Logical Reasoning

PT137 · S4 · Q18 Psychologist: Birth-order effects

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Psychologist: Birth-order effects, the alleged effects of when one was born relative to the births of siblings, have not been detected in studies of adult personality that use standard personality tests.

Conclusion

Birth-order has no lasting effect on personality; it just affects how a sibling's behavior is perceived.

Evidence

If you test adults using standard personality tests, then birth-order does not seem to have any effect on personality.

But if you test adults by asking for responses from parents and siblings, you'll notice differences based on birth order.

Evaluate

This is a He Said / She Said type argument. The author presents two different things that have different views on a subject. She then arbitrarily acts like one of them is the correct view, without justifying why that view has more credibility than the conflicting view.

We usually see this in Flaw:

How do we know the newer studies are correct and old ones are wrong? Does "newer = more likely correct"?

In this argument, does "standard personality test = probably the correct data", whereas "asking parents / siblings = less trustworthy data"?

Goal

Look for an answer saying that the author assumes the standard personality test provides more accurate data than the interviews with siblings and parents do.

18.

Which one of the following is an assumption required by the psychologist's argument?

  1. Correct

    Standard personality tests will detect

    Why this is right

    Our author is assuming stuff much stronger than this, but that still means that she's assuming this. i.e. If I'm assuming that "Tony has at least 20 bucks" then I'm also assuming that "Tony has at least 10 cents". Our author is assuming that standard personality tests are a better source of data than are parents' and siblings' reports. In order to assume that, you'd have to assume that standard personality tests are even capable of measuring the thing we're asking them to measure. If we negate this answer, it's saying that if there is such a thing as birth-order effects on personality, a standard personality test will detect none of them That negation would badly weaken the argument, since it would make the standard personality test (which the author is trusting) sound like a totally worthless measuring instrument, since it would not be able to detect the phenomenon we're looking for.

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

    63% picked this

  2. The behavior patterns people display

    Too Strong: significantly different

    The author doesn't need to assume that people act at all differently around family vs. around other people. She could be content saying "sure, we act the same around everyone, but parents and siblings will perceive that behavior differently, including assigning some made up birth-order effect to that behavior".

    6% picked this

  3. Parents' and siblings' perceptions of

    Too Strong / Specific

    Too Strong / Specific: tend not to change "Tend to" = "most of the time" = "in more than 50% of cases". Words that mean "most" are wrong 99% of the time on Necessary Assumption, because when you negate "most" you're really just going from thinking something occurs 51% of the time to thinking it's true only 49% of the time. Big whoop. If we negated this answer and said, "actually parents' and siblings' perceptions of a family member's personality only change between early childhood and adulthood about 49% of the time", would that change anything about the author's argument? No. Our author had no position on whether the perception of birth-order effects held by parents and siblings was a constant perception throughout life vs. a changing perception as the family member went from kid to adult. It wouldn't make a difference either way to the author's argument.

    15% picked this

  4. Standard personality tests have detected

    Strengthens, Not Necessary

    If true, this answer somewhat strengthens, since it shows us what (A) is saying -- standard personality tests can detect birth-order effects when present. But does this author need to assume that standard personality tests have detected effects in younger children? No. Her conclusion allows for the idea that there are initial birth-order effects, because it says "birth order has no lasting effect". But we interpret that as, "If there's any effect, it's not lasting". We don't interpret that as, "There is an initial effect, but it wears off." So it wouldn't hurt the author's argument if standard tests had never detected birth-order effects in younger children.

    2% picked this

  5. Parents and siblings have accurate

    Opposite

    Our author is trusting standard personality tests to be the accurate voice in this conversation. Her final claim is a mildly dismissive idea that the perceptions parents and siblings have about supposed birth-order effects are "merely how the behavior is perceived".

    14% picked this

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