Counterfactual thinking in patients with amnesia.
Bottom Line: They could deconstruct reality, add in and recombine elements, change relations between temporal sequences of events, enabling them to determine plausible alternatives of complex episodes.A difference between the patients and control participants was evident, however, in the patients' subtle avoidance of CF simulations that required the construction of an internal spatial representation.Overall, our findings suggest that mental simulation in the form of nonepisodic CF thinking does not seem to depend upon the hippocampus unless there is the added requirement for construction of a coherent spatial scene within which to play out scenarios.
Affiliation: Institute of Neuroscience, Henry Wellcome Building for Neuroecology, Newcastle University, Newcastle upon Tyne, United Kingdom.Show MeSH
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Mentions: In order to probe this further, we investigated whether patients could actually generate these alternate realities by asking participants to simulate two full CF alternatives of the day's events out loud. They therefore had to identify a specific fault-line, mutate it, and then simulate a coherent and logical sequence of events that could have arisen following this mutation. The simulations were scored in two ways. First, we asked if the participant generated a coherent narrative in which one specific event (CF fault-line) was mutated (Yes/No; for 100% of patients and 100% of controls the answer was Yes). Second, we asked whether the generated simulation demonstrated that the participant successfully recombined the previously given information with internally generated events/thoughts/actions to form a (1) coherent, (2) logical, and (3) novel sequence of events. A CF simulation was only considered acceptable if all three criteria were met. All the CF simulations provided by the patients and the controls met all three criteria, showing that both groups could easily simulate alternative scenarios. An example of a generated simulation from a patient and a control participant is shown in Figure 2. Difficulty was also formally assessed using a questionnaire that participants completed after simulating each CF alternative. From this, a CF generation score was derived whereby a negative score (range: −2.5 to +2.5) reflected an underlying difficulty generating spontaneous CF thoughts and simulating the corresponding CF alternative. Both groups scored comparably (U = 39.5, Z = −0.21, P = 0.83) and within the positive range (patients 1.67, SD 0.82; controls 0.95, SD 0.96; Fig. 3A). This suggests that the patients were not only able to identify predictable CF thoughts but they were also able to simulate with ease “what might have been.”
Affiliation: Institute of Neuroscience, Henry Wellcome Building for Neuroecology, Newcastle University, Newcastle upon Tyne, United Kingdom.