Biological Psychology (Sensation and Perception) PDF Notes

1|Pag e BIOLOGICAL PSYCHOLOGY (Sensation and Perception) Sensation: Receiving Messages About the World  Sense organs –enables us to see, hear, taste, smell, touch, balance, and experience such as feeling...

1|Pag e BIOLOGICAL PSYCHOLOGY (Sensation and Perception) Sensation: Receiving Messages About the World  Sense organs –enables us to see, hear, taste, smell, touch, balance, and experience such as feeling of body stiffness, soreness, fullness, warmth, pleasure, pain, and movement.  Operate through the sensory receptor cells. Sensory receptor cells are specialized forms of neurons, the cells that make up the nervous system. Instead of receiving neurotransmitters from other cells, these receptor cells are stimulated by different kinds of energy (light for example)  Sensation –the process of receiving information from the outside world, translating it, and transmitting it to the brain.  Sensation occurs when special receptor cells in the sense organs are activated allowing various forms of outside stimuli to become neural signals in the brain. HUMAN SENSE STIMULUS SENSORY RECEPTOR CELLS Light -sensitive rods and cones Sight (Vision) Light waves in the retina of the eye Pressure –sensitive hair cells in Hearing (Audition) Sound waves the cochlea of the inner ear Molecules dissolved in fluid of Taste cells in the taste buds of Taste (Gustation) the tongue the tongue Molecules dissolved in fluid on Sensitive ends of olfactory mucous membranes in the neurons in the mucous Smell (Olfaction) nose membranes Sensitive ends of touch Touch (Somesthetic Sense) Pressure on the skin neurons in the skin  Stimulus –is any aspect of the outside world that directly influences our behavior of conscious experience.  Transduction –the process converting stimuli into codes of electrochemical impulses that the neurons can carry and the brain understands.  Absolute Threshold –the smallest magnitude that can be detected. INPSYC130 Introduction to Psychology 2|Pa g e Stimulus Absolute Threshold Vision A candle flame seen at 30 miles on a dark clear night Hearing The tick of a watch at 20 feet under quite conditions Taste One teaspoon of sugar in 2 gallons of water Smell One drop of perfume diffused into a 3-room apartment Touch The wing of a fly falling on your cheek from a distance of 0.5 inch  Difference Threshold –the smallest difference between two stimuli that subjects can detect half the time.  For example, let's say I asked you to put your hand out and in it I placed a pile of sand. Then, I add tiny amounts of sand to your hand and ask you to tell me when you notice any change in the overall weight. As soon as you can detect any change in the weight, that difference between the weight of the sand before I added that last bit of sand and the amount of sand after I added it, is the difference threshold.  Sensory Adaptation –weakened magnitude of a sensation resulting from a prolonged presentation of the stimulus. SENSE OF SIGHT (VISION)  Receptor organ: The Eye  Receptor cells: Photoreceptors (rods and cones)  Stimulus: Light (Electromagnetic energy) The Anatomy of Vision  Cornea –the transparent bulge at the front of the eye where light enters  Sclera –the white opaque outer wall of the eye  Aqueous humor –clear fluid that fills the front chamber of the eye  Pupil –an opening surrounded by the iris through which light passes into the eye.  Iris - the pigmented muscular curtain near the front of the eye, between the cornea and the lens, that is perforated by an opening called the pupil. INPSYC130 Introduction to Psychology 3|Pa g e  Lens - focuses the light rays that pass through it (and onto the retina) in order to create clear images of objects that are positioned at various distances.  Retina -a thin layer of tissue that lines the back of the eye on the inside. The purpose of the retina is to receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition  Optic Nerve -The optic nerve connects the eye to the brain. The optic nerve carries the impulses formed by the retina, the nerve layer that lines the back of the eye and senses light and creates impulses. These impulses are dispatched through the optic nerve to the brain, which interprets them as images Properties of Light  Hue –the visual dimension seen as a particular color; determined by the length of a light wave  Brightness –the intensity of color; determined by the height of a light wave as such that the higher the wave, the greater the amplitude, and the brighter the color.  Accommodation –the bulging and flattening of the lens in order to focus an image on the retina. Looking at nearby objects, the lens becomes thick whilst looking at far objects, the lens thins. INPSYC130 Introduction to Psychology 4|Page  Rods –receptors in the retina that are most sensitive in dim light; do not respond to color.  Cones –receptors in the retina to color and fine detail  Dark Adaptation –visual adjustment that increases the sensitivity of the rods and cones and allows us to see better in dim light.  Light Adaptation –the visual adjustment of the rods and cones that reduces sensitivity to bright light Common Vision Problems  Myopia –nearsightedness  Hyperopia –farsightedness  Nyctalopia –night-blindedness  Presbyopia –farsightedness at old age  Glaucoma –increased pressure within the eyeball  Cataract –a disorder in which the lens becomes cloudy  Color Blindness  Caused by defective cones in the retina of the eye and as a more general term, color- deficient vision, is more accurate, as most people with “color blindness” have two types of cones working and can see many colors.  Monochrome color blindness –people either have no cones or have cones that are not working at all.  Essentially, if they have cones, they only have one type and, therefore, everything looks the same to the brain -shades of gray.  Dichromatic vision –are caused by the same kind of problem-having one cone that does not work properly.  Protanopia – is due to the lack of functioning red cones  Deuteranopia –results from the lack of functioning green cones  In both cases, the individual confuses reds and greens, seeing the world primarily in blues, yellows, and shades of gray. SENSE OF HEARING (AUDITION)  Receptor organ: The Ear  Receptor Cells: Hair Cells INPSYC130 Introduction to Psychology 5|Page  Stimulus: Sound Waves Anatomy of the Ear  Outer Ear  Pinna  The visible, external part of the ear that serves as a kind of concentrator, funneling the sound waves from the outside into the structure of the ear  Auditory Canal  the short tunnel that runs down to the tympanic membrane or eardrum.  Tympanic Membrane (Eardrum)  a thin layer of cone-shaped tissue that separates the outer ear from the middle ear. It facilitates hearing by transmitting sound vibrations from the air to the bones in the middle ear.  Middle Ear  Ossicles [malleus (hammer), incus (anvil), and stapes (stirrup)]  The three tiniest bones in the body form the coupling between the vibration of the eardrum and the forces exerted on the oval window of the inner ear.  Oval Window  a connective tissue membrane located at the end of the middle ear and the beginning of the inner ear.  Inner Ear  Cochlea(Basilar membrane, Organ of Corti, & Hair Cells)  Cochlea filled with fluid. When the oval window vibrates, it causes the fluid in the cochlea to vibrate.  This fluid surrounds a membrane running through the middle of the cochlea called the basilar membrane.  Basilar membrane is the resting place of the organ of corti which contains the receptor cells for the sense of hearing.  Auditory Nerve  a bundle of nerve fibers that carries hearing information between the cochlea the brain. INPSYC130 Introduction to Psychology 6|Page  Sound waves –vibrations of the air or of another medium that vary in frequency and amplitude  Intensity –density of vibrating air molecules, which determines the loudness of sound  Pitch –the highness or lowness of tones or sounds, depending on their frequency  Timbre –the characteristic quality of a sound as determined by the complexity of hertz (a unit of frequency representing one cycle (vibration) per second.  Decibel –measurement of the intensity of perceived sound Hearing Problems  Conduction deafness –temporary deafness caused by the building up of fluid that prevents the eardrum and ossicles from vibrating.  Nerve deafness –hearing loss that stems from damage to the nerve cells in the cochlea or by the simple process of aging. SENSE OF TOUCH (SOMESTHETIC SENSE) INPSYC130 Introduction to Psychology 7|Pag e  Receptor organ: The Skin  Receptor Cells: Meissner’s corpuscle, Merkel’s discs, free nerve endings, Krause’s end bulb, Pacinian corpuscle, Corpuscle of Ruffini, Golgi-Mazzoni Corpuscle  Stimuli: Pressure, Temperature, and Pain Four Basic Sensation of the Body  Pressure –caused by anything that comes in contact with the skin  Pain –caused by the stimulus being strong enough to cause damage to skin  Warmth and Cold SENSE OF SMELL (OLFACTION)  Receptor Organ: The Nose  Receptor Cells: Olfactory Receptors  Stimuli: Gaseous Substances (Chemical Energy)  The sense of smell of the chemical senses, the other is the sense of taste. They are so called because they sense chemicals, and smells are, chemicals.  Sense of smell results from stimulation of receptor cells embedded in the olfactory epithelium (a mucus-coated membrane lining the top of the nasal cavity)  Adaptation –Wearing-off of olfactory sensitivity to odors which seem initially overpowering.  Anosmia –loss of smell INPSYC130 Introduction to Psychology 8|Pa g e Seven widely used classification of odors and their examples  Floral (roses)  Musky (oil)  Resinous (camphor)  Minty (peppermint)  Putrid (rotten eggs)  Ethereal (pears)  Acrid (vinegar) SENSE OF TASTE (GUSTATION)  Receptor organ: The Tongue  Receptor Cells: Taste Cells  Stimuli: Liquids and Soluble Substances  Taste receptors for four basic sensations: sweet, sour, salty, and bitter  Papillae –small bumps on the surface of the tongue that contain taste buds.  Taste buds –are flask-like structures containing taste cells in the papillae.  Global sensation –both smell & taste are working  Ageusia –loss of the sense of taste Other Senses: PROPRIOCEPTION: Kinesthesis & Vestibular Senses  Proprioception –the general term for our sense of body position, involve two senses:  Kinesthetic  Sense of movement  Receptors are in the muscles, tendons, and joints.  Tells us when our muscles are straining, when our arms are out of control, and when our torso is unbalanced  Vestibular  Sense of Balance  Also called as equilibratory or labyrinthine sense  Deals with the total body as a whole. INPSYC130 Introduction to Psychology 9|Page  Located near cochlea in the inner ear. ORGANIC SENSITIVITY Sensitivity to changes occurring inside the body through receptors located in the internal organs such as feelings of nausea, hunger, indigestion, and the like. INTERRELATION OF THE SENSES All sense are working together. Related to Global sensation. PERCEPTION  A common criterion of consciousness is whether an individual is “AWARE” of his surroundings, or more specifically, the amount of information that the individual is aware of.  Understanding the kind of surrounding information we are aware of is dependent on the variety of information we are attending to.  Understanding the information in our surroundings is more than just paying attention to it, as further processing is required. This process is known as PERCEPTION.  Perception generates a meaningful experience from the information.  Perception –process where raw neural energy (sensation) is organized and interpreted.  Visual Perception –a highly important sensing system where it works better than other perceptual systems do in telling us something about the world. Processes of Perception  Attention o Basic factor in perception. o The psychological process of focusing on certain stimuli while trying to ignore others (Neil) o Can be: voluntary, involuntary, and habitual o Voluntary attention –requires effort (e.g. attention in studying lessons). o Involuntary attention –aroused by the potency of the stimulus. o Habitual attention –grows out of practice. INPSYC130 Introduction to Psychology 10 | P a g e Attention getting devices o Intensity o Mobiles (moving objects) o Size o Colors o Novelty (unusual) o Location o Nature  Organization o Gestalt is also known as the "Law of Simplicity" or the "Law of Pragnanz" (the entire figure or configuration), which states that every stimulus is perceived in its most simple form. o Gestalt theorists followed the basic principle that the whole is greater than the sum of its parts. In other words, the whole (a picture, a car) carried a different and altogether greater meaning than its individual components (paint, canvas, brush; or tire, paint, metal, respectively). In viewing the "whole," a cognitive process takes place – the mind makes a leap from comprehending the parts to realizing the whole, o We visually and psychologically attempt to make order out of chaos, to create harmony or structure from seemingly disconnected bits of information. BASIC LAWS OF ORGANIZATION o Figure-Ground-This principle shows our perceptual tendency to separate whole figures from their backgrounds based on one or more of a number of possible variables, such as contrast, color, size, etc. Everything that is not figure is ground. Figure-ground refers to the relationship between an object and its surround. o Continuity -This Gestalt law states that learners "tend to continue shapes beyond their ending points". o The edge of one shape will continue into the space and meet up with other shapes or the edge of the picture plane. o The Gestalt law of proximity states that "objects or shapes that are close to one another appear to form groups". Even if the shapes, sizes, and objects are radically different, they will appear as a group if they are close together. INPSYC130 Introduction to Psychology 11 | P a g e o Gestalt law of similarity states that things which share visual characteristics such as shape, size, color, texture, or value will be seen as belonging together in the viewer’s mind. o Closure is the effect of suggesting a visual connection or continuity between sets of elements which do not actually touch each other in a composition. o The principle of closure applies when we tend to see complete figures even when part of the information is missing. Closure occurs when elements in a composition are aligned in such a way that the viewer perceives that "the information could be connected." o Perceptual Constancy –the tendency for perceptions of objects to remain relatively unchanged, in spite of changes in raw sensations.  Brightness constancy is our visual ability to perceive objects as having the same level of brightness even though the level of lighting changes. For example, something white will appear to be the same shade of white no matter how much light it is being exposed to  Colour constancy is the tendency of objects to appear the same colour even under changing illumination. A yellow banana appears yellow whether you see it in the tungsten light of the kitchen or in sunlight outdoors.  Size constancy refers to the fact that our perceptions of the size of objects are relatively constant despite the fact that the size of objects on the retina vary greatly with distance.  Shape constancy the tendency to perceive the shape of a rigid object as constant despite differences in the viewing angle (and consequent differences in the shape of the pattern projected on the retina of the eye) o Depth Perception –the ability to accurately estimate the distance of perceived objects and thereby perceive the world in three-dimensions.  Binocular depth cues –the product of perceiving a three dimensional world using both eyes.  Convergence -are information (or cues) taken in by two eyes (binocular), versus one eye (monocular). INPSYC130 Introduction to Psychology 12 | P a g e  Retinal Disparity -defined as the way that your left eye and your right eye view slightly different images. Retinal disparity is important in gauging how far away objects are. The more difference (or greater disparity) between the image each eye has of the same object, the closer it is to you. The farther away an object is, on the other hand, the more similar it looks from viewing it with each eye alone. This is really adaptive as it allows us to determine how far away cliffs are, or predators, or a deep gorge so that these can be avoided and aid in survival.  By collecting information from your right and left eyes and then integrating it, your brain is able to construct a three-dimensional interpretation of the world. That's right, binocular cues are what allow us to see 3D!  You might be asking yourself, 'How, then, is our vision just one continuous image?' The two slightly different images produced in both eyes are blended into one view when both eyes are open, and this is one of the ways in which human depth perception is possible.  Monocular depth cues –the product of perceiving a three dimensional world using each eye separately.  Texture Gradient -The texture of an object can be seen clearly when close-by, but becomes less and less apparent the farther away the object is.  Linear Perspective -parallel lines that recede into the distance appear to get closer together or converge.  Superposition -monocular cue in which one object, by partly blocking a second, appears closer  Shadowing -When objects are darker or shaded they are perceived as farther away.  Motion Parallax -when an object closer to you tends to move at a speed much faster than an object that is farther away. INPSYC130 Introduction to Psychology 13 | P a g e  Aerial Perspective -the tendency of faraway objects to appear hazy or slightly blurred as a result of the atmosphere.  Relative size –size difference can make the larger object appear closer and the smaller object appears farther away o Optical Illusions can use color, light and patterns to create images that can be deceptive or misleading to our brains. The information gathered by the eye is processed by the brain, creating a perception that in reality, does not match the true image. Perception refers to the interpretation of what we take in through our eyes. Optical illusions occur because our brain is trying to interpret what we see and make sense of the world around us. Optical illusions simply trick our brains into seeing things which may or may not be real. o Auditory Perception o Concerned with the location of sound. o Two factors to consider: Distance & Direction o Rule: “the louder the sound, the nearer the source”  Interpretation o Factors that influence Interpretation:  Past Experiences  Motive  Interest  Set (readiness to respond) Perception of Time  refers to a person's subjective experience of the passage of time, or the perceived duration of events, which can differ significantly between different individuals and/or in different circumstances. For example, a person might perceive the time as slow if he is bored or a person might perceive the time as fast if he is engrossed and enjoyed doing a task. Perception of Emotion  a person’s subjective feeling toward an event. INPSYC130 Introduction to Psychology 14 | P a g e Stroop effect  The Stroop effect is a phenomenon that occurs when you must say the color of a word but not the name of the word.  It was first described during the 1930s by American psychologist John Ridley Stroop. His experimental results showed that people are more practiced at word reading than naming colours, there is less interference with word reading than there is with naming colours. As learnt experiences become part of our memory, it teaches us over time that the meaning of words holds greater significance than the colours they are written in.  Stroop conducted two main experiments. The first was to have people read the neutral stimulus – the words printed in black ink – and then read the words printed in colored ink. The challenge was that they were asked to say aloud the words they saw and not state the color they were printed in.  While it might sound simple, the Stroop effect refers to the delayed reaction times when the color of the word doesn't match the name of the word. It's easier to say the color of a word if it matches the semantic meaning of the word. Extra Sensory Perception (ESP)  Telepathy –refers to the transfer of thoughts between individuals.  Clairvoyance –perception of objects or events that are not available to the senses.  Psychokinesis –the ability to influence the movement of material bodies by the power of thought alone.  Precognition –the ability to foretell future events. Parapsychology –a science devoted to investigations of psychical phenomena INPSYC130 Introduction to Psychology