Effects of prospective thinking on intertemporal choice: The role of familiarity

Abstract

Imagining future events while performing an intertemporal choice task can attenuate the devaluation of future rewards. Here, we investigated whether this effect and its neural basis depend on the degree of personal prior experience associated with the simulated future scenarios. Functional magnetic resonance imaging was combined with a modified intertemporal choice task in which the delayed options were either purely monetary, or linked with a social event. Subject-specific events differed regarding familiarity, that is, meeting a close, familiar person or a celebrity in a café. In line with recent hypotheses on episodic construction, the simulation of future familiar and unfamiliar events equally attenuated delay discounting behavior in comparison with the control condition and both were imagined with similar richness. Imaging data, however, indicate that these results rely on differential neural activation patterns. The hippocampus was particularly involved in the simulation of unfamiliar future scenarios, probably reflecting enhanced construction processes when personal experience with similar past events is lacking. Consequently, functional coupling of the hippocampus with neural valuation signals in the anterior cingulate cortex predicted the subjective value only of rewards offered in the unfamiliar context. In contrast, valuation of rewards in a familiar context was predicted by activation in key nodes of emotional and autobiographical memory retrieval and dynamically modulated by frontal-striatal connectivity. The present data emphasize that the mechanisms underlying neural valuation of prospective rewards largely depend on the pre-experience with the context in which they are offered.

Keywords: autobiographical memory; decision-making; hippocampus; intertemporal choice; prospection.

Figure 1

Outline of the paradigm. Each trial started with a green dot, signaling the start of the trial. Next, the delayed reward option was presented for 6 s. Participants had to indicate their choice by selecting the red cross for the immediate reward (20 € that were not shown) or the green check mark for the delayed reward option. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Figure 2

Behavioral data. Square‐root transformed delay discounting rate k, plotted separately for the three conditions. Error bars represent standard errors of the mean. ** P < 0.01, n.s.: not significant. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Figure 3

Greater activation for both episodic (familiar and unfamiliar) conditions compared with the control condition was observed in the left posterior cingulate cortex (PCC), the left ventromedial prefrontal cortex (vmPFC) and the left lateral parietal cortex (LPC) (all P < 0.05 FWE). Activations are overlaid on the mean structural image of all participants (display threshold P < 0.005 uncorrected). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Figure 4

A: Activation in the right extended amygdala was significantly increased in the familiar compared with the unfamiliar condition (P < 0.05 FWE). B: The reverse contrast yielded a greater signal in the left posterior hippocampus (P < 0.05 FWE). Activations are overlaid on the mean structural image of all participants (display threshold P < 0.005 uncorrected). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Figure 5

Simple regression of the discounting parameter across the two episodic conditions and neural activation during the two episodic conditions yielded a significant correlation in the bilateral ACC (P < 0.05 FWE). Separate regression plots of parameter estimates in the peak voxel of the ACC and the individual discounting parameters of the familiar and unfamiliar condition confirm the presence of a correlation in both conditions. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Figure 6

Cortical activation in middle and inferior frontal gyrus, middle and inferior temporal gyrus, precuneus and the cerebellum was significantly increased during subjective value processing in the familiar compared with the unfamiliar condition (P < 0.05 FWE). L, left; R, right; B back. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Figure 7

A: The seed for the PPI analysis was placed in the left anterior cingulate cortex (ACC; −12,48,6, with 4 mm sphere). B: In comparison to the familiar condition, functional coupling between the ACC and the left hippocampus during subjective value (SV) processing was increased in the unfamiliar condition (P < 0.05 FWE). C: The reverse contrast revealed increased functional coupling between ACC and left ventral striatum for the familiar compared with the unfamiliar condition (P < 0.05 FWE). Activations are overlaid on the mean structural image of all participants (display threshold P < 0.005 uncorrected). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]