Inferential functioning in visually impaired children

Research in Developmental Disabilities 28 (2007) 249–265

Inferential functioning in visually impaired children Rebeca Puche-Navarro a,*, Rafael Milla´n b a

Centro de Investigaciones en Psicologı´a, Cognicio´n y Cultura, Instituto de Psicologı´a, Universidad del Valle, Ciudad Universitaria Mele´ndez, Edif. 385, 4to. Piso. A. A. 25360, Cali-Colombia, South America b Faculte´ de Psychologie et des Sciences de l’Education, Universite´ de Gene`ve, Switzerland Received 13 September 2005; received in revised form 12 November 2005; accepted 17 January 2006

Abstract The current study explores the inferential abilities of visually impaired children in a task presented in two formats, manipulative and verbal. The results showed that in the group of visually impaired children, just as with children with normal sight, there was a wide range of inference types. It was found that the visually impaired children perform slightly better in the use of inductive and relational inferences in the verbal format, while in the manipulative format children with normal sight perform better. These results suggest that in inferential functioning of young children, and especially visually impaired children, the format of the task influences performance more than the child’s visual ability. # 2006 Elsevier Ltd. All rights reserved. Keywords: Inductive inference; Relational inference; Visually impaired; Problem solving

1. Introduction Conceptual focus and theoretical assumptions in the study of the child determine the resulting types of intervention and practical applications. This has been a historical precedent in deriving educational implications from the results of research on the cognitive development of children with normal vision, although it has had more lasting consequences with respect to the cognitive development of visually impaired children. Despite the fact that since the 1960s there has been a re-evaluation of the adult-centered model that implicitly evaluated the performance of the child in several domains of knowledge in terms of what adults consider correct and normal, in the case of cognitive functioning models for visually impaired children, re-evaluation has been less rigorous.

* Corresponding author. E-mail address: [email protected] (R. Puche-Navarro). 0891-4222/$ – see front matter # 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.ridd.2006.01.003

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In fact, data on cognitive development of the visually impaired child reveal an inequality of perspective. This situation has occurred in part because many studies with visually impaired children have focused on typical performance for children with normal sight and, as a result of using these parameters, the functioning of the visually impaired child is frequently considered to be poor, deficient or systematically backward. Some authors (Pe´rez & Conti-Ramsden, 1999) agree that comparisons of visually impaired children with visually normal children in studies have frequently lead to the adoption of a model of visual deterioration as a deficit, as stated by Webster and Roe (1998). There is a similar problem with respect to methodological focus; it is important to consider the role played by the types of cognitive tasks used, as these are almost always designed according to the way visually normal children would respond to them. Also, it is important to highlight the restrictions imposed by the comparatively small size of the visually impaired population, which usually obliges researchers to rely on small captive samples with subjects differentiated by age and nosological characteristics, which are not always comparable. Other authors (Ochaı´ta & Espinoza, 1995) point out that the heterogeneity and variability in the development of visually impaired children implies difficulties for researchers. In the past three decades, differences in conceptual framework, as well as several methodological devices have figured in the literature on cognitive development of visually impaired children. Some studies (Fraiberg, 1977; Tobin, 1972) take comparative approaches, with a strong emphasis on an external model and use tasks created for subjects with normal vision for testing visually impaired individuals, putting them at an obvious disadvantage. Some of the more frequently cited studies are based on classical models of development by stages, and describe visually impaired subjects’ comprehension of substance invariants weight and volume (Brekke, Williams, & Tait, 1974; Gottesman, 1971, 1973), or development of concrete operations and multiplicative classifications (Ochaı´ta, Huertas & Espinoza, 1991; Ochaı´ta, Rosa, Pozo & Ferna´ndez, 1985; Rosa, 1980, 1981). Gottesman (1971) compared the discriminatory capacity of blind children with normal children, repeating a study by Piaget and Inhelder (1948) that consisted in constructing a visual image (the initial study was with normal children), incorporating haptic data on exploratory manipulations. The results showed three stages: in the first (2–4 years of age) visually impaired children are able to recognize familiar objects; in the second stage (4–6 years) the children initially make a rough differentiation of straight and curved lines, although they are not completely able to differentiate these two groups; during the third stage (6–8 years) they are able to distinguish complex forms through a precise and detailed exploration of objects. Although one might conclude that concentrating exclusively on haptic perception makes sense in researching visually impaired individuals, bias is inevitable. Gottesman’s study (1971) made an interesting advance, giving rise to a succession of studies (Brambring & Troster, 1994; Ochaı´ta & Espinoza, 1995; Ochaı´ta & Rosa, 1988) for more than a decade, but it should be pointed out that all of these studies suffer from the typical limitations of comparative studies. They focus on the deficits of visually impaired children, and his results are projected with an external and finalistic perspective in which the frame of reference is the visually normal child, to detriment of the visually impaired child. Another factor that has contributed to emphasizing the deficits of the visually impaired child is the evaluative focus of many of these studies, specifically the evaluation of performance of blind children in objective, standardized tests that are almost always based on parameters for evaluating children with normal vision. Methodologically, the role of ‘‘evaluator’’ involves the use of closed, dichotomous tasks constructed on the assumption that a lack of performance or absence of a behavior leads to the conclusion that such a capacity or ability is absent. Historically,

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in both psychology and education, this approach to determining the subject’s true knowledge has been costly and risky. The evaluator is not concerned with understanding or exploring the subject, but is focused on a restricted examination destined to reach hasty conclusions about the absence of behaviors and capacities. This situation may remain the norm if changes recommended in this study are not taken into consideration. Later we will consider the double effect of ‘‘evaluating’’ visually impaired children using methodological resources from studies of children with normal vision. One of the very examples of the implications of an evaluative focus (for example, excessive emphasis on deficits) in studies of visually impaired children is the use of language as a performance indicator in cognitive tasks. Frequently in studies with visually impaired children the researcher cannot use gestures or demonstrations, as are used with normal children, so the researcher is unable to establish whether the children lack ability or simply do not understand the instructions for the task. It is also possible that emphasis on the deficit is reinforced because language acquisition (as a result of special education) is slower. It is possible, then, that this limitation also makes the instructional level more difficult because language is not sufficiently developed at these ages (2–5 years) for verbal tasks to be used. It is also possible that verbal requirements in older subjects (from 10 to 12 years) assure a fairer comparison between normal children and visually impaired children (Rogers & Puchalsky, 1988). Another example revealed by an analysis of the literature, and one that offers an explanation of deficient conditions of visually impaired children, refers to type of tasks used. This is one of the fundamental criticisms of the approaches used in research on children who have some kind of visual impairment and one of the most important in relation to the purpose of the current study. The design of tasks for visually impaired subjects should consider whether vision contributes little or nothing to the solution of the problem, and most sensitive variables are whether or not the task requires spatial representations. This criterion can be used for selecting pertinent literature on cognitive development of visually impaired individuals. Can vision be replaced or not in cognitive tasks for visually impaired children? Ochaı´ta and Espinoza (1995) point out the importance of plasticity in the psychological system and, consequently, the feasibility of the use of alternatives to the visual system. They state that the nature of the human cognitive system ‘‘constitutes a possibility for developing programs of intervention, especially in early infancy and in the initial stage’’ (p. 155). This conception is very close to, or even derived from, the theory of sensorial compensation, about which much has been written in the last two decades. The theory of sensorial compensation states that the ‘‘absence of one perceptive system intensifies the use of the other systems’’ (Hatwell, Streri, & Gentaz, 2000 135). Among the abilities of a visually impaired individual, the treatment of haptic information stands out as an effective way to understand functioning in specific tasks. Haptic (tactile) information is the modality most commonly used by blind people to access spatial and physical information about their environment. This may be the reason why the results of studies such as those by Gottesman (1971, 1976) created such an impact. This study showed that visually impaired individuals identify many objects presented to them and appear to have slightly superior exploratory abilities compared to children with normal vision. Authors such as Bigelow (1991) even suggest that haptic and tactile exploration and auditory input can help visually impaired individuals to perceive spatial relationships between objects and compensate for the missing visual modality. In a recent study, D’Angiulli, Kennedy, and Morton (1998) give visually impaired children and normal children with the same recognition task, using shapes drawn with protruding outlines. The results show that both groups use similar principles to identify tactile objects, since

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for both normal and visually impaired children; the edges of the surfaces are tangible and recognizable, supporting the theory of tactile images. Although there is not significant difference for children with normal vision, performance of visually impaired children from 2 to 13 years of age stands out. The haptic perception tasks and those that demand recognition of objects were decisive factors that led researchers to consider the need for a compensatory effect in the education of visually impaired children. However, contrary to the idea that became generalized among non specialists, training in haptic abilities, though recommended, does not modify sensorial acuity thresholds. While this skill focuses attention on certain indices and improves exploratory procedures, which are not well organized in these children, it does not have any compensatory effect, as was believed for a long time. As Hatwell (2003) explained, ‘‘the so-called theory of compensation, although very popular, does not stand up to experimental scrutiny’’ (p. 67). However, it was the identification of limitations in traditional approaches that gave rise to some studies in the 80s and 90s that offer a more functional alternative, emphasizing the presence and characteristics of cognitive functioning in the ‘here and now’ of the visually impaired child (Bullinger & Mellier, 1988; Hatwell et al., 2000; Milla´n, 1997a, 1997b, 2001; Pe´rez & ContiRamsden, 1999). Results of these studies bring together the modes of functioning in visually impaired children and, as time goes by, they do not seem to be as definitive concerning the differences between normal and visually impaired children, these differences becoming somewhat unremarkable. 1.1. Cognitive functioning in visually impaired children It is important to review the literature and attempt to establish the most specific characteristics of the functioning of the visually impaired child. As was mentioned above, it is important to start with those aspects that constitute the real abilities of the visually impaired child in order to build up the most accurate possible picture of these abilities. Clearly explaining these functions allows us to better analyze the effects of methodological approach and methodological difficulties when considering the abilities of visually impaired children. Recent evidence and methodological advances are the result of both theoretical and applied research. In the area of theoretical research, there are studies dealing with the cognitive and intellectual development of visually impaired children (Bullinger & Mellier, 1988; Intxaurraga & Rodrigo, 1995; Milla´n, 2001); applied research includes studies concerned with therapeutic work with these children (Gilbert & Foster, 1995; Ochaı´ta & Espinoza, 1995; Rosas, Strasser, & Zamorano, 1995). Another criterion for analysis of literature on cognitive development is the division between longitudinal and cross-sectional research. The importance of longitudinal research is unquestionable; however this importance is inversely proportional to the number of studies found (Perez & Castro, 1996; Rogers & Puchalsky, 1986). The possibility of analyzing the same children during long periods in their development provides researchers with a wide spectrum of performance, leading to a better microgenetic approximation of cognitive activity and in general of the processual aspects of development. More frequent, however, are crosssectional studies (Ferna´ndez, Ochaı´ta, & Rosa, 1988; Huertas, Asensio, & Simo´n, 1988; Landau, Gleitman, & Spelke, 1984; Ochaita, 1984, 1993; Ochaı´ta & Rosa, 1988; Passini & Proulx, 1988; Rosa & Huertas, 1988). The study of spatial organizational skills produces important findings. The literature points to difficulties of the visually impaired child in this area. A variety of studies have shown that development of spatial organization in visually impaired individuals is slow (Ochaı´ta, Rosa,

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Ferna´ndez, & Huertas, 1988; Wheeler & Floyd, 1997). A possible explanation is the lack of early visual stimulation, resulting in visual information being presented in a fragmented manner, making spatial representation difficult for the visually impaired child. Ochaı´ta et al. (1988) insist that the difficulty for visually impaired children when faced with tasks with a spatial component, as opposed to a visual component, favors a process that is much more sequential and slow, because the haptic system provides more restricted information about the environment. An alternative has been proposed by Ungar (2000), whose study demonstrated that young visually impaired children could acquire knowledge about the spatial structure of an area through what he calls tactile maps, and that they use this knowledge to make spatial decisions. A similar process takes place with auditory and verbal tasks, leading many authors (Andersen, Dulnea, & Kekelis, 1984; Intxaurraga & Rodrigo, 1995; Mills, 1983; Mulford, 1988) to conclude that there are no great differences between normal and visually impaired individuals. This similarity is even clearer in the case of the development of language. In the same way, Brambring and Troster (1994), suggest that lack of vision does not negatively affect performance in auditory and verbal tasks. On the other hand, in tasks that require manipulation, impairment of vision does affect the performance of the children, and so this type of task is not considered to be neutral for evaluating visually impaired children. Despite the fact that visually impaired children do not show notable difficulties in recognizing objects, a skill necessary for manipulative tasks, there is a spatial component in some of the tasks, and this causes greater difficulties for visually impaired children, resulting in lower performance. One more aspect that stands out in studies of cognitive functioning in children with normal vision and also in visually impaired children is the use of inferential mechanisms, and this has been the subject of important studies in the area of cognitive development. The earlier, more traditional studies theorize that the first inferences in children with normal vision are based on perceptive similarities (Quine, 1973), and this justifies the strong focus of research in the 80’s on inductive inferences at early ages (Gelman & Coley, 1990; Gelman & Markman, 1986; Gelman & Markman, 1986, 1987; Gelman, Spelke, & Meck, 1983; Gelman & Taylor, 1984; Melkman, Tversky, & Baratz, 1981). In these studies, children had to make inferences about familiar objects, based on their similarities to objects that were new or unknown to them. These studies show the capacity of children from 2 to 4 years of age to identify properties of objects and, based on this analysis, to make inductive inferences. There are similar studies on the ability of babies to recognize the physical properties of objects. Through an experimental paradigm known as violation-of-expectation, the tasks reveal that babies notice when things that should fall do not fall, or that a solid object cannot pass through another object without being modified (Spelke, 1991), or that hidden objects – behind screens – can move even if we cannot see the movement (Spelke, Breinlinger, Macomber, & Jacobson, 1992; Baillargeon, 1992, 1994) and, at between 6 and 18 months, they understand the property of gravity that makes objects fall, and can use this knowledge to solve problems (PucheNavarro, 1996). The conclusion of these studies is that comprehension of the physical violation depends on the inference that the baby makes. An event is considered impossible because the baby has an expectation that allows him or she to infer what should happen according to particular properties of physical objects. The first and most important consequence of this paradigm is the implication that, at a very early stage, the baby possesses a harmonically predesigned mechanism or system for processing information in order to make inferences. Other studies have found that 2-year-old children make correct inferences about the meaning of words, based on information that they obtain from an action related to the form or texture of objects (Kobayashi, 1997), or about the location of objects, instruments for actions and the consequences

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of actions (Schmidt, 1988), and some authors insist that there is not only perceptual inference but conceptual control of inductive generalization, and that this begins very early in infancy (McDonough & Mandler, 1998). One more area that has recently been explored in the literature is inferential functioning in children, based on reading comprehension. One study of second grade children with normal sight (Inman & Dickerson, 1995) uses comprehension of stories and the causal relationship between possible events, and is better suited to the study of inferences. Authors observed whether the children inferred causal relationships, and established that the children remembered more event states when they were asked about them later, rather than during the actual reading of the text. These data reinforce the idea that comprehension is a necessary element for memory and not the other way around. They are also consistent with research on adults, which shows that propositions are remembered better when the strength of causal connection is high than when it is low. In synthesis, studies (Ordon˜ez & Bustamante, 2000) with 3.6 years-old children had shown that inference is a natural mechanism that forms part of the basic mental functioning of children and is fundamental for the acquisition of new knowledge. It is important to point out, however, that these studies acknowledge a type of inductive inference and that tasks used involve spatial information, making them more difficult for visually impaired children. This brings us to the question of inference in visually impaired children. A conclusion that might be drawn from a brief review of the literature on inference in normal children is that the studies of this mechanism depend heavily on the visual information that the child can process, and that the visual information which is the basis for the inference means that this type of cognitive task, designed for children with normal vision, is impossible to replicate with visually impaired children. This limitation has led some authors (Lo´pez & Colon, 1995) to design studies in which the different types of inferences (transitive inference, for example) can be explored through comprehension of discourse, and analysis of the results involves a verbal component. Lo´pez and Colon’s study provides evidence that visually impaired subjects have a significantly increased short-term memory, compared to visually normal subjects, making their performance in verbal tasks more precise. The question raised by this study alludes to the influence of diverse perceptive modalities in deductive reasoning. Based on eighty transitive inference tasks, controlled by WAIS digit items related to operative memory, Lo´pez and Colon conclude that tasks with spatial content present more difficulties for visually impaired subjects. On the other hand, verbal tasks reveal improved performance by visually impaired subjects (who even outperform subjects with normal vision). 1.2. The present study Considering the preponderance of studies that deal with inference from tasks that are neither discursive nor verbal, the current study approaches inferential functioning in visually impaired children through problem solving tasks, using both manipulative and verbal formats. The justification for this is that if alternatives to verbal methodologies have revealed complex inferential functioning in visually normal children, then obtaining a more precise picture of the cognitive functioning of visually impaired children, using tasks that rely on their more developed abilities, will produce a similar result for this group. This should lead to a better understanding of educational processes for these children. Before continuing it is useful to review what we currently know about the cognitive development of the visually impaired child: (a) some authors (Ochaı´ta & Espinoza, 1995) agree

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that development begins slowly and/or late, but by around 10 years of age development is comparable to that in visually normal children. (b) Some of the more common ‘‘deficits’’ of visually impaired children are in fact the result of comparative and evaluative focus of the research and of primacy of visual information over other types in the tasks realized. (c) Spatial development is undoubtedly more difficult and complex for the visually impaired individual, and (d) methodologies based on haptic perceptions or narrative structures are preferable for understanding natural and more sophisticated cognitive repertoire of visually impaired children. The following study would traditionally be classified as theoretical research, but it also contains concrete recommendations, in the tradition of applied research. It is a cross-sectional study of distinct age ranges, taking a perspective of development in stages. It examines the cognitive functioning of visually impaired children, focusing on their abilities instead of their disabilities in performance. Specifically, it deals with the functioning of particular types of inference, such as inductive and relational inference. The aim is ‘‘to identify the difficulties of the child, to understand his or her mode of organization, and to find tasks that are capable of revealing his or her capabilities’’ (Milla´n, 1997a, 1997b, p. 1), by using tasks specially designed for this purpose. 2. Method 2.1. Participants The subjects were 76 children between 4.8 and 10.6 years (42 girls and 34 boys). The children came from different cities in Colombia: Bogota´ (30 children), Cali (28 children), Pereira (10 children) and Ibague´ (6 children). Half of the sample was made up of visually impaired children who study at the National Institute for Deaf and Blind Children in their respective cities, and the other half was made up of children with normal vision. Both groups have variables such as age, socioeconomic level and schooling. All of the participants belong primarily to socioeconomic levels 1 and 2 (lower class), according to criteria provided by the Colombian National Administrative Department of Statistics (DANE), and school grade ranged from transition to fifth grade. During the selection process an effort was made to avoid other variables that could conflict with the vision variable. The children selected did not suffer from any neurological complication or any other identifiable problem. Regarding visual impairment, visual acuity of all the visually impaired subjects was at maximum 3/60. In other words, these children could not read letters that were 9 cm in size. 2.2. Materials Two experimental test conditions, generically denominated manipulative and verbal task were applied. Both tasks, with their different formats, involve the same problem, which requires the child to make relational inferences based on the relationship between certain indicators. For the manipulative task (see Appendix A) a number of physical objects were used: three models of houses made from balsa wood (one large house, one medium sized house, and one small house); seven animals (two large ones: a horse and a cow; two medium sized ones: a pig and a bear; and three small ones: a sheep, a dog, and a chicken); and three types of food (grass, popcorn, and cotton). Children’ performances in this test were recorded with a video camera. Verbal task was presented using a recording of a voice narrating a story (see Appendix A.1). Children’ verbal performances of in this test were registered using a tape recorder.

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2.3. Design and procedure Two groups were created: an experimental group with 38 visually impaired children and a control group with 38 normally sighted children. Both groups were presented with a manipulative task (see Appendix B). On a second occasion twenty children from Cali between 7.9 and 10.6 years were presented with a verbal task (10 visually impaired children from the experimental group and 10 children from the control group). In the third test both tasks were presented to 26 children between the ages of 4.8 and 7.5 years (13 visually impaired children and 13 children from the control group) and also to 50 children between the ages of 7.9 and 10.6 years (25 visually impaired children and 25 children with normal vision). For the groups presented with the two conditions, there was an interval of one month between the two tests, in this order (a) manipulative task, and (b) verbal task. In all cases, the two tasks were applied individually. The presentation of the task in the two formats began with a familiarization in which the child was expected to establish size relationships (large, medium, small) because this was a basic element for the comprehension of the problem presented in both tasks. In the manipulative task, the child was presented with the three houses, one by one, and was asked to establish comparative relationships using ‘‘bigger than’’ and ‘‘smaller than’’. In the verbal task, children were asked to classify, according to size, a list of animals that the experimenter named. For example, ‘‘Of the animals I am going to mention, which are the largest? Zebra, giraffe, chicken, bull, pig, duck, sheep, lion, tiger, bear, elephant, dove, horse, parrot, cow.’’ In each task, the order of the size relationships was not continuous (small–medium–large or vice versa) in order to confirm the child’s comprehension of this criterion. In the manipulative task, the size relation was medium– small–large, and in the verbal task it was large–small–medium. After the familiarization phase, the problem was introduced in the manipulative or verbal format. In the manipulative task, the child was presented with the materials according to the progression of a story about three animals: a large horse, a medium-sized pig, and a small dog. The animals live in houses according to their size (the child is asked to put them in the appropriate houses). Each animal prepares a dessert and keeps it in its house. Then, for different reasons, each one has to go out; leaving their house (the experimenter removes the animals). While they are out, four other animals (a large cow, a medium-sized bear, a small sheep, and a small chicken) arrive and eat the desserts, but their mouths and feet are covered with the remains of at least one dessert: grass pie, popcorn pie or cotton pie. Each animal and each dessert is introduced by the researcher (see Appendix A). In the verbal task, the child is told a story that is similar to that described for the manipulative version. The animals that steal the food are changed, but the original size relation is maintained. The characteristics of the food are also changed, and the food remains are characterized by their flavor or smell (onion, orange, and chocolate) so that they are more significant to the child in terms of sensorial experience. These modifications aim to avoid any influence from memory of the manipulative task. For the task involving both formats, the problem presented to the child was the need to discover in which house each dessert could originally be found, based on the remains of the food that the animal thieves had on their mouths and feet. The instruction that was presented to all of the children was ‘‘Before the owners arrive home, you have to help me discover which house each animal thief was in.’’ 2.4. The tasks as problem solving situations The tasks used in this study are characterized by being problem-solving situations that respond to some essential characteristics that we have identified (Puche-Navarro, Colinvaux,

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& Dibar, 2001): (1) they are constructed with a means-to-an-end architecture; in other words, they are not solved directly but require the child to eliminate an obstacle or to find a means to reach the goal, (2) they present restrictions for the child, which means that there will not be an immediate solution, (3) they are self contained: they contain all of the information necessary to solve them and do not require any external or previous knowledge in order to be solved, (4) they are transparent for the child, in that they are completely understood. Presenting the tasks as a game arouses the interest of the child, so that the child becomes involved in the task, resolving it in his or her own way, avoiding as far as possible the intervention of the researcher, and (5) they are translated into actions and do not depend solely on verbal productions. A central characteristic of the problem-solving situations is that they offer various possible routes for reaching the solution, and sometimes several solutions are possible so that the child’s possibilities for action are not restricted and it is possible to see how the child performs the task. Additionally, this type of task is sufficiently flexible to allow potential modifications in the presentation of information. This final characteristic is essential when working with visually impaired children, because it makes it possible to adapt the situation to different formats and materials. 2.5. Cognitive demands Both formats of the problem-solving tasks used in this study require the establishment of inductive and relational inferences. Inductive inferences correspond to the establishment of a relation based on two elements that lead to a new understanding; in other words, they correspond to the relationship that the child should establish between the size of the animal thief and the size of the house. This inference allows the child to discover which house the thief entered. Relational inferences correspond to the establishment of two relationships in order to establish a third relationship, which leads to a new understanding. In the tasks presented, these inferences allow the child to establish relationships between the size of the house and the size of the animal based on the remains of the desserts on the mouths and feet of the animals. This allows the child to identify where the desserts were before they were stolen. 2.6. Analysis of performance Children’ performance in each of the tasks was analyzed using a scale from 1 to 6, where a score of 1 indicates that the child picks up the elements of the situation in a fragmented manner without making inferences. A score of 6 indicates that the child relates the elements by using relational inferences. 3. Results The question posed by this study is ‘‘What kind of inferential functioning do visually impaired children use?’’ An overall analysis of the results of the manipulative test condition is presented in Table 1. As can be seen in Table 1, the existence of different types of inferences is confirmed, according to the manipulative task, at different stages of development of the visually impaired child. Approximately half (46.2%) of the children between 4.8 and 7.5, use inductive inference. This means that they establish relationships between the size of the house and the size of the

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Table 1 Types of inference under controlled condition in visually impaired children aged 4.8 and 10.6 (n = 38)

Inductive Relational

4.8 and 7.5 years old (%)

7.9 and 10.6 years old (%)

46.2 7.7

80 40

animal with the food remains on their mouths and the types of food. This contrasts with only 7.7% who use relational inferences. These results are good indicators of use of inferential relationships by visually impaired children. They also establish that inductive inferences appear at an earlier age than relational inferences. But what happens later in the children’s development? Table 1 also shows that between 7.9 and 10.6 years of age, 80% of the visually impaired children relate the size of the house to the size of the animal thief, which indicates that these children use inductive inferences, as do the younger children. On the other hand, in this age range 40% of visually impaired children relate the size of the house and the size of the animal with the food remain on their mouths and the respective foods. In other words, they use relational inference. A preliminary conclusion based on these data is that the use of both types of inference by visually impaired children increases with age, and that in the manipulative task inductive inference is more common than relational inference. This also indicates that relational inference develops later. Table 2 compares the performance of both age groups of visually impaired children with that of children with normal vision in the manipulative task. Table 2 shows that the percentage of children with normal vision in the age range 4.8–7.5 years that used inductive inference to successfully solve the task is 92.3%, while the percentage of visually impaired children who use this strategy is only 46.2%. The percentage of children with normal vision using relational inference is 30.8%, compared to 7.7% for visually impaired children. In summary, in the manipulative task and in this age range, the performance of children with normal vision is significantly better than that of the visually impaired, as is shown in the statistical analysis. The result of the Mann–Whitney test (U = 34.5, p < 0.05) reveals a significant difference between the two groups of children. This difference favors children with normal vision, taking into account measurements of central, which are always higher than those for children with normal vision. The same comparison between visually impaired and normally sighted children in second age group, from 7.9 to 10.6 years, reveals that inductive inference is present in 80% of the visually impaired group as opposed to 92% in the children with normal vision. The use of relational inference reaches 40% in the visually impaired children and 36% in the children with normal vision. In other words, older children with normal vision maintain the performance achieved Table 2 Comparison of the types of inference used by normal vision and visually impaired children in the two age groups under controlled conditions (n = 38) 4.8 and 7.5 years old

Inductive Relational

7.9 and 10.6 years old

Visually impaired (%)

Normal vision (%)

Visually impaired (%)

Normal vision (%)

46.2 7.7

92.3 30.8

80 40

92 36

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earlier, from 4.8 to 7.5 years. Meanwhile, between the ages of 7.9 and 10.8, the visually impaired children show notable advances in both types of inference, reaching the same level as the visually normal children. In conclusion, with respect to the results of the manipulative situation, the comparison between visually impaired and visually normal children reveals the presence of different types of inference, and the appearance of each is related to age. Inductive inference appears first and relational inference later. Additionally, this comparison reveals differences in the performance of two groups of children. At earlier ages the visually normal children have a greater level of use of the two types of inference. However, the data also reveal that differences tend to disappear as the children develop (in the 7.9–10.8 year age group). This research project was also designed to see if the types of inference identified depend on the type of experimental situation employed. To test this hypothesis a verbal or narrative task was designed that was similar in structure to the manipulative task. This second task was designed to help identify the resources of visually impaired children and the role of the task format in eliciting inferential functioning. This is based on the supposition that studies with visually impaired individuals should be able to ‘‘identify the child’s difficulties, understand his or her method of organization, and explore the situations that are likely to reveal their capabilities’’ (Milla´n, 1997a, 1997b, p. 1). For the verbal task, only a small sample of 10 visually impaired children from the city of Cali were tested. The results are presented in Fig. 1. The data shown in Fig. 1 reveal that 100% of the visually impaired subjects used inductive inference in the verbal situation, while 70% of visually impaired children used relational inference. The comparison of visually impaired children’ performance in both types of conditions highlights their achievements. The verbal task provides evidence of an important difference between two situations, indicating that the verbal situation facilitates qualitatively better performance in the visually impaired children. Differences in performance with regard to both types of inference are statistically significant in this group of children, but perhaps more surprising are the advances achieved by the visually impaired children with respect to relational inference.

Fig. 1. Comparison of the use of inference by normal vision and visually impaired children aged 4.8–9.6 in two types of situations.

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The result of the Wilcoxon contrast for paired samples reveals that the differences between scores is significant (W = 1.5 is less than 4, p < 0.05) The result shows improved performance for the vision-impaired children in verbal task (condition), when taking account of measurements of central tendency compared to the manipulative condition. This data supports the percentages obtained (n = 12) in favor of inductive inference in tasks based on verbal conditions. In order to gain an overall view, it is worth comparing the visually normal children with the visually impaired children in verbal problem-solving task. It can be seen that 100% of the visually impaired children relate the size of the house to the size of the animal thief, demonstrating use of inductive inference. Children with normal vision achieve 90% with regard to this relationship. The Mann–Whitney test result (U = 50, p < 0.05) shows that the difference between the two groups of children is not significant. Relational inference was observed in 70% of the visually impaired subjects and 30% of the visually normal children. In summary, in the verbal format the performance of visually impaired children is definitely better than in the manipulative format as well as in relation to the visually normal children. The result of the Mann–Whitney test (U = 50, p < 0.05) shows that the difference between the two groups of children is not significant. The evidence reveals better performance by the visually impaired group in the verbal condition, taking account of measurements of central tendency than in the manipulative condition. This evidence supports the percentages obtained (n = 12) in favor of the use of inductive inference in tasks based on the verbal condition. 4. Discussion and conclusions Research on cognitive development in visually impaired children, and specifically on their inferential functioning, shows that by returning to an investigation of cognitive functioning of the child as such and abandoning a comparative focus that evaluates the visually impaired child in comparison with the visually normal child, the prospects for the visually impaired child improve considerably. At the same time, the re-creation of a methodology that elicits the conditions for functioning instead of evaluating and verifying those conditions broadens and completes the panorama. The data from this study demonstrate that the visually impaired subjects from 4.8 to 7.5 years were less successful than the visually normal subjects in the manipulative tasks. However, between 7.9 and 10.4 years, the performance of both groups is more similar. In general, these data confirm others results on cognitive development, which also report this minor deficit in early development. What is new about the results from the current study is that the difference is shown with respect to a very specific mechanism in cognitive functioning: inference. A more precise interpretation of these data is that initially the visually impaired children may have more difficulties in their inferential functioning because much information, including inference, comes from visual information. Later, however, with the experience gained over the years, this information it will be very important and, as a result, the differences tend to disappear. These data coincide with the results of another study (D’Angiulli et al., 1998), which similarly did not show statistically significant differences in the average performance of visually impaired and visually normal children in haptic and perceptual activities in the majority of age ranges. The visually normal and visually impaired subjects of the same age work with verbal tasks instead of manipulative tasks. The changes in performance are important in that the visually

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impaired children tend to perform significantly better than the visually normal subjects in both inductive and relational inference. In summary, although it is clear that visually normal children perform better in the manipulative format, the opposite is true in the verbal format, where the performance of the visually impaired subjects exceeds that of the visually normal subjects. The information collected is conclusive: inductive and relational inferential abilities form part of the rationality resources that the visually impaired child employs, whose performance is even slightly better than that of the seeing child in the verbal format. It is worth pointing out one aspect of these data that disagrees with previous literature on the subject: in the case of the visually impaired children we found that inductive and relational inferences appear earlier in verbal problem-solving task than in the manipulative task. These results point to the value of verbal problem solving tasks in the educational process for visually impaired children. The question, then, is the following: does the use of verbal situations make it possible for visually impaired children to use their inferential tools? The role of short-term memory in visually impaired individuals, according to the study we reviewed (Lo´pez & Colon, 1995), is much greater than in visually normal subjects. Although the study by Lo´pez and Colon was conducted with adult subjects, our data suggests that this may apply to visually impaired individuals from 6 years of age. This may favor a condition that becomes functionally necessary and useful from an adaptive perspective. What this study shows is that in the case of inductive inferences, the child must store in his or her short-term memory information about the size of each house and each animal thief in order to figure out which house each animal can enter. With regard to relational inferences, the child must also remember information about the traces of food on each of the animals and each of the types of food in order to finally identify which house the food originally came from. In summary, the verbal problem-solving tasks allow the child to store a wider range of information and to use it to make the pertinent inferences when he or she extracts the new information from instructions provided about the tasks. Alternatively, we could argue that that short-term memory plays a role in the manipulative format; however, in this case the spatial elements are so salient that they require additional cognitive work for the visually impaired child, making the child focus on overcoming this aspect and making his performance in terms of inferential reasoning more difficult. Finally, sequential is a factor that makes the process of reasoning difficult for the visually impaired child; however, this does not appear to be a decisive factor in this case because the information is presented sequentially in both formats. This type of problem-solving task in a verbal format becomes an educational strategy that encourages the formulation of questions by the child and replaces the repetition of information given by the teacher, resulting in the development and practice of the visually impaired child’s cognitive abilities. Similarly, the fact that visually normal children can use holistic systems such as sight gives them an advantage over the visually impaired child when confronting the manipulative task and this appears to become a facilitating element of his or her reasoning. Acknowledgements This research was supported by Grant 209-2002 of COLCIENCIAS, INCI (National Institute of Blindness), and the Universidad del Valle. We thank Oscar Ordon˜ez, Tatiana Rojas, Marlenny Guevara and Julio Cesar Ossa for reviews and for their helpful suggestions and comments while this article was wrote.

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Appendix A A.1. Manipulative task Object

Size

Characteristics

3 Houses

Big Medium Small 2 Big ones 2 medium ones 3 small ones Grass Polystyrene Cotton

Grooved Smooth Titled Cow – Horse Sheep – Pig Goat – Sheep – Hen Grass Corn Sweet Cottom

7 Animals

3 Food items

A.2. Game ‘‘Let’s play. In this game you are a detective and you have to help me find out what happened in the story, which I am going to tell you. In a little town there were three houses – one with a big door, one with a medium size door, and one with a small door – in which three friends lived. In the big house lived the horse; in the medium size house lived the pig, and in the small house lived the hen. One day, each of the animals prepared a different meal which was kept at home, but they could not eat the meal because the horse had to visit his sick mother, the pig had to go the doctor because he had an upset stomach, and the hen went out to play with her friends. While away, other animals came in: a cow, a sheep, a rabbit, and a mouse who ate all the horse, the pig and the hen’s food. After eating, the cow smelled chocolate, the sheep smelled onion and chocolate, the rabbit smelled onion and orange, and the mouse smelled orange and chocolate.’’ Appendix B Purpose

Actions

Instructions

Participate in a game-like activity The existence of three houses in the task, each with its own door: a big one, a medium one, and a small one

The child is invited to participate

We have an animal game and want you to know it and play with us I am going to show several materials, which I want you to know. Touch each of the materials I am showing you. You can touch and feel them.

The existence of three animals in the task: a big one, a medium size one, and a small one

Where each animal lives

The materials are presented in the following order. (1) A small house. (2) An animal. (3) A medium size house. (4) A medium size animal. (5) A big house. (6) A big animal The houses are presented, each at a time in a specify order. After the child has touched the house, the door’s size is emphasized The child is asked to identify each animal being presented to him.

As each house is presented, the child is told what animal lives in that house. The child is allowed to introduce the animal in its corresponding house.

Here’s a house. You can touch it and feel it. Tell me is that door big or small? Is this door bigger or smaller than the previous one? I want you to tell me what animal you are touching. Where’s the animal’s head? Touch it. Where are the animal’s legs? Touch them. Where’s that animal’s belly? Touch it. I want you to tell me what animal you are touching. In this big house lives the horse. In this medium size house lives the sheep. In this small house lives the rabbit. In which house does this animal live?

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