Chapter 16

Signals

Messages transmitted between sender and receiver.

Honest Signals

Signals beneficial for both sender and receiver.

Sender-Receiver Goals

Similar goals increase signal honesty likelihood.

Signal Authenticity

Signals that cannot be faked indicate honesty.

Handicap Principle

Costly signals indicate sender's fitness.

Social Species Identification

Calls help recognize individuals in social groups.

Differing Goals

Conflicting objectives lead to dishonest signals.

Costly Signal Assessment

High costs prevent challenging false signals.

Signal Validity

Determining truthfulness of signals can be expensive.

Aggression in Social Groups

Dishonest signals can increase group aggression.

Signal Production Costs

Metabolic or behavioral costs increase signal reliability.

Sender's Dishonesty

Dishonest senders risk being ignored by receivers.

Signal Clarity

Clear signals enhance communication effectiveness.

Evolutionary Signal Maintenance

Social punishment helps maintain signal honesty over time.

Potential Cost

High risk if the receiver misinterprets a signal.

Threat Displays

Bluffs that deter challenges due to high cost.

Agonistic Signals

Costly signals used in male oryx confrontations.

Receiver-Bias Mechanisms

Focuses on receiver's characteristics in signaling.

Comparative Psychologists

Examine signaling through receiver biases.

Intention Movements

Initial movements indicating an animal's intended action.

Ritualized Behaviors

Signals evolve to become clearer over time. Behaviors evolved from intention movements for signaling.

Courtship Displays

Ritualized behaviors used to attract mates.

Metabolic Cost of Venom

Energy spent on venom production; warning saves energy.

Displacement Activities

Unrelated actions due to conflicting motivations.

Self-Directed Activities

Comfort behaviors during anxiety or uncertainty.

General Nervous System Excitation

Response leading to tail movements in rattlesnakes.

Selective Advantage

Benefit gained from signaling to avoid confrontation.

Food Exchange Ritualization

Behavioral signals developed from feeding interactions.

Stress-Induced Grooming

Increased grooming behavior under stressful conditions.

Autonomic Nervous System (ANS)

Regulates involuntary body functions like blood flow.

Vasodilation

Widening of blood vessels, often due to stress.

Ritualization Process

Evolution of behaviors into clear communication signals.

Stereotyped Signals

Behaviors become consistent to avoid misunderstandings.

Speed Variation in Signals

Altering movement speed for clearer communication.

Anatomical Signal Enhancements

Physical traits evolve to attract attention.

Emancipation in Signals

Loss of original function, serving only communication.

Sensory Exploitation

Signal evolves to exploit receiver's preexisting biases.

Spermatophore

Sperm packet transferred during mating.

Pheromones

Chemical signals influencing mating behavior.

Sensory Drive

Signal evolution influenced by environmental factors.

Sexual Selection

Mate choice drives trait evolution.

Conspecific Aggression Display

Behavior indicating aggression within the same species.

Mating Strategy

Behavioral approach to attract and mate with females.

Evolutionary Studies

Research on how behaviors evolve over time.

Common Ancestor

Species sharing a lineage in evolutionary history.

Sensory Drive Hypothesis

Receiver characteristics shaped by environmental factors.

Visual Systems Evolution

Species adapt vision for prey acquisition in environments.

Brightness Response

Deep-water species react to brightness variations.

Color Response

Shallow-water species react to color differences.

Male Color Patterns

Evolved to exploit sensory biases for mating.

Selective Pressure

Environmental conditions influence sensory bias evolution.

Physical Characteristics of Sender

Sender's anatomy affects message nature and strength.

Cryptically Colored Species

Choose alternative signaling modalities due to visibility.

Acoustic Signaling

Body size influences sound production in vertebrates.

Visual Communication Limitations

Less effective at night, often replaced by sound.

Auditory Signaling

Common in visually complex environments like rainforests.

Pheromonal Communication

Effective in environments with many potential predators.

Unintended Receivers

Predators may detect signals, affecting sender's evolution.