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False signs and the non-specificity of theory of mind: Evidence that preschoolers have general difficulties in understanding representations

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485 British Journal of Developmental Psychology (2008), 26, q 2008 The British Psychological Society The British Psychological Society False signs and the non-specificity
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485 British Journal of Developmental Psychology (2008), 26, q 2008 The British Psychological Society The British Psychological Society False signs and the non-specificity of theory of mind: Evidence that preschoolers have general difficulties in understanding representations Susan Leekam 1 *, Josef Perner 2,Laura Healey 1 and Claire Sewell 1 1 Department of Psychology, University of Durham, Durham, UK 2 Department of Psychology, University of Salzburg, Salzburg, Austria The discovery that 3-year-old children have difficulties understanding false belief has fuelled two decades of research directed at understanding why children have this problem. One unresolved question is whether false belief problems are due to difficulties with mental or representational aspects of mental states. This question has implications for current arguments about the domain specificity of theory of mind in typically developing children and in populations with autism and brain damage. We revisit this question, presenting evidence that preschoolers difficulty with false belief is not a domain-specific problem with mental states but a more general difficulty with understanding representations. The question of whether theoryofmind is either adomain-specific or adomain-general capacity has been debated for more than two decades. Theorists taking a domain-specific approach have argued that there is a dedicated theory of mind system with specialized mechanisms that process mental representations about one s own and other people s beliefs and other mentalstates. On the domain-general side of the debate, theorists have proposed that children s ability to understand mental representations such as beliefs reflects their conceptual understanding of representations more generally. Perner (1991), for example, argues that understanding of false belief is based on the ability to metarepresent, that is, to understand representations as representations. Support for the domain-general view was initially provided by evidence of changes in preschool children s understanding not only of mental representation such as beliefs, but also of external, non-mental representation such as photographs. In the false belief task, a protagonist observes a state of affairs (e.g. object in location 1) which then unexpectedly changes in their absence (object moved to location 2) leaving the protagonist with a false belief. Evidence from numerous studies suggests that a distinct change occurs in understanding of mental representations between the age of 3 and 5 years old (see Wellman, Cross, & Watson, 2001 for review). While task factors may *Correspondence should be addressed to Dr Sue R. Leekam, Chair in Developmental Psychology, Department of Psychology, University of Durham, South Road, Durham DH1 3LE, UK ( DOI: / X260154 486 Susan Leekam et al. facilitate performance on this task, these changes do not eliminate the robust finding of a developmental trajectory across age (Wellman et al., 2001). The false photograph task (Zaitchik, 1990) was designed to provide an analogue of the false belief task by testing understanding of a non-mental, external, and observable representation. In this task, a Polaroid camera is used to take a photograph of an object in a location (location 1), and while the photograph is developing, the object is then moved to location 2, leaving the photograph unaffected. Children are then asked to infer where the object will be in the photograph. Results for typically developing children showed that 3-year-olds had as much difficulty with the false photograph as with the false belief task. In contrast, the majority of 4-year-olds and older children showed competenceonboth taskswith slightlymore advanced performance on the false belief. These findings therefore indicated that younger children s difficulties with false belief were not due to aspecific problem with reasoning about mental states but to amore general difficulty with understanding representation. Subsequent evidence, however,challenged this domain-general account by showing that children with autism passed the false photograph task, while failing the false belief task (Leekam & Perner, 1991; Leslie & Thais, 1992). This new evidence, together with equivalent evidence from false drawing tasks (Charman & Baron-Cohen, 1992), was used to argue that children with autism have aspecific difficulty with the mental rather than the representational aspect of false beliefs (Frith & Frith, 1999; Leslie & Thais, 1992). While not all researchers agreed with this proposal (Leekam &Perner, 1991, p. 215; Perner, 1991; Suddendorf, 1999), the view of children s understanding of mental states as adomain-specific capacity continuedtoinfluencesubsequent researchinboth autism and typical development, contributing to a subsequent shift in the literature away from representational accounts of theory of mind and towards abroader focus on social cognition that emphasizes its social and mental content. To date, the claim for a domain-specific account of false belief understanding still rests on evidence from the photograph task used with children with autism. However, there is a fundamental difficulty with the photograph task that makes it an inappropriate measure to test between domain-specific versus domain-general theories. The problem is that the two tasks are not formally identical as often claimed (Frith &Frith, 1999, p. 1693). Instead, there is a difference between the tasks that goes beyond the mental/non-mental, observable/unobservable, and external/internal dimension. This difference is that the photographs in the false photograph task are not false. Unlike the false belief, that misrepresents current reality as being the same as the prior state of affairs, the false photograph correctly represents the prior state of affairs and does not take reference to the currentstate of affairs(leekam &Perner,1991, p. 215). The false photograph task therefore does not require a clear understanding of the difference between what is represented and how it is represented as being; hence, itisnot aclear test of the ability to metarepresent the ability that is central to children s understanding of representations. Empirical findings support this conceptual analysis. For example, Slaughter (1998) proposed that if the belief and photograph tasks were structurally equivalent, then training on one task would transfer to another. The results showed that training of typically developing 3- to 5-year-olds on the belief task did lead to enhanced performance on other tasks such as the appearance reality task and level 2 perspective taking that have previouslybeen proposed to relate to representationaltasks. However, training on the false belief task did not enhance performance on the photograph task and vice versa. Indeed, there was a dissociation in performance on these tasks. False signs and theory of mind 487 Further support for Slaughter s finding of non-association between photograph and belief tasks may be indicated by the mixed findings from previous studies. While several studies (Leekam & Perner, 1991; Sabbagh, Moses, & Shiverick, 2006) have found significant associations, others have shown either non-significant or weak correlations (Lewis, Freeman, & Smith, 1992; Perner et al., 1993) or correlations that become nonsignificant after partialling out chronological age (Sabbagh et al., 2006). Given that the belief and photograph tasks do not assess the same kind of representational understanding, comparisons between these tasks cannot settle the debate about whether understanding of false belief reflects a domain-specific or domaingeneral skill. To more accurately test children s difficulty with the representational demands that are intrinsic to the false belief task, another test is needed. One test is Parkin s (1994) false sign task. In this task, a signpost in a story scenario indicates a state of affairs (e.g. object in location 1). The object is then moved (to location 2), but the signpost is not and it therefore becomes afalse sign. Children have to infer where the sign shows that the object is. Afalse sign is like aphotograph in that it is anonmental, observable object. Like the case of false belief, however,inorder to understand what the false sign shows, one needs to understand that the signpost represents a situation that is different from how the signpost shows it to be. In other words, like a false belief, the false sign misrepresents(asa belief misconceives) current reality. Intwo unpublished experiments, Parkin obtained positive correlations between the belief tasks and the sign tasks and in addition the sign tasks also explained a significant amount of the variance on the false belieftasks even when agewas introduced first in a stepwise regression. As Parkin s research remains unpublished, we followed up his findings with two new experiments, one that also incorporated Zaitchik s photograph task. In addition to testing children on Parkin s false signpost task, we also included a different representational medium, a false label that falsely indicated the contents of a container.previous studies using identity and location forms of the false belief task do not show differences between these story types (Wellman et al., 2001). However, in these earlier studies, the same representational medium (a belief) was used to falsely depict either a location or an identity whereas for the false sign task, two different types of representational media, a signpost or a label, depict the referent. Since each has a different form, i.e. one provides directional information about the referent while the other does not, it was not known if adifference between the two types of task might be found. In Experiment 1, we compared preschool children s performance on true and false sign tasks with performance on true and false belief tasks. If the cognitive demands of the sign and belief tasks are equivalent, then children should pass the true tasks and find the two false tasks equally difficult. In Experiment 2, we examined associations between the false belief task and performance on the false sign and false photograph tasks. Positive correlations were expected between the false sign and the false belief task due to their similar representational nature. Correlations were also expected between the false photograph and false sign task due to similarities in their non-mental aspect. Given that associations have also been found in some, but not all previous studies between the false belief task and the false photograph task, correlations between these two tasks were also anticipated. However, if the false belief and false photograph task are coincidentally rather than structurally related, then we would not expect this correlation to holdwhen other factorsare also taken into account such as the cognitive demands of a more similar cognitive task (i.e. the false sign task) or chronological age. In contrast, any association found between the false belief and the false sign task should go beyond any relation that the false belief task has with false photographs. 488 Susan Leekam et al. EXPERIMENT 1 Method Participants Participants were 80 children (40 girls, 40 boys) aged months (M ¼ 47: 67 months, SD ¼ 7 : 24) from a school in a middle class (high SES) neighbourhood in East Sussex, England. Thirty-nine were aged 3 years ( M ¼ 41: 31 months, SD ¼ 3 : 62, range months) and 41 were aged 4years ( M ¼ 53: 71, SD ¼ 3 : 78, range months). Materials Stories were created relating to two types of change: location change, denoted by a signpost and identity change denoted by a label. Two different story themes were created for location change and two for identity change (examples of park and cake themes are in Table 1). All four story themes were used for all four experimental conditions (true belief, false belief, true sign, false sign). Each story was enacted using toy objects on a large paper sheet that depicted the story locations. Design and procedure This was a between-participants design. Each child was randomly assigned to receive one of the following conditions: true belief (TB), false belief (FB), true sign (TS), false sign (FS).There were 20 children in each condition with equal numbers of boys and girls and of 3- and 4-year-olds in each condition (with exception of the TB condition with nine 3- and eleven 4-year-olds). Each child received four different story themes (two locations and two identities) in the assigned condition in a single session lasting 20 minutes, with story theme and ordercounterbalanced between children. Children were given a score of 1 for each trial if they correctly answered the test question and both the memory questions. Results Table 2 shows the pattern of performance for each condition. Due to non-normal distribution of the data for some variables, non-parametric analyses were conducted. Initial analysis showed no significant differences between location (signpost) and identity (label) versions of each task forany of the four conditions. Therefore, data were collapsed across story theme. To test the hypothesis that children would pass the true tasks but find the two false tasks equally difficult, non-parametric (Mann Whitney U ) tests were run. Results showed that scores on the FB task were significantly worse than scores onboth the TB and TS tasks and scores for the FS task were also worse than the scores for the TS and TB tasks (p, : 0001 for all comparisons). However, performance on the FB and FS tasksdid not differfrom each other.neither did performance on the TB or TS tasks differ. Younger children performed worse than older children (U ¼ 575: 0, p, : 025). There was no age difference in performance on either the true belief or true sign condition. Older children performed better on the false belief task than younger children ( U ¼ 24: 0, p, : 025) and the agedifference forthe false sign task did not reach significance ( U ¼ 29: 0, p, : 098). False signs and theory of mind 489 Table 1. Tasks used for Experiments 1and 2 Identity change False sign (Experiment 1) False belief (Experiment 1) This is a cake shop. The shopkeeper sells cakes and biscuits. The shopkeeper keeps cakes in the red tin with the cake label on it and biscuits in the green tin with the biscuit label on it. Aboy comes in and says, I d like tobuy acake please. The shopkeeper shows him the cakes in the red tin. Prompt: Where are the cakes? Where are the biscuits? The boy buys the cake and goes home. (doll removed ). Now the shopkeeper decides to change the tins around. He puts the cakes in the green tin and the biscuits in the red tin Now the boy is walking back to the shop. The first cake was so yummy, he wants to buy another one! Test question: Where does the label show that the cakes are? Test question: Where does the boy think that the cakes are? Memory questions: 1. What is in the red tin now? 2. What did the shopkeeper put in the red tin at the beginning of the story? Location change False sign (Experiments 1 and 2) False belief (Experiments 1 and 2) False photograph (Experiment 3) This is a park. In the park there are two places: swings here and a lake over there. There is an ice-cream van next to the swings One day Tom is walking in the park and he wants an ice-cream Just ahead, he sees a signpost pointing this way to the swings. It is the signpost that shows where the ice-cream van is Just ahead, he can see the ice-cream van at the end of the path next to the swings Prompt: Where isthe ice-cream van by the swings or by the lake? But the ice-cream van is too far away and it is getting dark so Tom s going home and he ll come back tomorrow. (doll removed ) Prompt: Where is the ice-cream van by the swings or by the lake? Later that evening ::: Now let s take a photograph of the ice-cream van with the camera. Now we ve got to wait. While we re waiting ::: ::: the ice-cream van moves from the swings to the lake Now it s the next day. Here is the signpost Test question: Where does the signpost show that the ice-cream van is? Now it s the next day. Here is Tom Test question: Where does Tom think that the ice-cream van is? Now we ve finished waiting. Here is the photograph Test question: Where is the ice-cream van in the photograph? Memory questions: 1. Where is the ice-cream van now? 2. Where was the ice-cream van at the beginning of the story? Discussion The results of Experiment 1 showed that 3- and 4-year-old children performed well on the true versions of the belief and sign task and poorly on both the false sign and false belief tasks. Significant differences were found between the False Belief task and each of 490 Susan Leekam et al. Table 2. Number of correct trials and mean scores in Experiment 1 Number of correct trials Task Age N Mean SD True belief All False belief All True sign All False sign All the true tasks and the False Sign task and each of the true tasks. However, performance on the False Belief and False Sign tasks did not differ from each other. The different versions (Location/Identity) also made no difference to performance and children performed similarly on both versions indicating that at least in this context, children have an equivalent understanding of the representational status of both directional and non-directional signs at a similar age. Experiment 2 examined the three-way relationship between the false belief, false sign, and false photograph task. EXPERIMENT 2 Method Participants Participants were 48 children aged months (M ¼ 47: 54 months, SD ¼ 7 : 03)from schools in middle-class (high SES) areas of Kent and Essex, England. Twenty-three were 3 years, aged months (11 females and 12 males; M ¼ 41: 25, SD ¼ 3 : 64), and 25 were 4years, aged months (12 females and 13 males; M ¼ 53: 24, SD ¼ 3 : 73). Materials Six story themes were prepared, one identical to the location change story in Experiment 1. The other five also involved an object that changed its location. A Polaroid camera was used for the FP task. Design and procedure Each child was tested individually on four trials for all three conditions. Testing was completed in two sessions of approximately 30 minutes, with a break between of at least 2 hours. Task order was partially counterbalanced, giving a total of six different orders. Left/right position of object s starting location was also equalized. In session 1, each child was tested on two different story themes for each of the three tasks (FB, FS, False signs and theory of mind 491 and FP). The same procedure was repeated for the second session. First, a training phase to test understanding of true representations was administered, scored, and any misunderstandings corrected. Then, the test phase followed immediately. False belief task Training phase. In Part 1, the child was shownthreeshapes (a red circle, yellow triangle, and green square) and ateddy bear and asked (a) which shape the teddy bear was looking at and (b) to move the teddy bear so that it was looking at one of the other shapes. All children knew the names and colours of the shapes but any minor misunderstandings were corrected. In Part 2a, adoll was placed in one of two boxes (without the child being able to see). The teddy bear was then positioned so that it looked towards the box the doll was in and the child was asked atraining Question: Where does the teddy bear think that the little doll is? Incorrect answers were scored and children were subsequently corrected. In Part 2b, the procedure was repeated,with the doll hidden randomly in one of the two boxes. Testing phase. Experiment 1. The procedure and scoring was identical to the location task of False sign task Training phase. In Part 1, the child was shownthree shapes described above and an arrow (attached to asignpost) and asked (a) which shape the signpost was pointing to and (b) to turnthe signpost so that it was pointing to one of the other shapes. Misunderstand
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