Psych 311 -
Psychophysical Development
OUTLINES
Chapter 2
Origin and Function
of Embryonic Behavior
Rev.
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I. Early Modification of Behavioral Development
A. Behavioral Potentials – the enormous possibilities or potentials of behavior patterns that each neonate possesses within the limits or range of the normal morphological structure of its species
B. A principle task of developmental researchers is the identification of the factors that shape the course if development
C. Conditioning leads to the display of conditioned responses not only during the post-embryonic period but also by the embryo itself
II. Conditioning
A. Insects
1. Conditioning experiments performed using larvae
2. Borsellino, Pierantoni, and Schieti-Cavazza (1970)
a. Conditioning of mealworm beetle larvae
b. Move left or right in circular maze
c. Punished with bright light
d. Rewarded with darkness
B. Amphibia
1. Larvae salamanders conditioned to swim left or right in “Y”-maze when incorrect responses are punished with bright light
C. Birds
1. Fried and Glick
a. attached electrodes to 14-day-old chick embryos to monitor
electrical resistance of skin
b. administered electrical shock (USC) which evoked
an URS, decreasing the GSR
c. therefore conditioning took place as a decrease in the GSR,
in response to the CS, was observed
2. Hunt
a. USC an electrical current passed directly through the shell
b UCR was leg movement
c. CS was sounding of the bell
d. control group received CS alone, the USC alone, or neither
stimulus
e. some subjects were tested after hatching
f. CR no longer elicited after chick was exposed to
light, food, and water.
3. Impekoven
a. said ducks were responsive to maternal calls
b. burst of mallard call was made contingent on embryos
foot movement
c. compared with control embryo
d. tests show that frequency of foot movements were higher in
experimental subjects than in control subjects
e. embryonic vocalizations stimulate adult to emit
vocalization, which might result in hastening of hatching
4. Duck Embryos
a. trained to perform escape responses
b. one group received termination of electric shock, other
group received inescapable shock
c. conditioning took place as latencies of the flexion
response decreased
D. Mammals - Do Neonates exhibit learned aversion acquired as embryos
1. Smotherman and colleagues experiment
a. Performed on rat embryos
b. Injected with apple juice or saline at 20 days
c. 5 minutes later given LICl or saline
d. The
pups exposed to LICl and apple juice show least
preference for apple juice at birth
2. Conclusions
a. The
previously preferred flavor was no longer favored having assumed an aversive quality
because the nipples were coated with a test stimulus the pups had associated
with illness prior to birth
b. Suggests the olfactory system functions prior to birth
c. Shows that embryos are capable of forming associations
d. Taste and odor aversions
may be adventitiously established in human embryos as a consequence of the
material ingestion of chemical substances that produce suppression of behavior
(alcohol)
3. Spelt Conditioning Experiment
a. Classical conditioning with loud noise as UCS
b. Vibrotactile stimulus placed on abdomen as CS
c. Fetal movement was CR and UCR
d. Conditioned responses were observed after 15-20 seconds
e. CS-UCS pairings
4. Problems
a. Mother conditioned, not embryo
b. Spelt reported vibrotactile stimulus does not elicit movement prior to
conditioning but a later study found it does produce embryonic movement
5. Results
a. Embryonic behavior can be modified by conditioning
III. Early Sensory Exposure
A. Providing the embryo with sensory stimulation may influence post-embryonic behavior.
B. Early exposure establishes a bias because the post-embryonic organism tends to select the stimulus it was exposed to.
C. Sound Stimulation
1. There is evidence that the auditory system functions during the embryonic period.
a. Many anecdotal reports exist.
1) Forbes and Forbes recorded the case of a pregnant woman who reported a great deal of embryonic movement occurred when the audience applauded at a musical concert.
2) Grier, Counter and Shearer found that the chick embryo gave its initial response to sound by day 12 of incubation.
3) Rawdon-Smith,
4) Scibetter and Rosen discovered that the electrophalographic response to an auditory system is similar in late embryonic and newborn guinea pigs.
5) Gelman applied sound stimulation to the abdomen area of a pregnant woman, using ultrasonic imaging to record the number of eye blinks assumed to be startle responses.
b. The degree of sound stimulation is available to an embryo
1) Results
of two experiments indicate that the sounds accessible to human embryos are
from the maternal cardiovascular and digestive systems.
a) Henshall, Walker and Wood all monitored the uteri of pregnant women.
b) Bench placed microphones against the cervix.
c. Sounds
recorded from within the amniotic sac because the embryo is surrounded by fluid
and amniotic membranes.
1) Vince
inserted a transmitting radiohydrophone into the
amniotic sac of a pregnant ewe.
a) Internal sounds were recognizable.
b) External sounds were attenuated by 16 to 37 decibels
c) The ewe’s voice is a prominent part of the uterine sound environment, its above background noise.
2) Querleu, Renard and Crepin found that Vince’s findings concur with those of the
human embryo. The mother’s voice is audible in utero.
d. Examination of two infrahuman mammals: the guinea pig and sheep.
1) Vince
and others studied the pregnant guinea pig 2 to 3 weeks prior to giving birth.
a) The guinea pigs were exposed each day to the feeding call of bantam hens because its aversive to adult guinea pigs because of the wide range of frequencies.
b) Those animals who were exposed to the sound prior to birth exhibited a smaller change in heart rate.
2) Vince and colleagues also performed this experiment on sheep finding similar results.
3) Vince concluded that animals became adapted to their sound environment before birth, especially to internal sounds from the mother and repetitive external sounds.
2. Influence of Prenatal Auditory Exposure on infant behavior
a. Can discriminate and prefer maternal voice during first three days
b. DeCasper and Fifer
1) Non-nutritive sucking to determine if maternal voice could reinforce IBI’s
2) Procedure
a) Half: bursts that ended IBI’s longer than median time prior to conditioning yielded sound of maternal voice
b) Shorter times yielded the sound of strange female
c) Remaining half: conditions reversed
3) Results
a) 8 of 10 infants did discriminate and prefer maternal voice
c. DeCasper and Fifer #2
1) 4 seconds of tone and 4 seconds of silence
a) Half: sucking during tone yielded maternal voice
b) Sucking during no tone yielded stranger voice
c) Conditions reversed for half of subjects
2) Results
a) Prenatal/early postnatal experience causes the maternal voice to be reinforcing
d. DeCasper and Spence
1) Procedure
a) Preg.- recite passage twice daily for six weeks
b) Later – infants produce recordings of passage or novel by controlling sucking
2) Results
a) Passage preferred, even when read by stranger
b) Preference for maternal voice likely due to embryonic exposure to it
c) Lack of prenatal exposure to father’s voice may explain its lack of preference
3. Significance of ability to recognize maternal voice
a. Findings
1) I.D. of maternal voice might increase feeding efficiency, facilitate mom’s ability to reduce child’s distress, and facilitate new learning
2) Embryonic exposure plays a role in behavior development
4. Non-human Data - Gottlieb
a. Procedure
1) Tested newly hatched birds – presented one maternal call of own species and one of different species
2) Subjects could approach source of sound
b. Results
1) Young attracted to maternal call of own species
5. Possible role of prehatching auditory stimulus. - Does embryonic exposure to species- typical maternal calls contribute to post- embryonic attraction?
a. Grier exposed incubator reared chicken eggs to a series of beeps from days 12 to 18 of incubation.
1) After
hatching chicks were exposed to two speakers with different sounds.
2) The chicks were attracted to the sound to which they were exposed to prior to hatching.
b. The
influence of embryonic exposure to the call of a non-species member was
assessed by Bailey and Ralph.
1) Exposed
chick embryos to the attraction or alarm call of a male pheasant.
2) After hatching chicks were exposed to pheasant alarm call or attraction call vs. a human noise and it was found the pheasant sound was preferred.
3) The greater number of days of embryonic exposure, the greater the attraction.
c. Gottlieb
asked if exposure to a duck embryo’s own vocalizations is involved in
post-hatching responsiveness to the maternal call.
1) Assessed embryonic vocalizations by eliminating them.
2) He placed liquid surgical dressing collodion on the tympaniform membranes of embryonic mallard ducks.
3) This stopped the vocalization.
4) Once hatched the mallard ducklings distinguished the mallard call from other types of ducks. However, not from chicken call. This is because chicken calls are similar to mallard calls in respect to frequency and rate.
D. Light Stimulation
1. Light reaches the embryo in a more restrictive manor than sound
a. Jacques, Weaver & Reppert (1987)
1) Tried to determine the fraction of light that penetrates the uterus
2) Implant optical fibers in uteri of 20-day pregnant rats and 51 day pregnant guinea pigs
3) Amount of light transmitted in both was low
1) 10% of a 650-nm stimulus penetrated the uterus
b. Wiens (1970)
1) Using
tadpoles, tried to determine if the preference for particular visual patterns
can be established and maintained
2) Tadpoles were assigned to 1 of 4 groups
a) Featureless white pans
b) Black stripes affixed to the floor and wall or black squares arranged in linear pattern
c) First in experimental environment and then put into featureless environment
d) Kept in featureless chamber and then placed in experimental chamber
3) Each subject was tested three times
4) Revealed that preference for the rearing environment was showed by animals that were reared in the striped environment
5) no appearance of a critical period for establishing preference
2. Chicken embryos – capable of forming visual preference
a. Metcalfe (1976)
1) Exposed embryos to visual stimuli through incubation period
a) 200-W flashing light or 25 W flashing light
2) Chicks
were given a stimulus preference test 16 hours after hatching
a) Hatchlings exhibited a preference for the visual stimulus similar to the one they were exposed to as embryos.
3. Light exposure on imprinting – the predisposition of hatchlings to follow the first moving object to which they are exposed
a. Adam and Dimond (1971)
1) Chicken embryos exposed to light on day 19 of incubation required less time to approach the imprinting object than animals exposed prior to day 19
E. Chemical Stimulation
1. Taste Response
a. Both
mammalian and human embryos were found to both ingest and respond to the taste
of amniotic fluid
b. Sweetener thought to induce the embryo to ingest elevated amounts of the fluid
c. Embryos have a habitation to sweet tastes
2. Short-Term Effects
a. Smotherman and Robinson
1) Day
17 of gestation, rat embryo exposed to mint by amniotic injection
a) Found increased activity
2) Day 19 of gestation, when exposed
a) Found suspension of activity before increase of activity
b. Hepper
1) Exposed
rat embryos through mother ingesting of garlic at day 15 to 21 of gestation
a) Exposed through mother ingesting so it would enter the fetus bloodstream
2) Day
12 of life observed and compared rats, those who were exposed against those who
weren’t
a) Those who were exposed to garlic had a preference to it
IV. Embryos obey the laws of both classical and instrumental conditioning.
A. Capable of forming/maintaining association
B. Conditioning
1. Underlie conditioning factors are normally present during embryonic period
2. Function of conditioning must be demonstrated
3. Embryonic nervous system attains a level of sophistication that permits conditioning to occur
C. Stimulations and modifications of behavior
1. Conditions underlying embryonic stimulus exposure to occur
2. Exposure to maternal vocalizations, chemicals, and peculiarities of its own amniotic fluid
a. Embryonic exposure to stimulus is important
b. Leads to later recognition and preference for certain stimuli
c. Beneficial for out attachment to the appropriate adult
d. Certain circumstances may be to the organism’s advantage to remain in the environment in which it developed
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