Memory for Actions: A two-way mirror? Nicholas Lange, Timothy J. Perfect & Patric Bach, Plymouth University Confusing the sources of events or items has been observed in both the action and verbal domain, but domains differ in the proposed causes and characteristics of this confusion. BACKGROUND verbal domain action domain Source confusion is bidirectional, i.e. misattributions both towards (unconscious plagiarism) and away from the self (Perfect et al., submitted) proposed to result when contextual cues allowing inference of the source of an idea are not or cannot be used at retrieval  Source Monitoring account Source confusion is unidirectional, i.e. misattributions towards the self (observation inflation, Lindner et al., 2010 ) proposed to result from the creation of matching motor representations for both action execution and observation via mirror neuron network activation in the observer’s motor system  Action Simulation account Do characteristics of source misattributions differ between domains, i.e. bidirectionality of source errors? Does an action simulation account need to be invoked in the action domain? - 38 participants in pairs - 4 exemplars/participant generated for 15 shape cues Generation Phase: secondary tasks during observation of partner’s generation: 1. no secondary task, 2. a simple motor task (medium load, no action planning), 3. visual-spatial working memory task (high load, action planning) Retrieval Phase: 1 day delay, free recall of own or partner’s examples Simulation: estimation of chance performance in source and intrusion errors by matching a random partner to each participant while target of participants’ recall (self or partner) was not varied, resulting in stable correct rates METHOD 1. Source Monitoring account: source misattributions in the recall partner task 2. Source Monitoring and Action Simulation accounts: a. increase of other-plagiarism in generation phase and b. decrease in correct recall in recall partner task under secondary task load 3. Secondary task load leads to differing predictions in both accounts for source confusion in recall own task: - Source Monitoring: increase of source errors (distraction  inability to encode source cues) - Action Simulation: decrease of source errors (motor system occupied  inability to encode items) PREDICTIONS RESULTS generation phase retrieval phase u * Error bars: 95% confidence interval u 1. * p<.001 (from 0) u 2b. * p=.048 (linear contrast, p=.04) 2a. p=.078 (linear contrast, p=.02) 3. p=.48 * Error bars: 95% confidence interval While secondary motor task load during action observation affected performance at encoding (2a.) and retrieval (2b.), it crucially did not affect source error rates (3. ), contrary to Action Simulation and Source Monitoring predictions. Observed source misattributions of own actions away from the self (1. ) cannot be accounted for by an Action Simulation account, however, without assuming post-encoding Source-Monitoring-like decision processes which have explicitly been ruled out by prior research. Alternate accounts to consider are source errors resulting by chance from guessing processes or verbal encoding of largely non-verbalizable action items. However, overall the simulation shows that participants made more source errors and fewer intrusion errors than would be predicted by chance performance, suggesting that biases beyond chance are responsible for the observed results. DISCUSSION Lindner, I., Echterhoff, G., Davidson, P. S. R., & Brand, M. (2010). Observation inflation. Your actions become mine. Psychological Science, 21(9), 1291–9. Perfect, T.J., Berry, C., Lange, N., Levitt, C. & Dennis, I. (submitted). I told you so: during recall people give away more answers than they plagiarise. Nick.Lange@plymouth.ac.uk