Recent interest in the role of the hippocampus in temporal aspects of cognition has been fueled, in part, by the observation of “time” cells in the rodent hippocampus—that is, cells that have differential firing patterns depending on how long ago an event occurred. Such cells are thought to provide an internal representation of elapsed time. Yet, the hippocampus is not needed for processing temporal duration information per se, at least on the order of seconds, as evidenced by intact duration judgments in rodents and humans with hippocampal damage. Rather, it has been proposed that the hippocampus may be essential for coding higher order aspects of temporal mnemonic processing, such as those needed to temporally organize a sequence of events that form an episode. To examine whether (1) the hippocampus uses duration information in the service of establishing temporal relations among events and (2) its role in memory for duration is unique to sequences, we tested amnesic patients with medial-temporal lobe damage (including the hippocampus). We hypothesized that medial-temporal lobe damage should impair the ability to remember sequential duration information but leave intact judgments about duration devoid of a sequential demand. We found that amnesics were impaired in making judgments about durations within a sequence but not in judging single durations. This impairment was not due to higher cognitive load associated with duration judgments about sequences. In convergence with rodent and human fMRI work, these findings shed light on how time coding in the hippocampus may contribute to temporal cognition.

Theoretical accounts of moral decision making imply distinct ways in which episodic memory processes may contribute to judgments about moral dilemmas that entail high conflict between a harmful action and a greater good resulting from such action.Yet, studies examining the status of moral judgment in amnesic patients with medial temporal lobe (MTL) lesions have yielded inconsistent results. To examine whether and how episodic processes contribute to high conflict moral decisions, amnesic patients with MTL damage and control participants were asked to judge the moral acceptability of a harmful action across two conditions that differed in the framing of the moral question. We predicted that personal (but not abstract) framing would engage episodic processes involved in mental simulation, yielding a selective impairment in MTL patients in the personal framing condition. This prediction was not confirmed as neither patients nor controls were influenced by the framing of the moral question. With the exception of a patient whose lesion extended into the amygdala bilaterally, patients were less willing than controls to endorse the utilitarian option, rejecting the harmful action despite its beneficial outcome. They also rated actions as emotionally more intense than did controls. These findings suggest that episodic processes involved in mental simulation are necessary to prospectively evaluate actionoutcome contingencies.

When faced with intertemporal choices, people typically devalue rewards available in the future compared to rewards more immediately available, a phenomenon known as temporal discounting. Decisions involving intertemporal choices arise daily, with critical impact on health and financial wellbeing. Although many such decisions are “experiential” in that they involve delays and rewards that are experienced in real-time and can inform subsequent choices, most studies have focused on intertemporal choices with hypothetical outcomes (or outcomes delivered after all decisions are made). The present study focused on experiential intertemporal choices. First, a novel intertemporal choice task was developed and validated, using delays experienced in real time and artistic photographs as consumable perceptual rewards. Second, performance on the experiential task was compared to performance on a classic intertemporal choice task with hypothetical outcomes. Involvement of distinct processes across tasks was probed by examining differential relations to state and trait anxiety. A two-parameter logistic function framework was proposed to fit indifference point data. This approach accounts for individual variability not only in the delay at which an individual switches from choosing the delayed to more immediate option, but also in the slope of that switch. Fit results indicated that the experiential task elicited temporal discounting, with effective trade-off between delay and perceptual reward. Comparison with the hypothetical intertemporal choice task suggested distinct mechanisms: first, temporal discounting across the two tasks was not correlated; and second, state and trait anxiety both were associated with choice behavior in the experiential task, albeit in distinct ways, whereas neither was significantly associated with choice behavior in the hypothetical task. The engagement of different processes in the experiential compared to hypothetical task may align with neural evidence for the recruitment of the hippocampus in animal but not in classic human intertemporal choice studies.

When faced with intertemporal choices, people typically devalue rewards available in the future compared to rewards more immediately available, a phenomenon known as temporal discounting. Decisions involving intertemporal choices arise daily, with critical impact on health and financial wellbeing. Although many such decisions are “experiential” in that they involve delays and rewards that are experienced in real-time and can inform subsequent choices, most studies have focused on intertemporal choices with hypothetical outcomes (or outcomes delivered after all decisions are made). The present study focused on experiential intertemporal choices. First, a novel intertemporal choice task was developed and validated, using delays experienced in real time and artistic photographs as consumable perceptual rewards. Second, performance on the experiential task was compared to performance on a classic intertemporal choice task with hypothetical outcomes. Involvement of distinct processes across tasks was probed by examining differential relations to trait anxiety and state anxiety. A two-parameter logistic function framework was proposed to fit indifference point data, and was shown to improve upon hyperbolic fit. This approach accounts for individual variability not only in the delay at which an individual switches from choosing the delayed to more immediate option, but also in the slope of that switch. Fit results indicated that the experiential task elicited temporal discounting, with effective trade-off between delay and perceptual reward. Comparison with the hypothetical intertemporal choice task suggested distinct mechanisms: temporal discounting across the two tasks was not correlated; state anxiety affected choice behavior in the experiential task but not in the hypothetical task; and trait anxiety had contrasting effects across the two tasks. These findings were interpreted as reflecting differential engagement of episodic processes in the experiential compared to the hypothetical task, consistent with neural evidence for recruitment of the hippocampus in the former but not in the latter task.

A prevailing view in cognitive neuroscience suggests that different forms of learning are mediated by dissociable memory systems, with a mesolimbic (i.e., midbrain and basal ganglia) system supporting incremental trial‐and‐error reinforcement learning and a hippocampal‐based system supporting episodic memory. Yet, growing evidence suggests that the hippocampus may also be important for trial‐and‐error learning, particularly value or reward‐based learning. In the present report, we use a lesion‐based neuropsychological approach to clarify hippocampal contributions to such learning. Six amnesic patients with medial temporal lobe damage and a group of healthy controls were administered a simple value‐based learning task involving probabilistic trial‐and‐error acquisition of stimulus–response‐outcome (reward or none) contingencies modeled after Li et al. (Proceedings of the National Academy of Sciences , 2011, 108 (1), 55–60). As predicted, patients were significantly impaired on the task, demonstrating reduced learning of the contingencies. Our results provide further supportive evidence that the hippocampus' role in cognition extends beyond episodic memory tasks and call for further refinement of theoretical models of hippocampal functioning.