Can we fight social engineering attacks by social means? Assessing social salience as a means to improve phish detection

Phishing continues to be a problem for both individuals and organisations, with billions of dollars lost every year. We propose the use of nudges – more specifically social saliency nudges – that aim to highlight important information to the user when evaluating emails. We used Signal Detection Theory to assess the effects of both sender saliency (highlighting important fields from the sender) and receiver saliency (showing numbers of other users in receipt of the same email). Sender saliency improved phish detection but did not introduce any unwanted response bias. Users were asked to rate their confidence in their own judgements and these confidence scores were poorly calibrated with actual performance, particularly for phishing (as opposed to genuine) emails. We also examined the role of impulsive behaviour on phish detection, concluding that those who score highly on dysfunctional impulsivity are less likely to detect the presence of phishing emails.