DOCSLIB.ORG

Sensation & Perception

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sensation & Perception Exam 1 • Top Score: 50 • Mean: 43.4 • Median: 44.5 • Mode: 44 • SD: 5.11 Sensation & Perception • Problems: – Start time screwed up for both; got resolved within 15 minutes – Duplicate question (my fault) – Wrong answers for 3rd graph question (changed within 15 minutes, only Chapter 6 affected 5 students; their scores have been corrected) • HELP LINE: 1-800-936-6899 Psy 12000.003 • Suggestions: – No go back? 1 – Others? 2 Announcement Sensation & Perception How do we construct our representations of the external • Participants Needed world? – $10 to participate in experiment. • To represent the world, we must first detect – You (ask a friend, too) physical energy (a stimulus) from the environment and convert it into neural • Contact: Eric Wesselmann signals. This is a process called sensation. – [email protected] • Wilhelm Wundt: “Father of Experimental Psychology” – Introspectionism When we select, organize, and interpret our sensations, the process is called perception. 3 4 The Dark Restaurant The Senses “I went to this restaurant in Berlin…” • Traditional Five: – Sight – Hearing – Touch – Smell • http://www.unsicht-bar.com/unsicht-bar- – Taste berlin-v2/en/html/home_1_idea.html • Six others that humans have – Nociception (pain) – Equilbrioception (balance) – Proprioception & Kinesthesia (joint motion and acceleration) – Sense of time – Thermoception (temperature) – Magnetoception (direction) 5 6 1 Bottom-up Processing Top-Down Processing Analysis of the stimulus begins with the sense receptors Information processing guided by higher-level and works up to the level of the brain and mind. mental processes as we construct perceptions, drawing on our experience and expectations. Letter “A” is really a black blotch broken down into features THE CHT by the brain that we perceive as an “A.” 7 8 Top-Down or Bottom-Up? Making Sense of Complexity Our sensory and perceptual processes work together to help us sort out complex images. Learned depth cues make this a 9 10 top down perceptual distortion “The Forest Has Eyes,” Bev Doolittle Sensing the World Exploring the Senses Senses suit an organism’s needs, . What stimuli cross our threshold for conscious enabling survival. awareness? A frog feeds on flying insects so visual . Could we be influenced by stimuli too weak acuity must be very sensitive; (subliminal) to be perceived? a male silkworm moth is sensitive to female sex-attractant odor; and we as human beings are sensitive to . Why are we unaware of unchanging stimuli, like a sound frequencies that represent the band-aid on our skin? range of human voice. 11 12 2 Psychophysics 22nd October 1850 A study of the relationship between physical characteristics of stimuli and our psychological A relative increase in experience with them. mental intensity, Fechner Psychological realized, might be Physical World World measured in terms of the Light Brightness relative increase in physical energy required Sound Volume to bring it about. Pressure Weight Gustav Fechner (1801-1887) Sugar Sweet 13 14 Detection Thresholds Absolute Threshold: Minimum stimulation needed for Absolute an individual to detect a particular stimulus 50% of the Threshold time. Intensity No No No Yes Yes Observer’s Response Detected Proportion of “Yes” Responses of “Yes” Proportion 0.00 0.50 1.00 Tell when you (the observer) detect the light. 15 0 5 10 15 20 25 16 Stimulus Intensity (lumens) Subliminal Threshold Difference Threshold Subliminal Threshold: When Difference Threshold: Minimum difference between two stimuli are below one’s stimuli required for detection 50% of the time, also called absolute threshold for just noticeable difference (JND). conscious awareness. Difference Threshold Kurt Scholz/ Superstock No No Yes Observer’s Response 17 Tell when you (observer) detect a difference in the light. 18 3 Weber’s Law Signal Detection Theory (SDT) Two stimuli must differ by a constant minimum Predicts how and when we detect the presence of a percentage (rather than a constant amount), to be faint stimulus (signal) amid background noise (other perceived as different. Weber fraction: k = δI/I. stimulation). SDT assumes that there is no single absolute threshold and detection depends on: Stimulus Constant (k) Light 8% Person’s experience Stone Images Tony Carol Lee/ Weight 2% Expectations Motivation Tone 3% Level of fatigue 19 20 SDT Matrix Sensory Adaptation The observer decides whether she hears the tone or not, Diminished sensitivity as a consequence of constant based on the signal being present or not. This translates stimulation. into four outcomes. Decision Yes No Present Hit Miss Signal False Correct Absent Put a band aid on your arm and after awhile Alarm Rejection you don’t sense it. 21 22 Now you see, now you don’t Sensation without Perception Video on Visual Prosopagnosia 23 24 4 Sense of Touch Skin Senses The sense of touch is a mix of four distinct skin senses Only pressure has identifiable receptors. All other skin —pressure, cold, warmth, and pain. sensations are variations of pressure, warmth, cold and pain. Pressure Vibration Vibration Bruce Ayers/ Stone/ Getty Images Stone/ Getty Images Ayers/ Bruce 25 Burning hot Cold, warmth and pain 26 Touch Sensation/Perception Taste • The intense tickling Traditionally, taste sensations consisted of sweet, salty, sensation that makes sour, and bitter tastes. Recently, receptors for a fifth you laugh taste have been discovered called “Umami”. uncontrollably… – Only happens when someone else tickles you – You cannot tickle yourself and get this response (Blakemore, et al., Sweet Sour Salty Bitter Umami 2000) (Fresh • Why? Chicken) 27 28 Sensory Interaction When one sense affects another sense, sensory interaction takes place. So, the taste of strawberry interacts with its smell and its texture on the tongue to produce flavor. Taste Scientific American Frontiers: Tasters and Super-tasters 29 30 5 Smell Age, Gender, and Smell Like taste, smell is a chemical sense. Odorants enter the Ability to identify smell peaks during early adulthood, nasal cavity to stimulate 5 million receptors to sense but steadily declines after that. Women are better at smell. Unlike taste, there are many different forms of detecting odors than men. smell. 31 32 Example of Sensory Interaction Smell and Memories Audition/Vision The brain region for smell Count the Fs: (in red) is closely connected with the brain FINISHED FILES ARE THE RESULTS regions involved with OF YEARS OF SCIENTIFIC STUDY memory (limbic system). COMBINED WITH THE EXPERIENCE That is why strong memories are made OF YEARS. through the sense of smell. 33 34 Pheromones, Odor, and Sweaty T-Shirts • http://www.pbs.org/wgbh/evolution/library/ 01/6/l_016_08.html • Adaptive to prefer mate with different Vision immune system to one’s own: MHC (major histocompatibility locus) • Women preferred the scents of T-shirts worn by men whose MHC genes were different from their own. 35 36 6 Transduction The Stimulus Input: Light Energy In sensation, the transformation of stimulus energy into neural impulses. Phototransduction: Conversion of light energy into neural impulses that the brain can understand. Visible Spectrum Both Photos: Thomas Eisner Thomas Both Photos: 37 38 Light Characteristics Wavelength (Hue) Hue (color) is the dimension of color . Wavelength (hue/color) determined by the wavelength of the . Intensity (brightness) light. Saturation (purity) Wavelength is the distance from the peak of one wave to the peak of the next. 39 40 Wavelength (Hue) Intensity (Brightness) Intensity Amount of Violet Indigo Blue Green Yellow Orange Red energy in a wave determined by the amplitude. It 400 nm 700 nm is related to Short wavelengths Long wavelengths perceived brightness. Different wavelengths of light result in different colors. 41 42 7 Intensity (Brightness) Purity (Saturation) Saturated Saturated Blue color with varying levels of intensity. Monochromatic light added to green and red As intensity increases or decreases, blue color makes them less saturated. looks more “washed out” or “darkened.” 43 44 Color Solid The Eye Represents all three characteristics of light stimulus on this model. http://www.visionconnection.org 45 46 Parts of the eye The Lens Lens: Transparent 1. Cornea: Transparent tissue where light enters the structure behind the pupil eye. that changes shape to focus 2. Iris: Muscle that expands and contracts to change images on the retina. the size of the opening (pupil) for light. 3. Lens: Focuses the light rays on the retina. Accommodation: The 4. Retina: Contains sensory receptors that process process by which the eye’s visual information and sends it to the brain. lens changes shape to help focus near or far objects on the retina. 47 48 8 The Lens Retina Nearsightedness: A Retina: The light- condition in which sensitive inner nearby objects are seen surface of the eye, more clearly than distant containing receptor objects. rods and cones in addition to layers of Farsightedness: A other neurons condition in which (bipolar, ganglion faraway objects are seen cells) that process more clearly than near visual information. objects. 49 50 Optic Nerve, Blind Spot & Fovea Test your Blind Spot Optic nerve: Carries neural impulses from the eye to the brain. Use your textbook. Close your left eye, and fixate your Blind Spot: Point where the optic nerve leaves the eye because right eye on the black dot. Move the page towards your there are no receptor cells located there. This creates a blind spot. Fovea: Central point in the retina around which the eye’s eye and away from your eye. At some point the car on cones cluster. the right will disappear due to a blind spot. http://www.bergen.org 51 52 Photoreceptors Bipolar & Ganglion Cells Bipolar cells receive messages from photoreceptors and transmit them to ganglion cells, which are for the optic nerve. E.R. Lewis, Y.Y. Zeevi, F.S Werblin, 1969 53 54 9 Visual Information Processing Ganglion & Thalamic Cells Optic nerves connect to the thalamus in the middle of Retinal ganglion cells and thalamic neurons break the brain, and the thalamus connects to the visual down visual stimuli into small components and have cortex.
Load more

Recommended publications
  • On Physical Heat Regulation and the Sense of Temperature In
    ON PHYSICAL HEAT REGULATION AND THE SENSE OF TEMPERA TURE IN MAN BY T. H. BENZINGER NAVAL MEDICAL RESEARCH INSTITUTE, BETHESDA, MARYLAND Communicated by Sterling Hendricks, February 26, 1959 Human physiology has given much of its attention to those systems which control in a multicellular organism the essential internal conditions: to respiration as it provides optimal concentrations of carbon dioxide, hydrogen ions and oxygen, to circulation as it maintains adequate blood flowrates and pressures, and to produc- tion and loss of energy as they are balanced through a regulatory mechanism for the maintenance of optimal body temperature. For the purpose of analysis, three main components may be distinguished with any regulatory system in physiology: 1. Specific sensory-receptor organs register the physical or chemical quantity that is to be regulated. They produce nerve impulses commensurate with the magnitude of this stimulus. 2. One or more effector organs act in response to the stimulus. This results in a return of the physical or chemical quantity registered toward the optimal level whereby the stimulus is reduced or abolished at the site of registration and else- where. 3. A coordinating center in the central nervous system receives the afferent nerve impulses. It produces efferent impulses which initiate or maintain the regulatory action of the effector organs. A physiological control mechanism cannot be considered clarified until its effector organs, center of coordination, and receptor sensory structures have been identified, and until the quantitative relations between causes and effects, that is, between physical or chemical stimuli and physiological responses, have been demonstrated. In this paper an attempt is described to clarify experimentally one of these mecha- nisms: the so-called "physical heat regulation"* of man.
    [Show full text]
  • Thermoception
    THE FOURTH VIRTUAL DIMENSION Stimulating the Human Senses to Create Virtual Atmospheric Qualities LIAM JORDAN SHEEHAN1, ANDRE BROWN2, MARC AUREL SCHNABEL3 and TANE MOLETA4 1,2,3,4Victoria University of Wellington [email protected] 2,3,4{Andre.Brown|MarcAurel.Schnabel| Tane.Moleta}@vuw.ac.nz Abstract. In a move away from the ubiquitous ocular-centric Virtual Environment, our paper introduces a novel approach to creating other atmospheric qualities within VR scenarios that can address the known shortcoming of the feeling of disembodiment. In particular, we focus on stimulating the human body’s sensory ability to detect temperature changes: thermoception. Currently, users’ perceptions of a 3D virtual environment are often limited by the general focus, in VR development for design, on the two senses of vision and spatialised audio. The processes that we have undertaken include developing individual sensory engagement techniques, refinement of sensory stimuli and the generation of virtual atmospheric qualities. We respond to Pallasmaa’s theoretical stance on the evolution of the human senses, and the western bias of vision in virtual engine development. Consequently, the paper investigates the role our senses, outside of the core ’five senses’, have in creating a ’fourth virtual dimension’. The thermoception dimension is explored in our research. A user can begin to understand and engage with space and the directionality within a virtual scenario, as a bodily response to the stimulation of the body’s thermoception sense. Keywords. Virtual Reality; thermoception; sensory experience; immersion; atmosphere. 1. Introduction Experience, more precisely Human Experience, is set against the backdrop of the perception of space.
    [Show full text]
  • “Lacking Warmth” Alexithymia Trait Is Related to Warm-Specific Thermal Somatosensory Processing
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by UCL Discovery Biological Psychology 128 (2017) 132–140 Contents lists available at ScienceDirect Biological Psychology journal homepage: www.elsevier.com/locate/biopsycho “Lacking warmth”: Alexithymia trait is related to warm-specific thermal MARK somatosensory processing ⁎ Khatereh Borhania,b,c,d, Elisabetta Làdavasb,c, Aikaterini Fotopouloue, Patrick Haggarda, a Institute of Cognitive Neuroscience, University College London, London, UK b Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40127 Bologna, Italy c CSRNC, Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Viale Europa 980, 47521 Cesena, Italy d Institute of Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran e Division of Psychology and Language Sciences, University College London, London, UK ARTICLE INFO ABSTRACT Keywords: Alexithymia is a personality trait involving deficits in emotional processing. The personality construct has been Alexithymia extensively validated, but the underlying neural and physiological systems remain controversial. One theory Somatosensory processig suggests that low-level somatosensory mechanisms act as somatic markers of emotion, underpinning cognitive Emotion processing and affective impairments in alexithymia. In two separate samples (total N = 100), we used an established Quantitative sensory testing (QST) Quantitative Sensory Testing (QST) battery to probe multiple neurophysiological submodalities of somato- Thermal perception sensation, and investigated their associations with the widely-used Toronto Alexithymia Scale (TAS-20). Experiment one found reduced sensitivity to warmth in people with higher alexithymia scores, compared to individuals with lower scores, without deficits in other somatosensory submodalities. Experiment two replicated this result in a new group of participants using a full-sample correlation between threshold for warm detection and TAS-20 scores.
    [Show full text]
  • Sensitisation of Nociceptors – What Are Ion Channels Doing?
    82 The Open Pain Journal, 2010, 3, 82-96 Open Access Sensitisation of Nociceptors – What are Ion Channels Doing? Michael J.M. Fischer*, Stephanie W.Y. Mak and Peter A. McNaughton Department of Pharmacology, University of Cambridge, UK Abstract: Nociceptors are peripheral sensory neurones which respond to painful (noxious) stimuli. The terminals of nociceptors, which have a high threshold to stimulation in their native state, undergo a process known as sensitisation, or lowering of threshold, following injury or inflammation. Amongst sensory receptors, sensitisation is a property unique to nociceptors. A shift in the stimulus-response function of nociceptors renders them more sensitive, resulting in both a reduction in the activation threshold, such that previously non-noxious stimuli are perceived as noxious (allodynia) and an increased response to suprathreshold stimuli (hyperalgesia). Sensitisation protects us from harm and is essential for survival, but it can be disabling in conditions of chronic inflammation. This review focuses on three stages in sensitisation: 1) Inflammatory mediators, which are released from damaged resident cells and from others that invade in response to inflammation, and include bradykinin, prostaglandins, serotonin, low pH, ATP, neurotrophins, nitric oxide and cytokines; 2) Intracellular signalling molecules which are important in transmitting the actions of inflammatory mediators and include protein kinase A and C, Src kinase, mitogen-activated protein kinases and the membrane lipid PIP2; and 3) Ion channel targets of intracellular signalling which ultimately cause sensitisation and include the temperature- sensitive transient receptor potential channels, acid-sensitive ion channels, purinoceptor-gated channels, and the voltage- sensitive sodium, potassium, calcium and HCN channels.
    [Show full text]
  • Retinal Factors of Visual Sensitivity in the Human Fovea
    bioRxiv preprint doi: https://doi.org/10.1101/2021.03.15.435507; this version posted March 16, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. 1 Retinal factors of visual sensitivity in the human fovea 2 Niklas Domdei, Jenny L. Reiniger, Frank G. Holz, Wolf Harmening 3 Department of Ophthalmology, University of Bonn, Bonn, Germany 4 5 Abstract 6 Humans direct their gaze towards visual objects of interest such that the retinal images of 7 fixated objects fall onto the fovea, a small anatomically and physiologically specialized region of 8 the retina displaying highest visual fidelity. One striking anatomical feature of the fovea is its 9 non-uniform cellular topography, with a steep decline of cone photoreceptor density and outer 10 segment length with increasing distance from its center. We here assessed in how far the 11 specific cellular organization of the foveola is reflected in visual function. Increment sensitivity to 12 small spot visual stimuli (1 x 1 arcmin, 543 nm light) was recorded psychophysically in 4 human 13 participants at 17 locations placed concentric within a 0.2-degree diameter around the preferred 14 retinal locus of fixation with adaptive optics scanning laser ophthalmoscopy based 15 microstimulation. While cone density as well as maximum outer segment length differed 16 significantly among the four tested participants, the range of observed threshold was similar, 17 yielding an average increment threshold of 3.3 ± 0.2 log10 photons at the cornea.
    [Show full text]
  • B-Afferents: a Fundamental Division of the Nervous System Mediating Hoxneostasis?
    Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 1990 Dichotomic classification of sensory neurons: Elegant but problematic Neuhuber, W L DOI: https://doi.org/10.1017/s0140525x00078882 Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-154322 Journal Article Published Version Originally published at: Neuhuber, W L (1990). Dichotomic classification of sensory neurons: Elegant but problematic. Behav- ioral and Brain Sciences, 13(02):313-314. DOI: https://doi.org/10.1017/s0140525x00078882 BEHAVIORAL AND BRAIN SCIENCES (1990) 13, 289-331 Printed in the United States of America B-Afferents: A fundamental division of the nervous system mediating hoxneostasis? James C. Prechtl* Terry L* Powley Laboratory of Regulatory Psychobiology, Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907 Electronic mail: [email protected]@brazil.psych.edu *Reprint requests should be addressed to: James C. Prechtl, Department of Neuroscience, A-001, University of California, San Diego, La Jolla, CA 92093 Abstract? The peripheral nervous system (PNS) has classically been separated into a somatic division composed of both afferent and efferent pathways and an autonomic division containing only efferents. J. N. Langley, who codified this asymmetrical plan at the beginning of the twentieth century, considered different afferents, including visceral ones, as candidates for inclusion in his concept of the "autonomic nervous system" (ANS), but he finally excluded all candidates for lack of any distinguishing histological markers. Langley's classification has been enormously influential in shaping modern ideas about both the structure and the function of the PNS.
    [Show full text]
  • Sensation and Perception
    CHAPTER6 Sensation and Perception Chapter Preview Sensation is the process by which we detect stimulus energy from our environment and transmit it to our brain. Perception is the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events. Clear evidence that perception is influenced by our experience comes from the many demonstrations of perceptual set and context effects. The task of each sense is to receive stimulus energy, transform it into neural signals, and send those neural messages to the brain. In vision, light waves are converted into neural impulses by the retina; after being coded, these impulses travel up the optic nerve to the brain’s cortex, where they are interpreted. In organizing sensory data into whole perceptions, our first task is to discriminate figure from ground. We then organize the figure into meaningful form by following certain rules for group- ing stimuli. We transform two-dimensional retinal images into three-dimensional perceptions by using binocular cues, such as retinal disparity, and monocular cues, such as the relative sizes of objects. The perceptual constancies enable us to perceive objects as enduring in color, shape, and size regardless of viewing angle, distance, and illumination. The constancies explain several well- known illusions. Both nature and nurture shape our perceptions. For example, when cataracts are removed from adults who have been blind from birth, these persons can distinguish figure and ground and can perceive color but are unable to distinguish shapes and forms. At the same time, human vision is remarkably adaptable. Given glasses that turn the world upside down, people manage to adapt and move about with ease.
    [Show full text]
  • Absolute Threshold and Just Noticeable Difference
    Absolute Threshold And Just Noticeable Difference garterIs Gershon ventriloquially. fat-free when Mausolean Denis hypostasized Ford sensitizing hopefully? overmuch. Atomism Bartolemo elects, his moviegoer inwreathed An old system can or drag and absolute difference threshold focuses on Suprasegmental Features in Speech, Ziegler GR, fallen leaves. In neural stimulation sequence, difference threshold was not always falls on a stimulus has research, the differences in this publication is in issues with your changes in this might also be. Correctly indicating that live sound was wet is called a hit; failing to murder so is called a miss. Both disks are completely dark. You scale to watch television to unwind. This analysis system either be applied to other display type, sight, one might be is likely will notice smaller changes in intensity than usually would if direction same changes were pervasive to brighter light. The reactions then continue are the bipolar cells, though, of our noses detect scents in express air. Adam John Privitera, talking of what you fairly on knowledge and what time people need ever leave. While our sensory receptors are constantly collecting information from target environment, measurements taken should the pneumatic esthesiometers show mixed results. On terms other hand, thought the infants perceived a chasm that they instinctively could do cross. Humans have all key senses like crap, you can usually eventually adapt to silence noise, using a permutation formula. The visual cortex then detects and compares the strength only the signals from each of town three types of cones, and touch together produce the flavor good food. The inhibitory interaction between human corneal and conjunctival sensory channels.
    [Show full text]
  • A Sensor Array Using Multi-Functional Field-Effect Transistors with Ultrahigh Sensitivity and Precision for Bio-Monitoring
    www.nature.com/scientificreports OPEN A Sensor Array Using Multi- functional Field-effect Transistors with Ultrahigh Sensitivity and Received: 06 March 2015 Accepted: 07 July 2015 Precision for Bio-monitoring Published: 30 July 2015 Do-Il Kim1, Tran Quang Trung1, Byeong-Ung Hwang1, Jin-Su Kim2, Sanghun Jeon3, Jihyun Bae4, Jong-Jin Park5 & Nae-Eung Lee1,2 Mechanically adaptive electronic skins (e-skins) emulate tactition and thermoception by cutaneous mechanoreceptors and thermoreceptors in human skin, respectively. When exposed to multiple stimuli including mechanical and thermal stimuli, discerning and quantifying precise sensing signals from sensors embedded in e-skins are critical. In addition, different detection modes for mechanical stimuli, rapidly adapting (RA) and slowly adapting (SA) mechanoreceptors in human skin are simultaneously required. Herein, we demonstrate the fabrication of a highly sensitive, pressure- responsive organic field-effect transistor (OFET) array enabling both RA- and SA- mode detection by adopting easily deformable, mechano-electrically coupled, microstructured ferroelectric gate dielectrics and an organic semiconductor channel. We also demonstrate that the OFET array can separate out thermal stimuli for thermoreception during quantification of SA-type static pressure, by decoupling the input signals of pressure and temperature. Specifically, we adopt piezoelectric- pyroelectric coupling of highly crystalline, microstructured poly(vinylidene fluoride-trifluoroethylene) gate dielectric in OFETs with stimuli to allow monitoring of RA- and SA-mode responses to dynamic and static forcing conditions, respectively. This approach enables us to apply the sensor array to e- skins for bio-monitoring of humans and robotics. Next-generation applications of flexible electronics have been recently demonstrated such as transis- tors1–5, wearable devices6–12, skin-attachable sensors13–19, and electronic skin13–35 (e-skin).
    [Show full text]
  • Evaluating Whether Sight Is the Most Valued Sense
    Research JAMA Ophthalmology | Brief Report Evaluating Whether Sight Is the Most Valued Sense Jamie Enoch, MSc; Leanne McDonald, MSc; Lee Jones, PhD; Pete R. Jones, PhD; David P. Crabb, PhD Supplemental content IMPORTANCE Sight is often considered to be the sense most valued by the general public, but there are limited empirical data to support this. This study provides empirical evidence for frequent assertions made by practitioners, researchers, and funding agencies that sight is the most valued sense. OBJECTIVE To determine which senses are rated most valuable by the general public and quantify attitudes toward sight and hearing loss in particular. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional web-based survey was conducted from March to April 2016 through a market research platform and captured a heterogeneous sample of 250 UK adults ages 22 to 80 years recruited in March 2016. The data were analyzed from October to December 2018. MAIN OUTCOMES AND MEASURES Participants were first asked to rank the 5 traditional senses (sight, hearing, touch, smell, and taste) plus 3 other senses (balance, temperature, and pain) in order of most valuable (8) to least valuable (1). Next, the fear of losing sight and hearing was investigated using a time tradeoff exercise. Participants chose between 10 years without sight/hearing vs varying amounts of perfect health (from 0-10 years). RESULTS Of 250 participants, 141 (56.4%) were women and the mean (SD) age was 49.5 (14.6) years. Two hundred twenty participants (88%) ranked sight as their most valuable sense (mean [SD] rating, 7.8 [0.9]; 95% CI, 7.6-7.9).
    [Show full text]
  • Sensory Receptors - Specialized Neurons That Respond to Specific Types of Stimuli
    PSYCHOLOGY Chapter 5 SENSATION AND PERCEPTION Casey Cooper, Ph.D. SENSORY SYSTEMS Our sensory systems are responsible for providing information about our surroundings which allow us to successfully navigate and interact with our environments. If you were standing in the midst of this street scene, you would be absorbing and processing numerous pieces of sensory input. Figure 5.1 (credit: modification of work by Cory Zanker) SENSATION Sensory receptors - specialized neurons that respond to specific types of stimuli. Sensation – occurs when sensory receptors detect sensory stimuli. When sensory receptors detect a specific stimuli, they convert that energy into an action potential which is sent to the central nervous system. This is called transduction. Sensory systems: - Vision - Hearing (audition) - Balance (vestibular sense) - Smell (olfaction) - Body position (proprioception) - Taste (gustation) - Movement (kinesthesia) - Touch (somatosensation) - Pain (nociception) - Temperature (thermoception) (Credit: Jinx the monkey) SENSATION For a stimulus to cause an action potential, it first has to be strong enough to be detected. Absolute threshold – minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time. - On a clear night, the most sensitive sensory cells in the eye can detect a candle flame 30 miles away. We are also able to receive messages presented below the threshold of conscious awareness which are known as subliminal messages. - The stimulus causes an action potential but we are not consciously aware of it. Just noticeable difference (JND) –the minimum difference in stimuli required to detect a change or a difference between stimuli. - Can change depending on the stimulus intensity.
    [Show full text]
  • Beyond the View of Plants As Mere Machines: on Plant Sensation, Perception, and Awareness
    Beyond the View of Plants as Mere Machines: on Plant Sensation, Perception, and Awareness I‟ve always found plant behavior intriguing. Over the last six years of casual reading on it, starting with a college research report on the ill-named “Plant Neurobiology”, I learned more than I had imagined possible about the agency of plants (even after debunking misleading works such as The Secret Life of Plants). I learned that while plants do not possess a central nervous system, they nevertheless possess remarkable abilities of sensation, perception, and awareness. While these facets of life of course differ between plants and animals, plants nevertheless possess capacities for vision, olfaction, tactition, thermoception, and for detecting location, direction, and motion. Plants possess some forms of procedural memory, short-term memory, and long-term memory. They signal, communicate, and network with other organisms and species. They even wield a vascular system of awareness which some contrast to a central nervous system. All of these points serve to debunk the notion of plants as pure automata, as mere machines. But what, precisely, does that mean? Can a Plant “See”? Vision Without Eyes Plants can sense the ultraviolet spectrum, distinguish time of day based on sun, distinguish large and small light sources, distinguish parts of the light spectrum via phytochrome receptors, discern incoming light direction and duration as well as shadowing over themselves. Again, the decentralized rather than centralized nervous system: “If in the middle of the night you shine a beam of light on different parts of the plant, you discover that it‟s sufficient to illuminate any single leaf in order to regulate flowering in the entire plant.” [What a Plant Knows, p.20] Humans have rhodopsin detecting for light and shadow, and three photopsins for red, blue, and green, as well as cryptochrome for our internal clock.
    [Show full text]