False action memories in older adults: Relationship with executive functions?

ABSTRACT

Merely observing another person performing an action can make young people later misremember having performed this action themselves (the observation-inflation effect). We examined this type of memory error in healthy older adults. Overall, both young and older adult groups showed robust observation inflation. Although the number of people committing observation-inflation errors did not differ between age groups, those older adults who were prone to this illusion showed a greater observation-inflation effect compared to the corresponding young. At the same time, observation also had beneficial effects on subsequent action memory, especially in older adults. Surprisingly, executive functioning was not correlated with the degree to which older adults made observation-inflation errors, but it was related to the degree to which older adults benefited from observation. We consider accounts of observation inflation based on source monitoring, familiarity misattribution, and motor simulation.

Keywords:

• Source memory
• Reality monitoring
• Executive functions
• Imagination inflation
• False memory

This work was supported by the Deutsche Forschungsgemeinschaft (German Research Foundation), the KoelnAlumni—Freunde und Foerderer der Universitaet zu Koeln e.V. (Friends and Supporters of the University of Cologne), the Heart and Stroke Foundation Centre for Stroke Recovery, the University of Ottawa, and the Natural Sciences and Engineering Research Council of Canada. We are grateful to Gerhard Mutz for his dedicated technical assistance, Michael Mentzner for patiently serving as the actor, and Héloïse Drouin for her much appreciated help in collecting the data. We also wish to thank Cécile Schain for extremely valuable comments on earlier versions of this manuscript.

Notes

2. ¹Because a person can show observation inflation after either repeated or single observations or both it might be interesting to consider these numbers more closely. Observation inflation was found for 18 older and 15 young adults after five observations, and 14 older and 13 young adults after one observation (from a total n of 27 in each age group). Moreover, it was found that if older adults were prone to observation inflation they were more likely to show the memory illusion after both repeated and single observations (72%) compared to the young (40%), χ²(1) = 3.98, p = .046.

3. ² The same patterns were found when including city as a third between subjects’ factor, with no significant main effects of or interactions with this factor; ps ≥ .114. Also the same patterns were found when excluding two participants with borderline MMSE-scores of 25 and 26.

4. ³ Variability was higher in the older compared to the young adults. For instance, a Levene-test showed that variability of observation inflation (in terms of the difference between actions observed five times vs. actions not observed) was higher in the older compared to the young in the total sample, F(1, 52) = 6.76, p = .012, whereas there was no significant difference in the constrained sample, F(1, 36) = 2.68, p = .110.

5. ⁴The same pattern was found when including city as a third between subjects’ factor, with no significant main effects of or interactions with this factor; ps ≥ .307. There was a trend toward an interaction between frequency of observation and city, indicating that participants from Edmonton benefited more from observation than those from Ottawa, p = .073. The same patterns were found when excluding two participants with borderline MMSE-scores of 25 and 26.