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Arboreal Clambering: A Fancy Way of Saying Monkeys Climb Trees

Self-Conception and Evolution

I’m going to start off by defining four important aspects of self-conception as touched on in the reading 🙂

Self-conception is the awareness of self as…

1.      An object of knowledge

2.      The subject of experience

3.       An entity that exists through time

4.       A causal agent

In this article John G. H. Cant and Daniel J. Povinelli focus the most on number 4, self-conception as the awareness of self as a causal agent.

What exactly does being aware of yourself as a causal agent mean? Why should we care? And what are Povinelli and Cant exactly hypothesizing?

Well, a causal agent is an entity that produces an effect or is responsible for events or results. So basically it means possessing the awareness that your actions have specific consequences.

We should care because there is not much known regarding the evolution of these aspects of self-concept, and Povinelli and Cant have evidence to believe that number 4 (which they believe to be the most primitive) evolved relatively recently. Ironic, right?

Before we go any further, I just wanted to distinguish self-conception from self-perception.

Self-perception is defined by Leary & Butterworth as self-knowledge obtained through personal experiences and transferred to memory. Self-conception is when you can conceive of yourself and reflect on your own mental processes. It is widely believed that humans develop self-conception anywhere from 18-24 months of age.

There is strong evidence stating that only humans and some of the great apes possess the ability to self-conceptualize. We touched on this a couple of classes ago with self-recognition. Gorillas seem to be the exception to the rule as they don’t show any ability in experiments to recognize themselves in mirrors. There is an exception to the exception to the rule though, as specially trained Koko the gorilla showed some signs of self-recognition. It is unknown if Koko was exhibiting true signs of self-recognition or if she was trying to control the image without completely understanding she was the reflection. Gorillas and their exclusion are important to keep in mind when looking at predictions from this model.

Self-recognition is important in looking at the evolution of self-conception as it, according to Gallup, shows that the species under question is self-aware and capable of conceiving their existence. They have some idea of who they are or what characterizes them.

Schemata

Schemata (or schema singular) are defined as “internal(presumably neural) states that are triggered by stimuli in the outside world.” They control motor output because of this, are in a sense, causal. Infants graduate from simple schema like reaching, turning head, etc., to a more elaborate form, where they would grab a box of cheerios, open it up, reach into the bag, and pull out a cheerio to put in their mouth.

Schemata are causally connected to an external object or event, but do not serve as a source of representation. It is simply present in the mind.  Mental representations possess a connection with an object or event when it is not present. Connecting these two different things together creates a proposition. Propositions are linguistic or imaginal statements that connect the dots, so to speak. For example, it would be like a toddler picking up a doll and categorizing it as a toy.

Gorillas have the ability to possess schema, but not the ability to relate it to something non concrete or present. So when they look in a mirror, they see an image, but can’t connect the dots to what the image is. They just see it and are like…crickets. They have no knowledge about themselves and can’t draw on anything other than direct perception.

This relates to self-conception as the awareness of self as a causal agent because a species can look at the reflection in the mirror (the object of perception) and realize that it’s actions are caused by them (held only in mind).

How Does This Relate to Monkeys Climbing Trees?

Understanding the evolution of self-conception existent in great apes and humans (minus gorillas) is dependent on understanding when and why schemata based knowledge proved insufficient for our common ancestor and their ecological circumstances.

Let’s look at some theories that will help us better understand primate intelligence and its evolution…

Social Intelligence Hypothesis

·         It is proven that socialized species tend to have more sophisticated mental abilities and are overall more intelligent than those who live in isolation

·         The only problem with this theory is the gorilla factor. There are many species as social as the great apes, but they do not have the ability to self-conceptualize

The Hunt for ‘Nanners

·         Another theory is that the need to find food led to higher intelligence and mental capacity. Milton proposed that the benefits of having to remember where the spatial location of a food source is and phonological patterns associated with this = smarter monkey

·         Parker and Gibson argue that this “extractive foraging” causes the development of higher sensorimotor skills and/or brain size.

·         This theory doesn’t really make sense because other species with the same sensorimotor levels do not use this strategy, and also why would the extractive foraging of some species result in the evolving of higher intelligence while it doesn’t in others?

FINALLY- Cant and Povinelli’s Model

This model argues that self-conception initially evolved as a psychological mechanism to facilitate planning and execution of unusually flexible locomotor patterns existent in the ancestors of great apes and humans. They used the long-tailed macaque, siamang, and orangutan as a basis for their hypothesis.

Can this Branch Hold Me?

A key aspect to the model is vertical tree trunks. These species must swing from tree to tree avoiding falling where there are gaps. They must also be knowledgeable of the fact that branches become less and less stable the farther away they are from the trunk. The less stable branches are where the fruit is usually located. But, all other aspects of these species’ existence is reliant on their ability to solve this locomotor problems.

Body weight is a critical factor as it jeopardizes the stability of the branches and trees to hold up heavier species such as the orangutan. More weight on a branch also means the branch will bend downward, sometimes increasing the gap from tree to tree.

Another factor is that larger animals are more fragile than smaller ones, meaning that they have a higher fatality rate when falling out of the canopy.

Common Locomotion Solutions

  • Suspension
  •  Multiple supports
  • Habitat compliance

Cant and Povenilli also introduce the idea of stereotyped or nonstereotyped locomotion. Orangutans are proven to gear more towards nonstereotyped locomotion as they are at a higher risk of falling due to their body weight. This means they have to troubleshoot and be more aware of their environment because they have more to lose if they make a mistake. Because of this they have to vary their movements more, unlike smaller species such as the siamang or long tailed macaque.

Cant and Povenilli feel that this model best explains the evolution of primate intelligence and self-conception because, in order to breeze through the trees, these animals have to be extremely aware of themselves and their surroundings. The have to recognize themselves as a causal agent in order to survive and get their next meal.

This model gives more evolutionary insight than ever before as to why only humans and large-bodied apes possess the ability to self-conceptualize.