Evolutionary Psychology: Comparative Animal Cognition and the Human-Animal Divide

This lecture, titled "Evolutionary Psychology - animal minds," is part of the Psych 109 course delivered by Lecturer Russell Gray.
Lecturer Background: - Connections to New Zealand landmarks: Ko Whanganui te awa (The Whanganui is the river), Ko Mauao te maunga (Mauao is the mountain). - Emphasizes the importance of scientific thinking in psychological research.
Learning Objectives: - Explain the role and methods of comparative psychologists. - Understand the necessity of experimental design to differentiate between various accounts of animal cognition. - Distinguish between biological homology and evolutionary convergence. - Identify the four essential requirements for natural selection to occur. - Critically evaluate the broader ethical and philosophical implications of findings in animal cognition.

Common Ancestry: Humans are related to every living organism that has ever existed on Earth. Life is categorized into three domains: Eukaryotes, Archaea, and Bacteria.
Timeline of Evolutionary Milestones (Millions of Years Ago): - Earth Birth: Approximately $4000$ million years ago. - Oceans Rust / Global Ice Ages: Occurred between $3000$ and $2000$ million years ago. - Cambrian Explosion: Approximately $541$ million years ago. - Mass Extinctions: Key events occurred at $444$ , $370$ , $252$ , $201$ , and $66$ million years ago. - Specific Lineages: Evolution of Fish ( $500+$ mya), Amphibians ( $370+$ mya), Reptiles ( $300+$ mya), Birds ( $150+$ mya), and Mammals ( $200+$ mya).
The Romantics vs. The Killjoys: - Romantics: Argue that animals possess complex mental states such as causal reasoning, insight, theory of mind, mental time travel, empathy, cooperation, and "episodic-like" memory. - Killjoys: Argue that complex behaviors can be explained more simply through basic principles of learning (e.g., conditioning) without invoking higher cognitive states.

Comparative Psychology: The study of animal behavior and mental processes to learn more about the parts of our own minds that we share with animal cousins.
Homology: Structures that are shared because they were inherited from a common ancestor. - Example: The Vertebrate Limb: The humerus, ulna, radius, carpal, metacarpal, and phalanges are found in humans, cats, whales, and bats. - Example: Primate Brain Structure: Humans, Chimpanzees (Lulu), Bonobos (Jill), and Gorillas (Kekla) share common brain architecture, including the frontal lobe, parietal lobe, temporal lobe, occipital lobe, and sylvian fissure.
Convergent Evolution: The independent evolution of similar structures or traits in different lineages where natural selection has favored the same outcome from different ancestors (Ancestor 1 and Ancestor 2 yield the same outcome).
The Four Requirements for Natural Selection: 1. Variation: Differences exist between individuals, often created by mutation. 2. Heritability: These variations must be capable of being passed down to offspring. 3. Design Differences: Variations must affect the "design" or functionality of the organism. 4. Competition: Differential survival and reproduction where unfavorable mutations are selected against and favorable mutations are more likely to survive and reproduce.

Historical Perspective: Louis Leakey once defined humans as "Man the tool maker," suggesting tool use was the defining characteristic of humanity.
Tool Use in Other Species: - Observed in various primates (e.g., chimpanzees and baboons). - New Caledonian Crows: Known for tool culture, specifically making pandanus-leaf tools. Research by Hunt & Gray ( $2003$ , $2004$ ) published in Proc. Roy. Soc. B ( $270$ , $867-874$ / $271$ , $88-90$ ) explores these capabilities.
Experimental Testing: Researchers use complex setups (e.g., multi-step puzzles shown in BBC videos) to test if animals like crows can plan ahead rather than just reacting to immediate stimuli.

The Human "Operating System": Yuval Noah Harari suggests language is the operating system of the human species, enabling mass cooperation and activism.
Language Learning in Chimpanzees: - Gua and Viki: Common chimps raised by the Hayeses. Viki learned only $3$ - $4$ words: "mama," "papa," "up," and "cup." - Anatomical Barriers: Chimpanzees have a different vocal tract structure than humans. Humans have a lower larynx and a specialized nasal cavity/velum arrangement that allows for a wide range of speech sounds; chimps do not.
Nim Chimpsky: Project Nim attempted to teach sign language to a chimp. - Results showed no evidence of true grammar or syntax. - typical utterances: "Nim eat Nim eat," "Banana me me me eat," "Give orange give eat orange me eat orange give me eat orange give me you." - Utterances were often just drills or strings of actions/objects without linguistic structure.
Kanzi (Bonobo): - Used lexigrams and a speech synthesizer. Considered truly symbolic. - Learned approximately $100$ words but did not engage in human-like conversation. - Understood action/object relationships but remained reactive rather than grasping the full functionality of language.
Scientific Consensus (Terrace et al., 1979): While apes can learn isolated symbols, they show no unequivocal mastering of conversational, semantic, or syntactic organization of language.

Language vs. Thought: - Vygotsky: Language shapes thought; internalizing speech allows for complex cognition. - Piaget: Language merely provides labels for experiences; it is not central to the development of thought.
Probabilistic Reasoning: The ability to make predictions based on the likelihood of different outcomes.
The Kea Study (Bastos & Taylor): - Kea (Nestor notabilis) at the University of Auckland were tested on statistical inference. - Token Value: Kea learned that black tokens resulted in food (rewarding), while orange tokens resulted in nothing (unrewarding). - Experimental Condition: A Kea watched an experimenter place a hand into two jars. Jar 1 had $100$ black tokens and $20$ orange tokens ( $100:20$ ratio). Jar 2 had $20$ black and $100$ orange tokens ( $20:100$ ratio). Using a cardboard barrier to hide the specific token picked, the Kea had to choose the hand most likely to contain a black token. - Findings: Kea show three signatures of domain-general statistical inference.

Animal Welfare: Does the discovery of complex thought in birds like the Kea change our moral obligations toward them?
The "Unbridgeable Gap": Steven Pinker in The Language Instinct argues that maintaining a sharp distinction between humans and animals serves a practical, though perhaps unethical, role. - It allows humans to use, wear, and eat animals "without any disquieting tinges of guilt or regret." - It rationalizes high rates of extinction ( $100$ species a day) by claiming those beings are "not like us."
Ethical Reflection: Pinker suggests that acknowledging connections to other species might lead to a more optimistic view of the human future, especially considering animals that refuse to profit from harming their fellows (e.g., certain macaques).