Describe and evaluate social impact theory using the following emergency-planning scenario. A coastal town sends an evacuation message before a severe storm...

(a) Strength: influence is greater when the source has status, power, or importance [1]. Immediacy: influence is greater when the source is physically, socially, or psychologically close [1]. Number: influence generally increases as the number of influencing people rises [1]. These factors combine to affect the social impact on a target person or group [1]. (b) A message from the trusted emergency service may produce more evacuation than one neighbour because it has greater strength [1]. Several neighbours may have more influence than one because number is higher [1]. Residents close to the flood zone may respond more because the threat is more immediate [1]. Residents 12 km away may perceive less immediacy and be less likely to leave quickly [1]. (c) Any seventeen from: the theory gives clear, testable factors, such as source number and distance [1]; councils can manipulate these factors in field studies [1]; this gives practical value for designing warning systems [1]; it predicts that trusted official sources should be influential [1]; it can explain why local neighbours may also matter when they are socially close [1]; it considers group influence rather than only individual personality [1]; it can be applied to health campaigns, workplace rules, and emergency behaviour [1]; numerical predictions may be difficult because strength and immediacy are not measured in one standard way [1]; for example, trust in an emergency service varies between people [1]; counting sources ignores the quality of their message [1]; ten uninformed neighbours may not be more persuasive than one expert [1]; the theory may oversimplify complex decisions to leave home [1]; evacuation can depend on transport, pets, disability, income, or previous storm experience [1]; these situational factors can affect behaviour independently of social impact [1]; people may resist a powerful source if they distrust its motives [1]; this shows that influence is not always proportional to status [1]; cultural differences may affect whether people value official authority or family opinion [1]; therefore findings from one town may not generalise internationally [1]; some evidence uses artificial judgement tasks [1]; such tasks may lack the fear and real consequences of a storm [1]; field studies have greater realism but less control of weather, media coverage, and road conditions [1]; ethical concerns arise if researchers delay or vary genuine safety warnings [1]; the theory does not fully explain private attitude change after the immediate social pressure is removed [1]; minority influence can sometimes change majority views despite low initial number [1]; this challenges a simple assumption that larger groups are always more influential [1]; individual knowledge can lead a person to ignore a majority [1]; despite these limits, the theory is useful when combined with explanations of trust, risk, and practical barriers [1].