\b([A-Z\s]+)\b

This doesn't work because the space in the character class means it matches the first single space in the line and returns that. You need to ensure that the match starts with an UPPER alpha, and then continues with UPPER alpha or space: 

print $data =~ m/(\b[A-Z][A-Z ]+\b)/;;
TEST SENTENCE

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Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

In reply to Re^2: Extract sequence of UC words? by BrowserUk
in thread Extract sequence of UC words? by Anonymous Monk

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