We are in our living room sitting next to a relative. We observe our family member and we have no doubt that it is that person. Next to it is a vase. We look at the vase and we are sure of its shape, its outline, its colors and all its features. The task we are carrying out is known as recognition, and we do it hundreds of times throughout the day. We recognize our father, our mother, our friends, and we also recognize a mobile phone, a computer, a fork, etc. The differences in the recognition of faces and objects pose a challenge to scientific research.
So far, recognition tasks take place automatically: we see something and we know what it is. However, even though it seems the same, Many researchers have wondered if at the brain level there are differences in recognition between faces and objects. What parts of the brain are activated when we see a face? What parts come into play when we see an object? Are they the same or are they different?
- 1 Differences in the recognition of faces and objects
- 2 Differences in recognition at the neuronal level
- 3 Discussion
Differences in the recognition of faces and objects
Although the investigations still do not show a clear difference on whether the recognition mechanisms are the same or not, there is some evidence that this could be the case. Tanaka and Farah (2003), in their investigations, found that faces are processed as a whole and objects based on their components. The faces, unlike the objects, have an important biological and social relevance, since they provide information on important aspects of the people with whom we interact. For example, we can obtain data such as age, sex, gaze direction, mood, and this can directly influence social interaction and learning.
The faces are interpreted as a whole. The interaction of its components (nose, mouth, eyes, eyebrows, etc.) form this whole and goes beyond its components. Objects are usually recognized by their parts and compared with the image we have stored in our memory. When we look for a certain object, we compare the image we have of that object in our memory with the real object. We intend to find an object that responds to characteristics such as color, shape, etc.
The funny thing is that they found that inverted faces are also processed based on their components. In their experiment they exposed photos of objects and inverted faces, and the faces proved more expensive to interpret. Bartlett and Searcy (1993), state that when faces are presented in an inverted way, their characteristics are processed independently and not as a whole. On the other hand, Bruyer and Coget (1987), ensure that the relational characteristics (the set of components of a face) are distorted when the faces are inverted.
Differences in recognition at the neuronal level
Neural lesions have provided interesting data on the differences in the recognition of faces and objects at the brain level. As Luna and Tudela affirm, "lesions in the inferotemporal cortex fusiform virus in the right hemisphere generally cause prosopagnosia (inability to recognize faces) but practically do not affect object recognition ". On the other hand, these authors ensure that "the same lesion in the left hemisphere would cause inability to recognize objects, but it leaves almost intact the ability to recognize faces ".
Neuroimaging techniques also shed light on this difference in terms of different modular components in the visual recognition of faces and objects. Haxby's team (1994), through positron emission tomography (PET), showed that certain areas of the ventral tract were activated when face recognition tasks were performed. The same results were obtained when functional magnetic resonance imaging (fMRI) was used. This technique located activation more thoroughly in two areas: the superior temporal sulcus and the fusiform gyrus.
Kanwisher's team (1997), determined that a small region of the right fusiform gyrus is activated in the perception of faces. Different investigations have gone further and have found out that different areas of the human ventral current seem to be activated in view of houses or human beings. As John Pinel (2006) states, "First, there is more than one area of the ventral current that responds to each category of objects; second, there is a large overlap between the areas that respond to various categories of objects".
Pinel says that "If there are neural circuits in the human cortex that are specific for the visual recognition of specific categories of objects such as faces, it seems that they are interspersed with circuits to recognize other objects". The fact that these circuits are interspersed makes it even more difficult to investigate the neural centers associated with the recognition of faces and objects. It is therefore, necessary to continue with the investigation. In this way, by shedding more light on these differences, patients with difficulty in recognizing both faces and objects can be helped more precisely.
- Bartlett, J. and Searcy, J. (1993). Inversion and configuration of faces. Cognitive Psychology, 25 (3), 281-316.
- Haxby, J., Horwitz, B., Ungerleider, L., Maisog, J. Pietrini, P. and Grady, C. (1994). The functional organization of human extrastriate cortex: a PET-rCBF study of selective attention to faces and locations. Journal of Neuroscience, 14 (11), 6336-6353.
- Kanwisher, N., McDermontt, J. and Chun, M. (1997). The fusiform face area: a module in human extrastriate cortex specialized for face perception. Journal of Neuroscience, 17 (11), 4302-4311.
- Luna, D. and Tudela, P. (2007). Visual perception. Madrid: Trotta Editorial.
- Pinel, J. (2006). Biopsychology Madrid: Addison-Wesley.