Friess, M. (2010): Parietal expansion during later hominin evolution, and the validity of H. heidelbergensis – A quantitative approach. Bulletin der Schweizerischen Gesellschaft für Anthropologie 16(1–2): 55–61
The evolution of the modern cranial shape and globularity is the result of a variety of morphological changes that occurred during the later Pleistocene, parietal expansion being one of them. However, this trend has also been described in Neandertals, which bears the question, when and where this character appears, and what it implies for middle Pleistocene human phylogeny. This study presents a quantitative comparison of parietal shape in various species of Homo based on 3D geometric morphometrics. The results confirm the existence of a shared trend toward parietal expansion found in both H. sapiens and H. neanderthalensis, but absent in H.erectus and H. rhodesiensis. If confirmed by additional samples, this would be consistent with an afro-european last common ancestor of modern humans and Neandertals, though to the exclusion of Petralona and Kabwe.
Friess, M. (2010) Calvarial shape variation among Middle Pleistocene hominins: An application of surface scanning in palaeoanthropology. C.R. PALEVOL: 435-443.
The increasing availability of 3D data and tools offers new analytical perspectives in palaeoanthropology, such as the quantitative testing of opposing phylogenetic scenarios. Using optical surface scan data and geometric morphometric techniques, this study explores calvarial shape variation in the “Middle Pleistocene muddle”. The morphological variability between H. erectus on the one hand and H. sapiens/neanderthalensis on the other has long remained obscure: opposing views have attributed the known specimens to any of the three species and possibly one or two more. A large number of landmarks and semilandmarks was extracted from the braincase and the face, in order to quantify the calvarial shape differences among species and key fossils. The results are incompatible with the hypothesis that H. rhodesiensis is the exclusive ancestor of H. sapiens, and offer only weak support for an exclusively European ancestor of Neandertals.
We tested three surface scanning systems: the low cost NextEngine laser scanner, the white light Fringe Projection
Breuckmann Smartscan and the white light Fringe Projection Steinbichler COMET V 4M. We evaluate the potential of such
systems for digitalizing original anthropological specimens and compare it with a “nominal” 3D model derived from μCT or CT
data. Our results show that surface scanning of teeth is generally problematic even for high end systems. Even though studies
of the occlusal surface are possible with high end systems, high resolution μCT still has to be considered the best choice for
scientific studies dealing with details of the occlusal surface. However, for general digitalization purposes and recording of
dimensions even the NextEngine system is suitable.
In our tests, Breuckmann Smartscan produced the best models with the lowest deviation compared to the nominal μCTmodel.
The Steinbichler is the fastest system but the quality of the resulting models is slightly lower. NextEngine produces a clearly
lower quality than the tested high end systems but if one considers the different price margins of the systems, the
proportionally good data provided by NextEngine is remarkable. In the case of bones with a simple geometric structure, this
low cost scanner can compete easily with 3D models derived from medical CT for gross morphometric studies.
Friess,
M. (2006) The study of craniofacial growth patterns using 3D
laser scanning and geometric morphometrics. Proc.
SPIE Three-Dimensional Image Capture and Applications.
Throughout childhood,
braincase and face grow at different rates and therefore exhibit variable
proportions and positions relative to each other. This well-known growth
allometry is the object of the present investigation. Using a 3D imaging
technique, laser surface scanning, the geometry of the head and face of 840
children, aged 2 to 19, can be captured and analyzed. From each scan, a series
of 18 landmarks is extracted interactively, as fully automatic extraction of
landmarks is still in an exploratory state. The landmarks are registered using
General Procrustes Analysis (GPA). GPA eliminates unwanted variation due to
position, orientation and scale by applying as least-squares superimposition
algorithm to individual landmark configurations. This allows the investigator
to test for differences in size, shape as well as the interaction between the
two (allometry). With this statistical toolbox at hand, it is possible to test
whether the craniofacial growth in boys and girls follows the same trajectory,
or whether there are allometric differences. Another advantage of this approach
is the ability to visually represent differences in size and shape between
various age groups or between the sexes. This allows the investigator to create
a complex 3D model of head and face and their variation through life time. The
results of this study show that throughout adolescence, boys and girls follow a
different growth trajectory, leading to marked differences not only in size,
but also in shape. These differences can be observed during early childhood,
but become most noticeable after the age of 13 years, when craniofacial growth
in girls slows downs significantly, whereas growth in boys continues for at
least 3 more years.
Understanding the direction and
exact magnitude of these craniofacial differences, which is crucial for many
ergonomic applications, can be vastly improved by the recourse to advanced 3D
measuring methods and the use of geometric morphometrics for the quantification
of size and shape variation.
Friess, M.
(2005) Multivariate
accommodation models using traditional and 3D anthropometry. SAE 2005 Transactions,
Journal of Aerospace.
Various
statistical approaches have been advocated that aim at creating statistically
meaningful and representative models of human variation. While they all have in
common the idea to summarize the critical space needed by the user population
by a discrete number of cases, substantial differences exist as to how exactly
these cases are identified. The choice of statistical procedures also impacts
the number of representative cases (i.e. the efficiency of the model) as well
as the actual percentage of the accommodated population (accuracy of the
model). The purpose of the paper is to test strengths and fallacies of some of
the more commonly found approaches using real as well as simulated data.
Furthermore, an extension of multivariate accommodation models to 3D coordinate
data, which can be used in CAD/CAM environments, is presented.
The results suggest that
while overall accommodation percentages tend to improve when the number of
variables and representative cases increases, various other factors can be
identified that can significantly reduce or even invalidate the model accuracy.
Consequently, simplistic approaches based on multiplying variables/cases do not
necessarily guarantee pertinent models. Rather, optimization strategies must be
sought to reconcile model efficiency and accuracy.
Baylac, M. & Friess, M.
(2005) Combining Procrustes Superimposition and Fourier descriptors:
Analysis of midsagittal cranial outlines. In DE Slice (ed.): Modern Morphometrics in Physical Anthropology. Kluwer: 145-165
The increasing use of
geometric morphometric approaches for the quantification of shape variation,
particularly in anthropology, has put the emphasis on landmarks rather than
outlines. We propose a combination of a landmark based approach, Generalized
Procrustes Analysis (GPA), and Elliptic Fourier Analysis (EFA) for the
quantitative shape analysis of cranial profiles. This approach combines the
advantages of a multiple point registration with the detailed modeling of
outlines using elliptic Fourier harmonics. We applied
it to a sample of two-dimensional cranial profiles of four different
populations in lateral view. The samples include circumferentially (C) and
anteroposteriorly (AP) deformed crania from
Datasets derived from Fourier coefficients
consistently achieved lower cross-validated misclassification rates than
landmark based ones. Nevertheless, we demonstrate the interest to combine
outline and landmark analyses in order to gain insights into the geometric
scale and the regionalization of the shape differences. Our results clearly
point out that AP and C deformed crania both exhibit a significant modification
of the basioccipital and facial parts of the skull. They also clearly highlight
the particular importance of this region to discriminate the AP crania.
Generalized Procrustes analyses of the control points provided classification
percentages as good as the analyses of outlines in the case of AP deformations.
In the case of C deformation, outlines out-performed the landmark analysis,
while landmarks yielded similar discrimination power for the vault and the
entire cranium.
Friess, M.,
Rohlf, F.J., Xiao H. (2004) Quantitative
assessment of human body shape using Fourier analysis. In: Brian
D. Corner, Peng Li, Roy P. Pargas (Eds.) (2004): Proc.
SPIE Vol. 5302, Three-Dimensional Image Capture and Applications VI p.
117-124
Fall protection harnesses are commonly used to reduce the number
and severity of injuries. Increasing the efficiency of harness design requires
the size and shape variation of the user population to be assessed as detailed
and as accurately as possible. In light of the unsatisfactory performance of
traditional anthropometry with respect to such assessments, we propose the use
of 3D laser surface scans of whole bodies and the statistical analysis of
elliptic Fourier coefficients. Ninety-eight male and female adults were
scanned. Key features of each torso were extracted as a 3D curve along front,
back and the thighs. A 3D extension of Elliptic Fourier analysis was used to
quantify their shape through multivariate statistics. Shape change as a
function of size (allometry) was predicted by regressing the coefficients onto
stature, weight and hip circumference. Upper and lower limits of torso shape
variation were determined and can be used to redefine the design of the harness
that will fit most individual body shapes. Observed allometric changes are used
for adjustments to the harness shape in each size. Finally, the estimated
outline data were used as templates for a free-form deformation of the complete
torso surface using NURBS models (non-uniform rational B-splines).
Friess,
M. Corner, B.D. (2004) From XS to XL: Statistical Modeling of Human Body
Shape Change using 3D Surface Scans. SAE 2004 Transactions,
Journal of Aerospace, Volume 1: 215-220.
The
increasing trend towards larger body mass in work force and consumer
populations poses a challenge for accommodating and fitting the shifting range
of variation. The change of body shape and proportions under the influence of
weight can be addressed with multivariate statistical approaches, common in
allometry studies that use whole body models. We present results of a
multivariate allometry study applied to the human body. 3-dimensional outline
data were extracted from whole body surface scans (CAESAR) and analyzed using a
combination of geometric morphometrics techniques and Elliptic Fourier
Analysis. The results show that there is an overall allometric effect of relative
body weight onto body shape, but that different portions of the population are
affected differently by this allometry. The results can be used to accurately
predict body shape associated with an increase in body weight, and therefore
provide data that are of value to a wide range of manufacturing and design
applications.
Friess,
M., Bradtmiller, B. (2003) 3D Head Models for Protective Helmet Development. SAE
Technical Papers Series Proceedings
of the SAE 2003 Digital Human Modeling Symposium,
In
order to improve the fit and comfort of helmets, we developed digital head
models that represent the anthropometric and morphometric variability found in
the U.S. Navy. We analyzed the size and shape variation using two related
approaches. First, we used Procrustes superimposition, which minimizes the
distances between all landmarks of all subjects. This allowed us to visualize
the variation in landmark distribution of the face and to test for statistical
differences. Second, we extracted curvatures along the surface of the head.
This allowed us to characterize the variation in the shape of the head. To
create a series of sized digital models, we used principal component analysis
(PCA) to organize the variation in both the traditional measurements as well as
the locations of the 3D landmarks. Using an adaptation of multivariate
accommodation modeling we identified representative individuals who
characterize 95% of the variation in size and shape. Simultaneously, we used
traditional dimensions to divide the population into a specified number of
sizes, and then used the shape contours to create a summarized head form
representing the individuals in each size.
Friess, M.
(2003) 3D modeling of fall protection
harnesses. Proceedings
of the XVth Triennial Congress of the International Ergonomics Association 7th
Joint Conference of Ergonomics Society of
Korea/Japan Ergonomics Society.
This paper presents an
analysis of human torso shape in 3 dimensions with the goal of improving the
design and accommodation efficiency of fall harnesses. For this purpose, a
sample of 98 male and female adults of mixed ethnic background was scanned
using a Cyberware 3D whole body scanner. The initial scan data, representing
the body as a high density polygon mesh, were post-processed in order for key
features to be extracted and registered as Cartesian coordinates. The data
analysis was limited to the individuals' torso as the principal body portion
the harness has to fit and support. The coordinates form landmark data that
were used to describe the spatial relationship of body shape and harness design
under 'normal' and suspended conditions. The shape analysis of the landmarks
was performed using Generalized Procrustes Analysis (Rohlf, 2000). This
approach, also known as geometric morphometrics, has several advantages over
traditional morphometrics, such as aligning spatial data in a least-squares
type approach, which makes shape variation independent of predefined body
planes and orientations. It also provides a better control of size and size
effects that are relevant for the design of the harness. Finally, the derived
parameters of size and shape variation can then be used as input to a computer
analogue of the human torso, which can serve in the design process as well as
in virtual reality animations.
Friess, M. (2003) An application of the relative warps analysis to problems in human
paleontology - with notes on raw data accuracy. Image analysis and stereology 22:
63-72.
This study investigates the
use of geometric morphometrics as well as methodological aspects specifically
related to its application in paleoanthropology. Based on lateral photographs
taken from a fossil sample of 58 specimens, relative warps analyses were
computed in order to assess the variation of cranial shape among various
hominin groups. The fossil sample represents Middle and Late Pleistocene
populations commonly assigned to H.
erectus, H. neanderthalensis,
archaic H. sapiens as well as
anatomically modern H. sapiens. The
preliminary results indicate that several fossil skulls considered as belonging
to archaic H. sapiens have a distinct
shape compared to modern humans. The results suggest that these hominins are
not as closely related to modern humans as previously thought. Instead, their
morphometric affinities suggest that they are as distinct from modern humans as
are the Neandertals. Methodological aspects, such as raw data accuracy and the
use of type 2 and 3 landmarks that are directly related to this type of
quantitative analysis and that potentially affect their results, are discussed.
Friess, M. & Baylac M. (2003) Exploring artificial
cranial deformation using Elliptic Fourier Analysis of Procrustes aligned
outlines. Am. J. Phys. Anthropol. 122 (1): 11-22.
The
anatomical effects of artificial cranial deformation on the face and the base
have been subject to various metric approaches, including standard linear as
well as finite element techniques, and have produced controversial results
(Antón [1989] Am. J. Phys. Anthropol. 79:253– 267; Kohn et al. [1993] Am. J. Phys. Anthropol. 90:147–158). It can be argued
that diverging observations partly result from methodological constraints. The
present study compares samples of intentionally deformed and undeformed human
crania, using elliptic Fourier analysis (EFA), a morphometric approach which
has been shown to be particularly appropriate for characterizing the shape of
two-dimensional outlines and associated shape changes. We improve the standard
EFA approach by adding a preliminary orientation of the outlines following the
rotation parameters of a Procrustes superimposition, using multiple homologous
landmarks called control points. The results confirm that circumferentially
deformed skulls exhibit modifications of the basioccipital region, together
with increased anterior and inferior facial projection. However, the degree to
which basioccipital flattening is modified in circumferentially deformed
Peruvians was found to be less marked than changes observed in the face. Some
of the modifications observed here can be related to morphological trends
existing in the population from which our sample was taken. The observation of
other modifications may be subject to methodological constraints of standard
morphometric approaches.
Reddy, D.P., Frost, S.,
Friess, M., Marcus, L.F. & Delson, E. (2002). An interactive database for primate morphometric studies. Am. J.
Phys. Anthropol. Suppl. 34 (abstracts):
p 129.
Preparation, organization.
and screening of data is a major task in many conventional and geometric
morphometric analyses. In addition, formatting data sets for use in various
software packages for statistical and morphometric analysis can be very time
consuming. We have built a database that incorporates diverse formats of
morphometric data from our sample of over 5000 measured primate specimens from
worldwide collections. These data include linear dimensions collected by
calipers on both cranial and postcranial elements, 2 and 3 dimensional
landmarks, 3D space curves (connected sets of landmarks), laser-scanned 3D
surfaces, photographs and other 2D images, and volumetric data such as CT
images. Individual specimens are referenced by taxon, collection data, body
part, locality coordinates and other geographic parameters.
The database interface uses
an HTML browser to construct Structured Query Language (SQL) queries to the
database, allowing subsetting, iterative refining, and assembling of
morphometric data using-forms based web pages. Subsetted data sets then can be
formatted for convenient data analysis in morphometric and statistical software
packages. A demonstration version of the database is currently available over
the world wide web [http://research.amnh.org/nycep]. This work was supported by
NSF grants (ACI-9982351 to AMNH and BIR 9602234 for the NYCEP RTG).
Friess,
M. (2002) Revisiting human cold adaptation
- craniofacial shape assessed by 3D laser scanning. Am. J. Phys. Anthropol. Suppl. 34 (abstracts): p 72.
The morphology of the face in
modern as well as fossil human populations has been the focus of debates about
cold adaptation and / or masticatory stress. Published theoretical models are
not conclusive as to exactly how the underlying mechanisms of cold adaptation
might affect the face. In this study, a generalized cold adaptation model
following Bergmann's and Allen's rules is proposed, and its applicability to
present and past populations is tested. For this purpose, relative surface
areas as well as volumes were measured using a 3D laser surface scanner. The
modern human samples comprise supposedly cold adapted populations such as Inuit
and Fuegians, as well as several populations from intermediate and warm
climates (
Results to date indicate that
cold response in the human cranium tends to follow Bergmann's and Allen's rules
at a global scale of comparison and that Neanderthals fit this general model.
However, when populations are compared at a more localized level, the findings
are not consistent with theoretical predictions. It is concluded that cold
adaptation does play a certain role in craniofacial variation, but further
investigation is required in order to differentiate its effects from those of
other influential factors, such as masticatory stress.
Delson, E., Friess, M.,
Marcus L.F. & Reddy D.P. (2002) Assessment of quantitative characters in
the distal humerus among hominids (great apes and hominins). Am. J. Phys.
Anthropol. Suppl. 34 (abstracts): p 61.
The articular morphology of
the distal humerus is known to reflect adaptation to patterns of locomotion in
living primates. It has been argued that the more arboreal orangutans are
characterized by relatively deep fossae, whereas the large-bodied knuckle
walkers have relatively larger articular surfaces than smaller-bodied ones.
Numerous studies have provided comparisons based on conventional and landmark
morphometrics, some of which are restricted to 2D. However, a three dimensional
model of the humerus was expected to contain significantly more information
about the functional variability of the distal articulation. We collected data
with a Cyberware 3D laser surface scanner
having a physical resolution of 0.1mm. We sampled articular surfaces of
great apes (Pongo, Pan, Gorilla),
as well as living and fossil humans. These data allow for a comparative
analysis of terrestrial versus more arboreal quadrupedal locomotion, as well as
the unique bipedal pattern of humans. Ultimately, one of the goals was to
assess the morphometric affinities of hominin fossils whose phylogenetic
position remains unclear, such as TM 517 and KNM-ER 739. Area to Volume ratios
were determined for different functional components and compared across taxa.
Size-related variations, such as sexual dimorphism, were also taken into
account for extant taxa. Major differences at the generic level can be seen in
the size of the articular surface relative to the entire humerus, and in the
relative size of the capitulum. Our results suggest different allometric
patterns in chimpanzees compared to australopiths, contradicting previously
claimed affinities.
Friess, M.,
Marcus, L.F., Reddy, D.P. & Delson, E. (2002) The Use of 3D Laser
Scanning Techniques for the Morphometric Analysis of human Facial Shape
Variation. In Bertrand
Mafart and Hervé Delingette (eds.):
Three-Dimensional Imaging in
Paleoanthropology and Prehistoric Archaeology Acts of the XIVth UISPP
Congress,
The present study explores
the application of laser surface scanning to the analysis of craniofacial
morphology in living and fossil humans. We present a measurement procedure for
the assessment of relative surface areas and apply it to examine possible
craniofacial cold adaptations, for which we also present a theoretical model.
In it's current state of progress, our analysis supports the idea that the
braincase functions as a radiator, and that it's volume-to-surface area ratio
varies consistently with predictions derived from Bergmann's rule, for living
human populations as well as for Neandertals. The relative surface area of the
face is found to vary opposite to predictions derived from Allen's rule. This
suggests that the facial morphology seen among Inuit or Neandertal populations
is driven by factors that are mainly unrelated to climatic conditions.
Friess, M.
(1999b) Some aspects of Cranial Size and
Shape, and Their Variation among Later Pleistocene Hominids. Anthropologie (Brno) 37/3 : 231-238.
This paper
investigates allometric relationships in later Pleistocene fossil humans using
geometric morphometrics. The purpose is to re-evaluate variation of cranial
size and shape and to differentiate pure shape change from size-induced trends.
Cartesian coordinates were collected from 63 fossil specimens, mostly
originals, as well as from a large modern sample. Based on Bookstein's relative
warps analysis (Bookstein 1991, Rohlf 1993), shape variation was examined and
related to centroid size. Results confirm on the one hand strong affinities
between Near-Eastern Middle Palaeolithic humans and clearly modern populations,
and reveal on the other a common archaic vault shape among the Neanderthals and
archaic Homo sapiens. The role of
allometric phenomena for facial morphology is also discussed. It is concluded
that the evidence for a gradual evolution towards modern Homo sapiens in
Friess, M. (1999a) Taille et conformations crânienne chez
les Hominidés de la fin du Pléistocène. Contributions de la morphométrie
géométrique au débat sur l’origine de l’homme moderne. BAR International Series 799,
This volume is a slightly
abridged version of my PhD thesis, as it was submitted at the
Friess, M. (1997b)
Analyses de formes crâniennes fondées sur la photogrammétrie. Biom. Hum. et Anthropol. 15(1-2) :
19-22.
In the past years, several new
analytical techniques for the description of shape variation and shape change
have been made available tp Morphometricians (see Richtsmeier et al. 1992 for a
review). Since the majority of these methods require some sort of landmark or
outline data, raw data are mostly taken from graphic representations of
specimens. We evaluate the use of photogrammetric methods for the data
acquisition. The results of our experiments using casts of fossil crania show
that the mean measurement error can be less than 1mm as long as some basic
photo-optical principles are respected. Therefore, photogrammetry is not only a
reliable and efficient method, but also a very useful tool for the above
mentioned analysis techniques.