Scholarly Commons

Cognitive Bias - It May Not Be All About Stress

Emotional state can influence decision making, especially when available information for making the decision is ambiguous. This study examined the impact of acute stress on decision making in male Long-Evans rats. Rats learned to associate high value (chocolate) or low value (fruit loop) food rewards with tactile cues of either course or fine sandpaper. Training continued for a period of 5 weeks in which food rewards were buried progressively deeper in cinnamon or coriander scented sawdust in black or white foraging bowls placed on the right or left side of the goal box. These cues (scent, bowl color, and side placement) were counterbalanced within the cohorts of rats to minimize the possibility of bias. Results from training trials indicate rats naturally demonstrate an optimistic judgement when the sandpaper stimulus is ambiguous. It was found that rats in cohort 1 subjected to three days of acute stress (restraint, water, and footshock) and retested on the final phase demonstrated a negative cognitive bias by making decisions consistent with an expectation of a low value reward when the stimulus is ambiguous. However, there was a significant difference in the cognitive bias between rats in cohort 1 and those tested in cohort 2 after acute stress. The results are discussed in the context of other environmental factors that may have contributed to this difference.