Held And Hein - Kitten Carousel

Front 1

Held and Hein (kitten carousel) used three main tests to assess visual-spatial discrimination. They also did several additional tests to check the status of peripheral receptors and responses. Describe two of these additional tests. (Held&Hein)

Back 1

“the S, held in a standing position in a neckyoke and body clamp was light-adapted in the normally illuminated lab prior to observation...”visual pursuit of a moving object: elicited by E’s hand moving slowly across S’s visual field. pupillary reflex to light: change in pupillary size was then noted when a beam of light from a penlight was moved across the eye from outer to inner canthus [=corner of the eye] tactual placing response: the S’s body was held in E’s hands so that its head and forelegs were free [as in the visual paw-placing test]. It was then carried to the edge of the table where the dorsa [tops/backs] of its front paws were brought into contact with the vertical surface of the table [and compared to the response of normals, which place the paws on the horizontal surface].

Front 2

Describe the visual cliff results for the active and passive kittens.(Held&Hein)

Back 2

no active kitten crossed to the deep sideall passive kittens crossed to the deep side sometimes

Front 3

What did Held and Hein conclude from these results?(Held&Hein)

Back 3

that self-produced movement; with concurrent visual feedback; is necessary for the development of visually guided movement.

Front 4

What was already known about adult human visual adaptation prior to this study? (Held&Hein)

Back 4

that complete sensory adaptation requires movement-produced sensory feedback

Front 5

Explain whether the results for baby animals (neonates) were the same as those for human adults or different.(Held&Hein)

Back 5

the samebecause only the kittens which could move (so had movement-produced sensory feedback) developed normal visually guided behaviour and adults in visual rearrangement studies needed stimulation to be dependent on natural movement.

Front 6

Describe behaviours assessed using observation. (Held&Hein)

Back 6

visually guided paw-placement: legs down onto table when lowered from above

visual cliff: avoidance of deep side

blink to approaching object

Front 7

Outline one disadvantage of observations as a research method.(Held&Hein)

Back 7

data indirectly from participant – must be seen/scored/recorded accurately by observer so (potential) loss of validity (/ limited, can’t know why) e.g. kittens may have been more interested in something the researchers were unaware of across the shallow side

Front 8

Identify previous studies prior to this experiment (Held&Hein)

Back 8

Deprivation studies comes from two experiments on kittens reared under different conditions of deprivation. In one experiment Ss were allowed visual experience in an illuminated and patterned environment only while they were restrained in holders which prevented them from freely moving about. When subsequently tested they showed deficiencies in visually guided behavior compared with their normally reared litter mates. Related deficits followed rearing in a second experiment in which Ss were allowed to move about freely in light but with diffusing hoods over their eye. The exposure factor lacking under both conditions was the variation in visual stimulation produced by the full range of S's movement in normal circumstances.

Front 9

Why were head movements not restricted for kitten P (Held&Hein)

Back 9

This restriction seemed unnecessary since Riesen and Aarons have shown that kittens reared from birth with variation in visual stimulation consequent upon free head motions, but otherwise restricted, failed to learn a simple spatial discrimination. Because of its constraints, P could not locomote. However, its limbs were free to move and to slide along the smooth floor of the gondola. According to our observations these movements frequently occurred.

Front 10

Describe apparatus (Held&Hein)

Back 10

The apparatus was housed in a cylinder with black, white and metal-coloured vertical strips on the walls inside. The centre of the roundabout, which was also striped, prevented the kittens from seeing each other.

Front 11

Describe the 3 main tests (Held&Hein)

Back 11

1. Visually-guided paw placement. the kitten’s body was held in experimenter’s hands so that its head and forelegs were free. It was slowly carried forward and downward towards the edge of a table or some other horizontal surface. A kitten with normal visual experience extends its paws ready to make contact with the surface.

2. Avoidance of a visual cliff. The visual cliff consists essentially of a narrow platform supported by vertical sides that drop a few inches to a large plate of glass. The kitten placed on the platform can descend to the glass on either one of two sides. Its view on the "deep" side is through the glass to a patterned surface 30 inches. below. On the other side it views a similarly patterned surface attached to the underside of the glass. In our apparatus, both surfaces were illuminated from below and hence the clean glass surface was practically invisible. For the vertical sides of the platform, we substituted planes inclined 35° from the vertical.

3. Blink to an approaching object The kitten was held in a standing position in a neckyoke and body clamp with a large sheet of Plexiglas positioned directly in front of its face. The experimenter moved his hand quickly toward kitten, stopping just short of contact with the Plexiglas. A kitten with normal visual experience blinks in response

Front 12

Describe the additional tests (Held&Hein)

Back 12

Several additional tests were performed to check the status of peripheral receptor and response mechanisms. These included:Observations of pupillary reflex to light: The S, held in a standing position in a neckyoke and body clamp, was light-adapted in the normally illuminated laboratory prior to observation of the pupillary reflex. Change in pupillary size was then noted when a light beam from a penlight was moved across the eye from outer to inner canthus. The tactual placing response: To determine the presence of the tactual paw- placing response S was supported as in the visual paw-placing test. It was then carried to the edge of a table where the dorsa of its front paws were brought into contact with the vertical edge of the table. Observations of experimental Ss were compared with those of normals which, in response to this stimulus, place the paws on the horizontal surface of the table . Visual pursuit of a moving object: Visual pursuit was elicited by E'a hand moving slowly across S's visual field.

Front 13

Describe subjects (Held&Hein)

Back 13

Ten pairs of kittens were used; each pair from a different litter. were divided into two Groups, X and Y, whose members were reared with minor differences. Each of the eight pairs of Group X was reared in darkness from birth until member A attained the minimal size and coordinational capacity to move itself and its mate in the apparatus. This age varied between 8 and 12 weeks.

Front 14

Describe how kittens were placed in apparatus(Held&Hein)

Back 14

The P was placed in the gondola and held there by a neckyoke and body clamp. The lever from which the gondola was suspended was then balanced by appropriate placement of a counter- weight. When attached to the opposite end of the lever by a second neckyoke and body clamp assembly, A was free to move itself in both dire tions around the three axes of rotation a-a, b-b, and c-c while pulling P through the equivalent movements around a-a, b-b, and d-d by means of the mechanical linkages to the gondola

Front 15

Describe exposure in apparatus (Held&Hein)

Back 15

The pairs spent 3 hours per day in the apparatus for six weeks. When not in the apparatus all kittens were housed in darkness with their mother and litter mates

Front 16

What were the results of the visual cliff? (Held&Hein)

Back 16

All As behaved like normally reared Ss which had been observed previously in a pilot experiment. Each A descended to the shallow side of the cliff on every trial of the first day and repeated this performance on the trials of the following day. The P members of Group X were tested on the cliff on the same days as their actively exposed litter mates. They showed no evidence of discriminating the shallow from the deep side. Observations of the P members of Group Y on the cliff, after their prolonged passive exposure, gave similar results and they also failed to perform visual paw placement

Front 17

What happened after for 48 hours in light?(Held&Hein)

Back 17

Following the 48 hr. period of freedom in an illuminated room, the P members of Group X were retested. They then displayed normal visually-guided paw-placement and performed all descents to the shallow side of the visual cliff.

Front 18

State weaknesses of the study (Held&Hein)

Back 18

May have merely distorted inborn abilities rather than prove abilities were learned.Can the study be generalized to all mammals? even people?

Questions regarding ethics: is it ethical to raise kittens in an environment like this? is the knowledge gained worth it?

Ecological validity: the ecological validity is hurt by the use of a laboratory. Also the study is on animals whereas hum as are different.

Front 19

Describe strengths of the study (Held&Hein)

Back 19

The study was tightly controlled: All participants in each group were exposed to the same environment for the same amount of time and performed exactly the same tests.All participants had the same living conditions and spent time with their mother and litter mates.

Front 20

Aim of study (Held&Hein)

Back 20

The aim of the study is to test the theory that concurrent self produced movement is necessary for visually guided behavior. In other words kittens needs to see and move for itself in an environment for it to develop normal movement such as paw placement

Front 21

State findings of the study(Held&Hein)

Back 21

All kittens responded normally to pupillary reflex, tactual placing and pursuit of a moving object, showing no visual impairment or impaired response to moving objects.When the active kitten in group X showed visually guided paw placement (after around 33 hours of exposures) none of the passive kittens did. The same was found for the blink test.When tested on visual cliff all the active kittens showed behavior as if reared normally, whereas none of the passive kittens did.The group Y passive kittens showed the same paw-placement and visual cliff deficit behavior as the kittens in group X.After 48 hours of freedom in a normally illuminated room all kittens performed normally on all tests, so showing no after-effects of the experimental procedure.

Front 22

Describe one difference and one similarity in early visual experience of the kittens in group X compared with the kittens in group Y (Held&Hein)

Back 22

Difference: Group X was reared in darkness from birth until member A attained the minimal size and coordinational capacity to move itself and its partner in the apparatus. This age varied between 8 and 12 weeks. Group Y received 3 hour daily exposure, beginning at 2 ending at 10 weeks of age, to the patterned interior of the laboratory while restrained in holders that allow some head movement but prevented locomotion.Similarity: Each of the eight pairs of both group X and Y began exposure in the apparatus for 3 hours daily

Front 23

What is meant by the term visually guided paw placement (Held&Hein)

Back 23

This is where a kitten has developed paw-eye coordination. A kitten will look and place its paw in place where it has looked. A flippant example is that if a kitten with visually guided paw placement is dropped it will turn and successfully land on its feet. A kitten that does not have visually guided paw placement will hit the floor without turning and may not land on its feet.