CHAPTER 4 – SENSATION AND PERCEPTION
I. SENSORY AWARENESS
* Sensation is the awareness or a mental process which is aroused due to the stimulation of the senses. * The activation of a sense organ using physical energy that processes the receiving of stimulus from the external environment. A. Stimulus – anything that arouses a sense organ to activity. B. Receptor organs – a highly specialized part of the body selectively sensitive to a definite stimulus. C. Sensory receptors – are highly specialized cells that detect and transmit information to sensory nerves and brain. C.1. Photoreception
* Detection of light, perceived as light.
* Detection of pressure, vibration, and movement perceived as touch, hearing and equilibrium. C.3. Chemoreception
* Detection of chemical detected as smell and taste.
D. The receptors in the human body are the five sense organs. E. Distal senses – the eyes and the ears, are sensitive to external stimuli from a distance in the outside environment.
Terms to remember:
* The study of relationship between the physical aspects of stimuli and our psychological experience of them. 2. Transduction
* It refers to the process in which a sense organ changes, or transforms, physical energy into electrical signals that become neural impulses. 3. Adaptation
* It refers to the decreasing response of the sense organ the more they are exposed to a continuous level of stimulation.
I.A. Physical Stage
1. Refers to the action of some physical stimulus on a sense organ. 2. For each type of sensation, there is an adequate and appropriate stimulus that is one which is naturally present to activate a particular receptor.
I.B. Physiological Stage
1. Refers to the physiological process that has started the action of a stimulus on a receptor. It consists in the flow of nervous impulses from the receptor to some terminal points in the nervous system. 2. If the nervous impulses find their terminal points in the muscular or the glandular system, the typical reflex arc appears without further psychological stage.
I.C. Psychological Stage
1. Refers to the perception of the sensation or giving meaning to the sensation. 2. Consists of the awareness, and the interpretation, and the conscious reaction to the sensation.
II. THE ATTRIBUTES OF SENSATION
A. Modality of sensation – The different categories of sensation according to their experiences. B. Quality of sensation – The experience that even within the same modality they differ too from one another. C. Intensity of a sensation – The distinction in degree; the sensation may be stronger or more intense than another sensation of the same quality. D. Duration of the sensation – Indicates how long a sensation actually lasts in the consciousness. E. Reaction time of a sensation – The interval that elapses between the receiving of an impression by a sense organ and the recognition of this impression together with the subsequent outward manifested of this recognition.
III. LEVELS OF SENSATION
A. Absolute threshold – The minimum physical energy needed to activate a given sensory system. B. Differential threshold – The minimum amount of stimulation needed to determine the difference between stimuli. C. Sensory adaptation – The reduction in sensitivity to the stimulation persists throughout or the increase in sensitivity with the lack of stimulation.
IV. THE SENSE ORGANS
A. The Visual Sense
1. Physical Stage
* The physical stimulus for vision is the electromagnetic energy reflected from the object and transmitted in the air with a wavelength of about 400 – 800 millimicrons at a speed of about 186,000 miles per second.
The eye utilizes two basic properties of this light energy namely: 1. Brightness
* Amount of light energy the eye receives.
* Is determined by the amplitude of the wave – how high or how...
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