#16 - Herpetologist: Some psychologists attribute complex

[Jonathan Evans]

hi, Lathlee,

Good question. Let's discuss Assumption Negation here. Notice Answer Choice (D) has to do with conditional reasoning. If you are to negate a conditional implication, you need to consider what such a negation would mean.

Let's consider the following:

If John's a farmer, New York is a big city.

Great conditional there. Now what would it mean to negate it? Quick review:

If John's not a farmer, New York is a big city.

Nope. That doesn't work. Not negated. We've negated the sufficient condition, but who cares? Our necessary condition can still be true! However, check this out:

If John's a farmer, New York is not a big city.

Yes! That's where the problem is. We have negated the necessary condition thereby rendering the whole conditional statement definitely untrue.

Apply this logic to answer choice (D) with the Assumption Negation Test. First remember the conclusion:

~Make major changes in behavior ~complex reasoning

contrapositive: complex reasoning make major changes in behavior

Now let's negate Answer Choice (D):

"If Reptiles were capable of complex reasoning, they would NOT sometimes be able to make major changes in their behavior."

not sometimes never

"If Reptiles were capable of complex reasoning, they would never be able to make major changes in their behavior."

complex reasoning ~make major changes in behavior

This negated answer choice directly contradicts our conclusion:

complex reasoning make major changes in behavior

Thus, our conclusion is impossible, and answer choice (D) is the credited response.

[adlindsey]

I had this one between A & C. I had a hard time understanding the 1st sentence at first. Two questions: Could A, also be wrong because it refers to animals, and not reptiles? And, When using the negation technique on a conditional, would we always JUST negate the necessary condition, and NOT the sufficient?

[Adam Tyson]

Thanks for the question, adlindsey - let me see if I can add some clarification for you.

The problem with A is that it's backwards - it's a mistaken reversal of what we need. Our author's argument is "no major changes, so no complex reasoning". He is assuming that if they were capable of complex reasoning, they would make (or be able to make) major changes. In other words:

CR -> MC (or if you prefer, the contrapositve, MC -> CR

A is the opposite of that assumption:

MC -> CR

As to negating a conditional claim, since you are trying to make the answer untrue when you negate it, all you are doing is saying that the necessary condition is not, in fact, necessary. So, if I am negating the claim "if you are a bad child, you will get coal in your stocking", I want to show that coal is not necessary. I could do that by saying "you won't get coal in your stocking even if you are bad" or perhaps "if you are bad you still might not get coal in your stocking." Don't negate the sufficient condition, because then all you are doing is creating a Mistaken Negation, rather than showing that the necessary isn't necessary. "If you are not bad you won't get coal" does nothing to negate the truth of the original claim!

I hope that helped. Good luck!

[sdb606]

I'd like to contribute my own explanation for why E is wrong. Negated E seems to support the psychologists by showing that complex behavior can explain food gathering. However, the problem with E is it's too broad. Even if complex behavior could explain food gathering, it doesn't necessarily mean it explains that behavior in REPTILES. The herpetologist could dismiss negated E by saying it doesn't apply to reptiles. So negated E doesn't necessarily support the psychologists or weaken the herpetologist's argument.

[pelusolakes]

Isn't B a necessary assumption?

The negation of "simple stimulus-response explanations can in principle accounts for all reptile behaviour" is "stimulus-response explanations cannot account for all reptile behaviour"

If it were the case that simple-stimulus response explanations cannot account for all reptile behaviour, wouldn't it make the author's argument [that psychologists are wrong to believe that simple-stimulus explanations cannot account for all reptile behaviour] invalid? Isn't the very possibility that simple-stimulus response explanations can account for all reptile behaviour required (i.e. a necessary assumption) in order for the author to make his argument?

I'm disappointed that I ruled out answer choice D because I thought it was a trick; it seems to be a sufficient assumption, one that would fully and totally justify the conclusion that the author makes.

[Rachael Wilkenfeld]

One potential issue with your analysis, pelusolakes, is that the argument doesn't establish that the only possibilities are simple stimulus-response or complex reasoning. So if there's a behavior that isn't explained by simple stimulus-response but ALSO isn't complex reasoning, answer choice (B) would not prove the conclusion.

There's another issue with answer choice (B) here---just because simple-stimulus responses could explain a behavior doesn't mean that it does explain that behavior. For example, imagine a person hopping up and down holding a foot. That behavior could be a simple stimulus-response if they stepped on a nail or something hot. However, it could be part of complex reasoning, if they are hopping in order to win a challenge on TikTok.

We need to figure out what is required to know that reptiles are incapable of complex reasoning. The author choreographs this for us in the final sentence where they jump from incapable of making major alterations in behavior to incapable of complex reasoning. It's necessary to know that you can make that jump. That's why answer choice (D), the contrapositive of that suggested conditional, is the correct answer.