<p>Famous psychologists have proven their theories on a few subjects (really small sample sizes, like n = 3). Yet, now, we are taught that to prove any psychological theory right, we need to gather data from many subjects (with tongue-in-cheek: above 30). But seriously... (here's the question I'm asking):</p>
<p><strong>Q:</strong> is it somehow unscientific or wrong to only show a psychological theory with so small sample size such as n = 1 (one person, but many measurements on him/her)?</p>

CC BY-SA 4.0
2021-03-16T11:03:17.877Z
Which psychologists are you referring to? I'm aware of several who *used* just a few subjects to introduce theories which then turned out to hold some substance, but not of any who *proved* (read "justified") anything in the proper statistical sense...
David Cian
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2021-03-17T10:45:38.537Z
@DavidCian Skinner, Piaget...
Lil'Lobster
CC BY-SA 4.0
2022-07-17T08:07:13.340Z
Can you give an example of a proven theory in psychology? I am afraid you are actually speaking about psychologists who have constructed scientific hypotheses, not ones who have proven anything.
drabsv
<methodology><experimental-psychology><statistics>
Can you prove a psychological theory on a one-person research design?
Lil'Lobster
# Can you prove a psychological theory on a one-person research design?

(Asked by: username_0 on 2021-02-27)

Famous psychologists have proven their theories on a few subjects (really small sample sizes, like n = 3). Yet, now, we are taught that to prove any psychological theory right, we need to gather data from many subjects (with tongue-in-cheek: above 30). But seriously... (here's the question I'm asking):

**Q:** is it somehow unscientific or wrong to only show a psychological theory with so small sample size such as n = 1 (one person, but many measurements on him/her)?

**Tags:** methodology, experimental-psychology, statistics

> **Comments:**
> **username_1**: Which psychologists are you referring to? I'm aware of several who *used* just a few subjects to introduce theories which then turned out to hold some substance, but not of any who *proved* (read "justified") anything in the proper statistical sense...  
> **username_0**: @DavidCian Skinner, Piaget...  
> **username_2**: Can you give an example of a proven theory in psychology? I am afraid you are actually speaking about psychologists who have constructed scientific hypotheses, not ones who have proven anything.  

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## 0 answers

