Step 4: Test with an experiment.

"…The idea of the unintelligent Neanderthal is a misnomer. Neanderthals were actually fairly intelligent, creating the Mousterian tool complex. Early modern humans, however, were at an advantage as they were less robust and therefore more adept at achieving culturally what the Neanderthals only thought to achieve physically."

"Huh. So those Geico commercials are kind of insulting, aren't they?"

"Yes, I suppose they are."

It was Saturday afternoon and they had spent the last few hours wandering around the museum. Sheldon usually preferred to visit all the exhibits in a uniform, scheduled manner, but Penny was content to roam, and so he roamed with her. He did make sure, however, to provide her with all the proper information that the museum exhibits lacked.

"I didn't know you were into all this caveman stuff," she said.

"Well, the practical side of archaeology has never really appealed to me, but their results can be quite fascinating."

"Cool."

"…Penny… I need your assistance on something."

"Sure. What's up?"

"Could you label and describe the level of enjoyment you have received from today's excursion?"

"…What?"

"Do you… that is… Are you having… fun?"

She smiled. "Yeah. Yeah, I am."

"On a scale from 1 to 10, 1 being ordinary and 10 being exemplary, how would you rate that level of fun?"

"Hmm… Let's see… Well, I'd say today started out at an 8. But then you bought me ice cream at that kiosk back there, so I'd say that bumped it up to a solid 9. Thanks for that, by the way."

"You're welcome."

"What's with the questions, Sheldon? You look a little jumpy."

"Ah, well, you see… I'm assisting Leonard in an experiment he's conducting."

"Oh, really?" she said in confusion. "What kind of experiment? Something about cavemen? I didn't think cavemen and physics had much to do with each other?"

"They don't, really. It's more of a… social experiment."

"How so?"

He bowed his head a little so as to avoid her gaze, his hands hanging awkwardly at this sides. "Well, you see, Leonard has made a hypothesis based on several observations he has made over the last 5 months. He is relatively convinced that his hypothesis is correct; however, he needed to conduct an experiment based on his current data to validate his theory."

"A social experiment?"

"Yes."

"I'm a little lost, sweetie. You're gonna have to give me more than that."

Sheldon sighed. "Oh, alright. Leonard is under the impression that there has been a change in the dynamic of our platonic relationship. He has observed what he believes to be behavioral changes suggesting a shift from "friends" to… uh… "

"…Is this a date? Like, an actual date date?"

He cleared his throat nervously. "I suppose that would be the colloquial term for this type of outing."

"Oh."

They stood in awkward silence for a long moment, each studying their shoes in a very intent manner.

"So… um… what do you think about Leonard's hypothesis?" Penny finally asked.

He looked at her, putting on his very best neutral, scientist face. "I would rather not discuss my premature conclusions until the experiment is complete lest it interfere with the integrity of possible data and its subsequent interpretation."

"Okay."

Sheldon dared a quick glance at Penny. He understood his own nervousness, as inane as that emotional state was, but was surprised to find that she appeared nervous as well. He had often known Penny to be many things, most of them quite lovely, others downright scary. Nervous, however, was not one of them, especially not around him of all people.

"Do you wanna know what I think about Leonard's hypothesis?" she said suddenly.

"I suppose so."

She bit her lip a little, a light blush playing across her cheeks as she played with the bright bauble of a ring on her pointer finger, twisting it around and around. Then, quite unexpectedly, she took a breath and slipped her hand quickly into his. "I think he's probably right."

Sheldon froze, looking with wide eyes as Penny's fingers intertwined with his own. It was a completely foreign sensation and though he had nothing to compare it to, he supposed it was pleasant. More than pleasant. Exquisite, maybe. He didn't often contemplate his spatial relationships to others or his place within social interactions, but he suddenly felt very awkward, as if his limbs were too long for his body and he didn't quite know what to do with his feet.

But then he looked down at Penny, standing next to him just as awkwardly as he was standing next to her, with her shiny blonde hair and pretty pink cheeks and a brain more brilliant than she'd ever given herself credit for, and he mentally shoved his anxiety to the very back of his brain, prepared to see Leonard's experiment through, nerves be damned. He wasn't a scientist for nothing.

He tightened his grip on her hand, and his heart skipped a beat when she did the same.

"Would you like to see the new black hole exhibit they've installed on the second floor?"

She smiled. "I'd love to."

Step 5: Report results; draw conclusion: Hypothesis is true.