Summary by Reyna Avila, Gloria Gonzalez, Sharon Finkelstein and Marianela Silva

 

Introduction

 

               

Throughout the years scientists have developed many theories about the evolution of human cognition. This attempts to show the closest human ancestor from which present humans evolved. The research involving cognitive evolution is continuously expanding. For example Richard W. Byrne states that the molecular taxonomy identifies a close relative to the human (the African great ape or ‘Pongids’). On the other side, the archeological and geological evidence proposes that "hominidis -extinct creatures with physiological similarities to the actual human" - (p.71) are the closest human ancestors.

The toolmaker hypothesis is yet another theory that presents the idea of tools as significant objects related to the process of cognitive evolution. Despite this hypothesis the tools found in the same places, as those of hominidis fossils does not necessarily indicate that hominidis are the tool designers. In fact, there is evidence of a possibility in which more than one species was responsible for the tool making, because many skulls of other species were found in the same sites. For this reason it is difficult to find a correlation between the skulls and the tools. This evidence does not support the idea that a bigger brain corresponds to the toolmaker; however, it has been observed that monkeys in captivity have the ability to create tools in order to solve problems.

 Behavior cannot be easily found in fossils, but stone-tool making can presume the presence of cognitive skills. For example it was a required ability to walk upright, which allows the hands freedom for other movements. This significant position-change describes mental and physical coordination.

Different demonstrations of species behavior are becoming realistic evidence of non-human primates' intellectual skills, which are directly related to human evolution. Memory, social interaction, and tool making are some examples of signs of intelligence. According to Byrne this type of intelligence could be a “primate specialization”. Similarly, speed is a specialization for cheetahs as insulation is for whales. The behaviorists’ opinion was that; “mental faculties are similar in different species”. This theory has been disproved by naturalistic observations. Differences in behavior such as ‘protected threat' reciprocal help between individuals during contest, and reconciliation after dispute among different species has been recorded. This evidence explains that mental faculties vary among species.

 These and other non-human primate abilities are strong evidence that should be investigated and tested profoundly in order to understand the evolutionary history of human cognition.

 

Deducing Ancestral Species

 

            In order to classify our ancestral species, Byrne utilized the comparative method. Evolutionary classifications are compared to find a common and unique ancestor within species.  The discovery of these groups, or clades, “is tantamount to predicting the existence of a particular extinct species” (73).  Cladistics, the grouping into clades, is done by evaluating molecular similarities and identifying mutual derived features.  Once the clades are characterized, molecular dating can not only predict ancestral species, but also approximate the time they lived, “even if the fossils of these species are never found” (74).

This approach can be used effectively to identify descendants where fossils will most likely not be found and at the same time this approach will not be used to identify ancestral stages.  Instead of falsely attributing derived characteristics of modern primate species to our own ancestry, we can trace our characteristics through our “family tree” and find the ancestor in which the trait entered our family.  The comparative method is, however, limited by the extent of remaining hominoids available for comparison.  The human relatives have branched for about the past six million years (chimpanzees), since about 60 million years ago (lemurs).  A finer comparison between the hominoid gaps is needed to more precisely compare the living apes.

 

Machiavellian Intelligence and the Enlarged Brain

 

            Evidence demonstrates that monkeys and apes have developed sophisticated social skills.  Such social skills include, but are not limited to: cooperation when obtaining resources, dominant ranks on the basis of support given by others, lasting friendships in which you can predict mutual help, and the social technique of manipulation which includes deception. The complexity of these social behaviors among monkeys suggests an origin for the evolution of cognition. Humphrey suggested that human intelligence was an adaptation to social problem solving, or “Machiavellian Intelligence.” Machiavellian intelligence describes a combination between Waal’s comparison to the social strategies of chimpanzees and the advice given by Nicccolo Machiavelli to an aspiring prince that it is most beneficial to appear and act altruistic, merciful, humane and honest, but if need be could become the opposite. This characteristic becomes crucial for the individual survival of the animal and in turn this social complexity spreads quickly amongst the population increasing the overall social sophistication needed for the species' future survival.

            Supporting one another, returning favors and cooperation are traits that should, theoretically, evolve among any group of species that have the same cognitive capacity as the monkeys and apes. However, in species where the there is no distinction of conspecific group members as individuals and as kin, no recollection of their relative ranks and past affiliations, and no recollection of personal histories social traits will not develop. A species must have good perception, categorization, memory and discrimination in order to successfully use these tactics.

            Brain size is another important element for the development of cognitive skills. For example, a significant brain size is necessary for the efficient memory needed for social complexity. Absolute brain size tends to increase proportionately with body size. In fact, brain size scales with body size with a slope of .075. Unfortunately, there is no significant proof relating body size to brain size.

            Instead, the brain serves as an “on board” computer. Hence, it deals with the input and output information in the brain. A recent study relative to brain size is called the neocortex ratio or the ratio between the neocortex and the size of the rest of the brain, the neocortex being the centralized area of the intellectual part of the brain. Analysis has shown that mammals with social complexity such as dolphins, monkeys and wolves have relatively larger brains than do solitary species of similar size. Neocortex size is also a good predictor for the frequency of deception. Accordingly, brain enlargement is essential for the efficient memory storage needed to manage complex social living. The relationship between social skills, group complexity and brain size are all strong supporters of the Machiavellian hypothesis.

            This was the beginning of intellectual evolution of humans. An increase in memory and learning speed demonstrates the need for a larger brain. This allowed them to put these new tactics to use in their everyday social encounters.

 

Representational Intelligence

 

            Scientists claim, and are continually trying to prove, that primates display computational processes.  However, there are many a few who disagree with that statement.  Such conclusions concern only the great apes.  In an array of studies it has been found that the great apes engage in behavior that is subtle and more complex of any monkey.  Great apes often perform behavior that is similar to that of a monkey but aquires the behavior in a more powerful way.  Chimpanzees have been known to take “political” maneuvers in playing one competitor off on another, and it is known that all monkeys can learn subtle tactics of deception.  Only great apes sometimes seem to demonstrate a conceptual understanding of deception.  Whereas monkeys are known to learn in social circumstances, various apes have been known to learn behavior by imitation.  More importantly observations have been made suggesting that mother chimpanzees perform deliberate instructional teaching.  Although many animals show ‘local traditions’ in behavior, chimpanzee tool usage goes far beyond that, and has been coined 'material culture.'  This claim of material culture is controversial in the world of psychology.  Because they are used to claim that great apes have the human ability to retain informationwith out the presence of a visual stimuli (abstract thinking).  Caution must be taken here, in that monkeys show traits for deception when infect it is the result of rapid learning and a good social memory.  Despite this researchers are continuing to claim that great apes have an intellectually ability that surpasses and is highly different from monkeys.

            Socially this ability is described as mental state attribution/ theory of mind.  These capabilities of apes in not confined to social domains.  This attribute is clearly demonstrated in tool usage.  Monkeys understand the use of tools; they will not seek out a specific tool for a specific job.  Contrarily chimpanzees will select objects according to an appropriate pattern for a specific task.  It has also been shown that gorillas can understand cause-and-effect.  The difference between the monkey /ape should be described in mental representation rather than theory of mind.  Great apes can apparently compute with mental representations of information, which are not physically present at the time, not yet in existence, or unobservable.

            This line of reasoning leads to a second cognitive development in the evolution of human mentality.  Occurring around 16 million years ago in the common ancestor, individuals of this species acquired the ability to represent properties of the world, and use these images to compute future behavior.  This is an important precursor to the development of language.

One can hypothesis that mental representation is a characteristic of brain size.  Based on the notion that great apes posses a brain that is absolutely larger than that of any monkey, suggests a change in informational storage that in turn would allow for the flexibility needed in representation, instead of unstructured associations.  The Machiavellian Intelligence hypothesis is no explanation for the evolution in great apes alone.

            Because of this inability to explain the evolution of representational learning, alone in great apes, there has been a shift that now looks at how the physical environment might have affected the learning techniques applied to ancestral great apes rather than monkeys.  Several theories have emerged as a result of this change in direction.  One such theory suggests that  ‘arboreal clambering’, by large animals is too dangerous.  Advance planning and engineering is required or the fall would be lethal.  Suggesting that movement could have selected for representational ability.  Large size also indirectly indicates efficient feeding which allows the great ape to digest a wider range of plant foods that are nutritious but difficult to obtain from the plants' natural physical defenses.  When presented with the problem of obtaining food that is difficult to extract the animal performs manual actions that are acquired rapidly during development.  The great apes show complexity and the use of a mental organizational hierarchy in order to obtain the food. Showing a predisposition to mental solving techniques that are required for the acquisition of these foods.  A representational understanding is beneficial for the animal in both remembering the actions and well as understanding to teach others.  The most efficient food monopolization was enabled by sleeping near food, with the construction of platforms to give safety form predators.  All great apes for sleeping and resting construct these nests or beds.  These nests show a high degree of complexity.  It seems likely that physical changes of some sort resulted in the evolution of mental representation capability among the great apes.

 

Conclusion

 

            The evolutionary history of human cognition requires the analysis of the human mental abilities compared to that of the last human ancestors' skills.  As well as the identification of physiological similarities between the two. The large-brain species, which have the distinguished characteristics of learning at a faster rate and highly developed social skills, were the group of individuals who resolved problems via adaptations and subsequently evolved into what we now define as a capable human being. The human ancestors confronted different selection pressures that pushed them to find adaptive solutions. The human evolution through time is a result of problem solving, which was triggered by different cognition mechanisms such as bipedalism, and mental representation of 'cause-and effect' of every day events, these are the bases of the theory on human cognitive evolution.

 

 

  Five Main Points

 

 

1.  Behavior cannot be easily found in fossils; Have to infer cognitive evolution based on available information (primates).

 

2.  Evolutionary classifications are used to find a common and unique ancestor within a species by molecular similarities

 

3.  Machiavellian Intelligence combined with a large brain contribute to the social evolutionary development theories about cognition

 

4.  Environmental evolutionary theories that involve cognition are can be seen in the representational intelligence theory; which relies on the organism’s ability to learn and teach behavior that is pertinent to survival.

 

5.  Cognitive development can be represented by analysis and critiquing the ways in which other species, somewhat related to us behave.  Because of this there are many theories as to how humans have developed cognition.