3 Assignments 1 Feed back paper

Unit 6A: Chapter 11 Notes

Adapted from History of Psychology: The Making of a Science (Edward P. Kardas, 2014)

Susanne Nishino, Ph.D. 2013

Chapter 11: Biological Psychology

History of Biology

• Aristotle one of 1 st

to study living things systematically

• By 19 th

century biology became scientific & empirical science, footsteps of physics & chemistry

• Invention of microscope revealed unknown living universe beneath threshold of vision

• Discovery of fossilized bones, geologists began to move age of earth from few 1000s to billions

• By end of 19 th

century science of biology completely transformed

• Darwin’s evolutionary theory provided unifying, explanatory structure for previously difficult to

explain phenomena

• Mendel’s research in genetics, rediscovered in 20 th

century, missing pieces to explain how

evolution worked at molecular level leading to biology’s modern synthesis, the union of

evolutionary & genetic theories in early 20 th

century

• Watson & Cricks model of DNA molecule in 1953, aided by Rosalind Franklins crystallographic

images, launched new era in biology during 2 nd

half of 20 th

century, began to delve into

machinery of life itself

Biological Psychology: Border with Biology

• Biologists study living things, living things change over time, exhibit greater variability, resist

easy theoretical explanations of underlying mechanisms compared to physics & chemistry

• Biologists inspired philosophers to link study of mind to study of physiology, study their

interaction

• Rise of biological psychology, border between biology and emerging science of psychology

beginning to be drawn

• By 17 th

century European scientist had begun to apply scientific methodology to study of living

things

• By 19 th

century scientific biology well established, systematically collecting & classifying living

things

• Mid-century Charles Darwin’s evolutionary theory provided biology with principle explanatory

theory: evolution

• Although modified, evolutionary theory remain at core of modern biological theory

• “Nothing in biology makes sense except in the light of evolution” (Dobzhansky, 1973, quoted p.

236).

19 th

Century Psychophysiology

• By end of 19 th

century, philosophers began to use biological methods to better understand how

human mind worked

• Psychophysiological research created 1 st

inklings of empirical psychology, over 19th century

biologists experimentally worked out mechanisms of nervous system

• Psychophysiology = the scientific study of the relationship between the physiological

mechanisms of the body & corresponding cognitive states

• Ernst Weber & Gustave Fechner pushed psychophysics, independently discovered the 1 st

psychophysical laws

– Weber’s Just Noticeable Difference (JND)

– Fechner’s new methods linked physiology to sensory experience

• George Romanes & C. Lloyd Morgan helped found comparative psychology the study of animal

behavior, placed human psychology along naturally occurring Darwinian continuum

• Francis Galton groundbreaking psychological studies included anthropomorphic measurements,

descriptions of genius, use of fingerprints for identification, use of normal cure & statistics to

describe human populations

William Harvey (1578 – 1657)

• Biology’s late but rapid ascent as empirical science began with book by William Harvey, “The

Motion of the Heart and Blood in Animals,” marked beginning of modern biology

• Combined close observation with empirical tests, 1 st

to observed that heartbeat composed of

two phases: systolic (contracts) & diastolic (relaxes & expands)

• Adapted empirical methods of science, applied to biology

• Research provided one of first steps toward modern biological science

• Earliest signs of psychology came shortly after, early psychologists linked discoveries about

machinery of body to correlated cognitive processes

• Before linkage occurred, preliminary question in biology itself had to be answered

• The answers to nearly all those biological question fell into place following publication of

Darwin’s Origin of Species 1859

Biology Before Darwin

• Slow & fitful, biblical dates, issue of immutability of species, discovery of extinct fossilized

animals

• Many mysteries unsolved well into 20 th

century, including movement of continents & changes in

face of the earth

• Linnaeus 1735 began taxonomy system: kingdom, phylum, class, order, family, genus, species

• Taxonomy = the discovery, naming, & classification of animals, plants, & other living things

Darwin’s Influence on Biology & Psychology

• Origin of Species argument for evolution & natural selection

• Provided biology with principle theoretical backbone, the evolution of organisms by means of

natural selection

• By end of 18 th

century biologists struggled to interpret new evidence accumulating

• Lamarck argued species changed according to own efforts during lifetimes, pass improvements

to offspring

• Embryologists discovered process of differentiation, early embryonic forms of divergent species

closely resembled each other

• Idea of natural selection came to him after reading Malthus’s essay on external limiters (wars &

famines) on unchecked human populations

• Realized that all animals & plants subject to similar limits

• Competition (natural selection) was key to organismic evolution

Charles Darwin (1809 – 1882): Evolution & Natural Selection

• Voyage of the Beagle, collected 1000s of specimens plants & animals

• Struggled to make sense of observation, believed species changed over time but could not come

up with mechanism neither god (creationist) or directive (led inevitably to humans as pinnacle of

evolution

• After reading Malthus, mechanism of natural selection came to him, Malthus argued human

populations could grow much faster than food supply, thus had to compete in order to stay alive

• Darwin applied same logic to all creatures

• Natural Selection = the competitive process by which organisms that are better adapted to

survive the environmental conditions around them survive, and thus reproduce more

successfully leaving more offspring, and gradually altering the population characteristics of their

own species

• “This preservation, during the battle for life, of varieties which possess any advantage in

structure, constitution, or instinct, I have called Natural Selection” (Darwin 1868, quoted p. 241).

• Discovered mechanism for how species could change over time that did not depend on a

creator, method was random, not directed

• Darwin estimate natural selection required time, at least 300 Million years

• Arrival of Alfred Russell Wallace, forced Darwin’s publishing of book

• Wallace independent ideas about organismic evolution,

• Wallace & Darwin jointly presented summaries of their theories

• Origin of Species forever changed biology, eventually major impact on early psychology

Biology: Union of Genetics & Evolution

• Issue of how changes of natural selection passed from generation to generation remained

incomplete

• Emergence of genetics & subsequent synthesis with evolutionary theory still in the future

• Darwin waffled over Lamarck’s idea of acquired characteristics, by last edition of book he

introduced Lamarck’s ideas as another possible evolutionary mechanism

• After biology’s modern synthesis, the union of genetics and evolution, after much research to fill

in gaps in data, evolution came to hold central position in biology, continues today

Evolution, Creationism, & Intelligent Design

• Creationism = the belief that God created all things in substantially the same form as they

presently exist and that they did not evolve from distant ancestors

– William Paley made case for creationism, used watch analogy

– Darwin’s theory provided new, non-creationist, and non-directed alternative to Paley’s

approach

– By early 20 th

century, American fundamentalist Protestants revived Young Earth

Creationist theory, literal interpretation of Christian scripture, earth 6,000 years old,

climax “Scopes Monkey Trial” 1925

– Similar laws against teaching evolution until 1968, forced opponents of evolution to

adopt different tactics, began to argue evolution only a theory, Creationism alternative

scientific account to Darwinian evolution, Supreme Court eventually ruled that creation-

science based on religion and not a science

• Intelligent Design = the theory that all living things on earth were created by a designer because

no other mechanisms can account for the observed complexity of nature

– Most recent attempt to block evolution theories, revives Paley’s watch metaphor, argue

“designer” created all living organisms

• Substantial opposition to evolutionary theory, especially in U.S., all share dislike of evolutionary

theory & implications, lack hard scientific evidence

• Modern evolutionary theorists contend natural selection & biological findings “including gene

transfer, symbiosis, chromosomal rearrangements, and the action of regulator genes . .. fits the

evidence just fine” (Scott, 2002, quoted p. 243).

Neuroanatomy & Psychophysics

• Evolution just one of advances in biology important to emergence of psychology

• Major role two new biological areas of study

– Neuroanatomy

– Psychophysics

• Neuroanatomy = the study of the structure & organization of the brain and nervous system

• Psychophysics = the study of the relationship between physical stimuli & their detection &

interpretation by the conscious & unconscious mind

Neuroanatomy

• Scientific interest in neuroanatomical topics began to rise in early 19 th

century

• Two subcategories, organization of the brain & spinal cord along with relationship to senses to

the brain, lead to active present day areas of research in physiological psychology

• Another 19 th

century category, phrenology, did not survive to present

Franz Joseph Gall (1758 – 1828): Phrenology

• Interested in physiognomy study of the relationship between face and body & person’s behavior

• Fundamental assumptions

– Brain was organ of the mind

– Mind was organized into faculties that changed through experienced, would cause skull

to change shape

• Exerted effect on physiology, popularized idea brain controlled behavior, different parts of brain

responsible for specific functions, easier to promote empirically based theories of

neuroanatomy

• Popularity made it easier for people to accept new ideas about organization of brain & spinal

cord and functional relationships between the sense & the brain

Organization of the Spinal Cord

• Early 19 th

century, Sir Charles Bell (1774-1842) and Francois Magendie (1783-1855)

independently discovered organization of spinal cord by conducting experiments on animals

• Resulting Bell-Magendie Law = the role of the neural fibers that exist the exit the spinal cord on

its ventral side is to communicate commands from the brain and spinal cord to the body, role of

neural fibers that enter spinal cord on dorsal side is to communicate information coming from

the senses to the brain & spinal cord

• Late 19 th

century Gustav Fritsch (1838-1927) and Edvard Hitzig (1838-1907) experimentally

demonstrated that specific regions in the cortex responsible for motor movements, cortex was

topographical organized representation of body in the brain

• Beginnings of understanding intricate mechanisms of the body

Johannes Muller (1801 – 1858): Communication between the Senses & the Brain

• Johannes Muller’s Law of Specific Nerve Energies another important physiological discovery

• Law states that what is perceived comes from action of nerves and not from physical objects

that stimulate sense organs, implied that the mind is aware only of own activity, not the physical

world around it

• Muller published book on the relationship between physical world and mental activity it

stimulated, argued it was the action of nerves terminating at specific locations of the brain that

caused people to perceive things

• Muller had discovered that all the sense organs were organic transducers = in physiology,

transducers are the specialized organs, such as the eye & ear, that convert physical energy into

neural information

• Transducers took in physical stimulus such as light & sound, then transformed into neural

activity, sense organs all spoke the same language & brain could understand it regardless of

where it originated in any sense organ

Muller: Vitalism

• Muller = our minds access only to nervous energy plus innate tendencies of mind construct the

work, how manage became business of psychology for 100 years & non-behaviorist psychology

to today

• Muller vitalist, believed that living things possessed life force of their own, life force unknown

substance that made different from inanimate objects, somehow conferred life

• Vitalism = the doctrine that physical & chemical forces alone are insufficient to explain living

things, an additional and unknown life force is required

Hermann Helmholtz (1821-1894)

• Took exception to Muller’s vitalism, searched for strictly physical & non-vitalist explanations for

biological processes

• Midcentury succeeded in measuring speed of nerve impulses, discovered they are slow (approx

60 miles per hour), went on to discover basic facts about workings of body

• One of most important scientists of 19 th

Century

• Helmholtz’ scientific contributions would help overturn nature philosophy

• Joined Berlin Physical Society dedicated to providing strictly physical explanations for biological

phenomena, mechanistic views

• 1847 published important finding on conservation of energy, clearly explained & mathematically

demonstrated heat & energy equivalent & neither destroyed, relationship now called 1 st

Law of

Thermodynamics

Helmholtz: Psychophysics Pioneer

• Two subsequent important discoveries

– Measurement of speed of nerve impulse

– Development of ophthalmoscope, instrument permitted to see into the living human

eye for the 1 st

time

• Also important contribution to physiology of vision was theory of color perception, amplified

Thomas Young’s earlier ideas to create Young-Helmholtz trichromatic theory of color vision,

humans perceive color because of simultaneous activity of three types of visual receptors, cones

of the eye, activity of millions of cones tuned to red, green, or blue make color vision possible

• Also studied physics of sound & physiology of the ear, developed instruments to aid in

physiological research, pioneered study of psychoacoustics, student Heinrich Hertz (1857-1894)

extended Helmholtz’s early steps beyond sound into the study of radio waves and other

oscillating phenomena

• Also published on physical & mathematical topics including vortex motion, hydrodynamics, &

non-Euclidian geometry (allow parallel lines to touch), broke with Kant’s conception of space,

came to believe humans learned about nature of space through experience

• Laid earliest foundation of 20 th

century modern physics,

Observation, Sensation & Perception : Experimental Psychology

• By early 19 th

century, astronomers realized must correct previously unknown & large systematic

errors in observation, had previously assumed all observers were consistent in timing of transits,

• Friedrich Bessel (1784-1846) 1 st

to realize discrepancy between observers & that it was

involuntary, notices transits between two observers showed consistent differences, wondered

whether any two experienced astronomers would show similar differences, led Bessle to

develop personal equation = correction factor between two observers

• Astronomers began to search for new methods & equipment for conducting reliable

observations,

• solution with the development of chronograph clock lined to pen & paper recording device,

• Astronomer’s 1 st

to realize observations each made were not the same

Experimental Psychology

• Early psychologists became interested “after 1880 . . . Professional astronomers realized that

the question of the psycho-physical basis for personal error had been taken out of their hands . .

. A new science had come into existence; the science of experimental psychology” (Duncombe,

1945, quoted p. 248)

• Frithiof Holmgren (1831-1897) devised color blindness test, discovered 5% color blind, again

demonstrated that traditional assumptions about human perception in error

• By end of 19 th

, research in psychophysics overturned older assumptions about similarity &

consistency in human perception

Scientific Psychophysics: Physical Stimuli, Human Perception, Experimentation & Measurement

• Psychophysics one of psychology’s oldest areas, still active field of research

• Germans Ernst Weber & Gustave Fechner 1 st

to experiment systematically in psychophysics

• Weber’s Just Noticeable Difference (JND) discovery foundation of psychophysics

• Fechner put psychophysics on map, provided methods for conducting research, methods still

used today

• Historical importance of psychophysics it marked the 1 st

self-conscious attempt to create a

scientific psychology, one that attempted to measure variables as precisely as the physical

variables of physics & chemistry

Ernst Weber & the JND

• Research on the relationship between physical stimuli & human perception, helped give rise to

science of psychophysics

• Research concerned sensitivity to physical stimulus

• Discovered relatively consistent lawful relationship between given level of physical stimulation

& necessary difference in stimulation required for someone to report that they sensed the

difference, amount vary according to intensity of physical stimulus 1 st

presented, if small then

only small additional amount sufficient, if large then larger amount needed

• Called variable Just Noticeable difference (JND), afterwards noticed he could predict how much

more or less new physical stimulus had to for someone to notice the changes, noted each

sensory modality followed same pattern but sensitivities not the same, same mathematical

relationship held, Fechner later called this discovery Weber’s Law

• Weber concentrated on skin senses, also discovered “two point threshold” and the more objects

weighed, the more they had to be large in order to tell difference

• Discovery foundation of psychophysics, application of physical methods to the study of human

behavior

Gustav Fechner (1801-1887): Methods & Data

• Put psychophysics on the map, provided methods for conducting research still used today

• Psychological tasks detection, identification, discrimination, thresholds, reaction time,

comparative psychophysics

• Psychophysics = 1 st

self-conscious attempt to create scientific psychology that attempted to

measure psychological variables as precisely as had been physical variables of physics &

chemistry

• Published original research in electricity

• Concern to demonstrate unity of mind & body, inspired 1850 to develop scientific program

designed to make “the relative increase of bodily energy the measure of the increase of the

corresponding mental intensity” (Boring, 1950, quoted p. 252)

• Next 10 years worked tirelessly in area of psychophysics, set out 1 st

full set of methods &

corresponding data for what would become psychology’s 1 st

subject area

• Conceived two separate related types of psychophysics

– Outer psychophysics, relationship between mind & stimulus

– Inner psychophysics, relationship between stimulus and subsequent activity of nervous

system

• To research outer psychophysics developed three method: Limits, Constant Stimuli &

Adjustment

• Fechner’s methods especially useful for analysis of absolute & relative thresholds

– Absolute – least amount of sensation a person can detect

– Relative – detect smallest difference of sensation

• Realized needed to control for variations due to individual differences & chance variables,

introduced use of averages to balance differences

• In method of constant stimuli, randomly presented stimuli from chosen set, also presented

standard invariant stimulus

• After pioneering psychophysics, turned to scientific study of aesthetics

• Attempted to settle two city’s dispute by using opinion polls, unsuccessfully attempted to apply

statistical methods to settle dispute,

• 1 st

to put psychology on scientific footing, at same time animal (comparative) psychology

inspired by Darwinian emerging

Animal Intelligence, Comparative Psychology: Border with Biology

• One main controversy inspired by Darwin-Wallace theory of evolution was issue of continuity

• Continuity = the idea that all living things are related to each other in some degree

• Theory of evolution made human beings just another species rather than final, perfect product

of Aristotle’s scale of nature

• Adoption of continuity by scientists late in 19 th

opened door to study of animal psychology

• Darwin pioneered that subfield, George Romanes follower of Darwin popularized idea of

studying animal intelligence

• C. Lloyd Morgan Romanes, revised much of his work, interpreted monkey behavior cautiously,

had learned

• Morgan’s Canon = “In no case may we interpret an action as the outcome of the exercise of

higher psychical faculty, if it can be interpreted as the outcome of the exercise of one which

stands lower in the psychological scale”

• Comparison of animal intelligence & human intelligence disappears as psychological topic until

revival late in 20 th

century

• Comparative psychology part of early psychology that grew out of border with biology

Francis Galton (1822-1911): Psychometrics & Nature vs. Nurture

• Scientific study of animals, their minds, & their behavior on gave way to more practical

approach to an applied human psychology

• Origins of still dominant approach in seminal work of Darwin’s half cousin – Galton

• Darwin’s book led Galton to formulate theory of human intelligence based on heredity

• Questionnaires designed to uncover relationship between family kinship & worldly success

• Believed he had shown intelligence inherited

• Coined phrase “nature vs. nurture”

• Argued human intelligence mostly due to nature

• Turned to study of mental associations, came to believe that much of operation of mind hidden,

below level of consciousness

• Also turned to study of mental imagery, discovered that people exhibited wide range of

variation in ability to visualize images

• Set up laboratory, collected data from over 9,000 people, paid small fee

• Measured 17 physical & mental human characteristics, discovered many measurements he

made were normally distributed

• Hardly any of statistical techniques familiar to modern psychology existed then, Galton one of

1 st

to develop techniques, responsible with Karl Pearson for developing correlation coefficient,

regression line, concept of regression to the mean, median, & percentile

• Obsessed with trying to measure everything = father of psychometrics

Psychometrics: Applied Psychology

• Galton’s pioneering efforts in measurement of human abilities evolved into one of psychology’s

largest applied areas: psychometrics

• 1 st

breakthrough work of Alfred Binet, Theodore Simon, later Lewis Terman

• Work in measuring IQ of child led way to additional IQ tests for adults & preschoolers by David

Wechsler

• Today testing industry produces 1000s of psychological tests

• Students today accustomed to taking professionally designed standardized tests

Probability & Statistics

• 19 th

century fertile ground for development of probability & statistics

• Friedrich Gauss demonstrated utility of normal distribution for predicting observational errors

• Adolphe Quetelet described “average man”

• Francis Galton originated quartile

• Pearson built on Galton concept of regression to introduce correlation coefficient, later

developed chi-square statistics

• Many familiar statistical tools & concepts vital today origin during 19 th

century

Galton: Seeds of Applied & Behaviorism

• Also 1 st

meteorologist, use of fingerprints as method to identify, 1 st

to closely study & classify

fingerprints, one of direct sources for modern applied forensic psychology

• Near end searched for genetic mechanisms behind inheritance, failed to find them

• Coined term “eugenics” = “science which deals with all influences that improve the inborn

qualities of a race; also with those that develop them to the utmost advantage.”

• Failed to grasp importance of learned & environmental variables in psychology, assumed that

Europeans were genetically superior to all others in the world

• Much of his version of psychology, mathematical & hereditarianism, has persisted in modified

form

• Ideas of evolutionists colleagues lay dormant for decades, before ideas could rise again in form

of Behaviorism, truly original & introspective based psychology had to arise & run its course

Ideas

• Scientific study of biology breakthroughs in elucidation of machinery of the body

• Harvey’s description circulation of blood, spinal cord organization, sense organ transducers,

speed of nerve impulse, mechanisms of color vision

• Theory of evolution, reconciled older speculations about speciation, geological time, taxonomy,

& continental drift

• Later rediscovery of genetics combined with natural select led to biology’s modern synthesis

• Older concepts such as vitalism & Lamarckianism, also phrenology, fell to weight of empirical

data

• Psychophysics became 1 st

psychology subdiscipline, absolute & relative thresholds discovered,

new methods developed to study perception, limits, constant stimuli, adjustment

• Began to study animal thinking & behavior, led to comparative psychology

• Galton 1 st

steps in study of psychometrics, eugenics, forensic psychology, & statistics

Summary

• Biology origins in Greek medicine & Aristotle

• Harvey 1 st

modern biologist, slowly became science following Linneaus, Darwin set biology on

current course, completed altered biology, & later psychology

• By 20 th

century, biologists used Darwin’s evolution theory to explain many mysteries, aided by

modern synthesis of biology which combined Darwin & Mendel’s work

• 19 th

century progress in neuroanatomy understanding of spinal cord & how senses

communicated with brain, Helmholtz especially contributed with research on speed of nerve

conduction & perception

• 19 th

century progress in psychophysics, Weber & Fechner measure physical stimuli &

corresponding effects on perception, each independently developed 1 st

psychophysical laws and

research methods still used today

• Late 19 th

century two other areas of biology developed in psychology, comparative psychology &

psychometrics

• Comparative psychology extended discipline into animal kingdom, helped lay groundwork for

Behaviorism

• Galton developed psychometrics, now one of the largest areas of 21 st

century psychology