Andrew C. Gallup

Visual attention and the acquisition of information in human crowds

Pedestrian crowds can form the substrate of important socially contagious behaviors, including propagation of visual attention, violence, opinions, and emotional state. However, relating individual to collective behavior is often difficult, and quantitative studies have largely used laboratory experimentation. We present two studies in which we tracked the motion and head direction of 3,325 pedestrians in natural crowds to quantify the extent, influence, and context dependence of socially transmitted visual attention. In our first study, we instructed stimulus groups of confederates within a crowd to gaze up to a single point atop of a building. Analysis of passersby shows that visual attention spreads unevenly in space and that the probability of pedestrians adopting this behavior increases as a function of stimulus group size before saturating for larger groups. We develop a model that predicts that this gaze response will lead to the transfer of visual attention between crowd members, but it is not sufficiently strong to produce a tipping point or critical mass of gaze-following that has previously been predicted for crowd dynamics. A second experiment, in which passersby were presented with two stimulus confederates performing suspicious/irregular activity, supports the predictions of our model. This experiment reveals that visual interactions between pedestrians occur primarily within a 2-m range and that gaze-copying, although relatively weak, can facilitate response to relevant stimuli. Although the above aspects of gaze-following response are reproduced robustly between experimental setups, the overall tendency to respond to a stimulus is dependent on spatial features, social context, and sex of the passerby.

Yawning and thermoregulation

We review a growing body of medical and physiological evidence indicating that yawning may be a thermoregulatory mechanism, providing compensatory cooling when other provisions fail to operate favorably. Conditions such as multiple sclerosis, migraine headaches, epilepsy, stress and anxiety, and schizophrenia have all be linked to thermoregulatory dysfunction and are often associated with instances of atypical yawning. Excessive yawning appears to be symptomatic of conditions that increase brain and/or core temperature, such as central nervous system damage, sleep deprivation and specific serotonin reuptake inhibitors. Yawning is also associated with drowsiness, and subjective ratings of sleepiness are correlated with increases in body temperature. This view of yawning has widespread application for the basic physiological understanding of thermoregulation as well as for the improved diagnosis and treatment of diseases associated with abnormal thermoregulation.

The directional flow of visual information transfer between pedestrians.

Close behavioural coupling of visual orientation may provide a range of adaptive benefits to social species. In order to investigate the natural properties of gaze-following between pedestrians, we displayed an attractive stimulus in a frequently trafficked corridor within which a hidden camera was placed to detect directed gaze from passers-by. The presence of visual cues towards the stimulus by nearby pedestrians increased the probability of passers-by looking as well. In contrast to cueing paradigms used for laboratory research, however, we found that individuals were more responsive to changes in the visual orientation of those walking in the same direction in front of them (i.e. viewing head direction from behind). In fact, visual attention towards the stimulus diminished when oncoming pedestrians had previously looked. Information was therefore transferred more effectively behind, rather than in front of, gaze cues. Further analyses show that neither crowding nor group interactions were driving these effects, suggesting that, within natural settings gaze-following is strongly mediated by social interaction and facilitates acquisition of environmentally relevant information.

Yawning and stretching predict brain temperature changes in rats: support for the thermoregulatory hypothesis.

Recent research suggests that yawning is an adaptive behavior that functions to promote brain thermoregulation among homeotherms. To explore the relationship between brain temperature and yawning we implanted thermocoupled probes in the frontal cortex of rats to measure brain temperature before, during and after yawning. Temperature recordings indicate that yawns and stretches occurred during increases in brain temperature, with brain temperatures being restored to baseline following the execution of each of these behaviors. The circulatory changes that accompany yawning and stretching may explain some of the thermal similarities surrounding these events. These results suggest that yawning and stretching may serve to maintain brain thermal homeostasis.

Evidence for contagious behaviors in budgerigars (Melopsittacus undulatus): An observational study of yawning and stretching

Yawning is contagious in humans and some non-human primates. If there are social functions to contagious behaviors, such as yawning, they might occur in other highly social vertebrates. To investigate this possibility, we conducted an observational study of yawning and an associated behavior, stretching, in budgerigars (Melopsittacus undulatus), a social, flock-living parrot. Flock-housed budgerigars were videotaped for 1.5h at three time-blocks during the day (early morning, afternoon and early evening), and the times of all yawns and stretches for each bird were recorded. Both yawning and stretching were temporally clumped within sessions, but were uniformly distributed across the trials of a particular time-block. This suggests that clumping was not a result of circadian patterning and that both behaviors could be contagious. There was additional evidence of contagion in stretching, which occurred in two forms - a posterior-dorsal extension of either one foot or both feet. Birds that could have observed a conspecific stretch, and that then stretched themselves within 20s, replicated the form of the earlier stretch significantly more often than expected by chance. This study provides the first detailed description of temporal patterns of yawning under social conditions in a flock-living species as well as the first support for contagious yawning and stretching in a non-primate species in a natural context. Experimental evidence will be necessary to confirm the extent of contagion in either behavior.

Intrasexual peer aggression and dating behavior during adolescence: an evolutionary perspective.

It has been suggested that the use of intrasexual aggression is a form of competition associated with reproductive opportunities. Here the authors investigated the relationship between retrospective dating and flirting behavior and peer aggression and victimization during middle and high school. Results indicate that the use of peer aggression was associated with adaptive dating outcomes in both sexes, whereas experiencing peer victimization was correlated with maladaptive dating behaviors among females only. Females who perpetrated high levels of indirect (i.e. nonphysical) aggression reported that they began dating at earlier ages in comparison to their peers, whereas aggressive males reported having more total dating partners. Experiencing female-female peer victimization was correlated with a later onset of dating behavior, more total dating partners, and less male flirtation while growing up. This report strengthens the connection between adolescent peer aggression and reproductive competition, suggesting a potential functionality to adolescent peer aggression in enhancing ones own mating opportunities at the expense of rivals.

Handgrip strength and socially dominant behavior in male adolescents

Handgrip strength (HGS) is highly heritable and a good overall measure of strength and muscle function. Indicative of blood testosterone levels and fat-free body mass, HGS is also highly sexually dimorphic. Recent psychological research shows that HGS is correlated with a number of social variables, but only in males. We conducted three studies to further investigate the relationship between HGS and measures of aggression and social competition among adolescents. Consistent with previous reports, correlations were almost exclusive to males, but this was only visible during late adolescence (i.e., high school). These findings support evolutionary hypotheses regarding grip strength in male-male competition and suggest that similar to measures of testosterone, HGS is a measure that is predictive of social behavior in older adolescent males.

The thermoregulatory theory of yawning: what we know from over 5 years of research

Over the past 5 years numerous reports have confirmed and replicated the specific brain cooling and thermal window predictions derived from the thermoregulatory theory of yawning, and no study has found evidence contrary to these findings. Here we review the comparative research supporting this model of yawning among homeotherms, while highlighting a recent report showing how the expression of contagious yawning in humans is altered by seasonal climate variation. The fact that yawning is constrained to a thermal window of ambient temperature provides unique and compelling support in favor of this theory. Heretofore, no existing alternative hypothesis of yawning can explain these results, which have important implications for understanding the potential functional role of this behavior, both physiologically and socially, in humans and other animals. In discussion we stress the broader applications of this work in clinical settings, and counter the various criticisms of this theory.

Excessive yawning and thermoregulation: two case histories of chronic, debilitating bouts of yawning

BackgroundThis report details the case histories of two women who suffer from chronic and debilitating episodes of excessive yawning in the absence of sleep problems.MethodsEach woman independently provided information and answered questions about their excessive yawning symptoms and medical histories.ResultsBoth women show signs of thermoregulatory dysfunction, and each reports symptom relief and/or the postponement of yawning attacks through means of behavioral cooling. One woman recorded her body temperature before and after bouts of yawning, revealing a significant drop in temperature following each episode (p < 0.05).ConclusionsThe trigger for yawning in these patients appears to be related to increases in body/brain temperature. These cases are consistent with growing evidence showing that recurrent episodes of excessive yawning are not necessarily associated with a sleep disorder, but rather may be indicative of thermoregulatory dysfunction.

Yawning, sleep, and symptom relief in patients with multiple sclerosis

BACKGROUND Patients with multiple sclerosis (MS) suffer from thermoregulatory dysfunction, and repetitive yawning and sleep problems are symptoms of MS. Because yawning and sleep are involved in thermoregulation, we investigated the association between yawning, sleep, and symptom relief in patients with MS. METHODS Sixty patients filled out a questionnaire about how often they yawned, whether yawning provided relief of MS symptoms, and how sleep affected these symptoms. RESULTS Results showed that over one in three patients reported that their MS symptoms improved following a yawn, and of those experiencing relief, nearly half reported that it lasted for several minutes or longer. Not getting a good nights sleep often made MS symptoms worse, while napping during the day provided symptom relief. CONCLUSION This is the first study showing that yawning provides symptom relief in patients with multiple sclerosis.