Disease Recognition, Care-giving, and Cognition

Question 1

1. Why do we study disease recognition and care-giving?

Answer 1

• Evolution of Cognition - Understanding how selection to recognise cues of disease and avoid infection has shaped our cognitive abilities and our social lives
• Health & Conservation - Zoonotic disease: A zoonotic disease is a disease that can be spread between animals and humans. Zoonotic diseases can be caused by viruses, bacteria, parasites, and fungi. These diseases are very common. Scientists estimate that more than 6 out of every 10 infectious diseases in humans are spread from animals. Understanding how pathogens are transmitted or avoided can contribute to conservation and zoonotic disease monitoring efforts.

Host-Pathogen Coevolution - we can learn about this as pathogens are under selection to successfully infect hosts and the hosts are under selection to prevent this. this leads to an arms race in which hosts are under selection to evolve defences. each time a new defence evolves, the pathogens are under selection pressure to evade it. this means that to fully understand pathogens, we need to understand how they react to our behavioural defences against them. A particular salient example is the coronavirus.

Using evolution to understand ourselves - we can understand more about ourselves and how our own care systems evolved. some types of care such as social grooming are widespread across the animal kingdom. this indicates that they are likely to be shared and ancestral, that is, they may have been present in the last common ancestor of those species. other types of care giving may be derived (that is newly evolved in a lineage) through tracing what types of care evolve in what species. we can try to track when the behaviours evolved by looking at the animal kingdoms history to understand ourselves more.

Question 2

2. What is disease recognition?

Answer 2

•A process through which individuals recognize cues and/or signals of disease in others
 Cue: A trait that is assessed during communication (Candolin 2003)
Signal: A cue that has been at least partly modified by natural selection for the purposes of communication (Candolin 2003)
this is important because it can sometimes be difficult to identify what is a cue and what is a signal.

• Signalling Theory of Symptoms argues: easily discernible features of an immune reaction (or symptoms) serve not only defense and healing, but also signal the need for help and treatment (Steinkopf 2015)

Cues / signals may be:
 Visual: rash, flushing due to fever
Auditory: coughing, hoarseness
Olfactory: odour changes
Behavioural: lethargy, soliciting grooming

After disease recognition…
what the observer does in this situation is highly variable.
- avoiding others who are sick is common (seen in lobsters, pipe fish, and mandro monkeys)
- other? - did they notice the disease cues or just to decide to ignore them? or take advantage of a weakened rival?
- care -

Behavioural immune system:
is a suite of psychological mechanisms that detect cues indicating the presence of infectious pathogens in the immediate environment. they trigger disease relevant emotional and cognitive responses, helping us to facilitate avoidance. its out first line of defence against pathogens and when we avoid pathogens it reduces the burden on the physiological immune system because we don’t have to mount a costly immune defence. in particular, our avoidance responses are thought to be triggered by feelings of disgust. we tend to be disgusted by things that may bring infection risks.

Disgust in animals
•Disgust is difficult to define in nonhuman animals, but we do see evidence of avoiding feces.

Question 3

3. What is “care”?

Answer 3

•Healthcare behaviors: can control the spread of diseases.
 Separate from medical technologies
does not need to be related to empathy or compassion as well as medical technologies.

Health care behaviours can be divided into two categories. social care (behaviours directed towards a sick individual) and community health (benefit the group/community).

Question 4

4. How do these two types of care-giving evolve (social care and community health)?

Answer 4

social care - kin (relatives) selection, reciprocity (peers - e.g. grooming in exchange for social support)

community health - often evolve via kin selection (nest sanitation for birds generally benefits offspring in the nest). community health behaviours are a type of niche construction in which individuals modify the distribution of pathogens in their environment.

link between extensive social care and extensive community health behaviours:
social care should increase transmission risks between individuals because carers generally risk exposure when providing care. but community health behaviours will control pathogens in the environment and perhaps reduce the costs of engaging in social care. this means that a feedback loop is created in which more community health behaviours make more social care possible and more social care creates the need for more community health behaviours. still largely a hypothesis.

Question 5

5. Is human care-giving unique?

Answer 5

kin care or social care that gets given to genetic relatives is not, most of the care that gets given in the animal kingdom is given to kin. however, stranger care maybe; humans will fly around the world to risk their lives to treat someone with Ebola. other species only seem to provide care to individual they know and already have a relationship with. this large scale, organised co-operative care given to strangers does seem to be uniquely human. we don’t yet fully understand when stranger care evolved, though it was clearly after we diverged from other apes.