|Title||Featural and holistic processing in facial composite construction: the role of cognitive style and processing sets|
When a serious crime has been committed, eyewitnesses may be required to assist a police investigation by constructing a facial composite of the perpetrator of the crime with the help of a police operator. A large body of research has investigated the utility of composite construction systems and the ways in which they are implemented with eyewitnesses. There has been less research conducted on individual differences which might have an impact on the accuracy of facial composites which eyewitnesses produce. The first aim of the research presented within this thesis was to investigate whether individual differences in stable cognitive style have an effect on the accuracy of the facial composites they produce. The second aim of the research was to investigate whether manipulating the temporary cognitive processing state of individuals during face encoding and prior to facial composite construction affects the accuracy of the facial composites they produce. These issues were investigated using two facial composite construction systems currently in widespread use by UK police forces, E-FIT and EFIT-V.
Study One investigated, for the first time in the facial composite literature, individual differences in the cognitive style of field dependence/independence (Witkin, Oltman, Raskin & Karp, 1971). Results indicated that field independent individuals produced more accurate composites than field dependent individuals. Study Two investigated individual differences in holistic/analytic cognitive style (Riding & Cheema, 1991). Results indicated that individuals with a holistic cognitive style produced more accurate composites than individuals with an analytic cognitive style.
Study Three manipulated the way in which faces were encoded by individuals, and introduced a Navon (1977) task into the composite construction process using E-FIT. Results showed that the Navon task had an effect on the accuracy of the facial composites that individuals produced which was mediated by the way in which the target face had been encoded. Study Four introduced a Navon task prior to composite construction using the EFIT-V system. In addition, the field dependence/independence cognitive style of the participants who created an EFIT-V was measured. Results showed that the Navon task had an effect on the accuracy of the EFIT-V composites
that individuals produced, which was mediated both by the way in which the target face was encoded, and by the cognitive style of the individual.
Overall, the findings indicated that there is a strong featural cognitive processing element to facial composite construction which is at odds with the way in which faces are processed and represented in memory. Collectively, the results indicate that featural cognitive processing prior to the composite construction process may lead to more accurate facial composites. In addition to this, if an individual does not have a natural featural processing cognitive style, then inducing a featural cognitive processing state may also lead to more accurate facial composites.