People fail to take into account how they'll feel in the future compared to the present (e.g. "hot" vs. "cold" state). It's hard for people to empathise across different affective states: this applies personally but also interpersonally.
Personal example: Saying "I'm going to the gym after work" in a rational "cold" state but failing to appreciate how tired one is after work and not feeling up to it ("hot" state) and ultimately not going to the gym because of that.
Interpersonally, this applies too – people have a hard time empathising with others when their affective state is very different. (e.g. not being in any pain and trying to empathise with someone in pain).
An implication of this is that a person's preference at one point in time is influenced by their affective state – can it be trusted? To get a better sense of true prefences, they should be measured over time. (Ideas about this are explored in Kahnemann's book "Noise").
Tags: psychology decision-making
Source: Loewenstein, George. "Hot-cold empathy gaps and medical decision making." Health psychology 24.4S (2005): S49. https://www.andrew.cmu.edu/user/gl20/GeorgeLoewenstein/Papers_files/pdf/hotColdEmpathyGaps.pdf
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