- Journal of the Royal Society, Interface / the Royal Society
- Published over 6 years ago
The study of social identity and crowd psychology looks at how and why individual people change their behaviour in response to others. Within a group, a new behaviour can emerge first in a few individuals before it spreads rapidly to all other members. A number of mathematical models have been hypothesized to describe these social contagion phenomena, but these models remain largely untested against empirical data. We used Bayesian model selection to test between various hypotheses about the spread of a simple social behaviour, applause after an academic presentation. Individuals' probability of starting clapping increased in proportion to the number of other audience members already ‘infected’ by this social contagion, regardless of their spatial proximity. The cessation of applause is similarly socially mediated, but is to a lesser degree controlled by the reluctance of individuals to clap too many times. We also found consistent differences between individuals in their willingness to start and stop clapping. The social contagion model arising from our analysis predicts that the time the audience spends clapping can vary considerably, even in the absence of any differences in the quality of the presentations they have heard.
To examine the diagnostic utility of applause sign scores for the diagnosis of dementia and mild cognitive impairment.
The present study aims to investigate the potential clinical utility of applause sign in Alzheimer’s disease (AD), exploring whether it is consequent to the severity of cognitive impairment or to specific neuropsychological profiles. According to the current debate, the role of apraxia is also investigated. A total of 105 patients with AD were enrolled and classified on the basis of the severity of the disease: 37 had mild AD, 38 moderate AD, and 30 severe AD. They were compared to 42 normal subjects. The applause sign was detected using the three clap test. All patients underwent a broad neuropsychological examination and 95 AD patients were tested for the presence of apraxia with a detailed praxis battery. Applause sign was present in all AD patient groups, which showed a significant difference with respect to normal controls, but not between each other. No significant difference was reported between apraxic and non-apraxic patients. Applause sign correlated with measures of frontal lobe dysfunction. No correlations were found between the applause sign and other cognitive functions examined.