Bias in self-evaluation: Signal probability effects.
People’s own scorecards slide up or down depending on how often success really happens, so treat self-ratings as a separate behavior, not a verdict.
01Research in Context
What this study did
College students played a simple game. They pressed one key if a red light blinked, another if a green light blinked.
After each round they told the researcher how many times they got it right. The real catch: the lights blinked red or green at different rates for different students. Some saw red 20 % of the time, others 50 %, others 80 %.
The study wanted to know if the true rate of success would twist the students’ own reports of how well they did.
What they found
When success was rare (20 % red), students said they did worse than they really did. When success was common (80 % red), they said they did better than they really did.
Their self-reports slid up or down like a thermometer, following the true odds. The pattern looked just like classic “signal-detection” curves used for seeing dim lights or hearing faint tones.
How this fits with other research
Rapport et al. (1996) asked students to report emergent equivalence relations and also saw small mismatches. Both papers show that verbal reports can drift away from actual stimulus control, so always check data first and words second.
Anonymous (1993) used the same lab set-up and population but focused on which stimulus controlled choices. Turkkan (1994) flips the lens: it asks what happens when the learner tries to describe that control afterwards. Together they warn that self-report is a second behavior, not a mirror of the first.
Harte et al. (2017) found that directly stated rules make people stick to old patterns even when pay-offs flip. Turkkan (1994) adds that the chance of success itself can quietly bend the “rules” people later claim they followed. Both studies remind us that verbal behavior is shaped by its own history of consequences.
Why it matters
If you ask clients to rate their own progress, remember their answers may be pulled by how often they usually get it right. A child who rarely hits the correct tile might say “I always mess up,” even after a good run. Check objective data before you adjust programs, and praise real improvement instead of self-talk that might still be stuck on old odds.
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02At a glance
03Original abstract
Two experiments examined apparent signal probability effects in simple verbal self-reports. After each trial of a delayed matching-to-sample task, young adults pressed either a "yes" or a "no" button to answer a computer-presented query about whether the most recent choice met a point contingency requiring both speed and accuracy. A successful matching-to-sample choice served as the "signal" in a signal-detection analysis of self-reports. Difficulty of matching to sample, and thus signal probability, was manipulated via the number of nonmatching sample and comparison stimuli. In Experiment 1, subjects exhibited a bias (log b) for reporting matching-to-sample success when success was frequent, and no bias or a bias for reporting failure when success was infrequent. Contingencies involving equal conditional probabilities of point consequences for "I succeeded" and "I failed" reports had no systematic effect on this pattern. Experiment 2 found signal probability effects to be evident regardless of whether referent-response difficulty was manipulated in different conditions or within sessions. These findings indicate that apparent signal probability effects in self-report bias that were observed in previous studies probably were not an artifact of contingencies intended to improve self-report accuracy or of the means of manipulating signal probability. The findings support an analogy between simple self-reports and psychophysical judgments and bolster the conclusion of Critchfield (1993) that signal probability effects can influence simple self-reports much as they do reports about external stimuli in psychophysical experiments.
Journal of the experimental analysis of behavior, 1994 · doi:10.1901/jeab.1994.62-235