Tue 17th July - Development of behaviours

Question 1

Introduction In today’s lecture

• Nature vs. nurture.
• Prenatal influences on development.
• Postnatal influences. – Imprinting.
• Filial, sexual. – Sensitive periods.
• Developmental homeostasis.

Answer 1

Learning Outcomes Learning outcomes

• Demonstrate understanding of the various influences on animals’ behavioural development.
• Ability to explain the differing time periods where behavioural development is affected, and the mechanisms behind these. – For example, be able to describe and explain filial and sexual imprinting.
• Understand the concept of behavioural homeostasis and how that may moderate behavioural development.
• Be able to discuss these concept using examples.

Question 2

Behavioural Development

Animals behaviour develops throughout their lives.

Patterns of behaviour come and go throughout animals lives,

e.g., play behaviour.

1. Define ‘Ontogenetic’ adaptations

&

2. At 8-10 weeks old puppies start displaying/learning fear responses. Why not younger, why not older?

Answer 2

– behaviour at certain stages may be more/less adaptive to the animal’s current environment.

– Some changes contribute to fitness immediately, or later in life.

– E.g., predator avoidance.

– E.g., mate selection.

Answer

• More mobile (learning how to use body and get around)
• Spending less time with mother (Exposed to more dangers)

.

Question 3

Nature vs. Nurture

Behavioural development is influenced by the interplay of _______ and the _________.

Describe how honey bees roles/behaviours change over their lifecycle:

• Bees’ roles/behaviour change over lifecycle.

Interactive development:

• Genes: transformation from ‘nurse’ to ‘forager’ correlates with changes in genes turned on in brains.

• Environment: pheromones from queen changes gene expression in workers; workers also produce pheromones.

• Internal: Juvenile hormone – low levels in nurses blood, higher in foragers’. – Applied to young bees = foragers.

Answer 3

1. Genetics and the Environment.

Honeybees cont.

Experimental hives with all young workers, still divide into roles.

– Transition times change.

How?

Social influences.

• Tested by adding different cohorts.

– Older vs. young.

– Old inhibit development of foragers.

– When only young present, some forage far earlier than usual.

• Foragers produce ethyl oleate, nurses receive some via nectar transfer. This probably slows transition from nurses to foragers.

– When only young present, this product isn’t present to slow development.

Question 4

Nature vs. Nurture

An example of how genetic predispositions and environment effects interplay, seen in rats (Cooper & Zubek, 1958).

• Tested rats artificially selected for good/poor performance in maze.

– ‘Maze-bright’ and ‘maze-dull’, normal lab environment.

• Changed environmental conditions: ‘maze-bright’ raised in restricted, ‘maze-dull’ raised in enriched.

Answer 4

Rats cont. (Cooper & Zubek, 1958)

• Environmental conditions had a big impact on behaviour.

– ‘Maze-dull’ in enriched environments performed sig. better.

– ‘Maze-bright’ in restricted conditions performed worse.

• Genetic predisposition for [‘maze-dull’ = more errors] was overcome.

Question 5

Prenatal Influences

Differing in utero environments associated with behaviour differences.

• Litter-bearing mammals have foetuses in different positions, conditions.

– E.g., more nutrient rich blood at the ends of the uterine horns, for mice and pigs – heavier birth weight.

– E.g., testosterone produced by male foetuses can affect female foetuses.

Answer 5

Prenatal Influences Example

Testosterone is produced by male mice foetuses earlier and in higher amounts than females.

• Affects neighbours: females =

0M (0 male neighbours)

1M (1 male neighbour)

2M (2 male neighbours)

– 2M females have higher blood/amniotic fluid testosterone.

Adult 2M females

• Less attractive to males.
• More aggressive to ♀ intruders.
• More environmental marking.
• Larger home ranges.
• Delayed first oestrous.
• Produce fewer successful litters.

Question 6

Prenatal Influences

Social environment also influences behaviour long-term

• E.g., pregnant guinea pigs living in unstable social environments, produced offspring with abnormal behaviours.

– Daughters: sig. higher amounts of male-typical play and courtship, higher testosterone levels.

– Sons: more behaviours associated with very young guinea pigs, e.g., body contact resting; courtship and play intermixed.

Answer 6

Postnatal Influences Animals are born/hatch in differing development states.

Altricial aka human baby: (Latin root: ‘to nourish’)

• Relatively helpless.
• Often no/little fur/feathers.
• Can’t eat solid food.
• Incapable of locomotion.

Precocial aka wildebeest juvenile: (Precocity, Latin root: ‘early ripening’)

• More advance state.
• Frequently able to eat some solids.
• Can move around independently.

Question 7

Postnatal Influences Precocial species

– offspring are ‘up and running’ quickly.

Question: what is a crucial behaviour for these young to learn whilst up and running?

Answer 7

Following the parents

Question 8

Imprinting

Imprinting =

Answer 8

1. A learning process where by a young animal’s social preferences becomes restricted to a specific stimulus/stimulus class.
   https: //www.youtube.com/watch?v=cJmFB69HNFs

Example: non-typical imprinting

When duckling hatched it was around the cat first of all

Question 9

Imprinting

Example: applied uses of imprinting.

https://www.youtube.com/watch?v=XCiB5QkfLx4

*whooping crane

Answer 9

Question 10

Imprinting

Lorenz’s original thoughts on imprinting:

• Different to other types of learning, not requiring reinforcement.
• Irreversible.

Main function is to learn characteristics of future mates.

Only occurs during ‘critical’ periods of development.

These days, considered differently, including two types:

Filial Imprinting

What is the first stimulus that a bird will encounter upon hatching?

These offspring can imprint on other immediately-encountered stimuli.

Other animals.

Other species.

Objects.

Stimuli variables affect imprinting:

Ducklings peck items smaller than matchbox, but approach and follower larger stimuli.

Chicks imprint on red/blue objects better than yellow/green.

Sound …

Answer 10

Filial Imprinting

Example: Gottlieb et al. (1960s-1970s), mallard ducks

• relative importance of auditory vs. visual cues.

224 eggs, hatched in incubator – not exposed to mother.

4 groups, tested in arena with stuffed conspecific, various calls (graph).

Following measured.

Question 11

Filial Imprinting

Example: Gottlieb et al. (1960s-1970s), cont., exp. 2.

• Incubator-hatched (naïve to maternal calls).
• Stuffed conspecific hen emitting mallard calls vs. chicken calls.
• Choice test: preference (76%) for conspecific call at 1 day post- hatch.

These experiments show maternal vocalisations influence young hatchlings’ behaviour.

• Preference in ducklings with no prior exposure to mothers’ vocalisations.

So how important is experience (learning)?

• Very…

Answer 11

Filial Imprinting

Example: Gottlieb et al. (1960s-1970s), cont.

• How and when does experience/learning fit into this?

Chicks start vocalising in-egg, 2-3 days prior to hatching (‘contentment calls’).

• Prenatal experience is important for development of behavioural preferences for conspecific calls.

– They must hear their own/conspecifics’ calls.

• If muted and isolated, they don’t demonstrate this strong preference.

Question 12

Filial Imprinting

In nature, fidelity to a parent is the rule – but that parent is generally frequently present amongst few other distractions.

• Bolhuis & Bateson (1990) showed there can be flexibility.

– Test 1 = 3 days of exposure to

either stimuli (pref. test).

– Test 2 = re-tested after 3 days with OTHER stimulus.

– Test 3 = re-tested after 3 days with BOTH stimuli.

Answer 12

Sexual Imprinting

This ensures conspecific mate selection.

• Separate process, later in development (may overlap).
• Two-stage: early experiences learning characteristics of parents and siblings (‘acquisition’), and later exposure to a species when sexually mature (‘consolidation’).

Cross-fostering experiments.

• Cross-fostered offspring can show a sexual preference for their foster-species.

Question 13

Sexual Imprinting

Different tendencies for imprinting are seen across species

• E.g., brood-switching amongst blue tits & great tits.

– Fostered great tits: 3/11 mated, all with blue tit females (who had been cross-fostered [c-f]).

– Fostered blue tits: all mated; 3 with great tits (who had been c-f).

• Degree of imprinted varied across species – most c-f blue tits mated

with conspecifics.

• Developmental impact of cross-fostering was greater for great tits.

Question 14

Developmental Periods

Life stages where there is differences in/sensitivity to external experiences have previously been described as ‘critical periods’.

‘Sensitive periods’.

– Times arise when there is increased sensitivity to certain

experiences.

Example: experiments by Scott & Fuller.

Conditions unlikely to be found in nature.

Applied poorly at times.

Scott & Fuller aka Dick Bags - 50/60’s

Took litters of puppies and raised them in really different situations, some completely socially isolated, didn’t get to see humans and or dogs for weeks and weeks

(ANIMAL ETHICS WOULD NEVER APPROVE OF THIS NOW)

Answer 14

Imprinting

Early beliefs about imprinting:

Different to other types of learning, not requiring reinforcement.

Irreversible.

Main function is to learn characteristics of future mates.

Only occurs during ‘critical’ periods of development.

Current:

• Imprinting stimuli may be reinforcers.
– Animals will work for visual access to these stimuli.

Not necessarily irreversible, unlikely in real life.

Sexual imprinting is a separate process.

Periods of development redefined as sensitive; important periods.

Question 15

Developmental Homeostasis

Individuals experience differing circumstances during development. • E.g., less than ideal environments, genetic mutations, etc.

However, most adults are functional, and display species-typical behaviour (within a range).

Experimentally-manipulated situations are highly abnormal and animals development differently:

– E.g.,ducklings.

Or they develop normal behaviour patterns despite exp. condt.:

– E.g., male crickets living in isolation sing species-specific song.

– Belding’s ground squirrels raised without mothers will respond to

recorded alarm calls.

How does this happen?

Answer 15

Developmental Homeostasis

“Ability of developmental processes to buffer themselves against potentially harmful influences to produce functional adults”

(Goodenough, 2010, p. 453.)

Developmental processes have resilience against the varying circumstances individual animals experience during development.

• Results in reasonably (but not perfectly) predictable behavioural outcomes.

Question 16

Developmental Homeostasis

Example: Harlows’ et al. experiments with rhesus monkeys

Reared under various conditions, including total isolation, with cloth/wire mother surrogates, peer-groups,
with mother.

Resulting behaviours included:

withdrawal, poor understanding of communication, rocking and swaying, huddling, poor maternal behaviour.

:(

‒ Severity depended on age of monkeys and duration of treatment.

Answer 16

Example: Harlows’ et al. experiments, cont.

Some infants were allowed to spend daily time with conspecifics (same rearing conditions).

‒ 15 mins/day.

‒ Initially clung to each other, then played.

Result: near-normal behaviour developed

‒ Could interact socially and sexually with conspecifics.

‒ Lack of aggression/withdrawal displayed by infants raised in complete social isolation.