by Damion Grasso, PhD
It’s fascinating to watch young children begin to interact with and understand our world – everything a question and a discovery. All of this newness is instrumental in fine-tuning their fast-developing brains, which need nurturance and stimulation to grow to their potential. These experiences are necessary for reaching developmental competencies, such as honing cognitive and motor skills, regulating emotions, understanding right from wrong, negotiating social interactions, and beginning to formulate early concepts of self. These early accomplishments lay the foundation for attaining competencies at later stages of development. Not only do suboptimal environments deprive these young brains of this essential, healthy growth, but can shape their brains in ways that place them at higher risk for developing psychological problems, like anxiety, depression, and disruptive behavior. In particular, young children exposed to family violence are developing in environments where safety is unpredictable, violence is frequent, and the very people they most depend on for security and nurturing may be unavailable or causing psychological or physical harm. As such, these children may develop an enhanced capacity to detect and respond to threat in the environment (LeDoux, 2000; McEwen, 2007). While this may be adaptive to survival in harsh situations, it may come at a steep price, with compromised ability to attain developmental competencies and difficulty resigning from survival tendencies when in safe, more secure environments.
Laboratory studies have linked violence exposure in children to alterations in the way they detect threat, as well as the amount of attention they allocate to a threatening stimulus once it is detected. Detection of threat happens quickly – just a fraction of a second from the onset of a stimulus. Studies using electroencephalography (EEG) can capture these very rapid responses by isolating electrical brain patterns evoked by a stimulus. These are called event-related brain potentials (ERPs). ERP studies show evidence of enhanced brain responses to perceived threat images in violence and trauma-exposed individuals (Karl, Malta, & Maercker, 2006; Shackman, Shackman, & Pollak, 2007). What is striking is that these responses are automatic and occurring before even one becomes consciously aware of the stimulus.
Other studies have found associations between violence exposure and attention bias to threat such that some children respond more quickly or more slowly to threat-related pictures relative to neutral pictures. This suggests that violence exposure may be associated with a tendency to either allocate more attention to threat -or- to avoid or divert attention away from threat – both patterns have been linked to violence exposure and psychological impairment in children and adults (e.g., Bar-Haim et al., 2010; Sipos, Bar-Haim, Abend, Adler, & Bliese, 2014; Briggs-Gowan et al., 2015; Mian, Carter, Pine, Wakschlag, & Briggs-Gowan, 2015). Individuals with a bias towards threat may become stuck or fixated on threat cues, which may compromise their ability to attend to other tasks. A bias away from threat, on the other hand, may reflect individuals who are quick to perceive threat but then divert their attention away in an effort to avoid it – perhaps without even fully processing it. More work in this area is being done at our lab at UConn and elsewhere towards better understanding the implications of these patterns.
Once threat is detected, the flight-or-flight stress response system ensues by activating the autonomic nervous system. A number of studies have linked violence exposure and related impairment to exaggerated autonomic reactivity (e.g., heart rate, skin conductance) to threat cues in adults (e.g., McTeague et al. 2010; Pole, 2007) and in children (e.g., Grasso & Simons, 2012; Scheeringa, Zeanah, Myers, & Putnam, 2004). Not surprising, many of the symptoms that characterize posttraumatic stress disorder (PTSD) are defined by physiological arousal to trauma reminders and other threat cues. Interestingly, there is even some evidence that physiological indicators assessed prior to or very soon after trauma exposure can predict whether one goes on to develop PTSD symptoms (Bryant, Salmon, Sinclair, Psychol, & Davidson, 2007; Pineles et al., 2013). This may have implications for secondary prevention efforts.
In summary, the picture that is emerging from this research literature is one that implicates childhood violence exposure in altered detection of and reaction to stressors in children’s environment. If we can achieve a deeper understanding of the processes by which violence exposure interacts with contextual risk and protective factors, as well as biological mechanisms, we may be better equipped to design preventive interventions and treatments that can more effectively harness the adverse effects of family violence exposure on children.
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