Applied Psychology OPUS

In Between the Images: The Therapeutic Benefits of Unconscious Exposure

by Don Asher Cohen

The way psychologists think about and treat phobias may be facing imminent change. Damour and Hansell (2008) define a phobia as an intense, persistent and irrational fear and avoidance of a specific object or situation. However, recent research suggests that phobias are more than simply intense fears. In fact, psychologists have discovered that exposure to phobic-stimuli (specific object of phobia) activates different part of the brain than the one which activates when people are exposed to fearful-stimuli (anything else someone is afraid of) (Carlsson, Petersson, Lundqvist, Karlsson, Ingvar & Ohman, 2004). In other words, phobias may be neurologically different from fears. Furthermore, when unconsciously exposed to fearful-stimuli, the brain reacts differently than it reacts when consciously exposed to fearful stimuli (Morris, Ohman & Dolan, 1998), suggesting that people use different parts of their brains to process conscious and unconscious emotions. Understanding these unique properties of phobias is instrumental in treating them.

One strategy, exposure therapy, requires that people face their fears in the most literal sense (Damour & Hansell, 2008). It has been shown to be highly effective in the treatment of phobias (Barlow, Raffa & Cohen, 2002). In exposure therapy, the eradication of phobias is accomplished by gradually exposing individuals to the object they are afraid of. Eventually, individuals come to realize that the feared object is not intrinsically dangerous, because they are not harmed by the object itself. When individuals can reach this conclusion, they are less avoidant of the feared object. Effective as the treatment may be, Damour and Hansell (2008) note that exposure therapy can cause people to experience anxiety during treatment. However, there may be a way to achieve similar effects without requiring clients to experience such anxiety.

Carlsson et al. (2004) used backwards masking to unconsciously expose participants to phobic and fear relevant stimuli. In backwards masking, people are shown to an image for a brief period of time before it is covered up by a different image. This technique exposes participants to images they are unable to report seeing. In Carlsson et al.’s (2004) study, half of participants exhibited arachnophobia (phobia of spiders) and the other half exhibited ophiophobia (phobia of snakes). Participants were exposed to six image-mask pairs, each in randomized order and repeated twice. Images included two phobic stimuli (spiders and snakes respective to the participant), fear relevant stimuli (spiders and snakes respective to the participant) and two mushrooms. Positron Emission Tomography (PET) images showed that unconscious exposure to phobic stimuli and fear-relevant stimuli elicit similar responses. However, when the participants were given time to consciously process the stimuli being exposed, differences emerged. Consciously-exposed, phobic stimuli elicited an affective processing response that fear-relevant stimuli did not elicit. In other words, on a conscious level, when people suffering from phobias are exposed to their phobias, their fear response is different from exposure to other things of which they are non-pathologically afraid.

Morris et al. (1998) also used backwards masking to unconsciously expose people to "fearful faces" which were later covered up by "neutral faces". They measured participants’ fearful responses to these stimuli with PET scans and magnetic resonance images (MRI) of brain activity in the amygdala, a region central to emotional functioning. The images showed that unconsciously exposed faces elicited a neural response in the right amygdala without eliciting a response in the left. When the faces were unmasked, the amygdala response was different: unmasked faces elicited neural responses in the left amygdala without eliciting response in the right amygdala. This discrepancy shows that the human brain responds to conscious and unconscious stimuli in different ways. Understanding these differences may prove useful in better understanding and treating phobias in the future.

The effect of unconscious exposure to phobic stimuli was explored by Siegel and Weinberger (2009), whose work more directly suggests unconscious exposure may be useful in therapy. Siegel and Weinberger (2009) conducted three experiments, one of which tested the effect of unconscious exposure on behavior. Their first experiment established that, through backwards masking, participants can be exposed to stimuli without being able to report exposure to these stimuli. Their second experiment showed that when individuals suffering from fear of spiders were unconsciously exposed to spider images, they were less behaviorally avoidant of a caged tarantula than people suffering from a fear of spiders that were not exposed to those images. In a third experiment, participants were separated into two groups. During the first week of their experiment, participants completed a behavioral approach task, during which they approached a caged spider. In the second week, one group of participants was unconsciously exposed to the phobic stimuli (spider images), while the other was not. Participants in the group that was unconsciously exposed to the spider images were less avoidant of the spider in the second week, compared to their first week. Participants in the group that was not exposed to the spider images were not less avoidant of the spider. Siegel and Weinberger’s (2009) work suggests that the effect of unconscious exposure is similar to the effect of current exposure therapy in that both successfully reduce avoidant behavior.

Because the highlighted studies only examined the effects of unconscious exposure in the short-term, further research is needed to investigate the effectiveness of unconscious exposure in treating phobias. Additionally, the aforementioned studies have only investigated the use of unconscious exposure with two phobias - arachnophobia and ophidiophobia. If the effects of unconscious exposure prove to be long lasting and applicable to a wider range of phobias, unconscious exposure therapy should be integrated into current interventions. Because unconscious exposure circumvents the anxiety conscious exposure causes, it has the potential to become a preferred treatment option.


Barlow, D. H., Raffa, S. D., & Cohen, E. M. (2002). Psychosocial treatments for panic disorders, phobias, and generalized anxiety disorder. In P. E. Nathan & J. M. Gorman (Eds.), A guide to treatments that work (pp. 301-336). New York: Oxford University Press.

Carlsson, K., Peterson, K. M., Lundqvist, D., Karlsson, A., Ingvar, M., & Ohman, A. (2004). Fear and the amygdala: Manipulation of awareness generates differential cerebral responses to phobic and fear-relevant stimuli. Emotion, 4, 340-353.

Damour, L. K., & Hansell, J. H. (2008). Abnormal Psychology (2 ed.). New York, NY: Wiley.

Morris J.S., Ohman A, & Dolan RJ. (1998). Conscious and unconscious emotional learning in the human amygdala. Nature, 393, 467- 70.

Siegel, P. & Weinberger, J. (2009). Very brief exposure: The effects of unreportable stimuli on fearful behavior. Consciousness and Cognition. doi: 10.1016/j.concog.2009.08.001