Communication in evacuation

Communication in evacuation


Communication in emergencies, and so also in evacuations, has always been developed in an attempt to not lead people to panic. Until very recently, indeed, there were the commonplace that telling people about an emergency incident would lead to panic (Quarantelli & Dynes 1972; Tierney 2003). On the basis of this assumption, notification procedures and specific languages were developed trying to give as less information as possible about the emergency but, at the same time, enough to make people perform the actions needed to respond to the problem. In the last years, research and practical experience have observed that people need detailed information as early as possible. This would lead more likely to a quick, efficient and reactive response to the emergency, reducing the risk of delays and misunderstandings. “The availability of this information encourages people to accept the emergency procedures and to improve their familiarity with the required response, and later informs the decision-making process that determines their response. People need information in order to act” (Kuligowski, et al., 2012, p.2).

Nowadays it is widely accepted that the more efficient way to communicate in emergencies is to provide much information as possible. Verbal messages are preferred to ring signals (Benthorn & Frantzich, 1996) not only because verbal message can give more detailed information, but also because some authors founded problems in recognizing a fire alarm from another type of alarm (Bellamy & Geyer, 1990; Benthorn & Frantzich, 1996).An experiment conducted on the understandability of an alarm signal revealed that 41% of the subjects perceived the ring signal as if it was an ordinary unspecified alarm or warning signal and 17% thought it was a telephone ringing, while only 19% perceived it as a fire alarm (Benthorn & Frantzich).  In particular, clear and concise information is more able to convince people.

Literature on communication in evacuation has mainly focused on warnings. Rogers and Sorensen (1991) divide the warning process in 2 phases: alerting and notification. “Alerting deals with the ability of emergency officials to make people aware of an imminent hazard.

Alerting frequently involves the technical ability to break routine acoustic environments to cue people to seek additional information. In contrast, notification focuses on how people interpret the warning message” (Rogers & Sorensen, 1991, p. 118). Indeed, evacuation is not merely a function of hearing a warning and responding. It is the definition of the situation as dangerous that must be seen as the intervening mechanism between cue perception and evacuation behavior. For this reason, a requirement for evacuation is warning belief (Mileti & Beck, 1975). This means that the warning process involves features related to both warning message and receiver. Warning belief depends on four communication-related variables:

    1. communication mode – that is the manner in which the warning message is communicated (e. g. telephone, face-to-face conversation). Different channels of communication have different degrees of authoritativeness, credibility and legitimacy for occupants (Williams, 1964).
    1. content of the warning message – according to Janis (1958), an effective warning message has to be balanced between fear-arousing and fear-reducing statements. Feararousing statements should evoke mental scenarios of the potential threat. Fearreducing statements, instead, should suggest appropriate avoidance and protective emergency actions.  A person-specific message will be more effective than an impersonal one (Moore, 1963), as well as a message consisting of specific information rather than general information.
    1. perceived warning certainty – it is a subjective interpretation and it depends also on prior disaster experience, relative proximity to the source of disaster, confidence in the source of warning, interpretation of the warning and discussion with members of the social network (Rogers & Sorensen, 1991).
    1. confirmation – it is a direct function of perceived warning certainty.

Another important factor of communication in evacuation is the features of the warning source. For example, information is more influential if it came from a trusted and legitimate source (Gershon et al., 2007).

Another communicative tool in emergency is the signage system. Indeed, an effective signage system can be crucial for the way-finding task that an evacuation process needs.  Most of the times information are needed to locate the exit, because of the limited visibility (due, for example, to smoke) or to the building layout (which can be complex). The indications communicated by the signage system aim to reduce the complexity of a building. Nevertheless this means more than putting some signals to indicate the exit door, because several physical, cognitive and psychological aspects influence the interaction between the occupants and the system (Xie et al., 2009).

According to Leik and Gifford (as cited in Aguirre, 2005), greater amounts of information result in a delayed evacuation because more time is needed for the decision making stage. On the other hand, other findings show that people well informed about what is happening and what they are expected to do evacuate quicker (Benthorn & Frantzich, 1996).