Week 9 Lecture

Vertebrates

Animals with a backbone, have conserved central nervous systems

Brain Size

Correlates with body size (allometry), raw size is a crude measure

Allometry

The relationship between traits and body size

Encephalization Quotient (EQ)

Corrects for body size, it is the deviation rom expect human size for a taxonomic group

Human EQ

About 7.4-7.8, ~3.5x larger than expect fro an ape our body size

Neuroecology

Study of specialization of brain and cognition, brain regions evokes due to ecological challenges

Neuroecology Examples

Food-Storing Birds: Larger hippocampus than non-storying birds

Meadow Voles (polygynous): Males have larger hippocampi and outperform females on special tasks (larger ranges)

Prairie Voles (monogamous): No sex differences in hippocampus size

Australopithecines Brains

Brain size as expected for apes of their body size

Gene Homo Brains

~ 2 MYA: Rapid expansion - possibly linked to dietary changes, cooking, and more meat consumption

~ 0.2 MYS: Further expansion - possibly liked to social intelligence demands

Modern Human Brains

Brain size is very recent

Triune Brain Theory (Misconception)

Idea that humans have 3 distinct evolutionary layers: Reptilian (lizard), Paleomammalian (mammal), Neomammalian (human), Scala Naturae Fallacy

Triune Brain Reality

All vertebrates share major brain subdivision, emotion and cognition are distributed across regions, and not localized to “layers”

Computational Theory of Mind

The mind is an information processing system, not LIKE a computer, it IS a computer

Marr's Three Levels

Computation Theory, Representation & Algorithms, and Hardware Implementation

Computation Theory

What problem/task is solved? What is the computation for?

Representation and Algorithm

What computational steps required to complete the task?

Hardware Implementation

How are computational steps physically performed?

Marr’s Levels EP Focus

Computational Theory and Representation & Algorithms

Massive Modularity Hypothesis (Fodor)

Mind consists of distinct, almost independent modules with no general-purpose mechanism, like a Swiss Army Knife

Modularity Santa Barbra School

Adopted and extended, both brain and mind are modular

Patient DF

Specific ventral visual stream damage - cannot name object visually but can draw from memory and person visually guided grasping (dissociation between visual-for-perception and visual-for-action)

Patient HM

Specific antergroade amnesia for declarative memory with intact procedural memory

Williams Syndrome

Severely impaired spatial/arthematic abilities with relatively intact language and social skills

Specific Language Impairment (SLI)

Impaired language with intact spatial cognition, contrast with Williams Syndrome

Critics of Cognitive Modularity

Developmental disorders differ fundamentally from focal brain damage in adults because development involves compensatory effects, apparent modularity in Williams syndrome (e.g., language) actually develops differently than in typical individuals

Neoconstructivism

Biological processes and environmental condition interact to shape brain development, brain has plasticity and is context-dependent

Non-Associative Learning — Sensitization

Increased responsiveness to a stimulus following exposure to an intense or noxious stimulus.

Non-Associative Learning — Habituation

Decreased responsiveness to a stimulus following repeated exposure; adaptive because it frees attention for novel or more relevant stimuli.

Associative Learning

Learning associations between stimuli (classical conditioning) or between stimuli and responses (operant conditioning); likely evolved during the Cambrian (~540 MYA), possibly accelerating predator-prey co-evolution and species diversification.

Garcia Effect

Single-trial conditioned taste aversion; stimulus-specific in that illness becomes associated with taste rather than light or sound; demonstrates preparedness — species are biologically predisposed to learn certain associations more readily than others.

Preparedness in Learning

Different species are differentially prepared to learn certain associations; not all stimuli and responses are equally associable; reflects the evolutionary history of what was adaptive to learn in a given ecological context.

Heritability of Learning

Artificial selection and pedigree analyses show moderate heritability of learning ability (e.g., maze-bright vs. maze-dull rats); GxE interactions are important in determining how learning ability is expressed.

Maze-Bright and Maze-Dull Rats

Rats selectively bred for fast vs. slow maze learning; GxE interaction showed that performance differences depended heavily on the environment (enriched vs. deprived), illustrating that heritability is context-dependent.

Observational Learning

Acquiring information by watching others rather than through one's own trial and error; does not follow standard rules of conditioning.

Language Learning and Conditioning

Language acquisition does not follow the rules of conditioning or associative learning; one of Chomsky's key reasons for arguing that children must have an innate language capacity.

Types of Long-Term Memory

Multiple dissociable systems including episodic (specific events), semantic (general knowledge), procedural (motor skills), and working memory; different systems support different types of action.

Memory Function — Evolutionary View

Memory's function is not to store information in the absence of emotion and meaning; it is to store and retrieve information to support behaviour and action.

Ebbinghaus Approach to Memory

Used nonsense syllables to study memory; strips away emotion and semantic content to reveal the raw capabilities of the memory system but tells us little about its evolved function.

Bartlett Approach to Memory

Used meaningful materials such as passages of text; revealed intrusion of prior knowledge into recall and the creation of false memories; more ecologically relevant than the Ebbinghaus approach.

Library Analogy for Memory

Memory must balance accessibility with storage capacity (like archives vs. short-term loan); Anderson's research shows recall speed is adapted to frequency of past exposure — high-frequency words are recalled faster.

Anderson's Memory Adaptation

Word recall speed is related to frequency of past exposure; argued as evidence that memory is adaptively designed to match the structure of the information retrieval environment.

Multiple Memory Systems — Sherry and Schacter

Argued that evolution leads to adaptive specialization of multiple memory systems due to functional incompatibilities; associative memory ignores event details but remembers relationships; episodic memory must record specific event details.

Schacter's Seven Sins of Memory

Transience, absent-mindedness, blocking, misattribution, suggestibility, bias, and persistence; these apparent failures may reflect the adaptive design of a functioning memory system, similar to how illusions reveal adaptive perceptual design.

Transience

Gradual weakening or loss of memory over time; adaptive because most information is mundane and older information is less likely to be relevant to current behaviour.

Absent-Mindedness

Breakdown between attention and memory (e.g., forgetting where keys were left because the action was not consciously attended to); adaptive because attention directs memory encoding and we cannot attend to everything simultaneously.

Misattribution

Forgetting the source of information while retaining its content; results from derived memories that discard source information to increase efficiency; can result in false memory formation.

Suggestibility

Incorrect memories formed as a result of leading questions; e.g., "how fast was the car going when it smashed into the tree?"; derived memories make it difficult to recover the original source.

Derived Memories

Memories that have been processed and abstracted from original experience; more efficient and may enable abstract thought, but lead to misattribution and suggestibility as side effects.

Seven Sins as Design Features

Memory failures may reflect how the memory system evolved to work well in most cases; analogous to visual illusions revealing how vision evolved to work efficiently in the natural environment.

Unbounded Rationality

An unrealistic model of decision-making assuming unlimited knowledge, unlimited computational power, unlimited time, and the ability to calculate precise probabilities; not how minds actually work.

Bounded Rationality

A realistic model of decision-making that recognizes computational limits; uses heuristics to reduce computational demand; proposed by Herbert Simon.

Satisficing Heuristic

Search through a set of options and select the best one encountered rather than exhaustively evaluating all options; stops before a full search; produces a "good enough" rather than optimal solution.

Fast and Frugal Heuristics

Simple rules of thumb that allow decisions to be made quickly with minimal information; often perform surprisingly well compared to complex algorithms.

Heuristics — General

May not provide the best solution, just one that is good enough; computationally inexpensive and fast; e.g., using name recognition to judge which city is larger.

Recognition Heuristic

If one of two options is recognized and the other is not, infer the recognized one has a higher value on the target dimension; e.g., judging New Orleans to be larger than Campbellford simply because it is familiar.

One-Good-Reason Heuristic

Use a single decisive cue to make a judgment rather than weighing multiple pieces of information; e.g., choosing between two towns based on which one you recognize as a university town.

Representativeness Heuristic

Judging the probability of something by how well it matches a prototype or stereotype rather than by calculating actual probabilities; can lead to the conjunction fallacy.

Conjunction Fallacy — Linda Problem

Linda is described as a feminist philosophy student; 85% of respondents say it is more probable that she is "a bank teller active in feminism" than simply "a bank teller," despite the conjunction being logically less probable; people match the description to a prototype rather than applying probability rules.

Base-Rate Neglect

Failure to incorporate prior probability (base rate) when estimating the likelihood of an outcome; one of the most pervasive and consequential cognitive biases.

Base-Rate Neglect — Medical Example

1% prevalence of breast cancer; 80% true positive rate on mammogram; 9.6% false positive rate; actual probability of cancer given a positive test = 7.8%; medical students estimate 70–80%, completely ignoring the low base rate.

Bayes' Theorem

A mathematical formula for updating probability estimates given new evidence; humans are poor at applying it intuitively, even when trained.

Frequency vs. Probability

Humans are better intuitive statisticians when information is presented as frequencies (X out of 1000) rather than as single-case probabilities; reflects our evolved ability to track event frequencies in memory.

Frequency Format — Village Elder Example

When the same base-rate problem is phrased using frequencies ("8 out of 103 people with black urine had the disease"), most people correctly calculate the answer as 7.8%, whereas probability format leads to systematic errors.

Consciousness — Sentience

The capacity to experience sensations, perceptions, awareness, and emotional reactions; likely widespread among animals to varying degrees.

Consciousness — Autonoetic

Self-awareness; awareness of oneself as a continuing entity through time; tested (imperfectly) by the mirror test.

Episodic Memory and Consciousness (Tulving)

Tulving argues episodic memory requires autonoetic consciousness and is unique to humans; other species show episodic-like or "what-where-when" memory but may lack the full autonoetic component.

What-Where-When Memory

A type of episodic-like memory demonstrated in food-caching birds; they recall what food was stored, where it was stored, and how long ago; suggests rudimentary episodic memory exists in non-humans.

Mirror Test

A test of self-awareness in which an animal is marked and then shown its reflection; chimpanzees and orangutans pass, gorillas and monkeys do not; criticized because mirror-responding may not actually indicate genuine self-awareness.

Consciousness — Multi-Component View

Consciousness is likely not a single unitary trait but made up of multiple cognitive abilities including sentience, episodic memory, theory of mind, and language; many uniquely human aspects pose challenges for testing adaptive hypotheses.