The topic of dreams and their relative function or purpose has long been a topic of research and discussion. “Evolutionary psychologists have proposed that dreams may offer a safe way to rehearse ways of dealing with dangerous situations” (Franklin & Zyphur, 2005, as cited by Zimbardo, Johnson, & McCann, 2009, pp 351). Antti Revonsuo is in agreement with these evolutionary psychologists and has developed the Threat-Simulation Theory (TST) that suggests dreaming serves an evolutionary function. Revonsuo’s TST suggests that dreaming is specialized in the simulation of threatening events which provides an offline context in which threat perception and avoidance skills could be rehearsed (Revonsuo & Valli, 2008). According to Revonsuo and Valli (2008), “The main predictions of the TST are that threatening events are frequent and overrepresented in dreams, that exposure to real threats activates the threat-simulation system, and thats dream threats contain realistic rehearsals of threat avoidance responses”. The TST also predicts that individuals that experience more real life threats will produce more threat-simulations and have more effective simulated responses (Revonsuo & Valli, 2008). Revonsuo conducted a study in which, according to his research, proves the TST to be true. Susan Malcolm- Smith and Mark Solms re-tested Revonsuo’s theory in which they state their research evidence contradicts the key aspects of the TST.
In the study conducted by Revonsuo, Valli, Palkas, Ismail, Ali, and Punamaki, The threat simulation theory of the evolutionary function of dreaming: Evidence from dreams of traumatized children (2003), they sample and compare 187 children from Kurdish, Iraq and Finland. From this point forward I will refer to this study as “Revonsuo’s study”. This study used a sample of 117 children from the highly traumatized area of Kurdish. These children were split into two groups according to their relative reported amount of trauma experienced. The amount of trauma was determined based on a scale of 20 items referring to events typically experienced by children of this area. The Trauma group, or the children that experienced the most amount of trauma, consisted of 64 children ages 9-17 (M/F=28/36). The Control group, or the children that experienced the lesser amount of trauma of Kurdish children, consisted of 53 children ages 9-17(M/F=20/33). The sample of non-traumatized children came from a Finnish sample that had experienced significantly less environmental, political or military traumatic experiences. This Non- Trauma group consisted of 70 children ages 7-12 (M/F=23/47).
In the study conducted by Malcolm-Smith and Solms, Incidence of threat in dreams: A response to Revonsuo’s threat simulation theory (2004), the research sample came from a group of undergraduate students at the University of Cape Town in South Africa. From this point forward I wil refer to this study as the “Malcolm-Smith’s study”. The authors state that violence and trauma are commonplace in South Africa (Malcolm-Smith & Solms, 2004). There were 401 participants (M/F=100/301) and the research only states that the median age of the sample is 20 years.
I see many issues with these samplings. Again, I believe that if Malcolm-Smith and Solms were looking to replicate the previous Revonsou study than the sampling should have been more comparable in all aspects. Malcolm-Smith’s study only selected one group from a high trauma environment, there was no non-trauma group selected in which to compare results, the age range is not provided, the median age is much higher, and the male:female ratio is skewed much more than in Revonsuo’s study. Malcolm-Smith’s study also used college educated participants. It is much more likely that this group has knowledge of psychology and research methods than do the Revonsuo sample. I do not believe these sample groups are comparable.
Data Collection and Method