Children between the ages of 4 - 16 years were tested for a sense of direction using the 'chair experiment'. Results revealed that a sense of direction was present in older children. However. the relationship between the development of a sense of direction and age appeared more complex than originally thought. Children under 11 years of age were unable to judge direction significantly in the chair experiment. It was suggested that this inability could be related to anatomical andlor perceptual constraints. Sex differences in ability were analysed. Although both males and females could significantly judge direction, female orientation was significantlY better than that exhibited by males. Analysis of the patterns of performance during the test revealed that male success was apparently due to an ability to follow the turning of the chair. with only the first estimate exhibiting significant ability. Females. although they probably followed the turning of the chair initially, showed a second peak of significant ability in the latter estimates. Whilst wearing a magnet. this second peak was not observed. Magnetic manipulations carried out on females aged between 11 - 18 years revealed that their ability to judge direction was based on an ability to use the earth's magnetic field to judge direction. However. this relationship was not straightforward. Both the polarity of the magnet and the bed orientation of the subject had an affect on ability to judge direction. Bus experiments were also used to test for a sense of direction. Subjects were aged between 16 - 20 years. Half the subjects were blindfolded and half were sighted. Results revealed that feBBles, whether blindfolded or sighted, relied on the earth's magnetic field when judging direction and exhibited disruption of ability whilst wearing a magnet. Kales apparently required sight and an unaltered magnetic field to judge direction. Thus, if sighted and wearing a magnet, or if blindfolded and in an unaltered magnetic field, males were unable to judge direction. Although male ability in the chair experiment did not seem to be based on an ability to use the earth's magnetic field to judge direction, the bus experiments suggested that magnetism was involved in their ability and this required further investigation.