Head Movements and Anchoring Adjustment
The authors hypothesize that nodding makes people more willing to accept an estimate while adjusting from a self-generated anchor, leading to less adjustment and faster answers. They predict no corresponding effect for externally supplied anchors; this excerpt does not report the results.
THE IDEA
STUDY 2
When people adjust from self-generated anchors, they may do so in one of two ways. One possibility is that people "slide" along some mental scale continuously testing until they arrive at a satisfactory final estimate. More plausible, we believe, is that they may "jump" some amount from the anchor – analogous to a saccade in reading – to a more reasonable value and assess its plausibility. If the new value seems plausible, adjustment stops. If not, a new jump or saccade is made, the new value assessed, and so on.
Regardless of the continuous or discrete nature of adjustment, anything that influences participants’ thresholds for accepting or denying values that come to mind should influence the amount of adjustment. If a participant is more willing to accept values, he or she will terminate the adjustment process more quickly and provide a final estimate closer to the original anchor value. If a participant is less accepting, he or she should continue to adjust and arrive at a final estimate further from the anchor.
We sought to influence participants’ thresholds for acceptance or denial by using the tried-and-true influence of motor movements on attitudes and persuasion (Cacioppo, Priester, & Berntson, 1993; Forster & Strack, 1996, 1997; Martin, Harlow, & Strack, 1992; Priester, Cacioppo, & Petty, 1996). Previous research has demonstrated that people are more likely to accept propositions when they are nodding their heads up and down than when shaking them from side to side (Wells & Petty, 1980). We reasoned that asking participants to nod their heads would make them more willing to accept values that initially came to mind, and thus produce less adjustment from self-generated anchors. Shaking their heads from side to side, in contrast, should make participants more willing to reject values, and thus produce more adjustment from self-generated anchors. As a result of this difference in adjustment, we also predicted that participants would generate an answer more quickly when nodding than when shaking their heads.
Because nodding and shaking should not systematically influence the selective accessibility of anchor-consistent information, we predicted these head movements would not influence answers to externally provided anchoring questions.
When to use it
When studying anchoring, distinguish starting values generated by participants from values supplied by someone else.
In research on judgment, compare the size of an adjustment with the time taken to reach an answer.
When reading a study excerpt, separate the authors’ predicted mechanism from the results actually reported.
In a decision workshop, identify where initial estimates came from before applying findings about a particular kind of anchor.
FROM THEORY TO EVERYDAY LIFE
In practice
A Self-Generated Estimate
Someone estimating a historical date starts from a related date they remember, then adjusts. The authors predict that nodding could make an early candidate answer feel acceptable sooner, stopping adjustment closer to that starting point.
An Externally Supplied Offer
A salary figure supplied by a negotiator is an external anchor. The authors do not predict the same head-movement effect for such anchors, so their hypothesis does not support advice to shake your head at an offer.
A MOMENT TO REFLECT
Put it to work.
How does the proposed acceptance threshold explain a difference in adjustment from a self-generated anchor?
When estimating an unfamiliar quantity, what familiar value do you use as a starting point, and how do you decide when to stop adjusting?
What results would be needed before recommending head movements as a practical response to anchoring?
References
- Cacioppo, Priester, & Berntson (1993) — Cacioppo, J. T., Priester, J. R., & Berntson, G. G. (1993)
- Forster & Strack (1996) — Forster, J. & Strack, F. (1996)
- Forster & Strack (1997) — Forster, J. & Strack, F. (1997)
- Martin, Harlow, & Strack (1992) — Martin, L. L., Harlow, T. F., & Strack, F. (1992)
- Priester, Cacioppo, & Petty (1996) — Priester, J. R., Cacioppo, J. T., & Petty, R. E. (1996)
- Wells & Petty (1980) — Wells, G. L. & Petty, R. E. (1980)
CONTINUE THE CONVERSATION
Source texts
- Heuristics and Biases The Psychology of Intuitive Judgment (Thomas Gilovich, Dale Griffin, Daniel Kahneman)