The nature of these machines makes it possible for discrimination against ordinary persons. Ordinary persons who may have a predisposition towards certain tendencies could be found out and victimised even though they have yet to commit a crime they have the brain pattern of a criminal. This is the dark side of technology. More research is needed to determine whether or not there are differences between criminals and ordinary persons.
There is room for these tests to be manipulated by either the prosecution or the defence.
Which ever team pays for the tests can get the results that they so desire. Over sensitivity of the machinery needs to be controlled for in the tests in order for their reliability to be increased, and their usefulness enhanced. More research needs to be done to determine if there are genuine differences between the brains of criminals and ordinary persons. If the tests are genuinely able to discover differences between criminals and ordinary persons then maybe abnormalities can be controlled for before criminal behaviour is expressed.
Deregowski Depth Cue- Depth cues are (hints, guides, cues) which provide information about the spatial (positioning relative to each other) relationships among objects (three dimensional) in a picture (two dimensional). Familiar Size- The cue whereby objects, which are further away in the picture, are drawn smaller than objects of the same size which are closer. Overlap Cue- The effect of a nearer object obscuring parts of a more distant object. Perspective- This is given by the convergence of lines depicting edges which are parallel in the real world, but which appear to come together as they move into the distance e.
g. a railway track.
A person using a depth cue will extract a completely different meaning from a picture than will a person who is not using such pictures. Various drawings of an elephant, an antelope, a person, a tree, a road, some hills and a flying bird were shown. Empirical Test The tests are empirical because numeric information was collected. How many persons made different responses e.t.c These tests involved showing pictures and asking questions. What do you see? What is the man doing? Which is nearer the antelope or the elephant?
The questions were asked in the subjects, native language. This means the results were not affected by confusion resulting from the use of the interviewers language or from translations. They understood exactly what they were being asked. There was a potential problem with classification. If questions were answered correctly according to western standards it was automatically assumed that they were three dimensional perceivers. This could have impacted upon the results. The tests may not have been measuring cultural differences as noted but instead, educational and social levels. Evidence for this is provided by persons of better educational and social levels performing better on the tests. Remember children have better access to western culture and education than do adults. Additionally higher educational and social levels provide persons with access to western culture.
Deregowski reviewed Hudson’s work and put forward some different opinions. This means the results could have been a consequence of interpretation. The study includes information from different time periods. The results may have been as a result of this time elapse. For e.g. the info collected from Zambian school children-information was presented from both 1960 and 1972. There culture and circumstances may have changed tremendously during the time elapse. Adults and children were differentiated. Therefore a comparison could have been made to take into account changes in culture. Note Hudson found that children had higher rates of three dimensional perception than did adults. [note-Deregowski found that both adults and children had difficulties making three dimensional perceptions]
Ecological Validity The Subjects may have been put in artificial categories which were a consequence of the test-three dimensional and two dimensional perceivers. Persons are not normally required to view pictures under these conditions (circumstances) as existed during the study. The tests may have been picking up differences in educational and social levels and not culture as was suggested.