By Robert B. Cialdini, Ph.D.


Rule of Reciprocity
Commitment and Consistency
Social Proof


Robert Cialdini is a Professor of Psychology at Arizona State University and has spent many years devoted to the scientific investigation and research of persuasion techniques. His book "Influence" has become a classic. Within his book Cialdini lists six basic social and psychological principles that form the foundation for successful strategies used to achieve influence.

Those six principles are:

Rule of Reciprocity

According to sociologists and anthropologists, one of the most widespread and basic norms of human culture is embodied in the rule of reciprocity. This rule requires that one person try to repay what another person has provided. By obligating the recipient to an act of repayment in the future--the rule for reciprocation allows one individual to give something to another with the confidence that it is not being lost.

This sense of future obligation according to the rule makes possible the development of various kinds of continuing relationships, transactions, and exchanges that are beneficial to society. Consequently, virtually all members of society are trained from childhood to abide by this rule or suffer serious social disapproval.

The decision to comply with someone's request is frequently based upon the Rule of Reciprocity. Again, a possible and profitable tactic to gain probable compliance would be to give something to someone before asking for a favor in return.

The opportunity to exploit this tactic is due to three characteristics of the Rule of Reciprocity:

  1. The rule is extremely powerful, often overwhelming the influence of other factors that normally determine compliance with a request.
  2. The rule applies even to uninvited first favors, which reduces our ability to decide whom we wish to owe and putting the choice in the hands of others
  3. The rule can spur unequal exchanges. That is--to be rid of the uncomfortable feeling of indebtedness, an individual will often agree to a request for a substantially larger favor, than the one he or she first received.

Another way in which the Rule of Reciprocity can increase compliance involves a simple variation on the basic theme: instead of providing a favor first that stimulates a returned favor, an individual can make instead an initial concession--that stimulates a return concession.

One compliance procedure, called the "rejection-then-retreat technique", or door-in-the-face technique, relies heavily on the pressure to reciprocate concessions. By starting with an extreme request that is sure to be rejected, the requester can then profitably retreat to a smaller request--the one that was desired all along. This request is likely to now be accepted because it appears to be a concession. Research indicates, that aside from increasing the likelihood that a person will say yes to a request--the rejection-then-retreat technique also increases the likelihood that the person will carry out the request a will agree to future requests.

The best defense against manipulation by the use of the Rule of Reciprocity to gain compliance is not the total rejection of initial offers by others. But rather, accepting initial favors or concessions in good faith, while also remaining prepared to see through them as tricks--should they later be proven so. Once they are seen in this way, there is no longer a need to feel the necessity to respond with a favor or concession.

Commitment and Consistency

People have a desire to look consistent through their words, beliefs, attitudes and deeds and this tendency is supported or fed from three sources:

  1. Good personal consistency is highly valued by society.
  2. Consistent conduct provides a beneficial approach to daily life.
  3. A consistent orientation affords a valuable shortcut through the complexity of modern existence. That is-- by being consistent with earlier decisions we can reduce the need to process all the relevant information in future similar situations. Instead, one merely needs to recall the earlier decision and respond consistently.

The key to using the principles of Commitment and Consistency to manipulate people is held within the initial commitment. That is--after making a commitment, taking a stand or position, people are more willing to agree to requests that are consistent with their prior commitment. Many compliance professionals will try to induce others to take an initial position that is consistent with a behavior they will later request.

Commitments are most effective when they are active, public, effortful, and viewed as internally motivated and not coerced. Once a stand is taken, there is a natural tendency to behave in ways that are stubbornly consistent with the stand. The drive to be and look consistent constitutes a highly potent tool of social influence, often causing people to act in ways that are clearly contrary to their own best interests.

Commitment decisions, even erroneous ones, have a tendency to be self-perpetuating--they often "grow their own legs." That is--those involved may add new reasons and justifications to support the wisdom of commitments they have already made. As a consequence, some commitments remain in effect long after the conditions that spurred them have changed. This phenomenon explains the effectiveness of certain deceptive compliance practices.

To recognize and resist the undue influence of consistency pressures upon our compliance decisions--we can listen for signals coming from two places within us--our stomach or "gut reaction" and our heart.

At such points it is meaningful to ask a crucial question, "Knowing what I know now, if I could go back, would I have made the same commitment?"

Social Proof

One means used to determine what is correct is to find out what others believe is correct. People often view a behavior as more correct in a given situation--to the degree that we see others performing it.

This principle of Social Proof can be used to stimulate a person's compliance with a request by informing him or her that many other individuals, perhaps some that are role models, are or have observed this behavior. This tool of influence provides a shortcut for determining how to behave. But at the same time it can make those involved with using this social shortcut--vulnerable to the manipulations of others who seek to exploit such influence through such things as seminars, group introduction dinners, retreats etc. Group members may then provide the models for the behavior that each group plans to produce in its potential new members.

Social proof is most influential under two conditions:

  1. Uncertainty--when people are unsure and the situation is ambiguous they are more likely to observe the behavior of others and to accept that behavior as correct
  2. Similarity--people are more inclined to follow the lead of others who are similar.

Some recommendations on how to reduce susceptibility to contrived social proofs would include a greater sensitivity to clearly counterfeit evidence. That is--what others are doing and their behavior should not form a sole basis for decision-making.


People prefer to say yes to individuals they know and like. This simple rule helps to understand how Liking can create influence and how compliance professionals may emphasize certain factors and/or attributes to increase their overall attractiveness and subsequent effectiveness. Compliance practitioners may regularly use several factors.

Physical attractiveness--is one feature of a person that often may help to create some influence. Although it has long been suspected that physical beauty provides an advantage in social interaction, research indicates that this advantage may be greater than once supposed. Physical attractiveness seems to engender a "halo" effect that extends to favorable impressions of other traits such as talent, kindness, and intelligence. As a result, attractive people are more persuasive both in terms of getting what they request and in changing others' attitudes.

Similarity--is a second factor that influences both Liking and compliance. That is--we like people who are like us and are more willing to say yes to their requests, often without much critical consideration.

Praise--is another factor that produces Liking, though this can sometimes backfire when they are crudely transparent. But generally compliments most often enhance liking and can be used as a means to gain compliance.

Increased familiarity--through repeated contact with a person or thing is yet another factor that normally facilitates Liking. But this holds true principally when that contact takes place under positive rather than negative circumstances. One positive circumstance that may works well is mutual and successful cooperation.

A final factor linked to Liking is often association. By associating with products or positive things--those who seek influence frequently share in a halo effect by association. Other individuals as well appear to recognize the positive effect of simply associating themselves with favorable events and distancing themselves from unfavorable ones.

A potentially effective response that reduces vulnerability to the undue influence of Liking upon decision-making requires a recognition of how Liking and its attending factors may impact our impression of someone making requests and soliciting important decisions. That is-- recognizing how someone making requests may do inordinately well under certain circumstances--should cause us to step back from some social interaction and objectively separate the requester from his or her offer or request. We should make decisions, commitments and offer compliance based upon the actual merits of the offer or request.


In the seminal studies and research conducted by Milgram regarding obedience there is evidence of the strong pressure within our society for compliance when requested by an authority figure. The strength of this tendency to obey legitimate authorities is derived from the systematic socialization practices designed to instill in society the perception that such obedience constitutes correct conduct. Additionally, it is also frequently adaptive to obey the dictates of genuine authorities because such individuals usually possess high levels of knowledge, wisdom, and power. For these reasons, deference to authorities can occur in a mindless fashion as a kind of decision-making shortcut. When reacting to authority in an automatic fashion there is a tendency to often do so in response to the mere symbols of authority rather than to its substance.

Three types of symbols have been demonstrated through research as effective in this regard:

  1. Titles
  2. Clothing
  3. Automobiles.

In separate studies investigating the influence of these symbols--individuals that possessed one or another of these symbols, even without other legitimizing credentials, were accorded more deference or obedience by those they encountered. Moreover, in each instance, those individuals who deferred and/or obeyed these individuals underestimated the effect of authority pressures upon their behavior.

Asking two questions can attain a meaningful defense against the detrimental effects of undue influence gained through authority.

  1. Is this authority truly an expert?
  2. How truthful can we expect this expert to be?

The first question directs our attention away from symbols and toward actual evidence for authority status. The second advises us to consider not just the expert's knowledge in the situation, but also his or her trustworthiness. With regard to this second consideration, we should be alert to the trust-enhancing tactic in which a communicator may first provide some mildly negative information about himself or herself. This can be seen as a strategy to create the perception of honesty--making subsequent information seem more credible to those listening.


According to the Principle of Scarcity--people assign more value to opportunities when they are less available. The use of this principle for profit can be seen in such high-pressure sales techniques as only a "limited number" now available and a "deadline" set for an offer. Such tactics attempt to persuade people that number and/or time restrict access to what is offered. The scarcity principle holds true for two reasons:

  1. Things difficult to attain are typically more valuable. And the availability of an item or experience can serve as a shortcut clue or cue to its quality.
  2. When something becomes less accessible, the freedom to have it may be lost.

According to psychological reactance theory, people respond to the loss of freedom by wanting to have it more. This includes the freedom to have certain goods and services. As a motivator, psychological reactance is present throughout the great majority of a person's life span. However, it is especially evident at a pair of ages: "the terrible twos" and the teenage years. Both of these periods are characterized by an emerging sense of individuality, which brings to prominence such issues as control, individual rights, and freedoms. People at these ages are especially sensitive to restrictions.

In addition to its effect on the valuation of commodities, the Principle of Scarcity also applies to the way that information is evaluated. Research indicates that the act of limiting access to a message may cause individuals to want it more and to become increasingly favorable to it. The latter of these findings, that limited information is more persuasive--seems the most interesting. In the case of censorship, this effect occurs even when the message has not been received. When a message has been received, it is more effective if it is perceived to consist of some type of exclusive information.

The scarcity principle is more likely to hold true under two optimizing conditions

  1. Scarce items are heightened in value when they are newly scarce. That is things have higher value when they have become recently restricted--more than those than those things that were restricted all along have.
  2. People are most attracted to scarce resources when they compete with others for them.

It is difficult to prepare ourselves cognitively against scarcity pressures because they have an emotional quality that makes thinking difficult. In defense, we might attempt to be alert regarding the sudden rush of emotions in situations involving scarcity. Perhaps this awareness may allow us to remain calm and take steps to assess the merits of an opportunity in terms of why we really want and objectively need.

This is based upon the summary notes within the book--Influence. By Robert B. Cialdini, Ph.D. (Quill, NY, 1984 (Revised 1993)

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