The Like Switch
Jack Schafer & Marvin Karlins · 2015
"A former FBI behavior analyst argues that likability and rapport follow identifiable, learnable behavioral patterns — friendship signals, similarity, and validation — rather than being a fixed trait some people have and others don't."
Jack Schafer spent decades teaching FBI agents to build instant trust with sources and suspects who had every reason not to trust them. His conclusion: liking someone is triggered by specific, repeatable signals, not chemistry.
Schafer's 'Friendship Formula' — proximity, frequency, duration, intensity — predicts how quickly rapport builds, which is why repeated brief contact often builds more trust than one long conversation. His nonverbal 'friend signal' catalog (eyebrow flash, head tilt, genuine smile reaching the eyes) are largely involuntary cues people read subconsciously to judge trustworthiness in seconds. He also emphasizes the 'golden rule of friendship' — people like those who make them feel good about themselves — operationalized through specific tactics like the 'ask for a small favor' (the Ben Franklin effect, where doing you a favor makes someone like you more, not less) and validating the other person's self-image before making any request.
Why does asking someone for a small favor (the 'Ben Franklin effect') tend to make them like you more, according to this line of research?
Read more about the topic
The explanation above is written with AI assistance. These are the originals — go to them to check it.
- The Like Switch: An Ex-FBI Agent's Guide to Influencing, Attracting, and Winning People OverTouchstone
Influence: The Psychology of Persuasion
"People say yes for six predictable, exploitable reasons — reciprocity, commitment, social proof, liking, authority, and scarcity — and knowing the levers is the best defense against having them pulled on you."