Whilst humans have a large brain with regional specialization for solving complex tasks (Kandel et al.,2000), in certain cases the miniature brain of invertebrates performs analogous tasks. For example, bees are capable of using top-down visual processing (Zhang and Srinivasan,1994), can balance conflicting speed accuracy demands in task allocation (Chittka et al.,2003), learn principles of symbolic matching(Giurfa et al., 2001), solve complex maze-type problems and demonstrate context-dependent learning(Zhang and Srinivasan, 2004)and can use a symbolic coding system to communicate with conspecifics(von Frisch, 1967).
Studies of the capabilities of bees question the extent to which large specialized brains are required to solve sophisticated cognitive tasks(Zhang and Srinivasan, 2004). What we can learn from the miniature brain is the extent to which higher functions can be achieved without the complexity (and associated cost) of a large mammalian brain. For bees, it is reasonably straightforward to control the ontogenetic history of individuals, and if the bee's brain can reveal novel solutions for face processing this will potentially lead to algorithms for artificial intelligence.
Our recent study (Dyer et al.,2005) does not exclude the possibility that humans have regional specialization that allows for fast processing of a relatively large number of faces (p. 4713). However, the finding that bees can recognize stimuli representing human faces does question the extent to which regional specialization is actually necessary for a brain to perform particular tasks; especially for reasonably straightforward face recognition tasks (although even in humans very few subjects score perfectly on Warrington face tests) (Warrington,1996). It is clear from our study that some level of face recognition is possible from a miniature brain with absolutely no evolutionary history for this task.
It is unlikely that bees will be able to recognize conspecifics using facial cues, not because of a lack of cognitive ability but because individual bees probably have insufficient facial markings to enable a visual identification. An important factor in the impressive conspecific face recognition capabilities of paper wasps is that different individuals have specific face marks (Tibbetts,2002), which bees do not have. Even humans are typically poor at recognizing face stimuli when the stimuli class appears too similar; for example, recognizing individuals from a different race category(Valentine and Endo, 1992). Thus, it would not really be surprising if bees cannot recognize conspecifics,even though it is clear that highly trained individual bees are capable of recognizing human faces.
The study by Schwarzer et al. (Schwarzer et al., 2005) does show some evidence that children use configural processing less than adults (p. 352) and so does not fully discount the idea that the visual system develops configural strategies with experience. In agreement with previous work that demonstrates that humans use feature extraction and configural processing for face recognition(Collishaw and Hole, 2000), the study by Schwarzer et al. presents evidence that humans use both feature extraction and/or configural strategies(Schwarzer et al., 2005). The interesting point from recent insect vision studies is that bees also appear to use feature extraction and configural processing depending upon level of experience with stimuli (Giurfa et al.,2003), and thus bees serve as a good model to understand how processes might operate in a miniature brain. As visual strategies used by bees can potentially be wholly transferred to artificial intelligence applications (Srinivasan et al.,1997), this is an exciting model from which we might learn a great deal.