A study using the Young Lives data in Ethiopia found that young children whose mothers had died were 20 per cent less likely to enroll in school, 21 per cent less likely to be able to write, and 27 per cent less likely to be able to read.[41] Dybdahl[42] found that 5- to 6-year-old war-traumatized Bosnian children showed lower levels of cognitive competence. Pre-school and school age Palestinian children exposed to severe losses, wounding and home destruction suffered impaired cognitive capacity for attention and concentration.[43] Severe trauma has been found to be associated with inexcitable and narrowed attention and problem-solving strategies.[44] Since both physical and mental health are linked to language and cognitive development,[5] it is reasonable to assume that violent conflict has a negative effect on these areas of development.[6]