What if? Neural activity underlying semantic and episodic counterfactual thinking

Counterfactual thinking induces different neural patterns of memory modification in anxious individuals

Episodic counterfactual thinking (eCFT) is the process of mentally simulating alternate versions of experiences, which confers new phenomenological properties to the original memory and may be a useful therapeutic target for trait anxiety. However, it remains unclear how the neural representations of a memory change during eCFT. We hypothesized that eCFT-induced memory modification is associated with changes to the neural pattern of a memory primarily within the default mode network, moderated by dispositional anxiety levels. We tested this proposal by examining the representational dynamics of eCFT for 39 participants varying in trait anxiety. During eCFT, lateral parietal regions showed progressively more distinct activity patterns, whereas medial frontal neural activity patterns became more similar to those of the original memory. Neural pattern similarity in many default mode network regions was moderated by trait anxiety, where highly anxious individuals exhibited more generalized representations for upward eCFT (better counterfactual outcomes), but more distinct representations for downward eCFT (worse counterfactual outcomes). Our findings illustrate the efficacy of examining eCFT-based memory modification via neural pattern similarity, as well as the intricate interplay between trait anxiety and eCFT generation.

Perceived plausibility modulates hippocampal activity in episodic counterfactual thinking

Episodic counterfactual thinking (ECT) consists of imagining alternative outcomes to past personal events. Previous research has shown that ECT shares common neural substrates with episodic future thinking (EFT): our ability to imagine possible future events. Both ECT and EFT have been shown to critically depend on the hippocampus, and past research has explored hippocampal engagement as a function of the perceived plausibility of an imagined future event. However, the extent to which the hippocampus is modulated by perceived plausibility during ECT is unknown. In this study, we combine two functional magnetic resonance imaging datasets to investigate whether perceived plausibility modulates hippocampal activity during ECT. Our results indicate that plausibility parametrically modulates hippocampal activity during ECT, and that such modulation is confined to the left anterior portion of the hippocampus. Moreover, our results indicate that this modulation is positive, such that increased activity in the left anterior hippocampus is associated with higher ratings of ECT plausibility. We suggest that neither effort nor difficulty alone can account for these results, and instead suggest possible alternatives to explain the role of the hippocampus during the construction of plausible and implausible ECT.

The Spontaneous Counterfactual Inference Task: Misremembering What Might Have Been

Counterfactuals, thoughts about "what might have been," play an important role in causal judgment, emotion, and motivation, and spontaneously arise during daily life. However, current methods to measure spontaneous counterfactual thinking are cumbersome and subjective. The current research adapts a paradigm from the Spontaneous Trait Inference literature to develop the Spontaneous Counterfactual Inference measure (SCFI), which uses false recognition of counterfactual statements as a measure of spontaneous counterfactual thought. Studies 1a and 1b demonstrate that the SCFI is sensitive to precursors of counterfactual thinking: norm violation and counterfactual closeness. Study 2 demonstrates that the SCFI converges with the generation of counterfactual statements in an open-ended writing task. The SCFI also predicts two important consequences of counterfactual thought, blame (Study 3), and intention endorsement (Study 4). The SCFI thus offers a new tool for researchers interested in counterfactual thinking.

Neural differences between internal and external episodic counterfactual thoughts

Episodic counterfactual thoughts (eCFT) consist of imagining alternative outcomes to past experiences. A common sub-class of eCFT-upward eCFT-involves imagining how past negative experiences could have been better, either because one could have done something differently (internal) or because something about the circumstances could have been different (external). Although previous neuroimaging research has shown that the brain's default mode network (DMN) supports upward eCFT, it is unclear how it is differentially recruited during internal versus external upward eCFT. We collected functional magnetic resonance imaging data while participants remembered negative autobiographical memories, generated either internal or external upward eCFT for the memory, and then rated the plausibility, perceived control and difficulty of eCFT generation. Both internal and external eCFT engaged midline regions of cingulate cortex, a central node of the DMN. Most activity differentiating eCFT, however, occurred outside the DMN. External eCFT engaged cuneus, angular gyrus and precuneus, whereas internal eCFT engaged posterior cingulate and precentral gyrus. Angular gyrus and precuneus were additionally sensitive to perceived plausibility of external eCFT, while postcentral gyrus and insula activity scaled with perceived plausibility of internal eCFT. These results highlight the key brain regions that might be involved in cases of maladaptive mental simulations. This article is part of the theme issue 'Thinking about possibilities: mechanisms, ontogeny, functions and phylogeny'.

Episodic Past, Future, and counterfactual thinking in Relapsing-Remitting Multiple sclerosis

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Performance in episodic past, future or counterfactual thinking in relapsing-remitting MS and controls was explored.

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Behavioral and diffusion weighted imaging were used to evaluate associations between white matter integrity and group differences in performance.

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Relative to controls, MS patients showed reductions in episodic details across all three simulations.

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Reduced white matter integrity in three association tracts predicted this reduction in episodic details during counterfactual simulations.

Multiple sclerosis (MS) is a progressive disease characterized by widespread white matter lesions in the brain and spinal cord. In addition to well-characterized motor deficits, MS results in cognitive impairments in several domains, notably in episodic autobiographical memory. Recent studies have also revealed that patients with MS exhibit deficits in episodic future thinking, i.e., our capacity to imagine possible events that may occur in our personal future. Both episodic memory and episodic future thinking have been shown to share cognitive and neural mechanisms with a related kind of hypothetical simulation known as episodic counterfactual thinking: our capacity to imagine alternative ways in which past personal events could have occurred but did not. However, the extent to which episodic counterfactual thinking is affected in MS is still unknown. The current study sought to explore this issue by comparing performance in mental simulation tasks involving either past, future or counterfactual thoughts in relapsing-remitting MS. Diffusion weighted imaging (DWI) measures were also extracted to determine whether changes in structural pathways connecting the brain’s default mode network (DMN) would be associated with group differences in task performance. Relative to controls, patients showed marked reductions in the number of internal details across all mental simulations, but no differences in the number of external and semantic-based details. It was also found that, relative to controls, patients with relapsing-remitting MS reported reduced composition ratings for episodic simulations depicting counterfactual events, but not so for actual past or possible future episodes. Additionally, three DWI measures of white matter integrity—fractional anisotropy, radial diffusivity and streamline counts—showed reliable differences between patients with relapsing-remitting MS and matched healthy controls. Importantly, DWI measures associated with reduced white matter integrity in three association tracts on the DMN—the right superior longitudinal fasciculus, the left hippocampal portion of the cingulum and the left inferior longitudinal fasciculus—predicted reductions in the number of internal details during episodic counterfactual simulations. Taken together, these results help to illuminate impairments in episodic simulation in relapsing-remitting MS and show, for the first time, a differential association between white matter integrity and deficits in episodic counterfactual thinking in individuals with relapsing-remitting MS.

Integrating Philosophy of Understanding With the Cognitive Sciences

We provide two programmatic frameworks for integrating philosophical research on understanding with complementary work in computer science, psychology, and neuroscience. First, philosophical theories of understanding have consequences about how agents should reason if they are to understand that can then be evaluated empirically by their concordance with findings in scientific studies of reasoning. Second, these studies use a multitude of explanations, and a philosophical theory of understanding is well suited to integrating these explanations in illuminating ways.

Temporal Junctures in the Mind

Humans can imagine what happened in the past and what will happen in the future, but also what did not happen and what might happen. We reflect on envisioned events from alternative timelines, while knowing that we only ever live on one timeline. Considering alternative timelines rests on representations of temporal junctures, or points in time at which possible versions of reality diverge. These representations become increasingly sophisticated over childhood, first enabling preparation for mutually exclusive future possibilities and later the experience of counterfactual emotions like regret. By contrast, it remains unclear whether non-human animals represent temporal junctures at all. The emergence of these representations may have been a prime mover in human evolution.

Episodic Counterfactual Thinking

Our tendency to engage in episodic counterfactual thinking—namely, imagining alternative ways in which past personal events could have occurred but did not—is ubiquitous. Although widely studied by cognitive and social psychologists, this autobiographically based variety of counterfactual thought has been connected only recently to research on the cognitive and neuroscientific basis of episodic memory and mental simulation. In the current article, we offer an empirical characterization of episodic counterfactual thinking by contrasting it with related varieties of mental simulation along three dimensions: temporal context, degree of episodic detail, and modal profile (i.e., perceived possibility or impossibility). In so doing, we offer a practical strategy to navigate the nascent literature on episodic counterfactual thinking within the context of other mental simulations, and we argue that the evidence surveyed strongly indicates that although connected along the aforementioned dimensions, episodic counterfactual thinking is a psychological process different from episodic memory, episodic future thinking, and semantic counterfactual thinking.