New research suggests that when people are distracted by a visual task, they’re more likely to consciously notice neutral spoken words than negative ones. These findings published in the journal psychological scienceprovides evidence that the human brain may filter out distracting emotional sounds before they reach consciousness. This research helps explain how the mind manages the overwhelming amount of auditory information we encounter every day.
Our sensory environment is filled with a constant stream of sights and sounds. Because humans have limited attention spans, our brains must prioritize which information enters our consciousness. Conscious awareness refers to our ability to actively notice and report what we experience.
Much of the sensory input we encounter is managed by non-conscious processes that occur behind the scenes. Previous research investigating how the brain selects information for conscious processing has primarily focused on vision. In these visual studies, scientists often briefly flash images that participants cannot consciously report seeing.
Hearing presents a unique challenge because humans cannot simply close their ears or turn away from unwanted sounds. Sound is particularly difficult to learn because, unlike images, it cannot be conveyed instantaneously. Because auditory input is constantly flowing into the brain, cognitive systems need efficient ways to classify important sounds from irrelevant background noise.
The authors of the current study wanted to understand how the emotional tone of spoken words influences their likelihood of being consciously heard. Emotional valence refers to whether a stimulus is perceived as positive, negative, or neutral. Insight into this process could explain how non-conscious information influences an individual’s thoughts, feelings, and behavior.
Traditional psychological frameworks suggest that detecting negative emotional information is important for survival. Recognizing threats quickly allows people to react and adapt to dangerous situations. Based on this idea, one might expect the brain to prioritize negative words and notice them more easily.
“Initially, we thought people would notice more negative things, because that’s our conscious intuition,” said lead author Gal R. Chen, a doctoral candidate in psychology at the Hebrew University of Jerusalem. “There’s a lot of data showing that seeing or hearing negative things slows you down and makes more mistakes.”
On the other hand, another psychological perspective suggests that filtering negative information promotes adaptive behavior. If a negative sound is irrelevant to a person’s current goals, noticing it can be an unnecessary distraction and hinder performance. The researchers designed a series of experiments to test whether non-conscious mental processes prioritize or ignore negative spoken words compared to neutral mental processes.
“Most theories predict that emotionally negative information should be prioritized because it may indicate a threat,” Chen said. “Instead, we found that emotionally expensive information can be filtered out by the brain before we are aware of it. Think of a bus driver who has to ignore a passenger who speaks angrily on a cell phone. It may be beneficial to stop and process negative information instead of listening to it.”
To answer this question, scientists have developed a research method that mimics the phenomenon of inattentional hearing loss. Inattentional hearing loss occurs when a person’s attention is so focused on a demanding visual task that they completely stop hearing audible sounds. By creating this scenario in the lab, the authors were able to observe which types of words break through distractions and reach consciousness.
The researchers conducted three separate experiments with a total of 101 adults whose native language was Hebrew. Participants were instructed to complete a visual memory activity on a computer screen. This visual activity involved viewing images of a fictitious purple figure known as “Greeble” who appeared in various environments.
In the first two experiments, participants completed highly demanding memory tasks. I needed to indicate whether the currently displayed picture was the same as the picture displayed immediately before it. This required constant concentration on the computer screen.
While participants performed this visual task, a constant stream of auditory sounds was played through a speaker. Most of these sounds are pseudowords, combinations of pronounceable syllables that have no actual meaning in Hebrew. The pseudowords were played alongside quiet background chatter to avoid sudden onsets of sounds that would draw participants’ attention.
In some cases, the audio stream replaced meaningless pseudowords with actual meaningful Hebrew words. These real words were chosen to be either emotionally neutral, such as words for cube or telephone, or emotionally negative, such as words for sadness or prisoner. The audio was clearly audible and easy to understand.
After the target word was played, the visual task was temporarily stopped so that the researchers could measure the participants’ awareness of the sound. Participants first completed a subjective recognition test that assessed whether they heard meaningful words or only meaningless syllables. They then completed an objective test by attempting to identify the hidden word category from a series of multiple-choice options.
The first experiment included 29 participants who encountered 72 different target words across several test blocks. The researchers found that participants completely missed a significant portion of the actual words, confirming that the visual task was successful in distracting participants. When analyzing the highlighted words, scientists noticed certain patterns based on the emotional tone of the sounds.
Participants consistently showed a higher probability of consciously detecting neutral words compared to negative words. This pattern held true even when the researchers took into account other factors, such as the word’s arousal level and how the word was pronounced. This finding contradicts the idea that negative information automatically attracts human attention.
“This study is a good example of how our conscious intuition about what we notice doesn’t necessarily match our unconscious behavior,” Chen said. The unexpected pattern initially made the research team question their data.
“We thought it was a mistake,” Chen said. “So we repeated the study, adding new words, and found the same trend: people notice negative words less.”
The second experiment included 28 participants and served as a replication with a slightly expanded set of 75 words. The authors again found an overall tendency for participants to consciously detect neutral words more often than negative words. To ensure the results were not distorted by the acoustic properties of the sound, the scientists used artificial intelligence tools to analyze the speech patterns.
This computational analysis allowed the team to control certain linguistic features, such as the number of vowels and type of consonants in each word. Even after accounting for these acoustic features, the emotional tone of the words remained a strong predictor of conscious detection. Negative words failed to reach consciousness as often as neutral words.
The third experiment involved 44 participants and varied the difficulty of the visual task. The researchers wanted to see if the rate of noticing negative words would change if the primary task was easier and required less mental energy. Participants completed the original memory-demanding task in half of the experiment and the simpler visual task in the other half.
A simpler task required participants to simply indicate whether the fictitious person on the screen was face-up or upside-down. As expected, participants performed better and responded faster on easier tasks. However, the emotional tone of the spoken words still affected their consciousness in exactly the same way.
Neutral words were detected more often than negative words in both the difficult and easy visual tasks. The level of cognitive load did not change how the brain prioritized auditory information. This suggests that unconscious filtering of negative statements is a process that consistently occurs regardless of how much a person is focused on something else.
“It may be an unconscious default to suppress information that might be harmful to us,” Chen says. “If your main job is to talk to me, random words that pop up won’t help you. And if these words slow you down, your default unconscious bias may be ‘don’t bring that word in.'”
Although these findings provide new insights into auditory processing, the researchers acknowledge some potential limitations. One concern concerns the timing of awareness questions. Because the researchers waited a short while after the words were played and asked participants what they heard, the emotional tone of the words may have influenced short-term memory rather than initial recognition.
In this case, participants may have consciously heard the negative words but quickly forgotten them before reporting the experience. Even if the effect is associated with rapid forgetting, it still shows that the emotional meaning of a word significantly alters a person’s ability to report having heard that word. Another limitation is that only single negative and neutral words were investigated in this study.
This data does not provide information about how the brain processes highly positive or socially taboo words in similar situations. Future research could investigate whether the same effects emerge in full text, narrative, and more realistic listening environments. Additionally, the experiment only involved young Hebrew speakers, so further research is needed to see if these patterns generalize to older adults and speakers of different languages.
The findings also provide new avenues for studying mental health conditions such as phobias and PTSD. Chen speculates that future research could investigate whether this unconscious filtering process works differently in people with anxiety disorders. “The average person notices negative words less often than neutral words,” Chen says. “In clinical populations, this selection bias may not exist.”
By continuing to study how the mind prioritizes sounds, scientists hope to better understand how sensory gating mechanisms influence everyday life. “If you think of the unconscious as a gatekeeper that protects us from things that might hurt us or influence our decisions, you might wonder what happens if this gatekeeper fails,” Chen added.
The study, “Conscious detection of spoken words depends on their valence,” was authored by Gal R. Chen, Zaheera Maswadeh, Leon Deouell, and Ran R. Hassin.
