Comparing Species’ Intellects
Comparing Species’ Intellects
When comparing species’ intellects, what problems are likely to be encountered and how should they be avoided?
There are 2 main theories for the comparison of animal intelligence: A phylogenetic based approach: since the time of aritotle people have tried to organise the animal kingdom into a sequence of intelligence or “scala naturae” great chain of being. What has now become known as the phylogenetic scale of intelligence is based upon Darwins theory of evolution as laid out in his on the origin of the species 1859. As intelligence serves an adaptive purpose it is a reasonable assumption that the more evolved an animal is the more intelligent it will be. For instance we evolved from homo-sapiens around 100,000 years ago and we are much more intelligent than them. However this had been proven not to be the case. In fact evolution encourages tree like not linear organisation of organisms and their characteristics.
As gould said 1996 our species is a “tiny twig on the floridly aborescent bush of life” Evolution provides an example of the diversity of a species, it does not provide any grounds for ranking animals according to their intelligence. An alternative approach to comparing animal intelligence is the niche specific theory of intelligence. This theory argues that animals have different environmental pressures and that is reflected in their intellectual ability for example a bird has excellent navigation skills and a dog has an excellent sense of smell. However there are also common evolutionary pressures which all species share such as food illness learning. The underlying mechanisms for learning which foods to avoid is the same in all animals so this theory is also a shite way to explain the distribution of intelligence.
The main problem when comparing species intellects is how to define a test which is a fair test. All animals differ in their intellectual abilities and are better at some things than others so how can we define a test which tests them equally. There have been 4 main ways provided: Adaptation to the environment:
Many believe that the defining characteristic of intelligence is that it enables animals to behave adaptively. Barnett 1970 proposed “intelligence here means the ability to adapt behaviour to circumstances”. Therefore one way to compare animals intelligence is to look at how well adapted they are to their environment. However this measure of intelligence is very weak, it is not fair to compare different environments. This also implies that if an animal swapped environments they would become less intelligent.
Another method proposed for comparing animals intelligence is by comparing brain size. The brain is the organ responsible for intelligence and therefore it might be reasonable to expect animals with larger brains to have greater capacity for intelligence. However we would expect humans to be at the top and we are not because other animals have much larger bodies which need larger brains to control basic activities such as respiration and digestion. Therefore the method of comparing brain size to body weight has been proposed however this would put birds above humans also rendering it wrong. Jerrison 1973 however introduced a more complex ratio based on log scaling using a ratio o 2/3. This is called the encephalisaton quotient and does position man at the top. However there are still problems to be encountered with this method as well. Brains are not just for intellectual activity they are mainly used for basic processes like respiration and digestion so measure of brain size is contaminated.
Brain weight is also affected by neural density and ventricular capacity which are not necessarily mean more intelligence. To overcome these problems it has been suggested that we focus on the measurement of the neocortex as this is the part of the brain which is particularly well developed in humans and therefore it has been argued that a large neocortex reflects advanced intelligence. But even this measure has problems, for instance only mammals have a neocortex, birds brains have taken a different evolutionary path and have no neocortex at all, how then can we compare different parts of the brain when different species have differently designed brains. Another method for comparing species intelligence is to compare their rates of learning. For instance measuring how long it takes a species to learn they need to push a certain lever for food, or how quickly it takes to navigate a maze. However this method is also likely to encounter serious problems.
Skard 1950 found no difference in rats and humans navigated a complex maze for instance. Furthermore angermeier 1984 surprisingly found that human infants took the longest to learn a task where animals had to perform a simple response to obtain food. Human infants took an average of 28 rewards before they started to respond at a constant rate however bees for instance only took 2 rewards. Another problem encountered with mesasuring rate of learning is that different species require different apparatus in order to assess their learning and the apparatus use is likely to effect the speed of learning. Furthermore Bitterman 1965 refers to contextual variables as being responsible for any differences observed in learning between animals.
The inherent differences between species makes it very difficult to devise a task which imposes the same demands on both of them. One way to overcome contextual variables is to use the method of systematic variance. This involves testing a range of species in a wide range of environments to see if they are above average across all conditions. This all or nothing approach loses information however and is very costly and time consuming for researchers to implement. An additional problem people often encounter when studying animal intelligence is anthromorphism.
This is the tendency for humans to attribute human characteristics to an animal. For example we often think that animals have thoughts and feelings in much the same way as we do, so when a pet rubs your legs you assume they are thinking about food and are asking you to get them some. However this is very unlikely Lloyds canon much more likely to have the behaviour reinforced thye associate it with food. We often attribute emotion to animals as well when there is no evidence they experience emotion or feeling.
Sz essay studies:
1963 – Carlson and linquist developed dopamine hypothesis
1996 – laruelle et al. found that when ps injected with amphetamine produced positive symptoms of Sz. Also brain imaging showed higher amounts of dopamine released in the striatums of Sz patients. 2001 – kestler et al. review of PM and PET scans showed only moderate increase in the number of D2 receptors in the brains of Sz people. Providing weak support, unlikely that is the cause. 1991 – javitt et al – found that administration of NMDA receptor antagonists such as PCP or ketamine the positive and cognitive effects of Sz were produced in healthy individuals and those with existing symptoms were exacerbated.
2004 – Clinton et al. – critically examined post mortems and found that there was a reduction in the number of NR1 subunits of the NMDA receptor in the hippocampus and frontal cortices of Sz people 2003 – Harrison et al. – majority of genes associated with Sz can also effect the influence of modulatory sites of the NMDA receptor providing strong genetic support for GH 1982 – Weinberger and wyatt – found that brain ventricles of 88 Szs twice the size of 60 controls 2002 – holshoff-pol et al. – found that the loss of gray matter is much more in Sz than controls 1991 – kendell and adams – studied over 13,000 people in Scotland found much higher chance of Sz if birth month between feb and may 2000 – eaton et al. – found that sz more likely if live in busy city where flu virus thrives than if you live in a rural area
Problems animal intelligence
1859 – Darwin on the origin of the species
1996 – Gould “one twig on the floridly aborescent bush of life” 1970 p59 – Barnett “ability to adapt behaviour to circumstances 1973 – jerrison – animal EQ
1950 – Skard – no differenc between animals and mice in maze 1984 – angermeier – 2 rewards for bees and 28 for human infants to respond at constant rate on simple reinforcement task
Write an essay describing how social learning in animals has been studied. Explain the relatively trivial explanations that are possible for apparent social learning. Are any demonstrations immune from those trivial explanations?
Much research into animal cognition is involved with the individual. However in reality ,uch behaviour occurs in the presence of others, for example food competition or sexual selection. Many researchers have argued that social learning occurs in animals as a result of these interactions. Evidence for social learning in animals comes from learning of food preferences and fear of predatros, imitation and theory of mind and slef recog studies. However many of these studies have flaws and do not necessarily provide definitive evidence of social learning. Diet selection:
Food seeking behaviour in one animal can have a profound influence on the food seeking behaviour of another. For instance rats are neophobic meaning they are reluctant to eat food with a novel flavour and it has been shown that they might possibly learn from other rats and copy what they eat. For instance Galef et al. (1988) showed that when a demonstrator rat was allowed to eat food with distinctive flavour such as cocoa or cinnamon and then placed with an observer rat, the observer rat would show a preference for the same food when being allowed to choose between the two. This could be evidence of social learning in rats, however it is more likely that the observer rats simply detected the odour of the food on the rats breath or they consumed tiny particles from the rats fur. Therefore we should follow Lloyd morgans cannon – not social learning. In addition it has been suggested that animals can learn adaptive responses such as fear of predators.
Mineka and cook (1988) for instance found that monkeys reared in a lab showed no fear response to snakes. However when they saw a wild monkeys fear reaction to a snake they learnt the fear response and showed it themselves on subsequent contact with a snake. This could be argued as social learning however simpler explanation is simple associative learning. The monkey associated the snake with negative feelings and therefore was scared of it next time, a shock would produce the same effect. Another thing been looked at is imitation. Many naturalistic studies have found evidence of imitation in animals. For instance nishida (1987) found that macaque monkeys copied one who decided to start washing potatoes in the sea before eating. Soon all the macaques were seen to be doing it. However again can be criticised because might simply be trial and error, the spread of monkeys washing potatoes was linear not exponential. This has also been observed in birds such as blue tits.
Bonner (1980) argued that their ability to break through milk top made of foil developed through social learning. However more likely that it was through association of shiny foil tops with cream of milk. However more controlled experimental learning has been provided by heyes and dawson (1996) for example who developed a bidirectional control box in which an observer rat watched another press a lever in either left or right direction to get food. When put in box themselves they instantly new which way to press the lever. However whilst the confounds of stimulus enhancement and social facilitation are ruled out, it may just be there was food particles on the side of the lever the rat had been pressing and therefore observer rat was more likely to go to food and accidentally press lever in direction. Another thing been studied for sl is theory of mind. Deception was looked at by premack and woodruff (1979).
Chimp was presented with two boxes one with food underneatd. With teacher a they got the food if pointed to right one, with learner c they didn’t. They learnt to deceive the teacher who took the food for themselves suggesting theory of mind and deception However this can also be ripped apart because took many trials to achieve results, could just be trial an error and could have just learnt through operant conditioning what to do. Another thing studied is self recognition suggested that self awareness is required for social learning. Many studies have suggested that various animals are able to recongise themselves in a mirror. Gallup et al (1970) for instance found that when re spot painted on chimps they did not get it off however when presented with a mirror they wiped it off suggesting recognised it was themselves.
However has been criticised poivnelli (1993) who showed they touch the spot just as much when they don’t have a mirror. Also autistic people do not have normal self concept lack theory of mind however theri rouge test performance is normal. Overall therefore whilst there is much research which suggests that animals may use social learning however they certainly do not confirm. In all cases discussed there is a less complex explanation uch as simple learning through classical or instrumental conditioning and trial and error. According to Lloyd morgans cannon (1894) we should always accept the simplest explanation if possible
University/College: University of Chicago
Type of paper: Thesis/Dissertation Chapter
Date: 4 October 2016
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