What mental and emotional effects does the Veldt have on the children?
The difficulty that the veldt holds is that it provides so much in way of comfort and supposed happiness that the children become dependent on it. They view it as superseding any other emotional connection. Technology, in the form of the projection of the veldt in the nursery, has become the dominant means by which the children relate to their world. This becomes the root of the mental and emotional effects that the veldt has on the children. Peter becomes dependent on the veldt, seeing as the central aspect of his being.
George and Lydia understand that the projection of the veldt images of destruction, death, and superiority are dominating their children's mind. The projection of the veldt reflects how the emotional and mental effects that the technological nursery has on the children. The children are not seeing the world in terms of redemption, nurturing, and positive transformation. Rather, Peter and Wendy are seeing the world around them as a battle for superiority and power, something they wish to rip away from their parents. The mental and emotional effects that this dependence on the image of the veldt has on the kids is to wither away the bonds of attachment to their parents. In the setting of the veldt with the "hot sun, vultures, and feeding lions," it becomes clear that the children view reality as an appropriation of power and demand their their will is absolute. This condition of being is one where tender intimacy has become replaced with control and domination, reflection of the mental and emotional effects that the veldt and technology, in general, has on the children.