Do people have a tendency to stick to one opinion after they formed it?

Question

Scytale's assessment, from the science fiction novel "Dune Messiah" (1969)

When a creature has developed into one thing, he will choose death rather than change into his opposite.

While reading some discussions on Meta Stack Overflow, it dawned on me that it might not be the best format to start constructive discussions. Once people pick sides in a discussion, they have a very high tendency to stop approaching the discussion from the other angle. People will dislike certain parts of a proposal, and then become vehemently against the entire thing, instead of trying to participate in resolving the issues they raise.

Is this an established psychological phenomenon?

Answer 1

Yes. But why should it be so? One can approach the question from a number of directions. For instance, Cass Sunstein talks about how information cascades can create the path-dependent effects you describe: person A says something, which steers person B toward the same opinion, with the result that group decision-making heavily overvalues inputs of early responders. (James Surowiecki also did an excellent popular science treatment of this topic.)

So much for the hobgoblin of little minds for groups. Within the individual, the topic has been addressed through the dissonance literature, in which cogitation contrary to an established position carries unpleasant consequences, both hedonic and adaptive. Particularly, maintaining a consistent set of mental beliefs seems to be important for efficient action selection, possibly as a consequence of the way semantic information (including motor control programs) is represented in the brain.

The result of all this is that, as you suggest, people establish a position, and then are motivated to keep it, which is not news. What is surprising is that this annoying behavior is probably highly adaptive and a consequence of our neural architecture for knowledge representation and decision-making. In other words, a feature and not a bug.

Answer 2

Adding to what shanusmagnus said: What you refer to is indeed an established psychological phenomenon called Confirmation Bias. The bias consists of

the seeking or interpreting of evidence in ways that are partial to existing beliefs, expectations, or a hypothesis in hand (Nickerson, 1998).

Confirmation Bias apparently is among the most studied biases in psychology (Mercier & Sperber, 2011), and there is a lot of evidence for its existence (for a review see Nickerson, 1998). Mercier and Sperber (2011) also state that

While there is some individual variation, it seems that everybody is affected by some degree, irrespective of factors like general intelligence or open mindedness (Stanovich & West, 2007; 2008a; 2008b)

I also remember reading an interview with Hugo Mercier, in which he said that all attempts at training people to get rid of their Confirmation Bias have been unsuccessful, but I don't have any citations to back this up.

Mercier and Sperber (2011) recently formulated a theory called the Argumentative Theory, which is in line with what shanusmagnus said, namely that Confirmation Bias may be a feature rather than a flaw. In their Argumentative Theory Mercier and Sperber argue that reasoning may have developed not in order to be best suited for solving problems, but rather to convince others in discourse. They argue from an evolutionary point of view that the capability of doing so provides an evolutionary advantage.

_{Mercier, Hugo, und Dan Sperber. Why do humans reason? Arguments for an argumentative theory. Behavioral and Brain Sciences 34, Nr. 2 (April 2011): 57–74.
Nickerson, R. S. Confirmation bias: A ubiquitous phenomenon in many guises. Review of General Psychology; Review of General Psychology 2, Nr. 2 (1998): 175.
Stanovich, K. E., und R. F. West. Natural myside bias is independent of cognitive ability. Thinking & Reasoning 13, Nr. 3 (2007): 225–247.
Stanovich, K. E., und R. F. West. On the failure of cognitive ability to predict myside and one-sided thinking biases. Thinking & Reasoning 14, Nr. 2 (2008): 129–167.
Stanovich, K. E., und R. F. West. On the relative independence of thinking biases and cognitive ability. Journal of personality and social psychology 94, Nr. 4 (2008): 672.}

Answer 3

A possibly relevant take on this question is provided by a computational model described in [1]. Although the main thrust of the paper is that selfish agents, by being habitual (sticking with their choices), contribute to The Common Good (in spite of themselves, so to speak), the argument is also made that habituation increases individual fitness.

References:

[1] Davies, A. P., Watson, R. A., Mills, R., Buckley, C. L., & Noble, J. (2011). “If You Can’t Be With the One You Love, Love the One You’re With”: How Individual Habituation of Agent Interactions Improves Global Utility. Artificial Life, 17(3), 167–181. Link

Answer 4

Relevant entries from Wikipedia's list of cognitive biases:

• Backfire effect - when people react to disconfirming evidence by strengthening their beliefs.
• Confirmation bias - the tendency to search for or interpret information in a way that confirms one's preconceptions.
• Irrational escalation [or Escalation of commitment] – the phenomenon where people justify increased investment in a decision, based on the cumulative prior investment, despite new evidence suggesting that the decision was probably wrong.