Joe Biden Scoffs When Asked If He Has Taken a Cognitive Test: 'Why the Hell Would I?'

ANDREW CABALLERO-REYNOLDS/AFP via Getty Images Former Vice President Joe Biden

Former Vice President Joe Biden dismissed a question this week about whether he has taken a cognitive test — an issue President Donald Trump pushed into the spotlight while boasting of his mental capabilities and attacking Biden.

The Democratic presidential candidate was asked about the test by CBS News' Errol Barnett during a recent appearance at the convention for the National Association of Black Journalists and National Association of Hispanic Journalists (which is set to air in full on Thursday).

Biden, 77, compared the question to being tested for drug use for no reason.

"No, I haven't taken a test. Why the hell would I take a test?" he said during a clip from the interview, shared by CBS This Morning.

"Come on, man," he continued. "That's like saying you — before you got on this program, you take a test where you're taking cocaine or not. What do you think? Huh? Are you a junkie?"

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When Barnett followed up with a question about Trump's touting of his own "unbelievable" results on a cognitive test last month, Biden laughed. (Despite Trump's insistence that his test was difficult, reporters pointed out that it covered basic memory and other mental skills like identifying animals.)

"Well, if he can't figure out the difference between an elephant and a lion, I don't know what the hell he's talking about," Biden said, before adding that he's "looking forward" to the debate stage.

"I am very willing to let the American public judge my physical as well as my mental fitness," he said.

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Biden's reaction to the question drew quick criticism from the Trump campaign and other conservatives.

Senior White House aide Kellyanne Conway tweeted: "Stumbling and bumbling through why he doesn’t need to take a cognitive test, @joebiden shows why he needs a cognitive test." (The former vice president had stumbled repeatedly on the word "fitness"; he has also spoken about his childhood years with a stutter.)

In response to the CBS News exchange, a Biden campaign official tells PEOPLE: "It was a preposterous question deserving of a response that showed the absurdity of it all."

President Trump first raised cognitive testing earlier this summer. His detractors have said the test he "aced" proves nothing — and they note it is used to screen for problems like dementia.

Reporters have asked both candidates about the issue, too.

"Some have speculated sir that you are subject to some degree of cognitive decline," Fox News' Doug McKelway told Biden during a July press conference. "I’m 65. I don’t have the word recollection that I used to have. I forget my train of thought from time to time. You’ve got 12 years on me, sir. Have you been tested for some degree of cognitive decline?”

Biden appeared to laugh off the question at the time.

“I’ve been tested and I’m constantly tested,” he said. “Look, all you got to do is watch me. I can hardly wait to compare my cognitive capability to the cognitive capability of the man I’m running against.”

RELATED: Trump Boasts of ‘Unbelievable’ Cognitive Test Results as Biden Says He ‘Can Hardly Wait to Debate’

Former Vice President Joe Biden (left) and President Donald Trump

During a phone interview on July 9 with Fox News’ Sean Hannity, Trump brought up his test from 2018 and said it showed "I was all there .... I took it at Walter Reed Medical Center in front of doctors and they were very surprised. They said, ‘That’s an unbelievable thing.' "

"He [Biden] should take the same exact test," Trump told Hannity.

A few weeks later, in another interview, Fox News' Chris Wallace told Trump he'd taken the test as well and found it was actually "not the hardest."

"They have a picture and it says 'what's that' and it's an elephant," Wallace said then.

Another question, he said, was "count back from 100 by seven."

"No, no, no," the president replied.

"It's all misrepresentation," Trump said. "Because, yes, the first few questions are easy, but I'll bet you couldn't even answer the last five questions. I'll bet you couldn't — they get very hard, the last five questions."

"Okay, what's the question?" Wallace told him, to which Trump said: "I'll get you the test, I'd like to give it. I'll guarantee you that Joe Biden could not answer those questions."

In a third interview last month, Trump recounted being asked to repeat five words from memory during the test — like, for example, "person, woman, man, camera, TV."