Lecture 1: Introduction Flashcards
There are two traditions of psychological measurement. What are they?
Experimental tradition: Stimulus -> Response
Correlational tradition: Measurement of latent variables: no stimulus, measurement of traits.
Does psychological methods fall under the experimental or correlational tradition?
We’re in both; Psychological methods has its roots in psychometrics where we want to measure someone’s ability (e.g intelligence) as it is without manipulating anything.
How did psychology exist before it became a science?
Psychology is first part of philosophy and of the spiritual. It is believed that the soul or the mind cannot be part of science: it is
simply impossible to capture the mind in equations (the quantity objection). The mind was not of this world, but given to us by God and it is what distinguishes us from nature. However, there were huge triumphs in natural science, and human beings actually turned out to descend from apes. Maybe the human
being is a study object!
TLDR: Religion moment
Who was the founder of psychophysics and what is it?
Gustav Fechner (1801 – 1887): A physicist turned psychologist! It is the discipline that studied the relationship between external stimuli and sensations (physics and psychology).
How is psychophysics relevant to psychology today?
Physics was thus used as a model for psychological science. Psychophysics as bridge science between physics and psychology.
What units of measurements did Fechner use?
Just noticeable difference (jnd) as unit of measurement. Just noticeable differences are a measurement of sensation.
e.g adding weight until a person can notice a difference in the two
What is meant by Fechner’s Law?
There is a relationship as to when a person will notice the difference between two weights
(one of very few laws in psychology- still holds now)
Describe how Fechner carried out his jnd study
Fechner’s huge experiment: six standard weights (300, 500, 1000, 1500, 2000 and 3000 grams).
‘Each standard weights was judged to be heavier or lighter than a comparison weight [P (1 + 0.04] g or [P(1 + 0.080)] g. If Weber’s law was operative, then the proportion of “right” (correct) responses
should be identifiable for each of the six standard weights compared with the comparison weight [P(1 + 0.04)] g. The same prediction would
hold for the comparison weight [P(1 + 0.08)] g.’
It was in in a factorial design in which each comparison weight (.04 or .08) was applied in either an ascending or descending order and the weights were either applied to one hand or two hands. Within these conditions there was also conditions for which hand the weights get added to.
Finally, there was a way to take psychology out of the realm of philosophy and into science.
However, what question remained?
What was it that Fechner really measured?
•Can we call it psychology?
•Do we in fact measure the mental?
•What do we really measure when we say that a stimulus is heavier than another stimulus?
•How problematic is it that Fechner’s psychophysics relies on introspection?
Describe the beginning of the correlational tradition within psychology
Karl Pearson and Francis Galton invented regression and correlation. Suddenly there were statistical methods available that could be applied to behavioral data. Individual differences could now be quantified. They were also convinced
eugenicists: believed that these methods should be used for specific political and social purposes.
What was Francis Galton’s Idea of eugenics?
Who are the fittest? How can we create society that increases in genetic quality?
•Encouraging people to procreate that share desirable characteristics (high intelligence, ’good breeding’).
•Galton studied heredity: how traits could passed on from one generation to the next.
•Also the inventor of regression!
What did Charles Spearman contribute to the early days of experimental psychology?
Admirer of experimental psychology, but unimpressed by the lack of progress in experimental psychology.
•Inspired by Galton & Pearson, Spearman develops a measurement model based on correlational methods: the Common Factor Model
•Forms the basis of almost all psychometric models that have since been developed (factor models, IRT models).
•Wants to measure mental abilities as they are (so there’s no manipulation).
•Writes the famous 1904 paper: ‘“General Intelligence,” Objectively determined and measured.’
How do experimental psychology and correlational psychology differ in their definitions of measurement?
Spearman (correlational; psychometrics) does not use a very strict number of units to define intelligence; he uses correlations to extract someones level on a variable.
Who was James McKeen Cattell and what did he contribute to the field of experimental psychology?
American psychologist who trained with Wilhelm Wundt. Moved back to US and introduces psychometric measurement, and that’s when it all really lifts off!
Describe the complexity of psychological measurement in regards to science vs practice
- Scientifically, developing quantitative measurement for psychology proved an excellent method to make psychology more believable and reliable as a science.
- Practically, there was always a second motive: imagine the things (both good and bad) you can do when you can actually measure people’s skills!
