Communication (neuroscience)

communication

a signaler sends a signal carrying information to a receiver

why do animals communicate

long term - surviving and reproducing, short term - alarms, food and attracting mates

who first studied the honeybee dance

Karl von Frisch (1919)

‘round dance’

food sources less than 100m away, bee turns in circles alternating direction

‘waggle dance’

food sources more than 100m away, a figure of eight with a waggling straight run

how does the waggle dance show distance

duration of the waggle run shows how far the food is

how does the waggle dance show direction

the angle of the waggle shows bearing relative to the sun

Mischelsen et al (1992) - testing the waggle dance

used a mechanical bee which followed the distance and direction info

Riley et al (2005) - how did they test the waggle dance

used radar transponders to track bees actual flight paths after watching the dance

Struhsaker (1967) - vervet monkey

found 21 distinct call in vervets, including 3 alarms for leopards, eagles, and snakes

Seyfarth (1980)

played alarm calls with no predator present, monkeys still showed the right escape response

what does the vervet study suggest about calls

calls are referential, they mean something specific

‘boy who cried wolf’ vervet test

monkeys habituate to unreliable callers, they extract meaning, not just reflex responses

Manser (2001) - meerkat alarm calls

meerkats have different calls for aerial vs terrestrial predators, plus info about urgency

Pearce’s 4 criteria for language

arbitrariness, semanticity, displacement, productivity

arbitrariness

symbols have no natural link to what they represent

semanticity

signals carry meaning

displacement

communicating about things distant in time or space

productivity

following rules but using them flexibly to make new combinations

does the waggle dance count as language

has semanticity and displacement, but units aren’t arbitrary and content is limited (mostly food)

what is Clever Hans a warning about

researchers can unknowingly cue animals, making them seem smarter than they are

morgan’s canon

always explain behaviour using the simplest psychological process possible

Gardner & Gardner (1969) - Washoe

taught Washoe (chimp) American Sign Language - 132 signs after 5 years

did Washoe combine signs

‘water bird’ for swan, suggested some productivity

Terrace et al (1979) - Nim Chimpsky

Nim learned 125 signs and made short combos (1.1-1.6 words), but mostly imitation, little real grammar

why was Nim a setback for ape language claims

compared to a 2 year old (10 new words a day) ape's’ progress was slow and rule-poor

Lana the chimp - what was used

Yerkish keyboard with arbitrary symbols (lexigrams), trained by Duane Rumbaugh

(Premack, 1972) - Sarah the chimp

Plastic tokens as arbitrary symbols

Rivas (2005) - what did chimp signing mostly do

86% of chimp signs were request, limited communicative range

Herman et al (1984) - Akeakamai

Dolphin trained to understand gestures, could follow object-action commands 81% correctly

Why are reversible sentences important

tests is word order (syntax) is understood

Akeakamai’s score on reversible sentences

52% correct, with 0 reversal errors, suggests some grasp of syntax

do animals have language

they communicate but don’t tick all 4 language criteria, weak productivity and arbitrariness