The Cognitive Abilities of Species - Case Study Example

COGNITIVE NEUROSCIENCE 2009 YEAR 2, TERM COMPARATIVE COGNITION) THE COGNITIVE ABILITIES OF SPECIES ARE ENTIRELY ATTRIBUTED TO THE ECOLOGICAL FORCES ENCOUNTERED DURING THEIR EVOLUTION Student Number: Word Count: 2088 words THE COGNITIVE ABILITIES OF SPECIES ARE ENTIRELY ATTRIBUTED TO THE ECOLOGICAL FORCES ENCOUNTERED DURING THEIR EVOLUTION INTRODUCTION Several aspects of the behaviour of non-human animals have been found to be based on cognitive processes. Human cognitive systems and their properties such as those related to memory processes, and to perception and interpretation of sound and visual sources, are considered to have deep phylogenetic or evolutionary roots. A precise, evolutionary classification of these systems cannot be provided as yet, since “ecological factors play as large a role in the elaboration of an animal’s cognitive abilities” (Lock and Colombo 1999, p.596) as does an animal’s evolutionary status. Animals from lower taxa have shown unexpected levels of sensory abilities in the context of their ecological niches. At the same time, in primates, increasing levels of performance have been evident from prosimians to Great Apes on tasks such as reversal learning. The efficiency of adaptive behaviour to the environment is related to the massive complexity of the neural networks of the brain. The concept of Cognition explains the link between brain and behaviour. Theories are developed on observed behaviour, to help make testable predictions in natural environments, using the conceptual tools of cognitive science such as theory of mind and problem-solving. Cognitive explanations can be related to brain structures, but among animals further developments are required in imaging done under relatively natural conditions (Byrne and Bates 2006). Thesis Statement: The cognitive abilities of different species are attributed entirely to ecological forces encountered over the course of their evolutionary history. DISCUSSION Several non-human species exhibit the ability to form concepts, most of which have physical manifestations. Understanding the concepts of ‘same’ and ‘different’ is not found in pigeons and goldfish, it is uncertain whether monkeys possess these concepts, while there is evidence that the Great Apes, especially chimpanzees have a strong understanding of these concepts. In the great apes, the same-different judgements are more advanced than mere conceptualization, and include the skills for analogy and transitive inference, which indicate reasoning abilities (Lock and Colombo 1999). Cognitive Abilities: Ecological Niche, Evolutionary Ancestry and Survival Pre-Requisites Retrospective cognition by food-caching western Scrub Jays is an example of survival strategy explained by the species’ cognitive abilities developed by ecological forces experienced during their evolution (de Kort et al 2005). The scrub jay adds to its secret food cache, attempting to hide the stored food from pilferage by others. If they lack privacy, scrub jays choose to store food out of sight behind barriers, or if these are not available, they select poorly lighted spots which are furthest away from the view of the competitor. In circumstances where there is a complete lack of such options, scrub jays resort to confusing the competitor by re-caching their food in multiple spots. This behaviour is explained by the Theory of Other Minds (Emery and Clayton 2001). The Theory of Other Minds In psychology, the ability to distinguish the knowledge and beliefs of others as distinct from one’s own is termed as “theory of mind”. In children theory of mind develops slowly, and may be impaired in autism. According to Frith and Happe (2005), the attainment of theory of mind is key to linguistic communication, and is considered to be a crucial advancement in recent human evolution. It is observed that the behaviour of Scrub Jays which “adjust their food hiding according to the likely competition from other jays” (Byrne and Bates 2006, p.R445), show the jays possessing the same ability as humans to understand the thoughts of others. However, the bird’s behaviour of tactical deception is interpreted differently: as the outcome of a complex network of associations, with each association based on the concept of learning, similar to the laboratory white rat which is able to find the right way to complete a task to receive the reward at the end of the activity. This is explained as conditioning. “Behaviourism is the philosophy that all learning is fundamentally of this associative nature” (Byrne and Bates 2006, p.R445), and is applied even in circumstances where the accompanying mental images and thoughts indicate an understanding of others’ beliefs or intentions. This is supported by Lock and Colombo (1999) who state that rather than a higher order understanding of others’ intentionality, monkeys’ and apes’ occasional recognition that others have beliefs is based more on learned behavioural contingencies. However, apes such as chimpanzees have some ‘theory of other minds’, though there is no clear explanation for this yet. Abilities are frequently limited to particular activities, and this forms a major element of differentiation between the evolution of primate cognitive skills from those possessed by modern humans. Cognitive Abilities in Corvids and Primates There are great similarities in the cognitive abilities of corvids or members of the crow family and primates such as apes, despite the fact that the common ancestors of birds and animals lived over 280 million years ago. Both species have advanced skills in “tool manipulation, social reasoning and complex memory” and “Corvids are perhaps best known for their extraordinary feats of spatial memory” (Emery 2003, p.1). Further, Corvids and primates have been found to be good at solving laboratory tasks, particularly those that depend on an ability to develop a general rule to solve the task, rather than by simple rote learning (Emery and Clayton 2004). The ecological view is that development of these cognitive abilities is related to adaptive specialization necessary for survival and to cope with different ecological demands (Shettleworth 1998); on the other hand, the general processes view is that though the same intellectual processes are considered to be general to a wide range of species cognitive abilities are not related to ecological factors (MacPhail and Bolhuis 2001). Apes and crows are also similar in having very large brains as compared to their body size (Burish et al 2004). Moreover, corvids have the largest nidopallium which is the functional equivalent of the mammalian prefrontal cortex, in comparison to other families of birds. This increase in size in the nidopallium reflects the increase in size of the prefrontal cortex of the great apes, state Semendeferi et al (2002). Another common feature among corvids and primates is their long life spans, including a prolonged development period during which time they are dependent on their parents (Iwanuik and Nelson 2003). Additionally, the social complexity of some crows and that of chimpanzees have been found to be comparable. From these findings, Emery and Clayton (2004, p.1903) suggest that corvids and apes have “independently evolved similar complex cognitive abilities despite divergent evolution in brain structure”. Memory in Relation to Cognitive Abilities The Role of Episodic-Like Memory in Cache Recovery by Different Species According to Tulving (2005), episodic memory or awareness of past occurrences through retrospective mental time travel, is a uniquely human trait. Episodic memory as defined for humans has what-when-where components which form the content, these components are integrated to form a structure, and the memory has the flexibility to enable updating and generalizing for other situations. Clayton and Dickinson’s (1998) study revealed the scrub jay’s memory for what, where and when. On the other hand, from an open-field test of memory conducted by Hampton et al (2005) on rhesus monkeys (Macaca mulatta) it was found that rhesus monkeys demonstrate robust memory for what and where, but not when. Experiments with animals’ episodic memory cannot substantially prove the presence or absence of episodic memory because of the lack of specific behaviour markers to identify mental experience. The only exception can be supposedly language-trained apes and parrots. For other animals it is difficult “to establish whether an animal is experiencing the past when retrieving a memory” (de Kort et al 2005, p.160). In food caching by western scrub jays, the birds relate information from their previous experience of stealing from another’s hoard, to modify their strategies accordingly. Similarly, though cache-recovery carried out by the scrub jays is an adaptive specialization evolutionally developed for survival of the specie, it relates to the above three criteria of human episodic memory. This is strengthened by new evidence revealing explicit encoding of temporal information in the memory of scrub-jays (de Kort et al 2005). Recovery behaviour by food-hoarding rats is similar to that of the scrub jay. Laboratory rats carry out food hoarding which is different from caching, in that the stored food may not necessarily be hidden, and also engage in retrieval behaviour. According to an experiment conducted by Bird et al (2003), laboratory rats had accurate memories for the content and location of their hoarded food. The only difference between the rats and scrub jays was that the former could not remember the length of time since the perishable food was hoarded, as against the jays who would retrieve perishable food such as worms first, and leave the non-perishable food such as nuts for a later retrieval. However, evidence of indirect temporal encoding in trial-unique memory by rats was established from a research study by Fortin et al (2002) who revealed memory in rats as a result of temporal encoding, different from the concept of familiarity. Learning Among Non-Human Species Imitative copying as a part of observational learning is seen among the great apes, while social facilitation and stimulus enhancement is found among all the primate groups. As compared to humans, imitative copying in the great apes is less developed, and it is not possible to transfer the skills through teaching. Chimpanzees show novel problem solving responses in selected situations, while chimpanzees and organgutans show self-recognition when faced with a mirror, but all other primates approach the mirror image as that of another animal of the same species (Emery 2003). Cognitive evolution among the corvids is found to be of an advanced level. Although “corvids have much smaller brains than the great apes, with the relative absence of cortical structures” (Emery 2003, p.2), their cognitive abilities may rival that of the great apes, and the particular bird specie of Corvids can be considered as “feathered apes”. This theory equating corvids to the great apes is based on apes having a special status due to their evolutionary relationship to humans, the design of primate experiments not including ecological validity, and the comparative lack of research studies on avian cognition. The avian brain reveals adaptive specializations such as social intelligence in learning altruistic activities such as food sharing, forming coalitions and alliances, and is equated in this respect to the brain of primates and dolphins. Conditioning supports associative learning which results in reflexive behaviour (Pearce 2008). Classical or Pavlovian conditioning is associative learning in which there is no link between the behaviour of an animal and a biologically unconditioned stimulus. A previously neutral environmental event is the root of the unconditional stimulus. An example is Pavlov’s study in 1928 in which he trained dogs to relate the ring of a bell with a food reward. On the other hand, in Skinner’s Operant conditioning, producing a behaviour controls the uncontrolled stimulus presentations. Macphail’s (1985) theory of null hypothesis is based on a comparative study of learning in vertebrates. His argument puts forth two competing null hypothesis: first, that there are no differences in learning among vertebrates, and second, that no contextual variable is responsible for the proposed species differences. This means that species differences do not exist in the domain of learning. Macphail’s null hypothesis thus confirms that “one can never be certain that a species lacks a particular learning ability” (Real 1994, p.22). CONCLUSION This paper has highlighted the cognitive abilities of various species being attributed entirely to ecological forces encountered during their evolutionary history. Evolutionary ancestry, cognitive abilities, survival prerequisites such as the theory of other minds, episodic-like memory, and learning have been investigated, to understand cognition among the various non-human species as compared to humans. When cognitive abilities of different species were compared using an evolutionary approach it was found that: cognitive abilities may vary among members of the same specie, cognitive abilities are impacted by living conditions, and variances may be present in cognitive abilities. Hence, unequal comparisons will not reflect true species differences. This is supported by Boesch (2007, p.236), who states that meaningful results can be obtained only through comparing “individuals of different species that faced similar ecological imprinting experiences under similar sets of natural selection pressures”. As compared to any other primates, humans live in the most environmentally diverse conditions. Hence, differences in cognitive abilities is considered to be the largest among human beings. References Bird, L.R., Robers, W.A., Abroms, B., Kit, K.A. and Crupi, C. (2003). Spatial memory for food hidden by rats (Rattus norvegicus) on the radial maze: Studies of memory for where, what and when. 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