Complex interactions confound any unitary approach to social phenomena, not just biological ones.

Although Burt clearly explains how modern genomic techniques work, and describes their limitations, her conclusion that they are therefore not valuable additions to understanding social outcomes is unwarranted. Understanding the causes of complex social outcomes depends on understanding how social, individual, and genetic factors complexly interact with each other. None can be understood without reference to the others.

The composite effect reveals that human (but not other primate) faces are special to humans.

Recognising faces is widely believed to be achieved using "special" neural and cognitive mechanisms that depend on "holistic" processing, which are not used when recognising other kinds of objects. An important, but largely unaddressed, question is how much like a Human face a stimulus needs to be to engage this "special" mechanism(s). In the current study, we attempted to answer this question in 3 ways. In Experiments 1 and 2 we examined the extent to which the disproportionate inversion effect for human faces extends to the faces of other species (including a range of other primates). Results suggested that the faces of other primates engage the mechanism responsible for the inversion effect approximately as well as that mechanism is engaged by Human faces, but that non-primate faces engage the mechanism less well. And so primate faces, in general, seem to produce a disproportionate inversion effect. In Experiment 3 we examined the extent to which the Composite effect extends to the faces of a range of other primates, and found no compelling evidence of a composite effect for the faces of any other primate. The composite effect was exclusive to Human faces. Because these data differ so dramatically from a previously reported study asking similar questions Taubert (2009), we also (in Experiment 4) ran an exact replication of Taubert's Experiment 2, which reported on both Inversion and Composite effects in a range of species. We were unable to reproduce the pattern of data reported by Taubert. Overall, the results suggest that the disproportionate inversion effect extends to all of the faces of the non-human primates tested, but that the composite effect is exclusive to Human faces.

Amplified inversion effects for moving biological stimuli remain largest for faces and bodies.

Turning an object upside-down disrupts our ability to perceive it accurately, and this inversion effect is disproportionately larger for faces and whole bodies than most other objects. This disproportionate inversion effect is taken as an indicator of holistic processing for these stimuli. Large inversion effects are also found when viewing motion-only information from faces and bodies; however, these have not been compared to other moving objects in an identity task so it is unclear whether inversion effects remain disproportionately larger for faces and bodies when they are engaged in motion. The current study investigated the effect of inversion on static and moving unfamiliar faces, human bodies, and German Shepherd dogs in an old-new recognition memory task. Sensitivity and baseline corrected reaction time (RT) results revealed that inversion effects for faces and whole-bodies remained disproportionately larger than those for German Shepherd dogs, regardless of presentation type, suggesting that both static and moving faces and bodies are processed holistically.

Human Face Tilt Is a Dynamic Social Signal That Affects Perceptions of Dimorphism, Attractiveness, and Dominance.

Previous research has shown that manipulating the pitch of a face (tilting the face upward or downward) affects the perceived femininity, masculinity, attractiveness, and dominance of the given face. However, previous research has not considered the influence of direct eye gaze on dominance perceptions or the ambiguity surrounding the proposed social signals sent from a static face. The current research used 94 participants across two studies (women = 63%, age: M = 31). Stimuli varied in head pitch angle, eye gaze, and motion/static appearance. Participants rated the stimuli for levels of masculinity, femininity, attractiveness, and dominance. Both studies confirmed that pitching the face upward at incrementally increasing angles resulted in a linear increase in ratings of masculinity, physical dominance, and social dominance and a linear decrease in ratings of femininity, physical attractiveness, and behavioral allure. Study 2 showed that these effects can be dependent on either the perceived structural change of the face or the actual movement of the face, and these are different for each rating category. The perceived dimorphism, attractiveness, and dominance of a face will change dependent on the angle of pitch it is presented but also whether it is moving or not, where it is moving in space, and what direction it is moving.

Some Evidence for an Association Between Early Life Adversity and Decision Urgency.

The relationship between early life adversity and adult outcomes is traditionally investigated relative to risk and protective factors (e.g., resilience, cognitive appraisal), and poor self-control or decision-making. However, life history theory suggests this relationship may be adaptive-underpinned by mechanisms that use early environmental cues to alter the developmental trajectory toward more short-term strategies. These short-term strategies have some theoretical overlap with the most common process models of decision-making-evidence accumulation models-which model decision urgency as a decision threshold. The current study examined the relationship between decision urgency (through the linear ballistic accumulator) and early life adversity. A mixture of analysis methods, including a joint model analysis designed to explicitly account for uncertainty in estimated decision urgency values, revealed weak-to-strong evidence in favor of a relationship between decision urgency and early life adversity, suggesting a possible effect of life history strategy on even the most basic decisions.

Tinbergen's "four questions" provides a formal framework for a more complete understanding of prosocial biases in favour of attractive people.

We adopt Tinbergen's (1963) "four questions" approach to strengthen the criticism by Maestripieri et al. of the non-evolutionary accounts of favouritism toward attractive individuals, by showing which levels of explanation are lacking in these accounts. We also use this approach to propose ways in which the evolutionary account may be extended and strengthened.

Computer-animated stimuli to measure motion sensitivity: constraints on signal design in the Jacky dragon.

Identifying perceptual thresholds is critical for understanding the mechanisms that underlie signal evolution. Using computer-animated stimuli, we examined visual speed sensitivity in the Jacky dragon Amphibolurus muricatus, a species that makes extensive use of rapid motor patterns in social communication. First, focal lizards were tested in discrimination trials using random-dot kinematograms displaying combinations of speed, coherence, and direction. Second, we measured subject lizards' ability to predict the appearance of a secondary reinforcer (1 of 3 different computer-generated animations of invertebrates: cricket, spider, and mite) based on the direction of movement of a field of drifting dots by following a set of behavioural responses (e.g., orienting response, latency to respond) to our virtual stimuli. We found an effect of both speed and coherence, as well as an interaction between these 2 factors on the perception of moving stimuli. Overall, our results showed that Jacky dragons have acute sensitivity to high speeds. We then employed an optic flow analysis to match the performance to ecologically relevant motion. Our results suggest that the Jacky dragon visual system may have been shaped to detect fast motion. This pre-existing sensitivity may have constrained the evolution of conspecific displays. In contrast, Jacky dragons may have difficulty in detecting the movement of ambush predators, such as snakes and of some invertebrate prey. Our study also demonstrates the potential of the computer-animated stimuli technique for conducting nonintrusive tests to explore motion range and sensitivity in a visually mediated species.

Inconsistent with the data: Support for the CLASH model depends on the wrong kind of latitude.

We argue that the CLASH model makes a number of questionable assumptions about the harshness and unpredictability of low-latitude environments, calling into question the life history strategy approach used, and that it is inconsistent with more nuanced global patterns of violence. We suggest an alternative account for less violence at high latitudes, based on a greater need for cooperation.

Conditional same/different concept learning in the short-beaked echidna (Tachyglossus aculeatus).

Echidnas have evolved separately from other mammalian groups for around 200 million years and incorporate a mixture of reptilian and mammalian features. Because of these attributes, they have historically been considered "primitive" animals. However, they have successfully adapted to a wide variety of ecological niches and their neurophysiology demonstrates a number of unusual and apparently sophisticated characteristics, including a relatively large brain and cerebral cortex and a comparatively massive frontal cortex. Studies of learning in the echidna have thus far been limited to only a handful of experiments which demonstrated relatively basic abilities such as forming a position habit in a T-maze, successive habit-reversal learning, and simple visual and instrumental discrimination. This study aimed to expand on these results and test the "primitive" echidna on what are generally considered more advanced cognitive tasks-same/different and conditional same/different concept learning. The results demonstrated that echidnas are able to discriminate on the basis of a relational same/different concept, using simultaneously presented multi-element stimuli, and transfer that discrimination to novel stimuli. After further training, they were then able to repeat the performance when the correct choice was conditional on the background color of the stimulus panels.

Physical and psychomotor performance of Australian football and rugby league officials during a match simulation.

The onset of exercise facilitates an improvement in psychomotor performance until the second ventilatory threshold, after which performance is reduced. This inverted-U relationship appears valid for incremental and steady-state exercise, however, not for intermittent exercise. This study examined changes in psychomotor performance of team sport officials during a laboratory-based match simulation. Twelve elite Australian football (n = 5) and rugby league (n = 7) officials (32.5 ± 5.5 years; 180.0 ± 6.8 cm; 78.8 ± 7.6 kg) completed the match simulation on a non-motorised treadmill. Physiological measures were routinely taken, while psychomotor performance was assessed using the Eriksen flanker task (multiple-choice response time). Significant reductions (P < 0.05) were observed in distance covered and high-speed running during the second half when compared to the first. No significant differences (P > 0.05) in psychomotor performance at different time points were observed. Response time was significantly improved when running above 65% of maximal sprinting speed (P < 0.01). This data questions the application of the inverted-U hypothesis for intermittent exercise and suggests that the short high-intensity efforts may not result in the same physiological events that limit psychomotor performance during sustained high-intensity exercise. More so, the high-intensity efforts during the match protocol appeared to promote psychomotor performance during the intermittent exercise.

A mechanobiological model of endothelial cell migration and proliferation.

How angiogenesis is regulated by local environmental cues is still not fully understood despite its importance to many regenerative events. Although mechanics is known to influence angiogenesis, the specific cellular mechanisms influenced by mechanical loading are poorly understood. This study adopts a lattice-based modelling approach to simulate endothelial cell (EC) migration and proliferation in order to explore how mechanical stretch regulates their behaviour. The approach enables the explicit modelling of ECs and, in particular, their migration/proliferation (specifically, rate and directionality) in response to such mechanical cues. The model was first used to simulate previously reported experiments of EC migration and proliferation in an unloaded environment. Next, three potential effects (increased cell migration, increased cell proliferation and biased cellular migration) of mechanical stretch on EC behaviour were simulated using the model and the observed changes in cell population characteristics were compared to experimental findings. Combinations of these three potential drivers were also investigated. The model demonstrates that only by incorporating all three changes in cellular physiology (increased EC migration, increased EC proliferation and biased EC migration in the direction perpendicular to the applied strain) in response to dynamic loading, it is possible to successfully predict experimental findings. This provides support for the underlying model hypotheses for how mechanics regulates EC behaviour.

Dynamic composite faces are processed holistically.

Holistic processing is considered one of the hallmarks of face recognition. Recent studies using the composite task claim to show a lack of holistic processing for dynamic faces, however they only presented moving faces in the learning phase and tested with static composite images. So while previous research has addressed the question of whether moving faces influence the processing of subsequently viewed static faces, the question of whether moving faces are processed holistically remains unanswered. We address that question here. In our study participants learned faces in motion and were tested on moving composite faces, or learned static faces and were tested on static composite faces. We found a clear composite effect for both upright static and dynamic faces, with no significant difference in the magnitude of those effects. Further, there was no evidence of composite or motion effects in inverted conditions, ruling out low level or other motion signal properties as explanations of performance in upright faces. Together, these results show that upright moving faces are processed holistically, in a similar manner to static faces, extending decades of research with static faces and confirming the importance of holistic processing to familiar face recognition.

Substrate stiffness and oxygen availability as regulators of mesenchymal stem cell differentiation within a mechanically loaded bone chamber.

Mechanical stimuli such as tissue deformation and fluid flow are often implicated as regulators of mesenchymal stem cell (MSC) differentiation during regenerative events in vivo. However, in vitro studies have identified several other physical and biochemical environmental cues, such as substrate stiffness and oxygen availability, as key regulators of stem cell fate. Hypotheses for how MSC differentiation is regulated in vivo can be either corroborated or rejected based on the ability of in silico models to accurately predict spatial and temporal patterns of tissue differentiation observed experimentally. The goal of this study was to employ a previously developed computational framework to test the hypothesis that substrate stiffness and oxygen availability regulate stem cell differentiation during tissue regeneration within an implanted bone chamber. To enable a prediction of the oxygen levels within the bone chamber, a lattice model of angiogenesis was implemented where blood vessel progression was dependent on the local mechanical environment. The model successfully predicted key aspects of MSC differentiation, including the correct spatial development of bone, marrow and fibrous tissue within the unloaded bone chamber. The model also successfully predicted chondrogenesis within the chamber upon the application of mechanical loading. This study provides further support for the hypothesis that substrate stiffness and oxygen availability regulate stem cell differentiation in vivo. These simulations also highlight the indirect role that mechanics may play in regulating MSC fate by inhibiting blood vessel progression and hence disrupting oxygen availability within regenerating tissues.

Threat is in the sex of the beholder: men find weapons faster than do women.

In visual displays, people locate potentially threatening stimuli, such as snakes, spiders, and weapons, more quickly than similar benign stimuli, such as beetles and gadgets. Such biases are likely adaptive, facilitating fast responses to potential threats. Currently, and historically, men have engaged in more weapons-related activities (fighting and hunting) than women. If biases of visual attention for weapons result from selection pressures related to these activities, then we would predict such biases to be stronger in men than in women. The current study reports the results of two visual search experiments, in which men showed a stronger bias of attention toward guns and knives than did women, whether the weapons were depicted wielded or not. When the weapons were depicted wielded, both sexes searched for them with more caution than when they were not. Neither of these effects extended reliably to syringes, a non-weapon-yet potentially threatening-object. The findings are discussed with respect to the "weapons effect" and social coercion theory.

Why isn't everyone an evolutionary psychologist?

Despite a widespread acceptance that the brain that underpins human psychology is the result of biological evolution, very few psychologists in any way incorporate an evolutionary perspective in their research or practice. There have been many attempts to convince mainstream psychology of the importance of such a perspective, mostly from those who identify with "Evolutionary Psychology," and there has certainly been progress in that direction, but the core of psychology remains essentially unevolutionary. Here I explore a number of potential reasons for mainstream psychology continuing to ignore or resist an evolutionary approach, and suggest some ways in which those of us interested in seeing an increase in the proportion of psychologists adopting an evolutionary perspective might need to modify our tactics to increase our chances of success.

Physical and decision-making demands of Australian football umpires during competitive matches.

This study examined the physical and decision-making requirements of elite Australian football (AF) umpires during match play. Twenty-nine field umpires were assessed across 20 AF League matches. Physical demands were monitored using global positioning system devices to record the total distance covered and high-speed running (HSR; >14.4 km·h) demands across each quarter. Decision-making performance was assessed through video by 3 elite umpire coaches who reviewed free-kick accuracy during each match. These data were further analyzed according to the position (mid-zone or end-zone) of the umpire when each decision was made. The average distance covered was 10,563 ± 608 m, of which 1,952 ± 494 m was HSR. Significant reductions in distance covered were observed during the third (p = 0.006) and fourth (p = 0.001) quarters, compared with the first. An average of 44 ± 8 free kicks awarded per match with a decision accuracy of 84 ± 6%; however, there were no significant differences (p > 0.05) in these measures across a match. Significantly (p ≤ 0.05) higher physical (HSR; relative distance) and decision-making requirements were observed within the mid-zone. The current data quantify the physical and decision-making demands of AF umpiring and demonstrated that despite a high physical workload, free-kick accuracy is maintained across a match. This suggests that decision making may not be directly compromised by the intermittent running demands of AF umpires. Positional rotations between the mid-zone and end-zone position allow for the demands to be shared among all field umpires during a match.

Is there an own-race preference in attractiveness?

Even in multicultural nations interracial relationships and marriages are quite rare, one reflection of assortative mating. A relatively unexplored factor that could explain part of this effect is that people may find members of their own racial group more attractive than members of other groups. We tested whether there is an own-race preference in attractiveness judgments, and also examined the effect of familiarity by comparing the attractiveness ratings given by participants of different ancestral and geographic origins to faces of European, East Asian and African origin. We did not find a strong own-race bias in attractiveness judgments, but neither were the data consistent with familiarity, suggesting an important role for other factors determining the patterns of assortative mating observed.

The role of oxygen as a regulator of stem cell fate during fracture repair in TSP2-null mice.

It is often difficult to decouple the relative importance of different factors in regulating MSC differentiation. Genetically modified mice provide model systems whereby some variables can be manipulated while others are kept constant. Fracture repair in thrombospondin-2 (TSP2)-null mice is characterized by reduced endochondral ossification and enhanced intramembranous bone formation. The proposed mechanism for this shift in MSC fate is that increased vascular density and hence oxygen availability in TSP2-null mice regulates differentiation. However, TSP2 is multifunctional and regulates other aspects of the regenerative cascade, such as MSC proliferation. The objective of this study is to use a previously developed computational model of tissue differentiation, in which substrate stiffness and oxygen tension regulate stem cell differentiation, to simulate potential mechanisms which may drive alterations in MSC fate in TSP2-null mice. Four models (increased cell proliferation, increased numbers of MSCs in the marrow decreased cellular oxygen consumption, and an initially stiffer callus) were not predictive of experimental observations in TSP2-null mice. In contrast, increasing the rate of angiogenic progression led to a prediction of greater intramembranous ossification, diminished endochondral ossification, and a reduced region of hypoxia in the fracture callus similar to that quantified experimentally by the immunohistochemical detection of pimonidazole adducts that develop with hypoxia. This study therefore provides further support for the hypothesis that oxygen availability during early fracture healing is a key regulator of MSC bipotential differentiation, and furthermore, it highlights the advantages of integrating computational models with genetically modified mouse studies for further elucidating mechanisms regulating stem cell fate.

The evolution of holistic processing of faces.

In this paper we examine the holistic processing of faces from an evolutionary perspective, clarifying what such an approach entails, and evaluating the extent to which the evidence currently available permits any strong conclusions. While it seems clear that the holistic processing of faces depends on mechanisms evolved to perform that task, our review of the comparative literature reveals that there is currently insufficient evidence (or sometimes insufficiently compelling evidence) to decide when in our evolutionary past such processing may have arisen. It is also difficult to assess what kinds of selection pressures may have led to evolution of such a mechanism, or even what kinds of information holistic processing may have originally evolved to extract, given that many sources of socially relevant face-based information other than identity depend on integrating information across different regions of the face - judgments of expression, behavioral intent, attractiveness, sex, age, etc. We suggest some directions for future research that would help to answer these important questions.

The movement advantage in famous and unfamiliar faces: a comparison of point-light displays and shape-normalised avatar stimuli.

Facial movement may provide cues to identity, by supporting the extraction of face shape information via structure-from-motion, or via characteristic patterns of movement. Currently, it is unclear whether familiar and unfamiliar faces derive the same benefit from these mechanisms. This study examined the movement advantage by asking participants to match moving and static images of famous and unfamiliar faces to facial point-light displays (PLDs) or shape-normalised avatars in a same/different task (experiment 1). In experiment 2 we also used a same/different task, but participants matched from PLD to PLD or from avatar to avatar. In both experiments, unfamiliar face matching was more accurate for PLDs than for avatars, but there was no effect of stimulus type on famous faces. In experiment 1, there was no movement advantage, but in experiment 2, there was a significant movement advantage for famous and unfamiliar faces. There was no evidence that familiarity increased the movement advantage. For unfamiliar faces, results suggest that participants were relying on characteristic movement patterns to match the faces, and did not derive any extra benefit from the structure-from-motion cues in the PLDs. The results indicate that participants may use static and movement-based cues in a flexible manner when matching famous and unfamiliar faces.