It was a very nice surprise to see the Cumulative Pain method used here to guide this debate. The ‘value tag’ that is already placed on different causes by resource allocation decisions is often based on personal experiences, specialist opinion, tradition or often even empathic guesses. Yet the criteria underlying these decisions are seldom explicit or open to scrutiny. This is one of the things we wanted to help change with the method: to help inform decisions based on an atomized process, where every assumption is explicit, and can help debate in a more objective way, based on estimates and evidence about the actual hedonic experiences of the subjects/targets of the interventions (as is the case here!). The sensitivity app (https://www.pain-track.org/hens) was also created to ensure that anyone disagreeing with our assumptions/estimates could use their own.
Re. the comments:
like Michael, for an experience that someone is desperate to stop immediately, similar to “slicing into my leg with a hot, sharp live wire”, we would attribute a higher likelihood of Excruciating pain (as this does not seem as something that can be tolerated for a long time). We have not yet estimated any mathematical equivalence between the intensity categories for the reasons we discuss in the FAQ (https://welfarefootprint.org/frequently-asked-questions/), but Excruciating pain is likely much much worse (something similar to an exponential—rather than linear—function) than Disabling pain (we are working on a draft on this issue that should be released at some point this year).
You are right that Disabling pain possibly accepts a range of intensities, all fitting the Disabling definition (continuously distressing/disruptive, cannot be ignored, prevents positive welfare, reduces attention to other ongoing stimuli). We have chosen not to create more categories to ensure both resolution and tractability (given the scarcity of evidence typically available from animal studies), but subdivision of the intensity categories is certainly possible and desirable should evidence be available that enables it.
It is true that distressed behaviors can be present in the absence of suffering, but this is unlikely to be the case when these behaviors are conditional and proportional to the degree of aversiveness of the situation, and observed along with various other independent indicators of distress. For example, pre-laying behavior is very different for hens with or without access to a proper nest and excessive pacing (seen in the latter case) is associated with other aversive situations. Other indicators include the observation of inelastic demand for a nest (hens paying increasingly higher costs to get to a nest), the overcoming of aversive obstacles (e.g., narrow gaps, long walking distances, dominant/unfamiliar birds), and vocalizations typically associated with frustration in other contexts. We also need to consider the evolutionary importance of psychological distress in the absence of important resources for survival and reproduction. In the case of physical pain, it is the unpleasantness of the pain experience that protects individuals from provoking further tissue damage when the eliciting stimuli is no longer present. Negative affective states of a more diffuse nature (psychological pain) are similarly strongly selected to ensure that individuals do not give up seeking important resources, as is the case of a nest, mates and offspring.
The notion that a hen under higher levels of feed deprivation would work less hard for access to food is a thoughtful one. However, the levels of feed restriction applied where unlikely to deprive the hens from the energy needed to access food. More importantly, evidence has shown the opposite: within the time periods of food deprivation used in experiments (e.g. up to 50-60 hours) hens deprived of food for a longer period work harder than hens deprived of food for a shorter period (e.g. https://www.sciencedirect.com/science/article/abs/pii/0168159190900156)
On the extent to which it is possible to compare physical and psychological pain, or use similar criteria to define their intensity, this is an interesting discussion and one that we would also like to work more on. For example, it may be hard to identify, in the short term, reliable biological markers of psychological suffering, and the same is true for humans. Consider for example the lack of changes in adrenocortical function in prisoners held 10 days in solitary confinement (“Adrenocortical function, as measured by plasma cortisol levels, indicated that solitary confinement was not more stressful than normal institutional life”, https://psycnet.apa.org/doiLanding?doi=10.1037%2Fh0081866), despite the severity of the experience as reported by those who have undergone it.
Based on your intro, I take it that you are one of the authors of the pain scale. It’s been a while since I thought about this post, but I appreciate your info-dense comment, and given your apparent background I will take some time to read and think about it over the next week. It might be a bit before I can offer a substantive reply, but thank you for chiming in!
It was a very nice surprise to see the Cumulative Pain method used here to guide this debate. The ‘value tag’ that is already placed on different causes by resource allocation decisions is often based on personal experiences, specialist opinion, tradition or often even empathic guesses. Yet the criteria underlying these decisions are seldom explicit or open to scrutiny. This is one of the things we wanted to help change with the method: to help inform decisions based on an atomized process, where every assumption is explicit, and can help debate in a more objective way, based on estimates and evidence about the actual hedonic experiences of the subjects/targets of the interventions (as is the case here!). The sensitivity app (https://www.pain-track.org/hens) was also created to ensure that anyone disagreeing with our assumptions/estimates could use their own.
Re. the comments:
like Michael, for an experience that someone is desperate to stop immediately, similar to “slicing into my leg with a hot, sharp live wire”, we would attribute a higher likelihood of Excruciating pain (as this does not seem as something that can be tolerated for a long time). We have not yet estimated any mathematical equivalence between the intensity categories for the reasons we discuss in the FAQ (https://welfarefootprint.org/frequently-asked-questions/), but Excruciating pain is likely much much worse (something similar to an exponential—rather than linear—function) than Disabling pain (we are working on a draft on this issue that should be released at some point this year).
You are right that Disabling pain possibly accepts a range of intensities, all fitting the Disabling definition (continuously distressing/disruptive, cannot be ignored, prevents positive welfare, reduces attention to other ongoing stimuli). We have chosen not to create more categories to ensure both resolution and tractability (given the scarcity of evidence typically available from animal studies), but subdivision of the intensity categories is certainly possible and desirable should evidence be available that enables it.
It is true that distressed behaviors can be present in the absence of suffering, but this is unlikely to be the case when these behaviors are conditional and proportional to the degree of aversiveness of the situation, and observed along with various other independent indicators of distress. For example, pre-laying behavior is very different for hens with or without access to a proper nest and excessive pacing (seen in the latter case) is associated with other aversive situations. Other indicators include the observation of inelastic demand for a nest (hens paying increasingly higher costs to get to a nest), the overcoming of aversive obstacles (e.g., narrow gaps, long walking distances, dominant/unfamiliar birds), and vocalizations typically associated with frustration in other contexts. We also need to consider the evolutionary importance of psychological distress in the absence of important resources for survival and reproduction. In the case of physical pain, it is the unpleasantness of the pain experience that protects individuals from provoking further tissue damage when the eliciting stimuli is no longer present. Negative affective states of a more diffuse nature (psychological pain) are similarly strongly selected to ensure that individuals do not give up seeking important resources, as is the case of a nest, mates and offspring.
The notion that a hen under higher levels of feed deprivation would work less hard for access to food is a thoughtful one. However, the levels of feed restriction applied where unlikely to deprive the hens from the energy needed to access food. More importantly, evidence has shown the opposite: within the time periods of food deprivation used in experiments (e.g. up to 50-60 hours) hens deprived of food for a longer period work harder than hens deprived of food for a shorter period (e.g. https://www.sciencedirect.com/science/article/abs/pii/0168159190900156)
On the extent to which it is possible to compare physical and psychological pain, or use similar criteria to define their intensity, this is an interesting discussion and one that we would also like to work more on. For example, it may be hard to identify, in the short term, reliable biological markers of psychological suffering, and the same is true for humans. Consider for example the lack of changes in adrenocortical function in prisoners held 10 days in solitary confinement (“Adrenocortical function, as measured by plasma cortisol levels, indicated that solitary confinement was not more stressful than normal institutional life”, https://psycnet.apa.org/doiLanding?doi=10.1037%2Fh0081866), despite the severity of the experience as reported by those who have undergone it.
Thanks for the interesting discussion!
Based on your intro, I take it that you are one of the authors of the pain scale. It’s been a while since I thought about this post, but I appreciate your info-dense comment, and given your apparent background I will take some time to read and think about it over the next week. It might be a bit before I can offer a substantive reply, but thank you for chiming in!