which

[Fractal]

On the GMAT, 'which' needs to be preceded by a comma else its use is incorrect.

Is this statement correct?

thx,
fractal

[e-GMAT]

"which" is typically followed by a comma (that is not followed by a comma). Its more or less a standard practice. But GMAT does not test this concept (may be because its too easy or may be when the choice comes between comma + which and that, it is too contextual). So you will not to asked to select the correct one from the following answer choices -
1 ..., which...
2 ...which...
3 ..., that...
4 ...that...

Also, which when preceded by a preposition does not require a comma.
I live in the house in which there is a large kitchen. CORRECT sentence
[/u]

[winniethepooh]

But, what about this sentence?
Even the correct answer choice has that preceded with a comma.

The use of lie detectors is based on the assumption
that lying produces emotional reactions in an individual
that, in turn, create unconscious physiological
responses.
(A) that, in turn, create unconscious physiological
responses
(8) that creates unconscious physiological
responses in turn
(C) creating, in turn, unconscious physiological
responses
(D) to create, in turn, physiological responses that
are unconscious
(E) who creates unconscious physiological
responses in turn

OA:A

[e-GMAT]

that is not preceded but followed by a comma here...

Nevertheless, the comma after that is not used to separate out "that". It is used to separate "in turn". "In turn" presents additional information that just adds some more context to the sentence.

Lying produces emotional reactions.
These emotional reactions , in turn, create unconscious physiological responses.

Hope this helps.
Also, while we are on this topic, do check out this blog post for more details on the topic of comma + that.

[winniethepooh]

oops, I missed that!
Thanks for the explanation!

[786]

What is that modifying here ?
Emotional reactions OR individual . And how do we identify this ?

[e-GMAT]

"That" modifies reactions. A few pointers for this determination:

First of all from the context, it only makes sense to say that lying produces certain reactions. These in turn create physiological responses.
Now from grammatical standpoint, 'that' cannot be used for humans. So grammatically it cannot point to "individual". Furthermore check out the plural verb - create in choice A. This verb agrees with subject "that" since "that" refers to plural reactions.

[priya2gupta5]

Also, while we are on this topic, do check out this blog post for more details on the topic of comma + that.

This was a nice one...thanks for sharing...

[confuse mind]

that is not preceded but followed by a comma here...

Nevertheless, the comma after that is not used to separate out "that". It is used to separate "in turn". "In turn" presents additional information that just adds some more context to the sentence.

Lying produces emotional reactions.
These emotional reactions , in turn, create unconscious physiological responses.

Hope this helps.
Also, while we are on this topic, do check out this blog post for more details on the topic of comma + that.

Thanks e-gmat for the concepts.

One small confusion - if 'that' refers to emotional reactions meaning-wise, should it not be 'those' plural for a plural noun?