PSY 101 Chapter 3 PDF

CHAPTER 3 PSY 101 DR. OREM SENSATION V. PERCEPTION Sensation is the process by which sensory organs in the eyes, ears, nose, mouth, skin, and other tissues receive and detect stimuli. Perception is the organization and interpretation of these stimuli in the brain. These two work closely tog...

CHAPTER 3 PSY 101 DR. OREM SENSATION V. PERCEPTION Sensation is the process by which sensory organs in the eyes, ears, nose, mouth, skin, and other tissues receive and detect stimuli. Perception is the organization and interpretation of these stimuli in the brain. These two work closely together to allow us to experience the world as coherent and meaningful. Why is this important?  HOW DO WE PROCESS OUR EXPERIENCES? Bottom-up processing takes basic sensory information about incoming stimuli and processes it for further interpretation. Top-down processing takes this a step further by drawing on past experiences and knowledge to understand and interpret sensory information. Data-based processing records information without any expectations, whereas knowledge-based processing uses prior experience to make sense of the world.  TRANSDUCTION Stimuli from the environment are constantly bombarding us Each sensory system is designed to respond to different types of stimuli However, stimuli cannot affect the brain unless they are translated into electrical and chemical signals Transduction: the process of transforming stimuli into neural signals The brain must assign meaning to a sensation for it to be useful, and the process of understanding sensation is perception. DOES IT HURT?  WHAT IS YOUR THRESHOLD? Sensory thresholds: the smallest levels of stimulation people can detect Absolute thresholds: the weakest stimuli that can be detected 50% of the time The state of an individual’s body can influence the detection of a weak stimulus These thresholds may not be absolute for a particular person over time SENSORY PROCESSING: DETECTING CHANGES Many sensory experiences involve detecting changes in stimuli This allows us to focus on changes in our environment, which is a valuable survival skill A difference threshold is the minimum difference between two stimuli that can be noticed 50% of the time Sensory receptors tend to become less sensitive to constant stimuli through a process called sensory adaptation Weber’s law: each of the five senses has its own constant ratio that determines difference thresholds 7  FUSSY EATERS George Carlin: “Fussy eater” is a euphemism… 8 SIGNAL DETECTION THEORY & SUBLIMINAL STIMULI SDT: explains how various factors influence our ability to detect weak signals in the environment Internal and external “noise” can influence our ability to detect a weak signal Signal detection theory has many practical applications because it helps us to understand what might make a person “miss” a stimulus and then prevent that from occurring Subliminal stimuli: below our threshold but still picked up on a subconscious level  VISION Seeing = sensing and perceiving the light bouncing off the objects around us Light is an electromagnetic energy wave Types of electromagnetic energy can be distinguished by their wavelengths, which is the distance between wave peaks The wavelengths of this energy fall on a spectrum from short to long, and only a small portion of this spectrum is visible to the human eye Audition (hearing): the detection of sound waves from the environment with HEARING our ears When an object vibrates, it sends a pressure disturbance of molecules moving through the air Molecules move in sound waves, cycles of alternating high and low pressure Although all sounds are made of sound waves, sounds vary immensely  SMELL Olfaction (the sense of smell) helps us sense danger, fully taste food, recognize people, sense pheromones, and even trigger memories Involves sensing chemicals (smell molecules) in the environment Anosmia = loss of one’s sense of smell Hyperosmia = more sensitive to smells Phantosmia: smelling things that aren’t there (may indicate underlying medical condition 14  TASTE Gustation: involves receptors in the mouth that are sensitive to five basic tastes - sweet, salty, sour, bitter, and umami. Receptor cells for taste are found in the taste buds lining the tongue, roof of the mouth, and cheeks Chemicals are released into your mouth when you chew and bind to these receptor cells This sparks action potentials in sensory cells to relay the signals to the thalamus and higher brain centers  TOUCH Sensed by the outer layer of our skin (the epidermis), which is also the body’s largest organ Skin is the barrier between our internal organs and the outside world Constantly gathering data about the environment through 1) thermoreceptors that sense hot or cold, 2) Pacinian corpuscles that detect vibrations, and 3) Meissner’s corpuscles that are sensitive to the slightest touch Communicating pain: Nociceptive pain, caused by heat, cold, chemicals, and pressure, is sensed by nociceptors in the skin as well as the muscles and internal organs Pain, though an unpleasant sensation, is very important because it alerts us to injury and illness  PERCEPTION: PUTTING IT ALL TOGETHER When surrounded by multiple sensory experiences (e.g., smells, images, and sounds), our brain is responsible for organizing and integrating these sensations into a coherent perception of the world Our brain’s natural tendency is to organize stimuli into a whole, rather than perceiving the parts and pieces Gestalt psychologists studied the principles that explain how the brain perceives objects as wholes or groups Due to our learning history (expectations) and sensory interactions occurring around us, sometimes our perception does not match up with reality MAKING SENSE: PERCEIVING THE GESTALT WHEN RATS WON’T DO, GET BABIES  KINESTHESIA: PROPRIOCEPTION & INTEROCEPTION Proprioceptors: located in the muscles and joints; provide information about body location and orientation Allows us to coordinate and move all the appropriate body parts at the appropriate times Vestibular system: controls the senses of balance and equilibrium, which help the body deal with the effects of gravity, movement, and position in space Interoception: ability to sense and perceive internal bodily signals, such as heart rate, hunger, and emotions; helps us understand how we are feeling in the moment