s theory of mind, particularly the deception facet, affected by environmental influences? Previous studies have shown that the ability to attribute mental states such as desires, beliefs, or intentions to oneself and others (ToM) occurs in children of three or four. Research has also been conducted to further investigate whether outside factors influence the acquisition of this developmental milestone. They show to varying degrees that interaction, with older individuals, affects a general theory of mind score. However, little research has been gathered about environmental influences on deception. The concept of deception may be especially complex because it involves insight not only into the difference between the protagonistâ€™s and onlookerâ€™s mental state, but into the causal links between the two (Astington et al., 1988). Because deception may be a higher indicator of ToM, it might be more difficult to grasp and thus more susceptible to environmental influences. This present study specifically examines the effects father occupation and number of older siblings has on this theory of mind-related, deception task. 48 children, ranging in age from three to eight, from a local play school, answered questions relating to false belief, appearance reality, and deception tasks. Incorrect and correct answers were recorded and socio demographics were completed. Correlational analyses replicated previous findings: children performed at higher levels on all tasks as a function of age. In addition, one-way ANOVAs showed that children with white collar fathers had significantly higher deception scores than those with blue collar. There is also a significant increase in deception scores in children with two older siblings than those with less than two. These findings replicate and extend previous studies indicating environmental influences on theory of mind. The complex nature of deception and various validity matters are discussed.