One of the most interesting psychological features of young children are their relationships to their imaginary friends. Between 28-65% of young children have imaginary friends and contrary to stereotypes of such children being emotionally disturbed, withdrawn and shy recent research has shown having an imaginary friend to be associated with positive developmental outcomes. Some psychologists have wondered how having an imaginary friend in childhood might affect development in adulthood and have observed how talking to an imaginary friend bears a similarity to symptoms of psychopathology such as verbal hallucinations. A study of 80 young children (4-8) in Australia and the north of England asked them whether they had an imaginary friend and then carried out a jumbled speech task on them which measures participants' likelihood of perceiving words in meaningless but speech-like auditory stimuli. The researchers found that those children who had an imaginary friend were more likely to report hearing words and phrases in the jumbled speech task independent of their age, sex and verbal ability. The findings of the study were consistent with the hypothesis that engaging with imaginary friends is one aspect of a general susceptibility to imaginary verbal experiences.
Fernyhough, Charles ... [et al] - Imaginary companions and young children's responses to ambiguous auditory stimuli : implications for typical and atypical development Journal of Child Psychology and Psychiatry November 2007, 48(11), 1094-1101