Physiological Influences on Psychology Lecture Prepared by: Ms. Wilson, MS, LPC

The Importance of the Human Observer David Kinnebrook: Assistant to Reverend Nevil Maskelyne, the Royal Astronomer Worked at the Royal Observatory (Greenwich, England) Job was lonely, tedious, and highly demanding Noted times of star movements

Friedrich Wilhelm Bessel 1784-1846 David K. Makes a Mistake: The Importance of the Human Observer (cont’d.) 20 years later: Bessel: investigated David K’s errors “Personal equation”: there are personal differences among people over which they have no control Two conclusions: Astronomy affected by the human observer Human observer is important to all sciences Friedrich Wilhelm Bessel 1784-1846

Developments in Early Physiology Antecedents: Johannes Muller (1801-1858) Handbook of physiology of mankind Specific energies of nerves Example: stimulating the eye with different objects Specific Irritability-Adequate stimulation Johannes Muller (1801-1858)

Developments in Early Physiology (cont’d.) Research on brain functions: mapping from the outside Franz Josef Gall (1758-1828) Does the brain size and shape reveal any information? Proposition: Larger brains were more intelligent? Phrenology: belief that mental characteristics correspond to bulges on the skull

Phrenology Every psychological function is dependent on specific region of the brain Mind can be meaningfully and satisfactorily analyzed into thirty seven faculties Johann Spurzheim Popularized the practice of phrenology with books and demonstrations of its uses. https://www.youtube.com/watch ?v=80dZ71Km6_g

Developments in Early Physiology Research on brain functions: mapping from the inside Attempts to determine brain function Extirpation Clinical Method Electrical Stimulation

Research on brain function High interest in brain localization functions Pierre Flourens (1794-1867) professor of natural history in Paris Brain acts as a functional entity used extirpation Cerebral hemisphere was responsible for higher cognitive functions.

Developments in Early Physiology Research on brain functions: mapping from the inside Marshall Hall (1790-1857) Observed movements of decapitated animals Different levels of behavior arise from different parts of the brain and nervous system Voluntary movements Respiratory movements Involuntary movements Reflex movements Marshall Hall (1790-1857)

Research on brain function . Paul Broca (1824-1880) 1861: the clinical method Using the clinical method (observations in the clinical setting), they were able to localize language and communication functions in the brain. Case of Patient Tan Broca’s area: speech center

Research on brain function Gustav Fritsch and Eduard Hitzig 1870: electrical stimulation method Set out to electrically stimulate the cortex of a dog. Exposed the surface of the dog’s cerebral cortex and applied galvanic stimulation. stimulation of certain cortical areas results in motor responses This was considered as the beginning of modern neurophysiology

Developments in Early Physiology (cont’d.) Research on the nervous system Luigi Galvani: found that nerves are electrical Ramon y Cajal: discovered the direction of travel for nerve impulses He received the Nobel prize in physiology for the Neuron doctrine in 1906.

The Beginnings of Experimental Psychology Scientists responsible for initial application of experimentation to mind Hermann Helmholtz Ernst Weber Gustav Fechner Wilhelm Wundt

The Beginnings of Experimental Psychology Experimental psychology begins in Germany The German approach to science: Emphasis on the careful, thorough collection of observable facts Welcomed the study of biology when other nations did not The reform movement in German universities: Freedom unknown to other nations More resources as compared to Cambridge and Oxford More research universities John Hopkins University (1876) was the first research university in the US.

Hermann von Helmholtz (1821-1894) : His life Born in Potsdam, Germany 1838: enrolled at a Berlin medical institute Seven years as army surgeon continued to study mathematics and physics published articles Emphasized mechanism and determinism Assumed human sense organs functioned like machines

Hermann von Helmholtz (1821-1894) Principle of conservation of energy Invented ophthalmoscope Helmholtz’s contributions to the new psychology: Investigated the speed of the neural impulse: Used nerves of different lengths and recorded the delay between stimulation and muscle reaction Found that neural impulses travel at a rate of 90 ft. per second Nerve impulses are measurable and slow

Hermann von Helmholtz (1821-1894) Sensations are raw elements of experience and perceptions are sensations after given meaning by the person’s past experience. To explain the transformation from sensation to perception dependent he relied on the ideas of unconscious inference of past experience.

Hermann von Helmholtz (1821-1894) Research on vision and hearing Young Helmholtz theory of color vision Proposed three types of color receptors corresponding to the three primary additive colors The firing of these receptors in various combinations results in subjective color experiences corresponding to various wavelengths of light. Theory of auditory perception

Earnest Heinrich Weber (1975-1878) Obtained his doctorate from University of Leipzig. Interested in the physiology of the sense organs Demonstrated that sense of touch involves several senses

Ernst Weber (1795-1878) Researched physiology of the sense organs Two-point thresholds: the threshold at which two points of stimulation can be distinguished Just noticeable difference: the smallest difference that can be detected between two physical stimuli Just noticeable difference is a constant fraction of the standard weight. Drew attention to the experimental method

Weber’s Law

Gustav Theodor Fechner (1801-1887) (cont’d.) Fechner’s life: Born in southeastern Germany Translated texts, introducing him to physics Professor at Leipzig Plagued with many illnesses Eventually cured of his ailments and lived a long life

Gustav Theodor Fechner (1801-1887) (cont’d.) Mind and body: a quantitative relationship Stimulus increase does not produce corresponding increase in sensation Relationship not one-to-one Amount of sensation depends on amount of stimulation Absolute threshold Differential threshold S=K log R

Gustav Theodor Fechner (1801-1887) (cont’d.) Methods of psychophysics: Fechner introduced psychophysics: the scientific study of the relations between mental and physical processes Examples of experiments: lifting weights, visual brightness, visual distance, tactile distance Method of average error (or method of adjustment) Method of constant stimuli Method of limits