density.
- Motion Parallax:It is a kinetic monocular cue and is therefore not considered a visual cue. Occurs when objects at different distances are moving at different relative speeds. Distant objects appear to move slower than close objects. An object's speed of movement tells you its distance. For example, when traveling by bus, objects that are closer move "against" the direction of the bus, while objects that are farther away move "with" the direction of the bus.
Binocular cues are depth information based on the coordinated effort of both eyes. Three of them are:
- Retinal or binocular disparity:
- A retinal disparity occurs because the two eyes are separated horizontally by some distance.
- Because of this distance, the image formed on the retina of each eye of the same object is slightly different.
- This difference between the two images is called retinal disparity.
- The brain interprets a large retinal disparity as a close object and a small retinal disparity as a distant object.
- When we see an object nearby, our eyes converge inward to bring the image into the fovea of each eye.
- A group of muscles sends messages to the brain about the extent to which the eyes rotate inward, and these messages are interpreted as cues for depth perception.
- The degree of convergence decreases as the object moves away from the observer.
- Accommodation:Accommodation is a process in which we use the ciliary muscles to focus the image on the retina.
- These muscles change the thickness of the lens of the eye. When the object moves away (more than 2 m), the muscle relaxes.
- When approached, the muscles tighten and the thickness of the lens increases.
- The signal about the degree of muscle contraction is sent to the brain, which provides an indication of distance.
Question 10. Why do illusions occur?
- Illusions arise due to a discrepancy between physical stimuli and their perception by the individual.
- Incompatibility is caused by incorrect interpretation of information received from the sense organs.
- Illusions are called primitive organizations because they are created by an external stimulus situation that evokes the same type of experience in all individuals.
- Some illusions are universal in nature as they are found in all individuals.
- These are also called permanent illusions because they do not change with experience and practice.
- Delusions that vary from individual to individual are called personal delusions.
Question 11. How do sociocultural factors influence our perception?
- Several psychologists have studied perceptual processes in different sociocultural settings. For example, they used Muller-Lyer and vertical-horizontal illusion figures with different groups of people living in Europe, Africa and many other places and compared distant samples. African Villages and Western Landscapes.
- It was found that African subjects showed greater susceptibility to vertical horizontal illusions, while Western subjects showed greater susceptibility to the Muller-Lyer illusion.
- Similar results have also been reported in other studies. African subjects living in dense forests regularly experienced verticality (eg, tall trees) and developed a tendency to overestimate it.
- Westerners living in an angelic environment developed a tendency to underestimate the length of the enclosure indicated by lines (e.g., arrowhead).
- This research suggests that perceptual habits are learned differently in different cultural contexts.
- Hudson conducted a study in Africa and found that people who had never seen images had great difficulty recognizing objects depicted in them and interpreting depth cues.
- Sinha and Mishra conducted several studies on image cognition using a variety of photos with people from different cultural backgrounds, such as hunter-gatherers living in forests, farmers in cities.
- His studies indicate that the interpretation of images is strongly linked to people's cultural experiences.
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