Research by a team of scientists has now identified how our brains work to process phrases that include negation (i.e., “not”), revealing that it lessens rather than inverts meaning—in other words, in our minds, negation merely lowers the temperature of our coffee and does not make it “cold.”
According to Arianna Zuanazzi, a postdoctoral fellow in New York University’s Department of Psychology at the time of the study and the lead author of the paper, which appears in the journal PLOS Biology. He states "We now have a firmer sense of how negation operates as we try to make sense of the phrases we process,”
The researchers say that their results show how humans process such phrases while also potentially pointing to ways to understand and improve AI functionality.
In the experiments, participants read—on a computer monitor—adjective phrases with and without negation (e.g., “really not good” and “really really good”) and rated their meaning on a scale from 1 (“really really bad”) to 10 (“really really good”) using a mouse cursor.
This scale was designed, in part, to determine if participants interpreted phrases with negation as the opposite of those without negation—in other words, did they interpret “really not good” as “bad”—or, instead, as something more measured?
It was found that participants took more time to interpret phrases with negation than they did phrases without negation showing, not surprisingly given the greater complexity, that negation slows down our processing of meaning. In addition, drawing from how the participants moved their cursors, negated phrases were first interpreted as affirmative (i.e., “not hot” was initially interpreted as closer to “hot” than to “cold”), but later shifted to a mitigated meaning, suggesting that, for instance, “not hot” is not interpreted as either “hot” or “cold,” but, rather, as something between “hot” and “cold.”