Discovered: Money straight from the mint is more likely to be saved; brains respond well to harmony; shedding light on dark energy; human ancestors started eating grass 3 million years ago.

Crisp money less likely to be spent. This goest against everything we ever learned from rap videos where crisp Benjamins fly out of hands like so much confetti, but apparently the newer a bill is, the less likely people are to spend it. The team of researchers from the University of Winnipeg and the University of Guelph who came to this conclusion also found the converse to be true—the grubbier paper money is, the more people try to get rid of it. "The physical appearance of money can alter spending behavior," write lead authors Gabrizio Di Muro and Theodore J. Noseworthy. "Consumers tend to infer that worn bills are used and contaminated, whereas crisp bills give them a sense of pride in owning bills that can be spent around others." [University of Chicago Press Journals

Hardwired to enjoy harmonies. Why is it that no matter how cheesy we think syrupy vocal harmonies may be, they still hit a certain musical sweet spot no other sound can hit? The answer may lie in the structure of our ears and brains, according to research led by University of Montreal psychoacoustician Marion Cousineau. Certain spacings of aural frequencies sound pleasant, while others sound dissonant. And maybe those qualities aren't just a matter of taste, but rather a physiological reaction. Cousineau and colleagues studied people with amusia (the inability to discern pitch), discovering that even they disliked music that causes normal subjects to perceive "beating," the warbling effect provoked by musical dissonance. This suggests the perception of beating isn't what makes dissonance annoying, but that it has something to do with the perception of harmonicity. [Science Now]

Illuminating dark energy. As a depressed younger Alvy Singer knew all too well, the universe is expanding at an accelerating rate. And astronomers think that the substance spurring that expansion is dark energy. Now, the Baryon Oscillation Spectroscopic Survey team thinks they've come up with a way to study this dark energy more closely, even 10 billion years back. They think that by tracking the movement of quasars, they can trace the activity of dark energy way back to earlier eras of the universe's history. "We know very little about dark energy but one of our ideas is that it is a property of space itself—when you have more space, you have more energy," says Portsmouth University researcher and BOSS team-member Dr Matthew Pieri. "So, dark energy is something that increases with time. As the Universe expands, it gives us more space and therefore more energy, and at some point dark energy takes over from gravity to end the deceleration and drive an acceleration."  [BBC News]

Human ancestors started eating grass 3 million years ago. Some humans may have been vegetarian before they were even fully human, according to University of Oxford archaeologist Julia Lee-Thorp and her colleagues. They found evidence in the remains of a Australopithecus bahrelghazali specimen that this early human ancestor ate grasses and sedges, perhaps exclusively, as early as 3 million years ago. These proto-humans lived in Central Africa's savanna and wooded regions, where they shunned leaves, fruit, and other standard food sources for other early humans. "Australopithecus somehow made a living on the grassy savanna of Chad," comments University of Illinois at Urbana–Champaign anthropologist Stanley Ambrose. "Whether it ate a lot of grass or the meat of grazing animals cannot easily be determined from this chemical analysis." [Science News]