The effect of depressed mood on the interpretation of ambiguity, with and without negative mood induction

Abstract

Is there an effect of depressed mood on the interpretation of ambiguity? Are depressed individuals biased to interpret ambiguous information in a negative manner? We used a cross-modal semantic priming task to look for evidence of a negative interpretative bias. Participants listened to ambiguous prime sentences (e.g., Joan was stunned by her final exam mark) and made lexical decisions to target words presented immediately after the sentence offset or after a delay of 1000 ms or 2000 ms. For the semantically related targets, the target was negatively related (distress), positively related (success), or neutrally related (grades) to the ambiguous prime. The experiment was conducted with and without a negative mood induction. The expectation was that depressed participants would be more likely to consider the negative interpretations of the ambiguous primes and would therefore experience larger priming effects for negatively related targets. Although there were large priming effects for all semantically related targets, there was no evidence of a negative interpretative bias.

Acknowledgments

This research was supported by a Natural Sciences and Engineering Research Council (NSERC) grant to Christopher R. Sears. The experiments were conducted as part of a master's thesis by M. A. Suzie Bisson under the supervision of Christopher R. Sears.

Many thanks to Clair Lawson for providing us with the stimuli used in the Lawson and MacLeod (1999) study. The stimuli used in the present study are available from the authors upon request. We thank Tammy Yacyshen, Deyelle Sharamata, and Crystal Sharp for their assistance with data collection, and Keith Dobson, John Mueller, Mariko Nakayama, Melissa Crocker, Kate Nielsen, and an anonymous reviewer for their valuable comments on a previous version of this manuscript.

Notes

¹For ethical reasons, the women participated in a positive mood induction after they completed the semantic priming task. This began with a 3 minute and 30 second viewing of a selection of single-frame cartoons by Gary Larson (Larson, 1989, 1995). Participants then wrote a short paragraph about how their life would change if they won 10 million dollars, while listening to an 8-minute-and-24-seconds piece of uplifting music (Allegro Con Spirito, Mozart Sonata for Two Pianos in D Major, K.448 (1985), also used by Thompson, Schellenberg, & Husain, 2001). Following this positive mood induction a final mood rating was obtained. For both groups of participants the final mood rating was similar to or higher than the first, pre-induction mood rating. For the 64 participants in the low negative affect group, the mean mood rating prior to the negative mood induction was 6.29 (SD=2.6) and after the positive mood induction it was 6.30 (SD=2.3), t(63) = 0.28, p>.10. For the 22 participants in the high negative affect group, the corresponding ratings were 3.98 (SD=3.5) and 4.74 (SD=2.8), t(21) = 1.19, p>.10.