A new study by experimental psychologists from the University of
Bristol has examined whether cognitive bias modification (CBM) for
facial interpretation, a digital health intervention that changes our
perception for emotional expressions from negative to positive, might be
useful in treating depression.
The study, published recently in the journal Royal Society Open Science, also contributes to ongoing discussion over the viability of CBM in the clinic.
Have you ever walked away from a social interaction feeling
uncomfortable or anxious? Maybe you felt the person you were talking to
disliked you, or perhaps they said something negative and it was all
you could remember about the interaction.
We all occasionally focus on the negative rather than the positive,
and sometimes ruminate over a negative event, but a consistent tendency
to perceive even ambiguous or neutral words, faces, and interactions as
negative (a negative bias), may play a causal role in the onset and rate
of relapse in depression.
A growing field of psychological interventions known as cognitive
bias modification (CBM) propose that by modifying these negative biases
it may be possible to intervene prior to the onset of depression.
Given that access to proven psychological and pharmacological
treatments for mood disorders is limited, and that in countries like the
UK public treatment for depression is affected by long waiting lists,
high costs, and low overall response rates, there is a need for
effective treatments which are inexpensive, and both quick and easy to
But following early excitement from promising CBM findings,
considerable problems have been identified, not limited to publication
bias (positive findings are more likely to be published) and small
The study, testing a new CBM paradigm, questions these previous positive findings.
The study's lead author, Sarah Peters, who is a PhD student at the
University of Bristol's School of Experimental Psychology and Biomedical
Research Centre, said: "We wanted to test a novel CBM paradigm which
has previously shown robust bias modification effects, but for which the
impact on mood and mood-relevant measures was unclear."
Peters and her colleagues at the University of Bristol and
University College London ran a proof of principle trial in a
She further explained: "We do these to test potential new
interventions before we offer them to individuals seeking treatment.
Even if we show that a task is shifting your bias and we think that's
relevant to mood disorders, what matters is whether it impacts
mood-related outcomes and shows clinical utility."
The authors had two specific aims. Firstly, they aimed to replicate
previous findings to confirm that the intervention could indeed shift
the emotional interpretation of faces; could they make their
participants see negative faces as more positive. Secondly, they were
interested in whether this shift in interpretation would impact on
clinically-relevant outcomes such as self-reported mood symptoms.
Among these were self-report questionnaires of depressive and
anxious symptoms and the interpretation of ambiguous scenarios and daily
The cognitive tasks included a dot probe task to measure selective
attention towards negative (versus neutral) emotional words, a
motivation for rewards task which has been shown to measure anhedonia
(the loss of pleasure in previously enjoyed activities), and a measure
of stress-reactivity (whereby individuals complete a simple task under
two conditions: safe and under stress). This final task was included
because it is thought that the negative biases they were interested in
modifying are more pronounced when an individual is under stress.
While the intervention successfully shifted the interpretation of
facial expressions (from negative to positive), there was only
inconclusive evidence of improved mood and the CBM procedure failed to
impact most measures.
There was some evidence that daily stressful events were perceived
as less stressful by those in the intervention group post-CBM, weaker
evidence for reduced feelings of pleasure in the intervention group, and
some exploratory evidence for greater improvements seen by individuals
with higher anxiety at baseline.
Peters added: "Overall, it's unlikely that this procedure in its
current design will impact on clinically-relevant symptoms. However, the
small effects observed still warrant future study in larger and
clinical samples. Given the large impact and cost of mood disorders on
the one hand, and the relatively low cost of providing CBM training on
the other, clarifying whether even small effects exist is likely
Even if this procedure fails to result in clinical improvement,
documenting and understanding the different steps in going from basic
scientific experimentation to intervening in clinical samples is crucial
for both the scientific field and the general public to know.
Additionally, the negative findings shown in this study offer a
useful contribution to the field of CBM research. It is common for new
clinical interventions to initially appear promising (as a result of
early study methodologies and publication bias for positive results),
but it's only over time that more robust studies are conducted and
question these early findings.
In a body of research where positive results prevail and negative
results remain unpublished, studies which are methodologically sound and
question this status are necessary and informative.