Facial and detailed knowledge of the features in

Facial recognition is extremely important for everyday life.
It not only allows us to recognise people whom we know and may be close to, it
also allows us to be aware of any dangers of people we do not recognise and do
not know. It is also very important for human interaction and socialisation
which is an aspect of life humanity would struggle to live without. Humans are
able to recognise and identify an almost infinite number of different faces and
use this to recognise different individuals. Faces have both invariant (age,
sex and ethnicity) and changeable (mood and gaze) features (Haxby &
Gobbini, 2010). Face recognition is thought to be a ‘special’ aspect of object
recognition however there is evidence to suggest that face recognition and
object recognition use different neural systems within the brain and are
therefore different cognitive processes. Face recognition is very complicated,
much more so than object recognition, because individuals need more than just
the basic shapes and their rough location in order to recognise a face. This is
because faces are very similar in those basic terms, the eyes, nose and mouth
of individuals are all in the same format on a face. Facial recognition
requires more specific and detailed knowledge of the features in order to
recognise an individual. Furthermore, aspects such as expression or speech
(mouth movement) which are changeable features, must not change an individual’s
identity and therefore face recognition must not change across these
alterations. There is strong evidence to suggest that recognition of faces and
recognition of expression are two independent cognitive processes and therefore
do not influence one another (Bruce & Young, 1986).
Face recognition focuses on faces as a whole whereas object recognition takes a
stimulus apart. This is called the hypothesis of holistic face representation.
This hypothesis has been widely researched within psychology in order to gain
further understanding into face recognition and its difference to object
recognition, including its neural structure. Individuals have found to be able
to more accurately recognise parts of faces when presented in the whole object
than identifying the same part but in isolation (Tanaka
& Farah, 1993). This evidence supports the holistic face
representation hypothesis however there is still not enough substantial
evidence to claim that face recognition is holistic. The definition of holism
is unclear and undefined which make it difficult to put them into use in
research.

Facial recognition and attention to faces is thought to
develop from an early age or is innate. Newborns have a preference to faces
over objects and patterns just only 30 minutes after being born (Johnson, Dziurawiec,
Ellis & Morton, 1991).  In addition,
the neural systems of face recognition develop within the first six months of
life whilst faces and objects are being differentiated between (Nelson, 2001). Johnson (1990) reviewed the development of
face recognition and stated that infants shift from subcortical to cortical
visual processing within the first few months which provides an explanation of
the possible neural pathways in infant face tracking. Research into the development
of face recognition’s neural structures shows how the right fusiform face area
id double the size in 12-16 year olds than 7-11 year olds and even bigger in
adults (Golarai, Grill-Spector & Reiss, 2006). This early research
into the development of face recognition not only provides evidence of the
speciality of face recognition but also an understanding of how the brain
develops and more specifically, how the neural structures develop. This essay
will discuss the neural structures of face recognition whilst evaluating
supporting research. It will focus on the three core structures of face
recognition (OFA, STS and FFA) using different brain imaging methodologies to
assess them.

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Face perception is argued to be
carried out by domain-specific or domain-general mechanisms. Domain-specificity
argues that different cognitive processes are controlled by specialised and
specific areas. Domain-general opposes this and argues that the structures used
in face recognition are not particular and are responsible for a variety of
cognitive processes (Kanwisher, 2000). Evidence supporting domain specificity
is the face inversion effect (Valentine, 1988). This proposes that faces are
harder to recognise when inverted than when upright and also harder to
recognise than when other stimuli are inverted. This effect provides reasonable
amounts of evidence that face recognition could use its own neural system
however the effect could just be apparent because our initial perception of
faces does not allow for inversion effects. Although this effect suggests that
face recognition is ‘special’, inversion has only been focused on faces and so
other inversion effects could be possible for other stimuli. In addition, domain-specificity
in face recognition is supported by cases of individuals suffering with
prosopagnosia. Prosopagnosia is the inability to recognise familiar faces either
due to brain damage (acquired prosopagnosia) or a genetic disorder from birth
(developmental prosopagnosia) (de Gelder &
Rouw, 2000). Many cases of individuals suffering from prosopagnosia have been
used as evidence to show the difference between the neural structures of face
recognition and object recognition because of the individuals’ (mostly intact)
ability to recognise objects still. Therefore supporting the idea of
domain-specificity for face recognition. However, there is still the factor
that the results of these individuals on the object recognition task are still
lower than normal which suggests that there aren’t completely specialised
regions for face recognition. Taking this into account, there is still evidence
that shows the areas affected in patients with prosopagnosia which aids in the
understanding of regions that are used in face recognition. In her book Visual Agnosia, Martha Farah (2004)
analysed these regions. Interestingly, 65% of the patients had bilateral lesions
and 35% had unilateral lesions involving the occipital and temporal cortices,
suggesting them to be neural structures of face recognition. A model proposed
by Haxby, Hoffman and Gobbini (2000) proposes the specific core and extended neural
systems responsible for face recognition. McNeil and Warrington (1993) argue
that prosopagnosia is face specific with their study of a case whom could still
recognise his sheep however could not recognise human faces. These findings
suggest that human face recognition may be more complex because it can occur as
a face-specific deficit.

Regions within the brain activated
during face recognition have been recognised through the use of brain imaging
techniques such as fMRI, TMS and EEG. Some methodologies are used together as
they reveal different aspects of cognitive processes and regions within the
brain. Brain imaging is vital for the understanding of cognitive processes and
their neural structures. It indicates the parts of the brain responsible for
certain processes by looking at what areas of the brain are stimulated when the
cognitive process is happening or what part of the brain is damaged and the
side effects of this show what that part is responsible for e.g. damage of the
ventral occipitotemporal cortex causing prosopagnosia leads to the conclusion
that this is one part of the brain responsible for face recognition (Sergent
& Signoret, 1992). Although there are vast amounts of evidence supporting
domain-specificity in face recognition, it is not entirely clear that these
regions are only active for face recognition. Brain imaging highlights how some
regions are activated for face recognition but also for other cognitive
processes such as the recognition of objects (Chao, Martin & Haxby, 1999).
Studies of prosopagnosia patients are flawed because tasks are not always
matched and therefore these cannot state that individuals wouldn’t show similar
impairment on other tasks if properly matched (Gauthier, Behrmann & Tarr,
1999). Furthermore, studies have found that the regions responsible for face
recognition can also be significantly activated by objects and animals (Ishai,
Ungerleider, Martin, Schouten & Haxby, 1999; Kanwisher, Stanley &
Harris, 1999).

The core system is what is used to
process invariant facial features whereas the extended systems processes the
changeable characteristics of faces. The core system for face recognition is
made up of the; inferior occipital gyri (also known as the occipital-face-area
or OFA), superior temporal sulcus (STS) and the lateral fusiform gyrus (also
known as the fusiform face area or FFA) regions. Significant evidence has been
found for the lateral fusiform gyrus in evoking activity for face perception
and this has led to some people calling it the ‘fusiform face area’. This
study used fMRI to show how the lateral fusiform gyrus was more 80% more active
when identifying faces over objects such as cars and spoons, therefore
providing valid evidence that this area is a structure of face recognition (Kanwisher, McDermott & Chun, 1997). The extended system is made up of the, intraparietal sulcus,
auditory cortex, amygdala, insula, limbic system and the anterior temporal
regions. Each responsible for other functions as well such as emotion and
spatially directed speech perception (Haxby, Hoffman & Gobbini, 2000). Although
the occurrence of extended systems implies that face recognition is not
domain-specific, they are only aiding face recognition when working with the
core system. Therefore supporting domain-specificity because the core regions
are specific for facial recognition. Further evidence supporting this is a
study by Perrett, Smith, Potter, Mistlin, Head, Milner and Jeeves (1984) whom
identified neurons in the superior temporal sulcus and inferior temporal cortex
that respond to faces in the brains of macaques however the evidence for human
brains was not strong enough. Nevertheless, further experimentation and
research could find significant evidence within human brains and so this should
not be completely discredited. One hypothesis about the core systems is that
the FFA controls the processing of invariant face features whereas the STS
controls the processing of more dynamic features such as monitoring eye gaze or
handling lip reading. The study presenting this idea used fMRI brain imaging
and found that the FFA responded to all faces, regardless of the expressions
whereas the STS only responded to the faces that showed strong emotion when
showed images of faces for only 2 seconds (the invisible condition) (Jiang
& He, 2006). This evidence portrays the different roles of the neural structures
for face recognition and how they contribute to the process and supports Haxby
et al.’s (2000) model. A more complex hypothesis of face recognition comes from
research by Gauthier, Tarr, Anderson, Skudlarski and Gore (1999) whom proposed
that within-category discrimination and visual expertise cause activation in
the fusiform face area. This hypothesis supports domain-generality because it
proposes that FFA is not specific to face recognition because response to other
stimuli could also occur here. This is a weak argument because the results from
the study still showed significantly larger amounts of activity in response to
faces than to the expert category, suggesting that domain-specificity is not a
rigid idea as some areas can still aid other cognitive processes. Furthermore,
the properties of the expert stimuli (Cars and birds) both hold similar
features to faces (headlights and birds eyes) and this could explain why the
FFA was activated by these (Turati, 2004).This is where the study could be improved
on, stimuli in way similar to faces could be used to identify if the is still
activation within the FFA for expert categories. The study does put forward the
argument that face recognition is only special because we are all experts at it
because of its important use within everyday life and this is an idea that
needs to be further researched.