Back in 1405, Chaucer coined a saying that has resonated through Shakespeare, modern psychology, and mommy blogs alike:

“For loue is blynd alday and may nat see,” he wrote in Merchant’s Tale.

The saying “Love is blind” has also repeatedly been proven true by scientists, at least in the context of parental and romantic love. And a new study suggests that startup founders ought to heed the wisdom of the father of English literature, too.

The study, “Entrepreneurial and parental love—are they the same?,” published in the journal Human Brain Mapping on March 13, investigates the neurological and behavioral basis of entrepreneurial love.

Researchers at Aalto University in Helsinki, Finland hypothesized that male business owners would demonstrate the same neurological and emotional reactions when shown images of their companies that fathers experience when shown images of their own children.

Questionnaires were used to measure affect intensity, positive emotions, confidence, and closeness between father and child, entrepreneur and company, and fMRI scans were used to assess brain activity. The participants were 42 men: 21 entrepreneurs and 21 fathers, aged 24-45. The fathers had no entrepreneurial experience, and founders were growth-oriented and not serial entrepreneurs.

Behaviorally, fatherly and entrepreneurial love proved strikingly similar—on measures of closeness, joy, satisfaction, pride, and love, participants rated their own children and businesses higher than other people’s children and businesses.

Fathers’ and entrepreneurs’ ratings significantly differed on only one measure: Entrepreneurs displayed a more intense positive bias toward their companies than fathers did toward their children.

In previous studies, when parents viewed images of their children, researchers noted decreased activity in brain regions linked to social cognition and emotional processing—the regions that, when active, allow us to objectively reason. This is the science behind “blind love.”

In this study, entrepreneurs who reported feeling close or interconnected with their business experienced brain activation patterns identical to those of fathers. For these participants, brain activation in regions linked to social cognition—and the capacity for objective thought—significantly decreased when looking at images of their own businesses or children.

Self-confidence was also strongly correlated with brain activity: The more confident the entrepreneur or father was, the less activity occurred in brain regions that enable logical emotional processing. “These results suggest that overconfidence and the repression of negative emotions may lead to [entrepreneurs and fathers] overestimating the probability of success for their company or child,” says Marja-Liisa Halko, the study’s co-author and a professor of neuroeconomics at the University of Helsinki.

The opposite was true for less confident entrepreneurs and fathers, indicating that they were more attuned to their children’s and businesses’ flaws and risks, says Halko.

Startup founders may know their “brain children” better than anyone. But the more they consider their business an extension of their “self” (as a parent considers their child), the more they should seek outside advice. Emotional attachment is key to long-term startup success, but may also veil a venture’s weakness.