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[Music]
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we're about to see a simple reflex an
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automatic reaction man touches something
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hot and withdrawals instantly movement
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resulted from a rapid automatic sequence
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of signals passed per the nerves no
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thought was involved
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this chicken panting to cool itself also
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responds to heat by reflex action it
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didn't have to learn how to pant again
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no thought is involved response is
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automatic a reflex
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but simple though reflex actions appear
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they involve five separate steps the
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first is a change in the environment
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called a stimulus which triggers a
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response in these examples that stimulus
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was heat
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the second step is the detection of a
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stimulus by receptors in this case
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sensory nerve endings in the skin
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step three is coordination or processing
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in this example sensory neurons pass a
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message or impulse to an intermediate
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neuron in the spinal cord which
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processes it and generates an outgoing
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impulse this travels rapidly along a
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motor neurone to a muscle
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in step 4 this muscle known as an
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effector response to the stimulus
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this response is the fifth and final
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step in the chain of
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course people can also respond in more
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complex ways to stimuli like the chicken
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this woman feels hot but she's learned
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by experience how to cool the woman in
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using this information she demonstrates
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a learned reaction not a reflex
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scientists often define learning as a
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change in behavior resulting from
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experience of similar situations a
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learned reaction follows the same basic
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steps as a reflex it starts with
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stimulus and receptor and ends with
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effector and response but the
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coordination the processing in between
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is more complex with a result that
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individuals respond differently a
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reflex response to stimulus like this
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sudden noise is normally the same in all
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members of species and similar in most
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species
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but most learned responses are the
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result of signals being processed in the
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brain there they can take any one of
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literally billions of different routes
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and see one of the simplest
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we started a relay Center which sends
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the signal to a thinking decision-making
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area of the brain a decision is made the
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out gate impulse passes through the
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motor control center down the spinal
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cord and connects with a motor neurone
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and effector organ as before
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but it took a human to process this
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learned reaction hen's by contrast are
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only bird brains surely they can't learn
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think or can they now here's another
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uncool customer dealing with excess heat
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is
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this simply a reflex response in fact
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this hens been taught to peck a switch
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when she feels too hot which turns off a
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heater this involved learning from
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experience and the use of some very
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complex parts of the brain so this isn't
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a reflex like the woman the hen
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demonstrates a learned response
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animals as well as humans are capable of
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using their brains and reacting in a
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considered way to changes in that
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environment the extent of their learning
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and intelligence is much greater than as
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realized fifty years ago when these
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intensive rearing systems now widely
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used in food production were first
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devised
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the ancestors of our farm animals led
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active and complex lives in natural
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habitats in which learning from
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experience was essential to survival
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are they content in today's systems
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which allow them little to do other than
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eat and sleep
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in recent years animal behavior
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scientists have devised ways of asking
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animals such questions to discover what
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goes on in animals Minds and what they
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think a need for a satisfactory life the
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scientists have looked for answers in
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the stimulus response chain
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by studying animals responses to stimuli
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and with ever-increasing understanding
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of coordinating processes in the brain
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scientists now know that farm animals
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can learn remember reason and predict in
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quite remarkable ways their minds and
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consequently their needs are very much
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more complex and previously realized
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still not convinced these aren't just
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dumb animals then let's do what the
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scientists didn't ask the animals
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themselves just what they think and how
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they think to do so we too must track
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them through each step of the stimulus
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response chain
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[Music]
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you've seen how heat can stimulate a
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response these animals are reacting to
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another environmental stimulus light as
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the first light of day dawns free-range
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hens take a dust bath animals react to
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light by starting to groom feed explore
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play and
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socialize if they live in an environment
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which allows them to do so
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light also stimulates hens to start
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laying eggs these days usually dim
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artificial light and most laying hens
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are permanently caged by keeping lights
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on 17 hours a day farmers stimulate them
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to lay more eggs
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animals respond to some but not all
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stimuli from the first moments of life
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some of these piglets were born less
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than an hour ago yet already they
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respond to stimuli guiding them to their
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mother's teeth for milk
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let's see how scientists have asked
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newborn piglets to reveal which stimuli
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they perceive and which they don't
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this is an artificial adder it doesn't
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look like an adder to us it can hardly
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do so to a piglet but the black rubber
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sack feels like another and is filled
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with warm water bringing it to a similar
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temperature
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this piglet responds to the sack as if
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it were another it nozzles and attempts
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to find a teat test like this reveal
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that newborn piglets respond to stimuli
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of warmth and texture but little else
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but there's no fooling this piglet a
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much more sophisticated character at the
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age of just two hours already it's
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beginning to respond to additional
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stimuli such as color and chemicals
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detected by the sense of smell this
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piglet will have nothing to do with an
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udder that looks and smells wrong
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piglets learn fast
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like us animals also respond to constant
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changes inside the body the internal
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stimuli for instance brain sensors are
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measuring a decrease in blood water
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content cause thirst
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hormonal changes inside the animals
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stimulate responses involved in
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reproduction activities to prepare and
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care for the young like this pregnant
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sows nest building as well as processes
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of mating birth
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in intensive systems such as this
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animals are still driven by many
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internal stimuli prompting complex
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behaviors which would help them survive
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in the wild
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studies reveal the frequent yet futile
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attempts of caged hens to nest forage
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preen dust bathe and flap their wings
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despite lack of material and space in
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which to do so
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by releasing these hens their feathers
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pecked and worn for months in the cage
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we can discover how they respond to
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stimuli they've never before encountered
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but first we must consider how they'll
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detect such stimuli which brings us to
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the second step in the stimulus response
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chain the receptors
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[Music]
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like us animals have eyes to see ears to
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hear noses to smell and sensory nerves
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with which to feel the sense organs or
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receptors as they're called but don't
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assume these hens see exactly as we see
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birds eyesight is considerably more
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acute than ours they detect smaller and
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more distant things with eyes set to the
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side of their heads they also get a
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wider panoramic view of everything
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around them so these birds depend
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largely on their eyes to assess the rich
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new world of external stimuli in which
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they've suddenly landed
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sense organs or receptors of animals
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differ in efficiency and capacity from
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ours and those of other species some of
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their senses are more acute some less
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some just different
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this resting sow shows the powerful
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receptor on which pigs largely depend
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see how she uses it to keep an eye on or
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rather keep a nose on what's going on
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around her
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pigs as you see can quickly learn to
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perform domestic doggy tricks like dogs
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they also have hundreds of times our
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capacity to detect smells and are
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sometimes used to sniff out illegal
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drugs
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by hiding breakfast cereals among
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similar sized pebbles and placing them
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in an out of sight container we let this
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pig show the remarkable capacity of her
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scent receptor
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see how quickly she smells food
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this way she also demonstrates another
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highly efficient receptor the tissue
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around a pig's mouth is much more
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sensitive than our fingertips with this
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delicate and discerning sense of touch
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she has no difficulty picking out cereal
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from the pebbles
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despite centuries of domestication and
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decades of intensive farming farm
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animals retain most behavioral abilities
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of their wild ancestors those remarkable
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scent receptors still help pigs detect
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and respond to stimuli which signal
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danger in a way which would have
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increased their chances of survival in
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the wild
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[Music]
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these pigs are entering a slaughterhouse
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the usual loud noises of slaughter
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machinery have caused a previous sow to
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urinate in fear now though all is quiet
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the pigs thought to be able to smell an
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alarm substance in their predecessors
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urine hesitate alarmed and alerted
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in sheep ears are particularly efficient
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receptors you've heard of a kidnap
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you're about to see a lamb nap so that a
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you can show us how she uses her sense
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of hearing to locate and identify her
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own lamb
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while the user distracted by food the
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farmer captures a lamb and places it in
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a prepared hide
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[Applause]
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the mother's identity becomes clear in
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seconds she looks around and begins to
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call another you appears to respond to
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her concern scientists have observed
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that sheep often form a close
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companionship with another animal in the
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flock the
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you considers the possibility that the
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lamb has strayed into the next field
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see how in her search she uses her
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senses of sight and smell as well as
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hearing a light chemical and sound
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receptors
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the lamb is only a few days old and slow
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to bleat so till he hears his mother and
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she hears him
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even when several lambs are concealed in
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different hides at the same time studies
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reveal that each mother can identify our
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own lamb by sound alone
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[Music]
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the lamb is released see how the mother
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uses her scent receptor to confirm that
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yes this is indeed her own land
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[Music]
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by now spring is underway and warm
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enough for us still sparsely feathered
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battery hens to step outside into a new
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world of color reared indoors these
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birds have never even seen the color
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green yet their eyes are able to
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perceive an even wider color spectrum
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than ours a broader rainbow birds have
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the most complex color vision of any
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animal they detect color hues we cannot
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see
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no one knows exactly how colors appear
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to them but a bird's eye view may well
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be as different from ours as this what
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we see is not what they see
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their sensitivity to ultraviolet light
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also reveals patterns on petals visible
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to them but not detected by our own
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visual receptors
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[Music]
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their physical coordination has much
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improved since they released from the
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cage which didn't allow the exercise and
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necessary to maintain muscle and bone
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strength
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now at the next step in the
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stimulus-response chain we'll learn how
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they and other animals mentally
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coordinate and assess stimuli
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[Music]
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these cars are demonstrating the
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simplest form of learned response known
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as habituation
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see how vigorously they respond to a
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possible threat when a scientist opens
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an umbrella this is a technique used to
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train police horses for crowd control
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but as the umbrella is opened again and
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again they respond less and less they've
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learned this stimulus doesn't signal
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anything to fear and incorporated the
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lessons of experience into their
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response
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animals can also predict what is about
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to happen by employing a form of
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learning called classical conditioning
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they learn to associate a stimulus with
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a particular response these sheep
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grazing by Alene ignore passing vehicles
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they too have learned by habituation not
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to waste energy by reacting to something
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of no importance to them but a vehicle
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which is important to them is about to
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appear
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the farmers Land Rover which brings food
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each day they instantly distinguish its
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appearance and sound from that of other
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vehicles and react appropriately they
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learn to associate the Land Rover with
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food
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here by classical conditioning animals
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have learnt a link something the farmer
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does with a particular result but they
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can also learn to associate one of their
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own actions with a result
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on
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discovering the outcome of an action is
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desirable they often repeat it becoming
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increasingly skilled by such trial and
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error learning animals become capable of
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exerting some control over events
00:16:12
since their release our old friends the
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battery hens have learned to run an
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obstacle course which demonstrates a
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whole range of such learned responses
00:16:23
each hen must pick a key to release a
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catch squeeze through a small space
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tightrope across a thin pole
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[Music]
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pick a wire loop three times to instruct
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a computer to release a door
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[Music]
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take the right turn at a t-junction and
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leap over water all in order to reach a
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box where she can make an S to lay her
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eggs
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[Music]
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animals ability to learn by trial and
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error is put to good use in some more
00:17:15
welfare friendly farming systems these
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sours a group housed farm animals
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evolved from sociable species and retain
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a strong need for companionship of their
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own kind
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each sow wears her own electronic collar
00:17:29
to enable her to be fed a specific daily
00:17:32
quantity and ensure she doesn't eat her
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companions food
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the sows have no difficulty in quickly
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learning how to operate this feed
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station in which a computer recognizes
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each color dispensing food accordingly
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[Music]
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the animals can even learn to outsmart
00:18:00
the computer given half a chance those
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happening to find spare collars have
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been discovered regularly carrying them
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to the food dispenser to get a second
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helping
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in behavior patterns like this animals
00:18:15
have learned to link stimuli with events
00:18:17
which will affect them directly but not
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every type of learning can be explained
00:18:21
by such links
00:18:23
here lambs are engaged in observational
00:18:26
learning in which an animal learns from
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another animals experience
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see how the milk fed lamb explores his
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mother's Conte
