Ethological Explanations

What is the ethological explanation for aggression based on animal behaviour?

• Ethology is the study of naturally occurring animal behaviour, which can include human behaviour.

  • Ethologists usually look at a particular type of behaviour (e.g aggression) across species

• Lorenz proposed a theory of aggression-based animal behaviour, which he applied to humans too

  • He defined aggression as fighting instinct directed at members of your own species

What is an ethological explanation?

• An etiological explanation seeks to understand the innate behaviour of animals (including humans) by studying them in their natural environment. The focus of an ethological explanation is to try and account for behaviour in terms of its adaptive value to the specific species.

• Aggression can aid survival, as it can be used to protect resources such as land and food. Aggression can establish dominance hierarchies, and these are vital to allow access to other resources, such as females.

• The ethological explanation proposes that aggression can be the result of an evolved automatic biological response in the brain; it is believed that animals have a built-in neural structure (a network of nuerons) which, when exposed to specific stimuli (signs or releasers), such as facial expressions, will cause the release of an automatic behavioural response.

What is the background for the ethological explanation?

Ethologists believe that, while the potential for aggression may be innate, actual aggressive behaviour is triggered by environmental stimuli, known as releases.

What is an example of the ethological explanation through time?

For example, intraspecies aggression serves to distribute individuals within a group in a way that makes the most efficient use of available resources such as access to mates and territory

What os an ethological explanation?

Stresses the adaptive value of animal behaviours- they study the behaviour patterns of animals

What is a Fixed Action Pattern?

A selection of stereotyped behaviours which occur in specific conditions (i.e in response to triggers) and which do not require learning

What is Innate Releasing Mechanism?

A neural network that when stimulated by the presence of a sign stimulus, activities the (FAP)

What are Innate Releasing Mechanism?

• The IRM is alerted to the presence of a sign stimulus and communicates with motor control circuits to release the associated FAP.

• Tinbergen (1951) showed this with male sticklebacks who will produce a fixed sequence of aggressive actions when another male enters their territory.

• However, the sign stimulus is not the male but rather the sight of its red underbelly. If this is covered up, there’s no attack.

Why did Lorenz believe that aggression is an innate response?

Lorenz argued that aggression has evolved as an adaptive response- an individual will be more likely to pass on their genes if they’re able to gain the upper hand in competition for food, mates or territory

Why did Lorenz aggression as an innate tendency that’s triggered by environmental stimuli?

• The urge to engage in aggressive behaviour builds up continuously over time- the more time that has passed since the last release of aggression, the more an animal feels internal pressure to be aggressive

• Eventually, a stimulus (an external event or situation) will trigger aggression.

• As the internal pressure to release the aggression builds up, the strength of stimulus needed to trigger this decreases. If the pressure is very high then aggression might be triggered spontaneously.

• The stimulus triggers an innate releasing mechanism — this is a proposed 'innate pathway' in the brain (i.e. a brain network that we're born with), which sets off a fixed action pattern.

• A fixed action pattern is an instinctive behaviour which is identical across a species.

  • For example, babies instinctively grab things they're offered and hold on tightly.

What are Fixed Action Patterns?

• All members of the same species (conspecifics) have innate behaviours which occur in certain conditions and these are called Fixed Action Patterns (Niko Tinbergen)

• These FAPs are produced by a neural mechanism known as an Innate Releasing Mechanism (IRM) and are triggered by a specific stimulus known as a sign stimulus.

Why is a fixed action pattern in animals?

• During breeding season the male sticklebacks develop bright red bellies. In males, seeing the bright red of another male's belly stimulates an innate releasing mechanism, which triggers specific fighting behaviour (the fixed action pattern) directed towards the rival.

• Tinbergen (1947) found that this response was triggered more by unrealistic models with red undersides (such as diamond shapes with no features) than by real sticklebacks with no red belly.

• This supports the suggestion that the behaviour is instinctive and set off by a specific trigger.

Why did Lorenz also believe that most aggression is ritualised?

• A behaviour won't be passed on through genes if it gets an animal killed before it produces offspring.
  If animals were routinely killed during everyday power struggles or mating contests, it's likely the species would become extinct. So, there are ritual behaviours in place to stop confrontations from being fatal.

• For example, wolves end a fight by the loser exposing his jugular vein as a sign of submission.
  This puts the winner in a prime position to kill their rival, but in fact, the winner takes no further action.

• Lorenz claimed that sport was an example of harmless ritualised aggression release in humans, and argued that sport was an important method for reducing aggression in society.

What is Ritualistic Aggression?

• Aggressive behaviour may take the form of ritualised displays

• These help to assess relative strength and may prevent costly and dangerous physical aggression from taking place

• This behaviour has been found in human tribal warfare too. The Dani of New Guinea and males in the Tory Island are examples

Wolves and Doves

• Lorenz (1952) claimed that species that have evolved fearsome weapons (e.g. wolves’ teeth and jaws) must have instinctive inhibitions not to use these against their own species. A fighting wolf will expose its neck on submission and the fight stops so this must be instinctive inhibition.

• Doves, for example, are non-hunters and so haven’t developed this inhibition and the loser can simply fly away.

• Lorenz feels humans are more like doves but sadly can now develop weapons of mass destruction and don’t have instinctive inhibitions

Do Humans have Fixed Action Patterns (FAPs) for aggression?

• Eibl-Eibesfeldt (1972) suggests we have FAPs (like smiling and the ‘eyebrow flash’) but believes that FAPs such as aggression are not adaptive in modern times.

• Human behaviour is far more varied and less predictable than non-human species so we don’t respond in the same way to specific sign stimuli

Why aren’t killing conspecifics is not that rare?

• If instinctive inhibitions prevent the killing of own species according to ethologists, then it should only happen due to accident.

• However male lions and male chimpanzees kill more systematically (lions – cubs of other males; chimpanzees – members of another group) thus casting doubt on the claim that aggression may be ritualistic rather than real.

What is the Hydraulic Model?

• From everyday experience, we know that the more motivated we are, the more responsive we are to stimuli in our environment. For example, if I am very hungry, I am more likely to eat something that I am not particularly fond of just to satisfy my hunger.

• In Lorenz's model, motivation increases with time. This motivation is specific to one type of behaviour (e.g., feeding, fighting, or sexual behaviour). This specific source of motivational energy is called action-specific energy. It is represented by the accumulation of water in the blue reservoir, which is filled by a tap.

• It is called a hydraulic model because it views motivation as a liquid whose accumulation and discharge influences behaviour. consequently, some people call it 'Lorenz's water closet’

• Action-specific energy (motivational energy) accumulates in a reservoir until released by an appropriate sign stimulus, represented by weights on a scale pan, or until the pressure on the valve causes an action pattern to occur spontaneously (vacuum activity).

• The consummatory response or Fixed Action Pattern(s) released vary depending upon how much action-specific energy is released from the valve.

• Lorenz introduced the term innate releasing mechanism (IRM) to describe a central located somewhere in the brain) mechanism that handled the link between external stimulus, internal motivation and behavioural output. The scale pan, pulley, trough and outflow pipes in the model correspond to the IRM

• Models and theoretical systems are useful because they organise research findings and suggest further experiments. Models often help reveal the principles underlying the organisation of behaviour. But they do not necessarily tell us much about the actual brain mechanisms involved.

What are the benefits of ritualised aggression?

• Anthropological evidence suggests that ritualised aggression was also useful in humans to prevent physical aggression.

• The Yanomamo of South America used chest pounding and club fighting to settle conflicts (Chagnon, 1992).

• Hoebel (1967) found that Inuit Eskimos use song duels to settle grudges and disputes.

• This suggests that even in aggressive cultures rituals may be used to prevent injury or death.

What are the criticisms of ‘instinctive’ view?

• Lehrman (1953) believed that Lorenz had underestimated the role of environmental factors in the development of species-typical aggressive behaviour patterns.

• Fixed action pattern (FAP) tends not to be used within ethology now and rather are referred to as ‘behaviour patterns’ to acknowledge the complex interaction of experience and innate responses.

What are the strengths of the ethological explanation?

• Aggression does occur as a fixed action pattern in some animals, e.g. sticklebacks.

• This theory could explain why humans kill each other relatively often - without weapons human fighting isn't usually lethal, so we haven't evolved to back down. Now that we have access to weapons, fights are more likely to kill.

What are the weaknesses of ethological?

• This theory doesn't explain aggression which isn't an immediate response to an environmental stimulus, for example, premeditated murder.

• Arms et al (1979) found that watching aggressive sports increased aggression in participants, rather than dispersing it.