PHYSIOLOGICAL INFLUENCES ON PSYCHOLOGY CH 3 Lecture Prepared

PHYSIOLOGICAL INFLUENCES ON PSYCHOLOGY CH: 3 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

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=80 d. Z 71 Km 6_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

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