AD ALTA
JOURNAL OF INTERDISCIPLINARY RESEARCH
WHEN LEFT IS RIGHT: THE PREFERENCE FOR THE LEFT SIDE OF THE FACE IN
ATTRACTIVENESS AND EVALUATION RATINGS
a
SLÁVKA DÉMUTHOVÁ,
b
ANDREJ DÉMUTH
a
University of Ss. Cyril and Methodius in Trnava, Nám. J. Herdu
2, Trnava, Slovakia
email: slavka.demuthova@ucm.sk
b
Trnava university
, Hornopotočná 23, Trnava, Slovakia
email: andrej.demuth@truni.sk
This work was supported by the grant KEGA 004TTU-4/2015.
Abstract: The dominance of the right hemisphere in facial perception emerges as a
presumption of a preference for the left part of visual field over the right. The
outcomes of several studies are not consistent in verifying this hypothesis. This
research tested the preference for the left visual field using male and female mirror
images of the right half of the face and the left half of the face in two tasks – an
attractiveness assessment and in a specialized facial-evaluation task – by both male
and female evaluators. Subjects (N = 2,267) were Slovak females (N = 1,356; 59.8%)
and males with a mean age of 24.01 years. The Chi-Square Test showed a strong,
statistically significant (sig. = 0.000) preference for the perception of the left half of a
human face in both tasks; in both males and female evaluators. This tendency was the
most prevalent in the female face composites and in the attractiveness assessment.
Keywords: Visual field, dominance, face perception, hemisphere.
1 Introduction
Facial perception is considered to be a special type of visual
perception for various reasons. Facial perception, unlike the
perception of other “non-facial” objects, shows the signs of an
inborn characteristic (Maguinness and Newell, 2014), the
processing style used for recognizing faces is unique, as it is not
present when we perceive other objects and, from numerous
studies, it also seems, that there are face-specific neural
representations of facial perception (McKone and Robbins,
2014).
Within the uniqueness of the process of facial perception, several
brain regions involved in this activity have been identified. The
first cases that stressed the specificity of facial perception were
connected with prosopagnostic patients, who did not show any
sign of damage within visual perception, except in face
recognition. One of the first well documented cases comes from
1947 by Bodamer (Ellis and Florence, 1990) and turns attention
towards the fusiform gyrus region. Further studies revealed that
the most specific forms of prosopagnosia are due to lesions of
the right posterior network including the fusiform face area and
the occipital face area, whereas face identification defects are
mainly observed within left temporal-occipital lesions (Gainotti
and Marra, 2011).
Except for wide research that considered the areas of the brain
specifically involved in facial perception – e.g. occipital face
area – OFA (Pitcher, Walsh, and Duchaine, 2011), fusiform face
area – FFA (Fairhill and Ishai, 2007), superior temporal sulcus –
STS (Pitcher, Walsh, and Duchaine, 2014), intraparietal sulcus –
IPS (Hoffman and Haxby, 2000), auditory cortex (Campbell,
2014), limbic system and amygdala (Williams and Mattingley,
2004; Pitcher, Shruti, Rauth, and Ungerleider, 2017), or anterior
temporal lobe (Kriegeskorte, Formisano, Soger, and Goebe,
2007) studies opened the question of lateralization of functions
connected with facial perception. Generally, there is a tendency
to stress the importance of the right hemisphere (De Renzi,
Perani, Carlesimo, Silveri, and Fazio, 1994; Burt and Perrett,
1997; Yovel, Tambini, and Brandman, 2008
)
. From brain trauma
case studies it has emerged that the consequences of lesions were
more evident if the right hemisphere was damaged (De Renzi,
Perani, Carlesimo, Silveri, and Fazio, 1994) affecting e.g.
specific processes of configural features perception (Abbott,
Wijerante, Hughes, Perre, and Lindell, 2014). This has been
followed by studies in which the importance of the left and right
visual fields were compared (Franklin and Adams, 2010) or
studies on left-left vs. right-right facial symmetry (Nicholls,
Wolfgang, Clode, and Lindell, 2002; Chen, Liu, and Fu, 2007).
During facial perception, each hemisphere processes the
information that is presented in the contralateral visual field.
That means that information from the left visual field is sent to
the right hemisphere, whereas information from the right visual
field is sent initially to the left hemisphere (Jung et al., 2017).
The outcomes of the studies mentioned are not consistent with
the initial presumption, that the left visual field and right
hemisphere are generally more important for facial perception
than the right visual field and left hemisphere. E.g. faces rated in
a sexual context gave a better prediction of attractiveness rating
for faces shown in the left rather than the right visual field,
whereas faces rated in a nonsexual context gave a better
prediction of attractiveness of faces shown in the right rather
than the left visual field (Franklin and Adams, 2010). Different
results favouring the right or left hemisphere also emerged from
the study by Zhai and colleagues, where they found that the
perception of a father’s face involves the left inferior parietal
lobule and left middle frontal gyrus/right middle frontal
gyrus/right inferior frontal gyrus, whereas the perception of a
mother’s face involves the right inferior parietal lobe and frontal
network (Zhai, Yu, Zhang, Chen, and Jia, 2016).
Another type of study emerged from interest in the perfect
symmetry of the face. From an evolutionary point of view, facial
symmetry (as well as symmetry of the overall organism) is
considered an indicator of developmental stability (Simmons,
Rhodes, Peters, and Koehlerb, 2004). Symmetry deviations are
then the result of the failure of an organism to cope with various
adverse environmental (e.g. climate, pollution, malnutrition,
parasitism) or genetic (inbreeding, mutation, etc.) factors (Moller
and Anders, 1997). Since these qualities may be hereditary, a
preference for symmetry in human faces may have been
favoured by natural selection (Penton–Voak and Perrett, 2000)
and has been proven to be considered as attractive (Scheib,
Gangestad, and Thornhill, 1999; Jones, DeBruine, and Little,
2007; Little, Jones, DeBruine, and Feinberg, 2008). As a
consequence, the more symmetrical a face the higher the
attractiveness rating should be.
An attempt to verify this presumption brought a new research
area focused on the judgement of the attractiveness of faces
which have been made using mirror images of the left or right
face sections and thus considered to be perfectly symmetrical.
From the point of view of symmetry and thus the level of
attractiveness, there should be no difference in judgements for
left-left or right-right facial composites as they are both perfectly
symmetrical. However, results show, that the attractiveness
ratings differ according to the section (left, or right) from which
the mirror image was made (Butler and Harvey, 2005; Parente
and Tommasi, 2008) with a preference for the left side of the
face. Again, these findings are not universal; there are also
different results depending on the specifics of the judgements –
e.g. in the observation of emotions, the left-left facial composite
over the right-right composite was assigned with greater
importance (Nicholls, Wolfgang, Clode, and Lindell, 2002;
Chen, Liu, and Fu, 2007). On the other hand, Zaidel and Cohen
(2005) did not reveal any significant differences between left-left
and right-right composites in attractiveness assessments. In
another study Zaidel with colleagues, found that subjects
significantly rated right-right composites of ordinary women’s
faces as being more attractive than left-left, whereas men’s right-
right versus left-left was not significantly different (Zaidel,
Chen, and German, 1995).
2 Problem
From the mentioned results and numerous other studies, it seems
that the preference for right hemisphere and left visual field in
facial perception is not uniform in all cases. First of all, the
results may vary according to the type of evaluation task
connected to facial perception (e.g. attractiveness evaluation vs.
emotional expressiveness). Also, they could differ according to
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