Your baby is an excellent listener. She recognizes your voice, and she'll show you her pleasure by smiling at the sound of your greetings. You may notice that your baby seems to freeze when she hears a new sound — and it's only after she can figure out where it came from that she starts kicking or moving her arms again.
She's also excitedly using all five of her senses to learn about his world. You can actually see how hard she's working to assimilate the new information she's exposed to every day. If something grabs her attention, notice how hard she focuses on it and stares. She's taking it in on many levels.

More things that fascinate your baby now: the contrasting colors of a new toy, the motion of a ceiling fan or rustling tree leaves, the sound of running water, and the clattering of pots in the kitchen sink.

From babycenter.com