Psych 311 - Psychophysical Development

OUTLINES

Chapter 7

Play

Rev. 1/26/03

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I. Introduction

A. Play

1. Children engage in activities we assume to be no serious purposeless and enjoyable (play)

2. Young of nonhuman species also play

3. Play must be unique because it differs from adult behavior

B. Loizos (1966)

1. Unlike “serious” behavior, playful activities are exaggerated repetitive and incomplete

C. Schlogsberg (1974)

1. The reason certain behaviors of young organisms are incomplete or otherwise inadequate had to do with stimulus response associations rather than with a concept as vague and uninformative as play

D. Lazar and Beckham

1. Play as a category is redundant; it is nothing more then an immature form of adult behavior

E. Play is generally viewed as a separate category of behavior consisting of activities that consume much of the young’s waking hours

1. Play must serve a function-it must in some manner contribute to behavioral development

F. Conceptual and Methodological difficulties

1. A generally acceptable definition of play does not exist

2. The function or functions of play, although having been the subject of a great deal of speculation commencing formally during the 19^th Century remain within the realm of the conjecture

3. Play is believed to be exhibited by members of all mammalian species

a. Play must be important and perhaps essential for normal development

II. Difficulties With the Play Concept

A. Definitional Problem

1. Play

a. subset of behaviors that are believed to occur “only when the animals essential needs have been satisfied and not in stressful situations”

b. no “immediate” function

2. Play Fighting

a. behaviors associated

1) offensive acts

a) chasing

b) wrestling

c) biting

2) defensive maneuvers

b. these behaviors considered “playful” because they rarely lead to serious injury

3. Similarities Between playful acts and serious behavior

a. adult vs. juvenile

b. juveniles simply incapable of inflicting damage?

c. also found in nonsocial situations

4. Classifying Behaviors as “Play”

a. an act cannot be designated play merely because the actor is young

b. Hole and Einon (1984)

1) most powerful criterion for considering a behaviour as “play” is the extent to which it employs unique behaviour patterns

c. juveniles direct bites to body areas differing from those selected by adults

d. unlikely an adequate behavioral definition of play can ever be formulated

e. Panksepp (1986) – play is best defined neurobiologically

1) problematic because it requires a priori that certain behaviors be designated play

B. Problems with functional analysis of play

1. Lack of an adequate behavioral definition

2. Functions of play have been adequately delineated (possibility of no significance)

3. Difficult if not impossible to independently manipulate

4. Confounding occur with attempting to control play

a. I.e. social isolation, cohabitation with an older animal

5. Amount of play variability must differ sufficiently to be statistically to related to later behaviors

a. Naturally occurring variability is too small for statistical correlation

6. Three main early theories

a. Spencer 1878

1) Play results when excess energy is accumulated

2) Play serves to expend its build up of energy

3) Form of play behaviors is dependent upon how long nerve centers have been inactive longer inactivity increases chances of energy discharge

b. Groos 1898

1) Play serves as practice for instinctive behaviors exhibited later in life

2) Instead of idea that animals play because they are young rather, then they have a period of youth to play

3) Theory does not apply to humans

c. Hall 1908

1) Play serves the function of recapitulating the serious behaviors of ancestors

2) Theory influenced by the industrial revolution

3) Play does not imitate new behaviors, only old ones

7. Other more recent theories on play

a. Promotes muscle growth and general physical capacity (Fagen 1976)

b. Development of social relationships (Baldwin & Baldwin 1974, Bekoff 1974)

c. Toll use (Beck 1980, Huffman & Quiatt, 1986)

d. Motor skills (Chalmers & Locke-Haydon, 1984) and problem solving (smith & Simon, 1984)

e. Held the child bridge the gap between fantasy and reality (Partington & Grant, 1984)

f. Assimilation psychologically and painful experience (Walder, 1933)

8. Due to the inability to manipulate early playful experience, the myriad functions ascribed to play are predominantly theoretically rather then empirically based

a. That and the lack of an acceptable definition of play make it a difficult and controversial topic.

b. Factors that influence play behavior (assumption)

1) Play comprises a separate category of behavior.

2) Play is predominantly displayed by immature organism.

3) Play differs from “serious behavior” in that it serves no immediate function of consequence other then providing the organism with stimulation.

4) The adaptive significance of play becomes manifest later in development.

9. “Play Fighting” continues to be the behavior of choice for those who study play under controlled lab conditions, because

a. The behavior is relatively easy to quantify.

b. It is readily engaged in by standard lab animals.

c. The behavior possesses face validity, as it has a conspicuously playful appearance

d. It is believed that play fighting is important developmentally, permitting the organism to exercise, practice and refine the skills needed in future social encounters.

1) Mock fighting is rarely taken seriously be either animal.

10. Taylor (1980)

a. The amount of play fighting correlates positively with the amount of ostensibly serious fighting behavior exhibited in adults.

III. Play Fighting

A. Referred to as rough and tumble play

1. An encounter is generally devoid of most adults communicative behaviors that serve to signal threat or submission, the “playmates” do engage in species- typical patters of activity both offensive and defensive.

2. Often includes many role reversals, animals rapidly alternate between attacking and defending some behaviors that occur prior to fighting may also be included in play fighting.

3. It is important that one member of the pair “inform” the other that what is to follow is just play.

B. Bekoff (1974)

1. Identified preplay communication in dogs by a “bow”

2. The bow is a prelude to fighting in beagle puppies.

3. The bow is also exhibited by adult dogs to indicate to other dogs that it is just play.

4. He also looked at play fight signals in wolf, which included exaggerated head and body movements. (head- tossing and side –to- side swaying of the shoulders.)

C. Bouts of play fighting are age- dependent.

1. Rats begin to display behavior at about day 15 or 16, just as their eyes open.

2. It reaches its peak at 30 to 40 days and then declines.

D. Pellis and Pellis (1988)

1. Juvenile fighting differs from adult aggressive behavior with regards to the target of attack and defensive posture.

2. Hamster, isolated pairs of littermates for 24 hours, reintroducing them into their home cages and filmed the ensuring encounter.

3. Adult fighting was observed beginning on day 80 by placing an intruder into the home cage.

4. When young most bites are directed anterior to the shoulders (especially cheeks)

5. Referred to as an amicable encounter because they are normally contacted during sexual encounters rather then mutual investigation.

6. Adults tend to bite direct posterior to shoulders (mainly rump)

7. 80 day old and older animals defense mode is to flee and adopt an upright posture, most cases they lie supine.

E. Play Fighting in the Rat

1. Involves contact with the nape of the neck.

2. Animals do this orally or with the snout, usually without biting.

3. “Pinning” is another form of play fighting, involving one animal with its back to the ground and the other on top of or poised above it.

F. Experience

1. Does the lack of play experience affect future play behavior?

a. Play deprivation should lead to a increase in the frequency of play activity the same way as food deprivation enhances eating activity.

2. Muller-Schwarze (1968)

a. Concluded that with deer, there is no specific source of play motivation.

3. Panskepp and Beatty (1980)

a. compared rats weaned and isolated on day 18 to others weaned but not isolated from littermates.

b. On day 21 same-sec pairs were observed for 5 minutes separate cages.

c. For the three days of isolation, the nonisolated animals play fought for less than a third of the observation while isolated animals play fought throughout the entire period.

d. Concluded that play may be controlled by some facet of brain neurochemistry.

4. Panskepp et al. (1984)

a. Enhancement of play is caused by social rather than play deprivation.

b. They conducted their experiment by reducing play experience but in the absence of social deprivation.

c. Placed a young rat with an older animal, which is known to play less.

d. Pair of young rats was kept in a cage, which contained a “jungle gym” insert.

e. Found that the enhancement of play fighting following periods of social isolation in the rat is at least in part due to play deprivation.

5. Capitanio and Reite (1984)

a. Compared play fighting of four pigtail macaque monkeys having undergone a 10-day period of maternal separation to that of five nonseparated monkeys.

b. Consisted of removing the mother while allowing the offspring to remain in their social group made up of adult males and females and other young.

c. Observations were made between 1.5 and 3.0 years.

d. Results showed that maternally seperated animals played about half as much as did those who remained with their mothers.

6. Klinger and Kemble (1985)

a. Studied the influence of housing space on play fighting.

b. Found that small litters of 35 –39 day old rats played more frequently than larger litters when the size of the living space was small.

c. If the housing enclosure increased, it led to an increase in play fighting among the larger litter.

G. Physiology of the Brain

1. Research in the physiology of the brain during play fighting is difficult to interpret because various parts of the bran were removed in order to study the brain during research. No one can be sure if the results are affected at all by the brain damage.

2. Murphy et al (1981)

a. Neocortices of one and two day old hamsters were removed by heat or aspiration.

b. When compared to controls, there was no time difference in occurrence of various behaviors like seed cracking, hoarding, nest building and play fighting.

c. Panskepp (1984), this study supports Murphy’s findings. This also found that the components of decorticate rats play fighting is normal, though the amount of play fighting is decreased.

3. Meaney, et al (1981)

a. This study asked what role the amygdala played in play fighting.

b. Amygdala removed in day 21 or 22 of rats and play fighting was observed.

c. Play fighting was reduced in males, but not females.

d. Results were inconclusive because amygdalectomized rats were deficient in non-play fighting activities as well.

4. Other subcortical areas of the brain

a. Beatty and Castello (1983) found that lesions on the hypothalamusand thalamus were effective in decreasing play fighting.

b. Damage to preoptic-anterior hypothalamus decreases play fighting.

5. Increase in play fighting

a. Damage to septal area of rat’s brains increased play fighting.

b. Many believe that play fighting involves a circuit involving two or more brain structures.

H. Hormones

1. The endocrine system has been implicated in “play-fighting” by both descriptive and manipulative research

2. Descriptive Research

a. Devore and Owens (1975)

1) Males are more prone to “play fighting” than females

b. Kummer (1971)

1) Used free-ranging baboons

2) 2 year old juvenile males

3) Play more roughly and longer than females

4) Females spend more time with adult females and newborns

5) Groups consist of more males than females in hamadryas baboons as high as an 8:1 ratio

c. Goldfoot and Wallen (1978) and Goy (1978)

1) Male rhesus monkeys exhibited more intense play than females

d. Brown (1988)

1) There was no evidence of play difference between male and female gorillas

e. Blurton-Jones (1976)

1) 3-5 year old children

2) Similar to non-human primates

3) Roles rapidly alternate

4) “Play fighting” easily distinguished from hostile behavior

5) “Play fighting” consists of:

a) Chasing and fleeing; wrestling; jumping; beating at others with open hand (without hitting); beating at with object (without hitting); laughing

6) Observe males engage more than females

f. Non-Primate species also exhibit male/female differences in “play fighting”

1) Gentry (1974)

a) Male stellar sea lions exhibit more play fighting activities than female sea lions

2) Goldman and Swanson (1975)

a) Found same behaviors in hamsters

g. Role of endocrine system in the rat

1) Olioff and Stewart (1978)

a) “Paired Encounter”

(1) Same sex pairs of rats

(2) Play fighting for 10 minutes

b) Animals tested at ages 22, 26, and 30 days

c) Data summed across 3 ages

d) Found males spent twice as much time as females

e) At 40 days no difference was observed

2) Thor and Holloway (1984)

a) Differences are more likely to occur if subjects are tested in one member’s home cage

b) Differences more likely following days of social isolation

3) Pellis and Pellis (1990)

a) Differences are increased if subjects are paired with familiar juveniles than strange

b) Finding male/female difference depends largely on methodology

c) Difference more likely observed under ongoing social interaction than if subjects are removed and paired in strange environment

4) Focal observation technique

5) Meaney and Stewart (1981)

a) Groups of 6

b) Made 20 second observations 70 times a day

c) Ages 26 days and 40 days

d) Result: Males were 40% more active in play fighting than females

3. Manipulative Research

a. Olioff and Stewart (1978)

1) First demonstrated the effect of hormonal manipulation on play fighting of the rat.

2) Some one day old males and females were injected with testosterone while remaining animals received only sesame oil and the hormone was dissolved.

a) Oil treated males play fought more than oil treated females.

b) Testosterone treated females fought more than oil females, but didn’t differ from oil treated males.

c) Testosterone treated males didn’t differ at all.

b. Meaney and Stewart (1981)

1) Provided a confirmation and more detailed account of Olioff and Stewarts experiment.

2) Hypothesized that gonadectomy in males reduces play fighting.

3) Neither surgical removal of ovaries nor estrogen treatment alter the levels of play fighting in females.

4) Both hypothesizes were confirmed.

5) By day 23, the hormone is unnecessary and will not alter a behavior, if a gonadectomy is performed.

c. Beatty, Dodge, Traylor, and Meaney (1981)

1) Androgen is necessary prior to day 10 of life to produce a male-typical level of play fighting, it is not necessary during the period in which play fighting is exihibited.

2) Testosterone, rather than one of its by-products is responsible for the development of male-typical levels of play fighting.

d. Meaney and McEwen (1986)

1) Brain localization

a) Testosterone injected into the amygdala of one day old female rats enhanced their amount of play fighting.

e. Meaney, Stewart, and Beatty (1982)

1) Testosterone is not the only hormone that influences play fighting; glucocorticoids are also effective.

2) Females are not affected by corticosterone.

3) Male rats were only affected by corticosterone on days one and two or three and four, which caused a reduction in play fighting.

I. Neurochemistry

1. To identify a neurochemical substrate you have to administer pharmacological agents and see how they affect the central nervous system neurotransmitter function.

a. Behavioral Specificity- a drug that affects only the behaviors you are looking at, in this case play fighting.

b. Pharmacological specificity- when the administration of an agonist or antagonist, either yield opposite behavioral effects or neutralize one another.

2. Research: Panksepp et al.:

a. Research designed to explore the involvement of the endogenous brain opioid system (endorphins) in social behavior and in what has been referred to as social emotions.

b. Panksepp contends that brain opioids mediate social affect by reducing the distress associated with social separation.

c. Discovered the opioid morphine increases play fighting pinning behavior while the opioid antagonist naloxone decreases pinning; while these drugs have effects on play, they have no effect on overall activity levels.

d. In later experiments found that morphine tends to increase the dominance of submissive animals, and naloxone tends to decrease the dominance of dominant animals.

J. Conclusions

1. Experimental analysis of play fighting consists primarily in determining how the CNS governs its display.

2. Done by observing behavior of brain-damaged animals, those with altered brain chemistry, and hormonally aberrant subjects.

3. Young females exposed to androgen then play at levels charactoristic of the male, while males with reduced androgen play characteristically female.

a. Androgen therefore permanently modifies a component of the brain that governs play-fighting behavior.

b. Androgen also affects adult fighting behavior- question is play fighting a separate category or an immature model of adult behavior?