JOURNAL
OF
EXPERIMENTAL
The Meaning
CHILD
PSYCHOLOCiY
of Before HELEN The
University
and
After
19, 88-99
(1975)
for Preschool
Children
L. JOHNSON~,* of Iowa at Iowa City
Preschool children’s understanding of temporal relationships was examined in terms of their comprehension of sentences containing clauses linked by before and after. The relative importance of order of mention and mainsubordinate relations strategies in children’s interpretation of temporal order information was also evaluated. Divergent error patterns emerged on the tasks; omissions prevailed on the two tasks involving response to commands, reversals prevailed on the other. Further examination revealed that omissions reflected ambiguity in the linguistic structure of commands. Thus the effect of main-subordinate relations was confounded with directness of command. On all comprehension tasks, however, performance was superior on sentence forms in which order of mention and order of occurrence correspond.
The present study is concerned with preschool children’s ability to comprehend sentences expressing temporal relations between events. The study proceeds on the assumption that when a child uses a relational term (e.g., because, so, before, after, more, less), he does not necessarily intend the same meaning as the adult speaker does. The key to understanding the child’s interpretation of conceptual relations therefore lies in discovering the meaning he intends when he uses relational terms. By the same token, as Bloom (1970) has shown, the linguistic structures found in child speech cannot be fully understood apart from the functions they serve for the child. Recent studies (Clark, 1970, 1971; Amidon & Carey, 1972) have examined the role of different sentence features in children’s processing of temporal order information. In all of the studies discussed below, four basic sentence constructions were used:
II am extremely grateful to Dr. Robin S. Chapman for her comments and suggestions during the planning of the study. I am also indebted to Dr. Patrick B. Johnson for his help in the preparation of the manuscript. ‘Requests for reprints should be sent to Helen L. Johnson, Social Science Department, Kirkwood Community College, Cedar Rapids, IA 52496. This research was conducted while author was on a postdoctoral fellowship at the Department of Speech Pathology and Audiology, The University of Iowa. 88
Copyright @ 1975 by Academic Press, Inc. All rights of reproduction in any form reserved.
MEANING
(1) (2) (3) (4)
OF
BEFORE
AND
AFTER
89
Before 52, Sl; Sl before 52; After Sl, 52; 52 after Sl.
Note that in (2) and (3), the order in which events are described in the sentence (order of mention) and the order in which they occurred in the world (order of occurrence) correspond, while in (1) and (4)) they do not. When Clark and Clark (1968) used a recall task to study college students’ processing of temporal order information, the results indicated that sentences in which order of mention (the order in which events were mentioned in the sentence) corresponded to order of occurrence (the order in which the events occurred in the world) were easier to process than sentences where it did not. Using a questioning procedure (“What happened first/second?“) with college students, however, Smith and McMahon (1970) found no facilitating effect from correspondence between order of mention and order of occurrence. Instead, the data showed that information in the main clause was more accessible than information in the subordinate clause, and that whatever was asserted to have happened first was more accessible than whatever was asserted to have happened second. The importance of order-of-mention-order-of-occurrence correspondence in young children’s acquisition of temporal descriptions has been studied by Clark (1970, 1971). Analyzing preschoolers’ spontaneous speech samples, she found a preference for describing events in the order in which they actually occurred. In children’s comprehension of the temporal terms before and after (used in the sentence constructions discussed previously), Clark found three stages. At first, children did not understand before or after, and relied on order of mention. Children in the second stage understood before but not after. They either continued to interpret after-sentences in terms of order of mention, or treated after as though it meant before. In the third stage, children understood both before and after. Clark proposed two principles underlying comprehension responses. First, correspondence between order of mention and order of occurrence makes sentences easier to understand. Second, relational terms are learned gradually, one semantic feature at a time, beginning with the most general; before is therefore mastered earlier than after because it is the positive member of the pair. In contrast, Amidon and Carey (1972) hypothesized that children’s failure to demonstrate comprehension of temporal order might actually be due to difficulty with characteristics of the comprehension task. Ac-
90
HELEN
L.
JOHNSON
cordingly, they compared the effects of five training conditions on kindergarteners’ responses to two-action commands. All children were pretested with a set of commands in the temporal sentence constructions discussed previously; for all commands, the instruction was to limove the red/blue, etc., plane;” the posttest involved a new set of materials and instructions about putting them into a box. The results indicated significant improvement in the performance of children whose training had included feedback, and posttest errors for these groups were mainly reversals of clause order. The posttest errors of children whose training did not include feedback were primarily omissions, especially of the subordinate clause. Also, performance with first and last (coordinate clause construction) was better than with before and after (subordinate clause construction). Amidon and Carey therefore interpret their results as strong support for the effect of subordinate versus coordinate sentence constructions. The data indicate, they feel, that children focus on the main clause in interpreting temporal information, rather than on order of mention, as Clark had proposed. It should be noted that the sentences used by Amidon and Carey were not comparable in complexity to those used by Clark on her comprehension task. Each of the Clark sentences described two different actions performed by a third-person agent. In contrast, the Amidon-Carey sent’ences instructed the child (second-person agent) to perform two identical actions in sequence. Thus, the discrepancies between the findings of Clark and of Amidon and Carey may, in part, be a reflection of the differences in the structure of the sentences studied, and in the nature of the tasks used. The present study at.tempted to clarify the contradictions between the Clark and Amidon-Carey data on the relative importance of order of mention and main-subordinate clause strategies in young children’s processing of temporal order information. All Ss were given both the Clark and the Amidon-Carey tasks, so that the extent to which differences in response strategies reflect specific task features could be assessed. In addition, a command procedure, in which each sentence instructed two different actions and was therefore more comparable in complexity to the Clark items, was administered. METHOD
Subjects The Ss were ten girls and eight boys attending the University Preschool, Iowa City, Iowa. The children ranged in age from 4.2-5.2 years, with a mean age of 4.8 years. All children tested were native speakers
MEANING
OF
BEFORE
AND
AFTER
91
of English and came from highly educated families. There were two criteria for including children in the sample: (1) The child’s first language was English, and (2) the child was willing to participate (a ninth boy was dropped from the sample because he refused to continue after one task). Comprehension
Task
Comprehension procedure. This task (a replication of the Clark procedure) assessed the child’s comprehension of sentences specifying temporal relations between events through his ability to act out the sentences with toys. After a warm-up period which included a production task, E introduced the Comprehension task by saying: Now we’re going to switch. I’ll say something puppets and make them do what I say.
and you use the dolls like
The first eight sentences of the Comprehension task were then administered. Comprehension sentences. To generate the sentences for the Comprehension task, four event pairs were used: (1) (2) (3) (4)
girl boy girl boy
bounce ball ; girl eat cookie ring bell ; boy drop balloon throw stick; girl pat dog climb fence; boy jump puddle.
In each event pair, one event was arbitrarily designated Sl, the other S2. Sixteen sentences were then generated from the event pairs, four in each of the following constructions: (1) (2) (3) (4)
Before S2, Sl; Sl before S2; After Sl, S2; S2 after Sl.
For each child, a randomized order of the 16 sentences was prepared, under the constraints that no event pair could be repeated until every other pair had occurred, and that no sentence construction could be repeated until every other construction had occurred. The sentences were then split into two eight-item sets for each child. Comprehension materials. The materials used in the Comprehension task were two rag dolls (one boy and one girl), a balloon, jingle bells (attached to the boy doll’s hand), a cookie (made of paper), a small rubber ball, a plastic dog, a toothpick, a small wooden boy, a plastic fence, and a puddle of water (made of aluminum foil).
92
HELEN
Picture-Command
L.
JOHNSON
Task
Picture-Command procedure. This task served two purposes in the study. First, because it was informal and greatly enjoyed by the children, it served as a break between the more formal test procedures. Second, it assessed children’s comprehension of sentences specifying temporal relations between events through the children’s responses to commands. Following the eighth Comprehension item, E introduced the PictureCommand task by saying: Now we’re going to make a picture on this paper with these things; here’s a roof, this will be the house, a tree, some stars, a car, crayons, scissors, and paste. Listen carefully and I’ll tell you just how to do it..
The E then went through the eight items, and allowed children to make additions to the picture (some children spent an extra 15 min on this portion). Each child was told that he could take his picture home at the conclusion of the testing session. Picture-Command sentences. Unlike the Amidon-Carey procedure replicated in the Command task, the sentences in the Picture-Command task were constructed to match as closely as possible the complexity of the sentences in the Comprehension task. Every sentence included two different verbs (e.g., cut, paste, draw). For example, Before
you
paste
the
car
on,
draw
the
road.
There were eight items on the task, two in each of the four sentence constructions used to generate the sentences for the Comprehension task. Each sentence construction occurred once before any construction was repeated. Picture-Command materials. For the Picture-Command task, each child made his picture on an 8 X 11 in. piece of construction paper. The task also involved scissors, paste, crayons, embossed stars, and cutouts of a tree, a car, a roof, and a house.
Comm,and Task Com,mand procedure, This task replicated the Amidon-Carey procedure, in which children’s understanding of temporal information was evaluated in terms of responses to sentences containing two commands. At the conclusion of the Picture-Command task, E began the Command task by saying: tell
Now we’re you when
going to have to move each
The eight Command
a race with these cars. Listen carefully car. Then we’ll see which one wins.
items were then administered.
Following
and
I’ll
this, the
MEANING
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BEFORE
AND
AFTER
93
second set of Comprehension items was given to conclude the testing session. Command sentences. In contrast to the Picture-Command sentences, the sentences in the Command task included only one verb, move, which occurred in both clauses of each sentence. For example, After you move the pink car, move the green car.
The four sentence constructions used in the sentence lists for the other two tasks were also used here, with two sentences in each of the constructions. Unlike the Picture-Command task where sentence construction affected the order in which different actions were to be performed, however, on the Command task, sentence construction affected the order in which different toys (different colored cars) were to be moved. A randomized order of the eight Command items was prepared for each child, under the constraint that no sentence construction was repeated until every other construction had occurred. There was one child who had not mastered all the colors, and for him, the procedure was modified to use only the two colors he knew well. Command materials. For the Command task, four small toy cars (red, blue, pink, and green) were used. Testing Session Each child participated in three tasks: Comprehension, Command, and Picture-Command. The tasks were administered in sets of eight items, and the testing format was the same for all children. Each session began with a production task in which spontaneous descriptions of two action sequences were elicited. For each child, the 16 Comprehension items were split into two sets ; the first one was given immediately after the production procedure. The eight Picture-Command items were given after the first set of Comprehension items. Because the Picture-Command task was much more informal than the other task procedures, it served as a break for the children. The eight Command items followed the Picture-Command task. The session concluded with the second set of Comprehension items (this format allowed maximum space between the two sets of Comprehension items). The E reinforced all responses by smiling and saying ‘(good” or “fine.” The entire session lasted between 25 and 45 min, depending on the child’s response to the PictureCommand task. All answers were recorded on answer sheets, and the entire session was tape-recorded. RESULTS
The mean score on the Comprehension task (16 items) was 10.11, on the Picture-Command task (8 items), 3.61, and on the Command task
94
HELEN
L.
JOHNSON
TABLE PE:RCKNTAGE
OF CORRECT
RESPONSES
1
BY Tase
AND
SENTENCE:
CONSTRUCTION
Tasks
Sentence
types
Bejore Sd, Sl Sl before SZ After Si, S8 Sd aftw Sl Total
Comprehension
50
PictureCommand
Command
. 79 73 41
19 37 39 22
50 67 53 37
62
45
51
(8 items), 4.11. Responses to the three tasks were examined in terms of how response accuracy was affected by task and by sentence construction. The percentage of correct responses to each sentence construction on each task are reported in Table 1. A repeated measures analysis of variance of Subjects X Task (3) X Sentence Construction (4) indicated that the effects of task (F(2,34) = 13.56, p < .OOl) and of sentence construction (F(351) = 7.01, p < 901) were both significant. A Newman-Keuls test for comparison of means indicated that performance on the Comprehension task was significantly better than on the Command task (obtained difference between means (34) = 36.11, p < .05), and that performance on both of these tasks was significantly better than on the Picture-Command task (for the Comprehension task, obtained difference (34) = 133.34, p < .05; for the Command task, obtained difference (34) = 77.23, p < .05). A Newman-Keuls test on the sentence construction effect revealed that performance with the S1 before S2 form was significantly better than with the After Sl, S2 form (obtained difference (51) = 23.61, p < .05), and also that performance on both of these forms (these are the two in which order of mention and order of occurrence correspond) was significantly superior to performance with the Before 81, Sg and SS after Sl forms (for Sl before SZ, obtained difference (51) = 63.89, 73.61, respectively, p < .05; for After SI, ~‘32, obtained difference (51) = 40.28, 50.0, respectively, p < 95). There was no significant difference between performance on these last two forms (in which order of mention and order of occurrence do not correspond). Four types of errors were possible on every item of the Comprehension, Picture-Command, and Command tasks: (I) The child could act out both events, but in the wrong order (reversal) ; (2) the child could act out only one of the two events described (omission) ; (3) the child could act out both events simultaneously (unordered) ; or (4) the child could manipulate the objects without acting out either of the events described
Omission 5 1 3 6 15
Reversal
30 14 16 35
94
Sentence type
Before ~‘31, Sl Sl before ~5% After Sl, 52 52 after SI
Total
Comprehension
BREAKDOWN
0
0 0 0 0
Other
OF ERROR
2
10
11 43
9 12
1 3
19
12
4
Command
Tasks
SENTENCE
Omission
BY
TABLE
Reversal
TYPES
8
2
2 2
2
Other
CONSTRUCTION
AND
5
3
1 0
1
Reversal
TASK
92
0
0
0 0 24
0 19 21
0 ther 28
Omission
Picture-Command
$ e E3
2
8 3 si
%
96
HELEN
L.
JOHNSON
(irrelevant response). None of the children made irrelevant responses. One girl, however, gave unordered responses to all the Command items; both E and a hidden 0 were unable to detect any time interval between her performance of the two actions. The breakdown of types of errors by sentence construction and task is presented in Table 2. Two separate repeated measures analyses of variance were run, one for reversals and one for omissions. Each analysis examined the effects of task and sentence construction. In the analysis of reversals, the effects of task and of sentence construction were both significant (for task, F(2,34) =67.31, p < .OOl; for sentence construction, F(2,51) = 9.86, p < 901). Reversal responses were significantly higher on the Comprehension task than on either the Command or the Picture-Command tasks (obtained differenc’e (34) = 18.75, 22.5, respectively, p < .05). Reversal responses also were significantly higher on the two sentence constructions, S2 after Sl and Before S2, 81, in which order of mention and order of occurrence do not correspond, than on the two sentence constructions, After Sl, S2 and Sl before S2, in which order of mention and order of occurrence do correspond (for SZ after S1, obtained difference (51) = 10.0, 10.67, respectively, p < .05; for Before S2, S1, obtained difference (51) = 5.67, 6.34, respectively, p < .05). The interaction of task and sentence construction was not significant. In the analysis of omission responses, the effect of task was significant (F(2,34) = 16.28, p < .OOl). Omission responses were significantly higher on the Picture-Command task than on the Command task (obtained difference (34) = 12.25, p < .05), and on both of these tasks omission scores were greater than on the Comprehension task (obtained difference (34) = 20.25, 7.0, respectively, p < .05). Thus, on the Comprehension task, children had their highest reversal scores and their lowest omission scores; while on the Picture-Command task, children had their lowest reversal scores and their highest omission scores. DISCUSSION
When the data from the three tasks dealing with sentence comprehension were examined, several interesting task effects were evident. Response accuracy on the Picture-Command task was significantly lower than on the other two tasks, with low scores due primarily to omissions. This may indicate that changing two-command sequences to include two different verbs (the difference between the Command and Picture-Command sentences) greatly increases the difficulty of the task. However, some children became much more involved in making their pictures than others; as mentioned previously, some spent 15 min longer than others on this task. Thus, children who took a great deal of time in “drawing
MEANING
OF
BEFORE
AND
AFTER
97
the grass,” for example, might omit “pasting the house on” because during their involvement in the drawing, they forgot about pasting, although they had initially understood the sequence. The Command task procedure, in which two simple actions were instructed, therefore allows a more direct demonstration of the child’s grasp of sequential instructions. Even on the Command task (Amidon-Carey procedure), however, performance was significantly inferior to performance on the Comprehension task (Clark procedure). This suggests that the two tasks are not comparable measures of comprehension of temporal order information. Indeed, when the types of errors made on the tasks are examined, the difference in task features is striking. For on the Comprehension task (16 items), reversals exceeded omissions 94 to 15 (reversals accounted for 86% of all errors) ; while on the Command task (8 items), omissions exceeded reversals 43 to 19 (omissions accounted for 61% of all errors). A reversal response indicates that the child has extracted the notion of a two-event sequence from the sentence, but is unable to correctly identify the order between the events specified by the temporal marker. This type of response supports Clark’s contention that relational terms are learned feature by f,eature. For the child has grasped the features +Time and -Simultaneous for before and after, but is unable to correctly specify + Prior. The reversal response therefore reflects greater understanding of before and after than the omission response, in which a sequential ordering of events is absent. The child’s production of only one of the two events described suggests that he has failed to extract the notion of a twoevent sequence. As on the Amidon-Carey pretest, errors on the Command and Picture-Command tasks were primarily omissions of the instruction in the subordinate clause. This preponderance of subordinate clause omissions led Amidon and Carey to propose that children use a main-clause-subordinate-clause strategy in interpreting temporal order information. However, the results of the present study do not support this conclusion. For the same children who made reversal errors on the Comprehension task (Clark procedure) made omission errors on the Command task (Amidon-Carey procedure). There is, then, some qualitative difference between the tasks which resulted in different error patterns. The problem is to isolate the procedural feature which interfered with children’s performance of two-action sequences on the Command task, but not on the Comprehension task. Upon closer examination, the sentences used in the two tasks offer an explanation. In the Comprehension task, the instruction to act out both
98
HELEN
L.
JOHNSON
actions was given before presentation of the sentences, and therefore applied to both the main and subordinate clause actions with equal directness. In the Command task, however, the instruction to perform each action was carried within the sentences themselves. But in each Command sentence, only one of the actions actually appeared in a direct, command form. Thus, with the example below, Eat
your
cheese
before
you
drink
your
juice,
the child may very well be expected to wait for a second instruction, e.g., “Now you may drink your juice.” In other words, in complex sentences with before and after, only the main clause action is directly instructed. Omissions on the Command task, then, may mean not that the child has failed to extract a two-action sequence, but simply that he is responding only to direct commands. This interpretation of omission responses on the Command procedure is supported by the effects of training on errors made by the AmidonCarey Ss. On the pretest, errors were mainly omissions, suggesting that the children had failed to recognize that each sentence actually specified a sequential ordering of two instructions. If, however, the child had understood the temporal sequence expressed in the sentence, but did not interpret the subordinate clause as expressing a direct command, then feedback would significantly reduce omission errors on the posttest, which is what happened. On the posttest, children whose training had included feedback made primarily reversal errors. Thus, once the AmidonCarey Ss mastered the procedural features of the task (the ambiguity of the language of the subordinate clause command), they demonstrated the confusion about proper ordering which Clark had found. The reversal response is in keeping with Clark’s description of the child’s acquisition of relational terms. For the reversal demonstrates awareness that before and after express sequential time relations, but confusion about identifying the positive and the negative members of the pair. The data from the present study also demonstrate that children rely on order of mention in assigning sequential position to events described in language. On all three tasks, performance was superior with the sentence constructions in which order of mention and order of occurrence correspond. Again, this agrees with Clark’s account of temporal order information processing. Clark suggested that the order-of-mention strategy dropped out as the children mastered the specific semantic features of before and after. The present data, however, indicate that correspondence between order of mention and order of occurrence continues to have a facilitating effect on sentence comprehension even after the child has acquired some of the
MEANING
OF
BEFORE
AND
99
AFTER
more refined features of the terms. A similar facilitating effect from order-of-mention-order-of-occurrence correspondence was evident in data collected on the comprehension of causal statements in children in Grades 1, 3, and 5 (Epstein, 1972). But in both cases, order of mention may have served more as a clue to sentence meaning than as a processing strategy per se (Fodor and Garrett (1967) have given comparable treatment to relative pronouns as clues about underlying sentence structure). Feider (1970) has pointed out that children’s systematic errors or error types offer some of the most direct information about children’s linguistic compet.ence, or grammar. On the tasks in the present study, the error patterns provided insight into children’s processing of two-action sequences and into how specific task features affect children’s performance. On the three tasks, the dramatic shift in error patterns revealed that the language of test items was interfering with children’s demonstration of their understanding of temporal order information. Finally, in the present study, order of mention emerged as more important than coordinate-subordinate relations in describing children’s strategy for processing temporal order information. However, the possibility of a main-subordinate sentence strategy should be explored further in sentences where main-subordinate constructions are not confounded with other sentence features. For as the data on children’s sentence interpretation strategies increases, it is becoming increasingly evident that children may use a variety of strategies to interpret relational sentence content such as time and causality. REFERENCES AMIWN, A., & CAREY, P. Why five-year-olds Journal of Verbal Learning and Verbal BLOOM, L. Form and junction in emerging
cannot Behavior, grammars.
understand 1972, 11, Cambridge,
before
and
after.
417-423. MA:
MIT
Press,
1970. CLARK, E. How young children describe events in time. In D’Arcais & Levelt (Eds.), Advances in psycholinguistics. New York: American Elsevier, 1970. CLARK, E. On the acquisition of the meaning of before and after. Journal of Verbal Learning and Verbal Behavior, 1971, 10, 266275. CLARK, H. H., & CLARK, E. V. Semantic distinctions and memory for complex sentences. Quarterly Journal of Experimental Psychology, lQ68,20, 229-238. EPSTEIN, H. Children’s understanding of causal connectives. Unpublished doctoral dissertation, The University of Wisconsin, 1972. FEIDER, H. The grammar of asymmetric relations in child language and cognition. Glossa, 1970, 4, 197-205. FODOR, J., & GARRETT, M. Some syntactic determinants of sentential complexity. Perception and Psychophysics, 1967, 2, 289-296. SMITH, K., & MCMAHON, L. Understanding order information in sentences. In D’Arcais & Levelt (Eds.), Advances in psychoZinguistics. New York: American Elsevier, 1970.
OF
EXPERIMENTAL
The Meaning
CHILD
PSYCHOLOCiY
of Before HELEN The
University
and
After
19, 88-99
(1975)
for Preschool
Children
L. JOHNSON~,* of Iowa at Iowa City
Preschool children’s understanding of temporal relationships was examined in terms of their comprehension of sentences containing clauses linked by before and after. The relative importance of order of mention and mainsubordinate relations strategies in children’s interpretation of temporal order information was also evaluated. Divergent error patterns emerged on the tasks; omissions prevailed on the two tasks involving response to commands, reversals prevailed on the other. Further examination revealed that omissions reflected ambiguity in the linguistic structure of commands. Thus the effect of main-subordinate relations was confounded with directness of command. On all comprehension tasks, however, performance was superior on sentence forms in which order of mention and order of occurrence correspond.
The present study is concerned with preschool children’s ability to comprehend sentences expressing temporal relations between events. The study proceeds on the assumption that when a child uses a relational term (e.g., because, so, before, after, more, less), he does not necessarily intend the same meaning as the adult speaker does. The key to understanding the child’s interpretation of conceptual relations therefore lies in discovering the meaning he intends when he uses relational terms. By the same token, as Bloom (1970) has shown, the linguistic structures found in child speech cannot be fully understood apart from the functions they serve for the child. Recent studies (Clark, 1970, 1971; Amidon & Carey, 1972) have examined the role of different sentence features in children’s processing of temporal order information. In all of the studies discussed below, four basic sentence constructions were used:
II am extremely grateful to Dr. Robin S. Chapman for her comments and suggestions during the planning of the study. I am also indebted to Dr. Patrick B. Johnson for his help in the preparation of the manuscript. ‘Requests for reprints should be sent to Helen L. Johnson, Social Science Department, Kirkwood Community College, Cedar Rapids, IA 52496. This research was conducted while author was on a postdoctoral fellowship at the Department of Speech Pathology and Audiology, The University of Iowa. 88
Copyright @ 1975 by Academic Press, Inc. All rights of reproduction in any form reserved.
MEANING
(1) (2) (3) (4)
OF
BEFORE
AND
AFTER
89
Before 52, Sl; Sl before 52; After Sl, 52; 52 after Sl.
Note that in (2) and (3), the order in which events are described in the sentence (order of mention) and the order in which they occurred in the world (order of occurrence) correspond, while in (1) and (4)) they do not. When Clark and Clark (1968) used a recall task to study college students’ processing of temporal order information, the results indicated that sentences in which order of mention (the order in which events were mentioned in the sentence) corresponded to order of occurrence (the order in which the events occurred in the world) were easier to process than sentences where it did not. Using a questioning procedure (“What happened first/second?“) with college students, however, Smith and McMahon (1970) found no facilitating effect from correspondence between order of mention and order of occurrence. Instead, the data showed that information in the main clause was more accessible than information in the subordinate clause, and that whatever was asserted to have happened first was more accessible than whatever was asserted to have happened second. The importance of order-of-mention-order-of-occurrence correspondence in young children’s acquisition of temporal descriptions has been studied by Clark (1970, 1971). Analyzing preschoolers’ spontaneous speech samples, she found a preference for describing events in the order in which they actually occurred. In children’s comprehension of the temporal terms before and after (used in the sentence constructions discussed previously), Clark found three stages. At first, children did not understand before or after, and relied on order of mention. Children in the second stage understood before but not after. They either continued to interpret after-sentences in terms of order of mention, or treated after as though it meant before. In the third stage, children understood both before and after. Clark proposed two principles underlying comprehension responses. First, correspondence between order of mention and order of occurrence makes sentences easier to understand. Second, relational terms are learned gradually, one semantic feature at a time, beginning with the most general; before is therefore mastered earlier than after because it is the positive member of the pair. In contrast, Amidon and Carey (1972) hypothesized that children’s failure to demonstrate comprehension of temporal order might actually be due to difficulty with characteristics of the comprehension task. Ac-
90
HELEN
L.
JOHNSON
cordingly, they compared the effects of five training conditions on kindergarteners’ responses to two-action commands. All children were pretested with a set of commands in the temporal sentence constructions discussed previously; for all commands, the instruction was to limove the red/blue, etc., plane;” the posttest involved a new set of materials and instructions about putting them into a box. The results indicated significant improvement in the performance of children whose training had included feedback, and posttest errors for these groups were mainly reversals of clause order. The posttest errors of children whose training did not include feedback were primarily omissions, especially of the subordinate clause. Also, performance with first and last (coordinate clause construction) was better than with before and after (subordinate clause construction). Amidon and Carey therefore interpret their results as strong support for the effect of subordinate versus coordinate sentence constructions. The data indicate, they feel, that children focus on the main clause in interpreting temporal information, rather than on order of mention, as Clark had proposed. It should be noted that the sentences used by Amidon and Carey were not comparable in complexity to those used by Clark on her comprehension task. Each of the Clark sentences described two different actions performed by a third-person agent. In contrast, the Amidon-Carey sent’ences instructed the child (second-person agent) to perform two identical actions in sequence. Thus, the discrepancies between the findings of Clark and of Amidon and Carey may, in part, be a reflection of the differences in the structure of the sentences studied, and in the nature of the tasks used. The present study at.tempted to clarify the contradictions between the Clark and Amidon-Carey data on the relative importance of order of mention and main-subordinate clause strategies in young children’s processing of temporal order information. All Ss were given both the Clark and the Amidon-Carey tasks, so that the extent to which differences in response strategies reflect specific task features could be assessed. In addition, a command procedure, in which each sentence instructed two different actions and was therefore more comparable in complexity to the Clark items, was administered. METHOD
Subjects The Ss were ten girls and eight boys attending the University Preschool, Iowa City, Iowa. The children ranged in age from 4.2-5.2 years, with a mean age of 4.8 years. All children tested were native speakers
MEANING
OF
BEFORE
AND
AFTER
91
of English and came from highly educated families. There were two criteria for including children in the sample: (1) The child’s first language was English, and (2) the child was willing to participate (a ninth boy was dropped from the sample because he refused to continue after one task). Comprehension
Task
Comprehension procedure. This task (a replication of the Clark procedure) assessed the child’s comprehension of sentences specifying temporal relations between events through his ability to act out the sentences with toys. After a warm-up period which included a production task, E introduced the Comprehension task by saying: Now we’re going to switch. I’ll say something puppets and make them do what I say.
and you use the dolls like
The first eight sentences of the Comprehension task were then administered. Comprehension sentences. To generate the sentences for the Comprehension task, four event pairs were used: (1) (2) (3) (4)
girl boy girl boy
bounce ball ; girl eat cookie ring bell ; boy drop balloon throw stick; girl pat dog climb fence; boy jump puddle.
In each event pair, one event was arbitrarily designated Sl, the other S2. Sixteen sentences were then generated from the event pairs, four in each of the following constructions: (1) (2) (3) (4)
Before S2, Sl; Sl before S2; After Sl, S2; S2 after Sl.
For each child, a randomized order of the 16 sentences was prepared, under the constraints that no event pair could be repeated until every other pair had occurred, and that no sentence construction could be repeated until every other construction had occurred. The sentences were then split into two eight-item sets for each child. Comprehension materials. The materials used in the Comprehension task were two rag dolls (one boy and one girl), a balloon, jingle bells (attached to the boy doll’s hand), a cookie (made of paper), a small rubber ball, a plastic dog, a toothpick, a small wooden boy, a plastic fence, and a puddle of water (made of aluminum foil).
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Picture-Command
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Task
Picture-Command procedure. This task served two purposes in the study. First, because it was informal and greatly enjoyed by the children, it served as a break between the more formal test procedures. Second, it assessed children’s comprehension of sentences specifying temporal relations between events through the children’s responses to commands. Following the eighth Comprehension item, E introduced the PictureCommand task by saying: Now we’re going to make a picture on this paper with these things; here’s a roof, this will be the house, a tree, some stars, a car, crayons, scissors, and paste. Listen carefully and I’ll tell you just how to do it..
The E then went through the eight items, and allowed children to make additions to the picture (some children spent an extra 15 min on this portion). Each child was told that he could take his picture home at the conclusion of the testing session. Picture-Command sentences. Unlike the Amidon-Carey procedure replicated in the Command task, the sentences in the Picture-Command task were constructed to match as closely as possible the complexity of the sentences in the Comprehension task. Every sentence included two different verbs (e.g., cut, paste, draw). For example, Before
you
paste
the
car
on,
draw
the
road.
There were eight items on the task, two in each of the four sentence constructions used to generate the sentences for the Comprehension task. Each sentence construction occurred once before any construction was repeated. Picture-Command materials. For the Picture-Command task, each child made his picture on an 8 X 11 in. piece of construction paper. The task also involved scissors, paste, crayons, embossed stars, and cutouts of a tree, a car, a roof, and a house.
Comm,and Task Com,mand procedure, This task replicated the Amidon-Carey procedure, in which children’s understanding of temporal information was evaluated in terms of responses to sentences containing two commands. At the conclusion of the Picture-Command task, E began the Command task by saying: tell
Now we’re you when
going to have to move each
The eight Command
a race with these cars. Listen carefully car. Then we’ll see which one wins.
items were then administered.
Following
and
I’ll
this, the
MEANING
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BEFORE
AND
AFTER
93
second set of Comprehension items was given to conclude the testing session. Command sentences. In contrast to the Picture-Command sentences, the sentences in the Command task included only one verb, move, which occurred in both clauses of each sentence. For example, After you move the pink car, move the green car.
The four sentence constructions used in the sentence lists for the other two tasks were also used here, with two sentences in each of the constructions. Unlike the Picture-Command task where sentence construction affected the order in which different actions were to be performed, however, on the Command task, sentence construction affected the order in which different toys (different colored cars) were to be moved. A randomized order of the eight Command items was prepared for each child, under the constraint that no sentence construction was repeated until every other construction had occurred. There was one child who had not mastered all the colors, and for him, the procedure was modified to use only the two colors he knew well. Command materials. For the Command task, four small toy cars (red, blue, pink, and green) were used. Testing Session Each child participated in three tasks: Comprehension, Command, and Picture-Command. The tasks were administered in sets of eight items, and the testing format was the same for all children. Each session began with a production task in which spontaneous descriptions of two action sequences were elicited. For each child, the 16 Comprehension items were split into two sets ; the first one was given immediately after the production procedure. The eight Picture-Command items were given after the first set of Comprehension items. Because the Picture-Command task was much more informal than the other task procedures, it served as a break for the children. The eight Command items followed the Picture-Command task. The session concluded with the second set of Comprehension items (this format allowed maximum space between the two sets of Comprehension items). The E reinforced all responses by smiling and saying ‘(good” or “fine.” The entire session lasted between 25 and 45 min, depending on the child’s response to the PictureCommand task. All answers were recorded on answer sheets, and the entire session was tape-recorded. RESULTS
The mean score on the Comprehension task (16 items) was 10.11, on the Picture-Command task (8 items), 3.61, and on the Command task
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TABLE PE:RCKNTAGE
OF CORRECT
RESPONSES
1
BY Tase
AND
SENTENCE:
CONSTRUCTION
Tasks
Sentence
types
Bejore Sd, Sl Sl before SZ After Si, S8 Sd aftw Sl Total
Comprehension
50
PictureCommand
Command
. 79 73 41
19 37 39 22
50 67 53 37
62
45
51
(8 items), 4.11. Responses to the three tasks were examined in terms of how response accuracy was affected by task and by sentence construction. The percentage of correct responses to each sentence construction on each task are reported in Table 1. A repeated measures analysis of variance of Subjects X Task (3) X Sentence Construction (4) indicated that the effects of task (F(2,34) = 13.56, p < .OOl) and of sentence construction (F(351) = 7.01, p < 901) were both significant. A Newman-Keuls test for comparison of means indicated that performance on the Comprehension task was significantly better than on the Command task (obtained difference between means (34) = 36.11, p < .05), and that performance on both of these tasks was significantly better than on the Picture-Command task (for the Comprehension task, obtained difference (34) = 133.34, p < .05; for the Command task, obtained difference (34) = 77.23, p < .05). A Newman-Keuls test on the sentence construction effect revealed that performance with the S1 before S2 form was significantly better than with the After Sl, S2 form (obtained difference (51) = 23.61, p < .05), and also that performance on both of these forms (these are the two in which order of mention and order of occurrence correspond) was significantly superior to performance with the Before 81, Sg and SS after Sl forms (for Sl before SZ, obtained difference (51) = 63.89, 73.61, respectively, p < .05; for After SI, ~‘32, obtained difference (51) = 40.28, 50.0, respectively, p < 95). There was no significant difference between performance on these last two forms (in which order of mention and order of occurrence do not correspond). Four types of errors were possible on every item of the Comprehension, Picture-Command, and Command tasks: (I) The child could act out both events, but in the wrong order (reversal) ; (2) the child could act out only one of the two events described (omission) ; (3) the child could act out both events simultaneously (unordered) ; or (4) the child could manipulate the objects without acting out either of the events described
Omission 5 1 3 6 15
Reversal
30 14 16 35
94
Sentence type
Before ~‘31, Sl Sl before ~5% After Sl, 52 52 after SI
Total
Comprehension
BREAKDOWN
0
0 0 0 0
Other
OF ERROR
2
10
11 43
9 12
1 3
19
12
4
Command
Tasks
SENTENCE
Omission
BY
TABLE
Reversal
TYPES
8
2
2 2
2
Other
CONSTRUCTION
AND
5
3
1 0
1
Reversal
TASK
92
0
0
0 0 24
0 19 21
0 ther 28
Omission
Picture-Command
$ e E3
2
8 3 si
%
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HELEN
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(irrelevant response). None of the children made irrelevant responses. One girl, however, gave unordered responses to all the Command items; both E and a hidden 0 were unable to detect any time interval between her performance of the two actions. The breakdown of types of errors by sentence construction and task is presented in Table 2. Two separate repeated measures analyses of variance were run, one for reversals and one for omissions. Each analysis examined the effects of task and sentence construction. In the analysis of reversals, the effects of task and of sentence construction were both significant (for task, F(2,34) =67.31, p < .OOl; for sentence construction, F(2,51) = 9.86, p < 901). Reversal responses were significantly higher on the Comprehension task than on either the Command or the Picture-Command tasks (obtained differenc’e (34) = 18.75, 22.5, respectively, p < .05). Reversal responses also were significantly higher on the two sentence constructions, S2 after Sl and Before S2, 81, in which order of mention and order of occurrence do not correspond, than on the two sentence constructions, After Sl, S2 and Sl before S2, in which order of mention and order of occurrence do correspond (for SZ after S1, obtained difference (51) = 10.0, 10.67, respectively, p < .05; for Before S2, S1, obtained difference (51) = 5.67, 6.34, respectively, p < .05). The interaction of task and sentence construction was not significant. In the analysis of omission responses, the effect of task was significant (F(2,34) = 16.28, p < .OOl). Omission responses were significantly higher on the Picture-Command task than on the Command task (obtained difference (34) = 12.25, p < .05), and on both of these tasks omission scores were greater than on the Comprehension task (obtained difference (34) = 20.25, 7.0, respectively, p < .05). Thus, on the Comprehension task, children had their highest reversal scores and their lowest omission scores; while on the Picture-Command task, children had their lowest reversal scores and their highest omission scores. DISCUSSION
When the data from the three tasks dealing with sentence comprehension were examined, several interesting task effects were evident. Response accuracy on the Picture-Command task was significantly lower than on the other two tasks, with low scores due primarily to omissions. This may indicate that changing two-command sequences to include two different verbs (the difference between the Command and Picture-Command sentences) greatly increases the difficulty of the task. However, some children became much more involved in making their pictures than others; as mentioned previously, some spent 15 min longer than others on this task. Thus, children who took a great deal of time in “drawing
MEANING
OF
BEFORE
AND
AFTER
97
the grass,” for example, might omit “pasting the house on” because during their involvement in the drawing, they forgot about pasting, although they had initially understood the sequence. The Command task procedure, in which two simple actions were instructed, therefore allows a more direct demonstration of the child’s grasp of sequential instructions. Even on the Command task (Amidon-Carey procedure), however, performance was significantly inferior to performance on the Comprehension task (Clark procedure). This suggests that the two tasks are not comparable measures of comprehension of temporal order information. Indeed, when the types of errors made on the tasks are examined, the difference in task features is striking. For on the Comprehension task (16 items), reversals exceeded omissions 94 to 15 (reversals accounted for 86% of all errors) ; while on the Command task (8 items), omissions exceeded reversals 43 to 19 (omissions accounted for 61% of all errors). A reversal response indicates that the child has extracted the notion of a two-event sequence from the sentence, but is unable to correctly identify the order between the events specified by the temporal marker. This type of response supports Clark’s contention that relational terms are learned feature by f,eature. For the child has grasped the features +Time and -Simultaneous for before and after, but is unable to correctly specify + Prior. The reversal response therefore reflects greater understanding of before and after than the omission response, in which a sequential ordering of events is absent. The child’s production of only one of the two events described suggests that he has failed to extract the notion of a twoevent sequence. As on the Amidon-Carey pretest, errors on the Command and Picture-Command tasks were primarily omissions of the instruction in the subordinate clause. This preponderance of subordinate clause omissions led Amidon and Carey to propose that children use a main-clause-subordinate-clause strategy in interpreting temporal order information. However, the results of the present study do not support this conclusion. For the same children who made reversal errors on the Comprehension task (Clark procedure) made omission errors on the Command task (Amidon-Carey procedure). There is, then, some qualitative difference between the tasks which resulted in different error patterns. The problem is to isolate the procedural feature which interfered with children’s performance of two-action sequences on the Command task, but not on the Comprehension task. Upon closer examination, the sentences used in the two tasks offer an explanation. In the Comprehension task, the instruction to act out both
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actions was given before presentation of the sentences, and therefore applied to both the main and subordinate clause actions with equal directness. In the Command task, however, the instruction to perform each action was carried within the sentences themselves. But in each Command sentence, only one of the actions actually appeared in a direct, command form. Thus, with the example below, Eat
your
cheese
before
you
drink
your
juice,
the child may very well be expected to wait for a second instruction, e.g., “Now you may drink your juice.” In other words, in complex sentences with before and after, only the main clause action is directly instructed. Omissions on the Command task, then, may mean not that the child has failed to extract a two-action sequence, but simply that he is responding only to direct commands. This interpretation of omission responses on the Command procedure is supported by the effects of training on errors made by the AmidonCarey Ss. On the pretest, errors were mainly omissions, suggesting that the children had failed to recognize that each sentence actually specified a sequential ordering of two instructions. If, however, the child had understood the temporal sequence expressed in the sentence, but did not interpret the subordinate clause as expressing a direct command, then feedback would significantly reduce omission errors on the posttest, which is what happened. On the posttest, children whose training had included feedback made primarily reversal errors. Thus, once the AmidonCarey Ss mastered the procedural features of the task (the ambiguity of the language of the subordinate clause command), they demonstrated the confusion about proper ordering which Clark had found. The reversal response is in keeping with Clark’s description of the child’s acquisition of relational terms. For the reversal demonstrates awareness that before and after express sequential time relations, but confusion about identifying the positive and the negative members of the pair. The data from the present study also demonstrate that children rely on order of mention in assigning sequential position to events described in language. On all three tasks, performance was superior with the sentence constructions in which order of mention and order of occurrence correspond. Again, this agrees with Clark’s account of temporal order information processing. Clark suggested that the order-of-mention strategy dropped out as the children mastered the specific semantic features of before and after. The present data, however, indicate that correspondence between order of mention and order of occurrence continues to have a facilitating effect on sentence comprehension even after the child has acquired some of the
MEANING
OF
BEFORE
AND
99
AFTER
more refined features of the terms. A similar facilitating effect from order-of-mention-order-of-occurrence correspondence was evident in data collected on the comprehension of causal statements in children in Grades 1, 3, and 5 (Epstein, 1972). But in both cases, order of mention may have served more as a clue to sentence meaning than as a processing strategy per se (Fodor and Garrett (1967) have given comparable treatment to relative pronouns as clues about underlying sentence structure). Feider (1970) has pointed out that children’s systematic errors or error types offer some of the most direct information about children’s linguistic compet.ence, or grammar. On the tasks in the present study, the error patterns provided insight into children’s processing of two-action sequences and into how specific task features affect children’s performance. On the three tasks, the dramatic shift in error patterns revealed that the language of test items was interfering with children’s demonstration of their understanding of temporal order information. Finally, in the present study, order of mention emerged as more important than coordinate-subordinate relations in describing children’s strategy for processing temporal order information. However, the possibility of a main-subordinate sentence strategy should be explored further in sentences where main-subordinate constructions are not confounded with other sentence features. For as the data on children’s sentence interpretation strategies increases, it is becoming increasingly evident that children may use a variety of strategies to interpret relational sentence content such as time and causality. REFERENCES AMIWN, A., & CAREY, P. Why five-year-olds Journal of Verbal Learning and Verbal BLOOM, L. Form and junction in emerging
cannot Behavior, grammars.
understand 1972, 11, Cambridge,
before
and
after.
417-423. MA:
MIT
Press,
1970. CLARK, E. How young children describe events in time. In D’Arcais & Levelt (Eds.), Advances in psycholinguistics. New York: American Elsevier, 1970. CLARK, E. On the acquisition of the meaning of before and after. Journal of Verbal Learning and Verbal Behavior, 1971, 10, 266275. CLARK, H. H., & CLARK, E. V. Semantic distinctions and memory for complex sentences. Quarterly Journal of Experimental Psychology, lQ68,20, 229-238. EPSTEIN, H. Children’s understanding of causal connectives. Unpublished doctoral dissertation, The University of Wisconsin, 1972. FEIDER, H. The grammar of asymmetric relations in child language and cognition. Glossa, 1970, 4, 197-205. FODOR, J., & GARRETT, M. Some syntactic determinants of sentential complexity. Perception and Psychophysics, 1967, 2, 289-296. SMITH, K., & MCMAHON, L. Understanding order information in sentences. In D’Arcais & Levelt (Eds.), Advances in psychoZinguistics. New York: American Elsevier, 1970.
