Self-study
Galanin is a protein found in the brain. ██ ██ ███████████ ████ ████ ████████████ █████ ██ ███ █████ █████ ████ ███████ █ ██████ ███████ ████ ███ █████ █████ ████ █████ ██ ████ █████████████ ██████ ██████████████ ██ ███████ ██ █████ ██████ ████ ███ ████ ████ ████████████ █████ ████ ████ █████ ██████ █████ █████ ████████ ███████ ███ ██████████ ████ ███████ ██████ ████ ██ █████ █████ ██████
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that galanin makes rats crave fatty foods. Why? Because an experiment showed a correlation: rats who preferred fatty foods also had higher galanin concentrations in their brains.
Notable Assumptions
The author assumes the correlation results from one particular causation: that lots of brain galanin causes rats to crave fatty foods. This means assuming there’s no other cause for that correlation, such as the reverse causation: that eating fatty foods causes galanin to build up in rats’ brains.
20.
Which one of the following, ██ █████ ████ ████████ ███ █████████
a
The craving for █████ █████ ████ ███ ██████████ ██████ ██ █ █████ ████████ █████ █████ ████ ████ ██████
This doesn’t affect the argument. Rats could have “consistently” chosen fatty food without choosing it every single time.
b
The brains of ███ ████ ████ ████████████ █████ ██ ███ █████ █████ ███ ███ ███████ █████████████ ████ ███ ████ ███ ███ ██████ ██ ████ ████ ████████████ █████ ████ ██████
This is irrelevant. The author makes no claim about fat inside the rats’ brains—only the fat in their food and the galanin in their brains.
Failed alternate explanation
Failed alternate explanation
Weaken Qs: Answers that try to introduce an alternate explanation, but fall short, or try to explain a different phenomenon.
Strengthen Qs: Answers that try to eliminate an alternate explanation, but fall short, or try to eliminate an explanation for a different phenomenon.
c
The chemical components ██ ███████ ███ ███████ ██ ████ █████ █████ ███ ████ ██████
This doesn’t mean the fatty and lean diets contained similar amounts of galanin. This is fully compatible with the reverse causation: the rats who preferred fatty foods simply consumed more galanin in their diets.
d
The rats that █████████ █████ █████ ███ ███ ██████ ██████████████ ██ ███████ ██ █████ ██████ ██████ ████ ████ ███████ █████ ██████
This strengthens the argument by casting doubt on an alternative explanation. It makes the reverse causation—that rats had lots of galanin in their brains because of their high fat intake—less likely.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
e
Rats that metabolize ███ ████ ███████████ ████ ██ █████ ████ ███████ ████ ██████████████ ██ ███████ ██ █████ ███████
This detail is compatible with the conclusion, but it doesn’t strengthen the argument. It’s just as compatible with the reverse causation: rats who metabolize fat less efficiently crave fattier foods, and that higher fat consumption causes galanin to build up in their brains.