I've noticed the following pattern within my own thinking - multiple unrelated events "combine" to produce a certain action, particularly creativity and innovation. I'm trying to understand if this phenomenon is true or common among people. As a way to learn more about this, I thought that placebo effect would be a good place to start.

To clarify my question: imagine you are going to get a drug prescription. It will be a placebo, but you don't know that. Would combining factors like below increase the effectiveness of placebo?

  • clean doctors office
  • a traditional white coat doctor like on stock photos treating you
  • positive demeanor of staff
  • perception of privacy
  • thinking you are being prescribed a drug you have researched well and feel safe about
  • seeing a presentation about the advances of modern medicine within a week before

Contrast this with the following:

  • a dark, cramped waiting room
  • long wait and short consultation
  • a physician assistant or a nurse practitioner seeing you instead of MD
  • unknown drug you have never heard of
  • perceiving some negative news within last week

I'm trying to understand if a combination of unrelated events indeed does combine to affect the effectiveness of placebo? If so, is there the primary cause of change (like PA-C prescribing vs MD)?

I found the following on Wikipedia which makes me even more curious:

The expectancy effect[of placebo] can be enhanced through factors such as the enthusiasm of the doctor, differences in size and color of placebo pills, or the use of other interventions such as injections. In one study, the response to a placebo increased from 44% to 62% when the doctor treated them with "warmth, attention, and confidence."[47]

Here is what I think the traditional expectation of a doctor is:

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1 Answer 1


I think the field of persuasive communication is relevant for your answer, as well as research into the efficacy of psychotherapy.

Customers trust advertising if it is communicated by:

  • attractive persons
  • credible experts

Psychotherapy is more effective if:

  • the therapist believes that his methods are effective (!)
  • patient and therapist share the same world view and values
  • patient and therapist like each other

What constitutes attractiveness, expertise, common values, and sympathy, will differ among individuals. For some, expensive architecture makes a bank more trustworthy; for others it is a sign of waste and mismanagement. So you will have to identify the exact parameter value for each target group or, for perfect fit, even each individual person. But basically what you have here are moderators that affect the efficacy of a placebo.

What is noteworthy is that the belief of the person administering the placebo has an effect. So it's better they don't know it is a placebo, but have been given it by a person they in turn trust.

There is a lot of research into both areas; I give only one introductory source each (both of which respectively include what I quoted above):

  • Goldstein, N. J., Martin, S. J., & Cialdini, R. B. (2008). Yes!: 50 Scientifically Proven Ways to Be Persuasive. New York: Simon and Schuster.
  • Wampold, Bruce E. (2001). The Great Psychotherapy Debate: Models, Methods and Findings. New York: Routledge.

Don't be fooled by the popular nature of the first book; Robert Cialdini is an eminent expert on persuasion. If you want, there are more scientific publications by this author.

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    $\begingroup$ Looking at the article on persuasion, it seems to me like placebo effect is similar to persuading the patient that the treatment will be effective. The article on effectiveness of psychotherapy mentions that cooperation between therapist and patient is a key factor to effectiveness $\endgroup$
    – Alex Stone
    Feb 16, 2014 at 15:16
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    $\begingroup$ Yes, generally there are more factors at play than I mentioned in my answer, those were just the ones that seemed to me to most pertain to the question. All I wanted was give you a nudge in the right direction ;-) I also think that there is specific research on placebos, only I'm not familiar with that and searching for it only brings up articles on the use of placebos in the evaluation of other treatments, not in what makes placebos themselve more or less effective. I just guess it must be out there. $\endgroup$
    – user3116
    Feb 16, 2014 at 15:49
  • $\begingroup$ After reviewing the articles, it seems like they go in the right direction and mention the setting as one of the factors, but without specifics. I'm more interested in factors that are not perceived consciously and are passively perceived $\endgroup$
    – Alex Stone
    Feb 16, 2014 at 21:30
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    $\begingroup$ The factors in my answer are not consciously perceived by the participants as influencing their decisions. Pick up the books I recommended (or any other on the subject) and read them. Unconscious influence is the whole idea behind both persuasive communication and therapy efficacy moderators. $\endgroup$
    – user3116
    Feb 17, 2014 at 5:58

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