Thinking about investing in a stock? Buying a lottery ticket? Deciding between two cars? Watch what you ve been eating, touching and smelling.

Standard economic theory doesn t have much to say about the difference between having or not having had your morning bagel. But new research suggests that tactile cues like being casually touched by a woman, or inhaling the citrus scent of a new car, sway our decisions all the time.

Animals, after all, make their versions of economic decisions based on these types of cues all the time. Why wouldn t we?

It s precisely in the animal world where a recent paper in the open-access scientific journal PLoS ONE begins. In a paper published in June, a team of British researchers expert in neurology and metabolism investigate whether human decision making follows some of the same patterns as animal decision making when it comes to the relationship between hunger and risk-taking.

To simplify a bit, animals tolerance of risk increases the hungrier they are. In the wild, if an animal is below a certain baseline in terms of its metabolism, it will take more risks to obtain food and it will take more risks in what sources of food it s willing to consume (those red berries suddenly become worth the risk, even if they might be deadly).

Would humans react similarly, based on whether they were hungry or full?

To find out, the researchers recruited a group of healthy male volunteers and observed them in three conditions: fasting (having not eaten for 14 hours), immediately post-meal, and one hour post-meal. In each of these three states, on a randomized basis, the young men were asked to complete a standard test of risk tolerance, a gambling task where they chose between pairs of gambles, one always being riskier (but higher reward) than the other.

The result: The men who felt full an hour after eating (as measured by blood tests, reading for a hormone that registers when a person s hunger is satiated) were significantly more averse to risk on the gambling task than those who didn t feel full.

In other words, your hormones can influence your investment choices in a predictable way and hunger can make you more disposed to take risks.

How else might your hormones be affecting your judgment?

Another recent study, published in April in the journal Psychological Science, found that something as insignificant as a pat on the shoulder can affect how much risk we re willing to take. In a series of experiments on business school students involving hypothetical and real financial risks, the researchers found that a one-second pat on the back ( a light, open-palmed touch on the back of the shoulder blade ) was enough to significantly increase how much people were willing to gamble and how willing they were to invest in a risky stock. What s more, they found that this effect only showed up when it was a woman doing the patting regardless of the gender of the person being patted. A pat from a man, it turned out, had no effect. A handshake from a woman, as opposed to a pat, also turned out to be ineffective.

(To control for any possibility of sexual excitement, the researchers also measured the attractiveness of the people doing the patting. Good for research, but perhaps sad for the researchers, they all tested average in the looks department when rated by strangers.)

The researchers theory is that a pat from a woman mimics a comforting, maternal touch central to mother-child bonding in humans and other animals. That reassurance, it seems, makes us feel safer and thus more willing to face the unknown.

Of course, there s only so much businesses can do to manipulate how much we ve eaten or whether we ve recently felt the reassuring touch of a woman. Casinos can ply us with drinks while keeping food scarce (and even hire pretty, flirty girls to hang around the craps table). And any smart saleswoman knows the power of a touch on the arm.

But businesses want something they can deploy en masse. Enter scent marketing. While the science is as of yet thin, there is some preliminary evidence that smells can affect the way we buy. For instance, feminine scents like vanilla have been found to increase the sales of women s clothes (and to dissuade men from sticking around). And scents have been found to aid in brand recall something a chain like Abercrombie & Fitch counts on, with its signature fragrance permeating its stores.

Does all this mean a restaurant in Mooresville, N.C., which recently unveiled a billboard that pumps out grilling-steak scent, can expect a meat-mad public to bang down its doors? Maybe not. But in reaching out to hungry customers through their noses and ultimately their stomachs, they just might convince potential customers to take a chance.