C O N T A G I O N

Clapping reveals applause is a ‘social contagion’

The quality of a performance does not drive the amount of applause an audience gives, a study suggests.

Instead scientists have found that clapping is contagious, and the length of an ovation is influenced by how other members of the crowd behave.

They say it takes a few people to start clapping for applause to spread through a group, and then just one or two individuals to stop for it to die out.

The Swedish study is published in the Journal of the Royal Society Interface.

Public and Military Health Posters for Contagious and Infectious Disease

In everyday speech, and even in many news reports, the terms “contagious" and "infectious" are often used interchangeably. In epidemiology (the study of how diseases spread) and most other scientific fields, however, they have distinct definitions. All contagious diseases are infectious, but not all infectious diseases are contagious.

Infectious diseases:

Are caused by “infective agents” - that is, bacteria, viruses, fungi, parasites, or prions - which are non-self organisms.

Cause clinically evident disease.

Not caused by immune dysfunction, non-infected injury, or psychological conditions.

Not caused by bodily reactions to chemicals or poisons not secreted by infective agents.

Transmitted in many, many ways, but generally originate outside of the infected host. An exception is in immune-compromised patients who become infected by commensal organisms.

Contagious diseases:

Are infectious diseases transmitted from person-to-person, with no special agent or vector required.

Can be spread via airborne droplets, other bodily secretions, or fomites (any object or substance capable of carrying infectious organisms, such as clothing, money, doorknobs, or stethoscopes).

Are the cause of most epidemics (a notable exception is the Black Plague, which probably was caught through flea vectors).

Spread can be controlled by quarantine and isolation.

Another context in which “infectious” and “contagious” are used is to describe something as highly infectious or highly contagious. 

Highly infectious:

Symptomatic disease can be caused by a very low number of infectious agents being introduced into the body.

Some highly infectious agents (such as ebola), can be caused by a very low number of pathogens, but can only cause infection when introduced into the body in a specific manner - for example, ebola does not cause infection when inhaled, but a tiny droplet of infected bodily secretion landing on an open wound can cause disease.

Highly contagious:

Generally refers to the ability of the pathogen to survive outside of the host, and the number of ways it can be transmitted.

Can be spread through airborne droplets.

To use the ebola example, even though it can’t be caught through airborne droplets, it can be caught through fomites, dead bodies, sexual intercourse, and contact with almost any bodily fluids. Because it’s not airborne, however, it’s considered highly infectious but not highly contagious, at least by virologists.

However, for practical use, because it is so infectious, and has many other modes of transmission, it’s often called “highly contagious” in the media.

Map of the week: 57% of languages do not have gendered pronouns.

By Lisa Wade, PhD

The map above is an interactive available at the World Atlas of Language Structures.  It represents an extensive, but not quite comprehensive collection of world languages. Each dot represents one. White dots are languages that do not include gendered pronouns. No “he” or “she.” Just a gender neutral word that means person.

The colored dots refer to languages with gendered pronouns, but there are more than one kind, as indicated by the Values key. The number on the right, further, indicates how many languages fit into each group. Notice that the majority of languages represented here (57%) DO NOT have gendered pronouns.

The map at the site is interactive. Go there to click on those dots and explore.

1) In linguistic terms, a gender distinction is a distinction between various noun classes, and feminine/masculine is only one way to split up noun classes. Other common ways are animate/inanimate (for example Algonquian languages, aka many of the pink dots in North America) or having a much larger group of noun classes that may include human/nonhuman but not feminine/masculine (for example Bantu languages, aka many of the red dots in Africa). 

2) The languages that are represented on this map include disproportionate numbers of widely-studied languages, because the creators are working from published grammars. The most studied language family is Indo-European, in which most languages do have a masculine/feminine gender distinction in pronouns, but many less-studied language families do not. 

Linda Dement in an interview with Sadie Plant at the 1996 Virtual Futures: Datableed conference 

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