Physiological Physiological Influences in Influences in PsychologyPsychology

Mapping Brain Functions from the Inside

• Hall

• Flourens

• Mike, the headless chicken

ExtirpationExtirpation

a technique for determining the a technique for determining the function of a given part of the function of a given part of the animal’s brain by removing it or animal’s brain by removing it or destroying it and observing the destroying it and observing the resulting behavior changesresulting behavior changes

Clinical methodClinical method

posthumous examination of brain posthumous examination of brain structures to detect damaged structures to detect damaged areas assumed to be responsible areas assumed to be responsible for behavioral conditions that for behavioral conditions that existed before that person died existed before that person died

Paul Broca

Broca’s areaUsed clinical methodPhineas Gage

Research on Brain Functions, Research on Brain Functions, mapping from the Outsidemapping from the Outside

Franz Josef Gall Franz Josef Gall (1758-1828)(1758-1828)

PhrenologyPhrenology SpurzheimSpurzheim

Luigi Galvani (1737-1798)Luigi Galvani (1737-1798)

Electric stimulation in the leg of a Electric stimulation in the leg of a frogfrog

Santiago Ramon y Cajal (1852-1934) Santiago Ramon y Cajal (1852-1934)

The Beginnings of The Beginnings of Experimental PsychologyExperimental Psychology

GermanyGermanyHelmholtzHelmholtzWeberWeberFechnerFechnerWundt (next chapter)Wundt (next chapter)

Herman Helmholtz (1821-1894)

Jack of all tradesInvented opthalmoscopeYoung-Helmholtz

Ernst Weber (1795-1878)

Just noticeable Differences: The smallest difference that ca be detected between two physical stimuli.

Two-Point Thresholds: the threshold at which two points can be distinguished as such

Gustav Fechner

• Dr. Mises• The effects of the

intensities are not absolute but relative to the sensation that already exists.

Thresholds

• Absolute threshold: the point of sensitivity below which no sensations can be detected and above which no sensations can be experienced.

• Differential Threshold: The point of sensitivity at which the least amount of change in a stimulus gives rise to a change in sensation.