However, it was not clear whether such effects existed among people who experience a situation that triggers anxiety.
“We were specifically trying to answer the question: how does our current level of anxiety influence how we see the world, and in particular emotions in faces?” said Marcus Munafò, professor of biological psychology at the University of Bristol and a co-author of the new study.
To tackle the conundrum, Munafò and colleagues from the University of Bristol looked at the impact of an anxiety-inducing situation on the ability of 21 healthy participants to interpret emotion in facial expressions. The participants’ general tendencies to worry about situations varied, but none had anxiety disorders.
The participants were each fitted with a face mask delivering either normal air, or air enriched with carbon dioxide – an approach known to induce worry and tension, as well as a raised heart rate and blood pressure. After completing each part of the study, the participants repeated the experiment breathing the alternative type of air.
In the first part of the study, the participants were shown images, one at a time, of a man’s face expressing various levels of anger, sadness, surprise, disgust, fear or happiness. The 15 images for each emotion were shown to the participants twice. The participants were asked to assign each face to one of the six emotions.
In the second part of the study, participants were each presented with 45 images featuring 15 faces that showed an emotion somewhere between the two extremes of anger and happiness and asked to judge the expression.
Both experiments were then repeated with a further group of more than 40 participants.
The results, published in the journal Royal Society Open Science, reveal that after adjusting for factors such as age, sex and whether participants were generally more anxious, individuals were 8% worse at accurately identifying the correct emotion of a face when breathing in the carbon-dioxide rich air.
“We do know that anxiety can essentially take up cognitive resources and so it is perhaps not surprising that we see this general deficit,” said Munafò.
The team also found that, when anxious, participants more often saw anger than happiness when presented with ambiguous facial expressions, although the association was weaker when the experiment was carried out with the bigger group of participants.
Finally, participants were recruited to an online study in which they were asked to assign the six emotions to a range of both men and women’s faces, including those of different ethnicities. Participants also completed self-report questionnaires to probe their levels of anxiety, both at that moment and in general.
Results from 1,994 individuals revealed that the higher their levels of anxiety were at that moment, the less accurate they were at recognising emotions in the faces presented to them.In addition, the team found that once factors including current levels of anxiety were taken into account, those who were generally more anxious were better at recognising facial emotions.
“It raises this interesting possibility that dispositional anxiety might be related to emotion recognition in a different way to current anxiety,” said Munafò, although he said the finding needed to be replicated before any conclusions could be drawn.
Tim Dalgleish, a clinical psychologist and director of the Cambridge Clinical Research Centre in Affective Disorders who was not involved in the study, said the research was interesting but that there were difficulties in interpreting its results.
“The main problem is that we don’t know if [the link between anxiety and emotional face recognition] is anything to do with emotion recognition at all or just when you are more anxious you are not as good at doing other tasks,” he said. Munafò argues that previous research has not shown a general negative impact of breathing carbon-dioxide rich gas on cognitive function.
Dalgleish added that the finding that episodes of anxiety were not linked to increased abilities in reading particular emotions such as fear, did not rule out the relationship, adding that it might be an effect that is larger among those who are generally more anxious. “The absence of proof isn’t proof of absence,” he said.
More about: #Anxiety
