Lisa Feldman Bar­rett, a psy­chology pro­fessor, says that our mood has a direct effect on our per­cep­tion of the world. When we’re happy, she says, we’ll see neu­tral faces as smiling. When we’re sad, they’ll appear as scowls.

People treat their feel­ings about the world as evi­dence for how the world really is,” says Bar­rett, who joined the Col­lege of Sci­ence this fall after almost 20 years at Boston Col­lege and the Penn­syl­vania State University.

Bar­rett, who studies how emo­tions func­tion in the mind by using expe­ri­en­tial, behav­ioral, psy­chophys­i­o­log­ical, and brain-​​imaging methods, is also co-​​director of the Lab­o­ra­tory of Aging and Emo­tion at Mass­a­chu­setts Gen­eral Hospital.

Col­lab­o­ra­tors include cog­ni­tive neu­ro­sci­en­tists at Mass Gen­eral Hos­pital, Har­vard Med­ical School, Emory Uni­ver­sity and the Uni­ver­sity of Colorado.

For one study, she employed a tech­nique in visual neu­ro­science called binoc­ular rivalry, in which one image — say, a house — is pre­sented to a subject’s left eye and a very dif­ferent image — a smiling or scowling face — is pre­sented to the other.

She mea­sured which image the sub­ject saw first and for how long he looked at it. The results were clear, says Bar­rett: “Our feel­ings influ­ence whether we’re con­scious of seeing some­thing or how we see something.”

Her research is backed by fed­er­ally funded grants from the National Sci­ence Foun­da­tion, National Insti­tutes of Health and Army Research Institute.

In 2007, she earned the NIH Director’s Pio­neer Award, which is awarded to sci­en­tists who take trans­for­ma­tive approaches to solving chal­lenges in bio­med­ical and behav­ioral research.

She also studies how lan­guage affects our ability to rec­og­nize emo­tions using a tech­nique called semantic satiation.

Say the word “anger” over and over again, until it “sounds like mumbo jumbo,” she says, and you won’t know the meaning of the furious scowl on the face of the person sit­ting next to you on the subway.

Repeat the word “smile” over and over, and you won’t be able to tell whether two happy kids with ear-​​to-​​ear grins are con­veying the same emotion.

Dis­abling the semantic pro­cessing of words reduces our ability to see emo­tions,” she says.

Words, she explains, act like glue to shape our per­cep­tions. Inter­fering with the pro­cessing of a word “inter­feres with our per­cep­tions” in the same way that unfa­mil­iarity with a word — like, say, “cow” — makes it impos­sible to find the animal in an abstract design.

If you make lan­guage inac­ces­sible to a sub­ject by taking away the word ‘cow,’ he won’t know what it means as a phys­ical entity,” she says. “When you give him a black and white blot, he’ll never find the cow.”