Nicholas Lange


This thesis investigates source memory for performed and observed actions in recall and recognition tasks. The motor simulation account predicts that motor activation during action observation results in source misattributions of observed actions as self-performed. Alternatively, source judgements at test may be based on the evaluation of source features (source monitoring framework) or memory strength (relative strength account). Experiments 1, 2 and 3 in Chapter 2 test if the motor simulation account explains false memories of self-performance after observation. Interfering with participants’ ability to encode the motor trace during observation does not reduce participants’ propensity to falsely recall observed actions as performed, but increases it. Experiment 4 in Chapter 3 manipulates motor and visual interference at retrieval. Participants’ false recognition of observed actions as performed and performed actions as observed is not significantly affected by motor or visual interference. Experiments 5, 6 and 7 in Chapter 4 test if participants are better able to discriminate performed and observed actions if they generate the idea for the action they perform themselves. Participants’ source discrimination in a recall task improves if they generate the ideas for self-performed actions (Experiment 5 and 6), only if they do not also generate ideas for actions they observe (Experiment 7). Experiment 8 in Chapter 5 manipulates participants’ visual perspective of actions they observe. There is no evidence for a significant effect of visual perspective during observation on subsequent false memories of self-performance in a recognition paradigm. In my thesis I find no substantial support for a motor simulation account. While the results are broadly compatible with the source monitoring framework, model-based analyses show that participants’ performance may be based on items’ overall strength, in line with the relative strength account, rather than evaluation of source features.

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