Exploring the Influence of Object Similarity and Desirability on Children’s Ownership Identification and Preferences in Autism and Typical Development

Identifying ‘who owns what’ is a crucial foundation of children’s social development. However, this task is complicated by the fact that ownership is a cognitive construction rather than a visible object quality. Accurate detection of ownership is contingent on tracking invisible associations between people and their property. By the time they reach preschool, typically developing (TD) children are highly sensitive to ownership history and recognise the distinction between liking and owning an object (Nancekivell & Friedman, 2014; Noles & Gelman, 2014). Ownership also influences TD children’s preferences for objects – they often consider their self-owned objects to be more valuable and desirable than similar non-owned objects (Gelman & Echelbarger, 2019; Gelman et al., 2012; Hood & Bloom, 2008). Conversely, recent research has shown that children with autism spectrum disorder (ASD) may be less accurate at identifying ownership (Hartley et al., 2021) and that their object preferences are not influenced by ownership history (Hartley & Fisher, 2018; Hartley et al., 2020). Here, we investigate how the perceptual similarity and relative desirability of objects impacts ownership identification accuracy and object preferences in children with ASD.

TD children can accurately match people to property even when object discriminability is very low and ownership is at odds with desirability. In Gelman et al. (2012), 2-year-olds, 3-year-olds, and adults were presented with sets of three objects; one object was assigned to the participant and another was assigned to an experimenter. Participants were then asked to match the objects to their corresponding owners. In ‘varied’ trials, the three objects were perceptually distinct and similarly desirable (e.g. three different toy vehicles), meaning that children could succeed by associating unique objects with different owners. In ‘identical’ trials, the three objects were exactly the same (e.g. three indistinguishable toy taxis), meaning that accurate owner identification required children to track invisible associations between people and specific exemplars of a single object type. In ‘participant-plain’ trials, the three objects were perceptually distinct, but the child’s object was relatively undesirable in comparison to the other objects (e.g. a boring wooden cube vs. a toy train and toy motorcycle). These trials tested participants’ understanding that they can own an object that they dislike, and that desiring another’s object does not confer ownership to the self. Adults and 3-year-olds identified their objects and the experimenter’s objects with above-chance accuracy in each trial type. The 2-year-olds identified their own objects and the experimenter’s objects with above-chance accuracy in varied trials, and the experimenter’s objects in participant-plain trials, but struggled to identify themselves as the owner of relatively boring objects and could not accurately match objects to either party in identical trials. Thus, although TD children can accurately match objects to owners based purely on historical associations from 3 years, object similarity and differences in object desirability may hinder owner-object tracking for children with less-developed understanding of ownership.

In addition to assessing owner identification accuracy, Gelman et al. (2012) also asked participants to indicate which objects they and the experimenter preferred. It is well-documented that neurotypical children consider their property to be more valuable, desirable, and memorable than similar non-owned property (Harbaugh et al., 2001; Hartley & Fisher, 2018; Hood & Bloom, 2008). Establishing ownership forges a mentalistic connection between a person and an object, and because people tend to view themselves favourably, this can trigger the transfer of positive self-perceptions to self-owned property (Hood et al., 2016). Accordingly, Gelman et al (2012) found that their participants aged 2 and 3 years preferred their designated objects above-chance in varied and identical trials, but not participant-plain trials (which is unsurprising given the relative undesirability of their objects). However, 2- and 3-year-olds only inferred that the experimenter preferred their assigned item at above-chance rates in participant-plain trials. By contrast, adults only preferred their designated objects above-chance in identical trials, but inferred that the experimenter preferred their designated objects above-chance across all trial types. Together, these findings demonstrate that merely establishing ownership is sufficient to induce preferential biases for randomly allocated objects in neurotypical pre-schoolers when ownership is not at odds with desirability. However, preschool children did not assume that other people preferred their owned items when object desirability was controlled, potentially reflecting limitations in mentalistic reasoning (Wellman et al., 2001).

ASD is characterised by pervasive differences in social skills (APA, 2013), and children with this condition often spend less time interacting with others (McConnell, 2002). As ownership is a cultural convention acquired through social interactions (Kanngiesser et al., 2015), it may be that children with ASD differ in their development of ownership understanding, which may in turn contribute to their difficulties in social settings. Research has only recently begun to investigate the impact of ASD on children’s understanding of ownership, with just two studies to date examining owner identification accuracy. In Hartley and Fisher (2018), TD children and children with ASD matched on receptive vocabulary (~ 4.8 years) were randomly assigned one of three visually distinct toys to keep, before being offered the chance to trade for a preferred alternative. The remaining two objects were designated to the experimenter and a puppet. When asked to identify the owner of each object, both populations achieved comparably high accuracy for self- and other-owned objects. In Hartley et al. (2021), similar samples of vocabulary-matched children with ASD and TD controls were presented with sets of three objects of the same type (e.g. three differently-coloured drinking bottles) – one object belonged to the child and two objects belonged to experimenters – and were asked to identify the owner of each object. While both groups identified their own objects with similar accuracy, children with ASD were significantly less accurate at identifying objects belonging to other owners than TD children.

One explanation for the reduced owner identification accuracy of children with ASD in Hartley et al. (2021) relates to the objects’ perceptual distinctiveness. Unlike in Hartley and Fisher (2018), the three objects belonged to the same category and shared similarities in global shape. Thus, it may be that owner identification accuracy in ASD is increasingly dependent on perceptual discriminability. Whereas TD 3-year-olds are highly sensitive to what they and others own (Pesowski et al., 2019), ASD may reduce children’s attention to ownership history, particularly when tracking relationships between other owners and their property. In addition to testing this hypothesis, the present research also explores the influence of object desirability on owner identification accuracy in children with ASD. If understanding of ownership is delayed in ASD due to early differences in social-cognitive development, it is possible that object desirability may confound their tracking of owner-object associations as observed in TD 2-year-olds (Gelman et al., 2012). Indeed, difficulty separating the concepts of ownership and desire would have important implications for children’s navigation of social situations with peers and potentially cause inadvertent breaches of others’ ownership rights.

Hartley and Fisher (2018) also collected data pertaining to the influence of ownership on object preferences for children with ASD. While TD children demonstrated a “mere ownership effect” by showing a reliable preference for their randomly assigned toy and rarely trading, children with ASD often traded for an alternative toy that they liked more. Furthermore, unlike TD children, children with ASD did not assign significantly higher values to self-selected or randomly assigned toys in comparison to different non-owned toys or identical copies. More recently, Hartley et al. (2020) found that children with ASD did not over-value authentic items with special ownership histories (e.g. SpongeBob’s spatula) in comparison to similar inauthentic objects belonging to non-famous owners (e.g. my brother’s whisk), whereas TD children assigned significantly higher values based on authentic ownership history. However, TD children and children with ASD did not differ in their sensitivity to object qualities unrelated to ownership (e.g. newness and rarity) as determinants of value. Taken together, these findings suggest that ownership history in relation to the self or other special owners does not influence object preferences for children with ASD (for further evidence concerning the absence of ‘self-reference’ effects in ASD, see Gillespie-Smith et al. (2018), Nijhof and Bird (2019), and Wuyun et al. (2020)). Rather, children with ASD may be principally concerned with an object’s qualities (i.e. what an object is) rather than whom it belongs to.

As prior studies have focused on examining the influence of ownership on children’s object preferences, it is currently unknown how children with ASD perceive ownership to influence others’ object preferences. TD children understand that other people may prefer non-owned objects if they are more desirable than self-owned objects by 5 years (Pesowski & Friedman, 2018) and, as their understanding of ownership matures, are likely to infer that other owners prefer their property when ownership and desirability are not at odds (Gelman et al., 2012). Such judgements require the ability to take the perspective of another agent and generalise knowledge of how ownership influences one’s own object preferences. Given that differences in mentalistic reasoning are a common characteristic of ASD (Altschuler et al., 2018; Berenguer et al., 2018), and recent evidence suggests that children with ASD are less likely to defend the ownership rights of others (Hartley et al., 2021), the assumption that other owners hold preferences for their property may be developmentally delayed.

The objective of this study was to investigate how ownership identification and object preferences in children with ASD are influenced by visual distinctiveness and differences in desirability. Vocabulary-matched children with ASD and TD controls completed a slightly modified version of Gelman et al.’s (2012) task, in which they were presented with sets of three objects and asked to identify their owners and indicate which objects they and an experimenter preferred. Object sets corresponded to either varied, identical, or participant-plain trials as described above. Based on previous evidence, we predicted that children with ASD would be less accurate than TD children at identifying owners when objects are visually similar and, potentially, when objects differ in desirability. We also predicted that ASD would suppress preferences for objects associated with the self across trial types, and that children with ASD would be less likely to infer that the experimenter preferred items designated to them. The results of this study will advance theoretical knowledge by providing new insight into how fundamental aspects of ownership cognition are influenced by ASD.

Children’s responses to each of the four test questions were coded 0 or 1 (yielding a total score of 4 per question). For the owner identification questions, children scored 1 if they correctly selected the objects that were assigned to them or the experimenter. When asked which object they preferred, children scored 1 if they selected the object that was assigned to them (indicating a mere ownership effect). When asked to identify the experimenter’s preferred object, children scored 1 if they selected the object that was assigned to the experimenter (thus inferring that they would display a mere ownership effect).

This study investigated how object discriminability and differences in desirability influence ownership identification and preferences in children with ASD and TD children. While TD children identified their objects and the experimenter’s objects with above-chance accuracy across trial types, children with ASD had difficulty identifying their objects in participant-plain trials and the experimenter’s objects in identical trials. Across trial types, children with ASD were significantly less accurate than TD children at identifying their objects, but not the experimenter’s objects. In keeping with prior research, children with ASD preferred their assigned objects at chance rates in each trial type. By comparison, TD children showed a tendency to prefer their assigned objects in identical trials, and very rarely preferred their relatively undesirable objects in participant-plain trials. Neither group inferred that the experimenter would prefer their assigned items, with the exception of children with ASD in participant-plain trials. Collectively, these results suggest that children with ASD are less accurate at tracking owner-object relationships, and that associations with the self do not increase the attentional or preferential salience of objects for this population.

Much like the 3-year-old and adult participants in Gelman et al. (2012), our TD control group successfully matched objects to themselves and other owners with above-chance accuracy. However, the response profile of our children with ASD resembled that of TD 2-year-olds; they identified owners with above-chance accuracy in varied trials, but struggled to identify themselves as owners of relatively boring objects and keep track of the experimenter’s objects when they were not visually distinctive. On average, our children with ASD were aged 7.7 years with a mean receptive vocabulary age of 4.9 years, clearly exceeding the age at which TD pre-schoolers attain above-chance accuracy across owners and trial types (Gelman et al., 2012). This suggests that ASD may be characterised by an atypical developmental trajectory whereby high sensitivity to ownership history as a heuristic for accurately matching people to property emerges unusually late.

Perhaps owing to their differences in social-cognition and social motivation (APA, 2013; Chevallier et al., 2012), children with ASD appear to have greater difficulty detecting invisible ownership associations between people and property, particularly when they are unable to associate unique objects with different owners. Indeed, for children in both populations, the visual similarity of objects in identical trials hindered identification of the experimenter’s objects, whereas perceptual distinctiveness in varied and participant-plain trials had a facilitative effect. The finding that participants identified the experimenter’s objects significantly more accurately than their objects in participant-plain trials appeared to be most prominent in the ASD sample (TD children identified self- and other-owned objects in participant-plain trials with 65% and 71% accuracy respectively, whereas the corresponding scores for children with ASD were 47.5% and 64%). This suggests that children with ASD may have difficulty acknowledging their ownership of relatively undesirable objects, possibly indicating that differences in desirability may confound their tracking of owner-object relationships.

Our owner identification analyses also showed that children with ASD identified their objects and the experimenter’s objects with similar accuracy across trial types, whereas TD children identified their objects significantly more accurately than the experimenter’s objects. These findings show that, for TD children, merely associating novel objects with the self is sufficient to increase their attentional salience, resulting in greater tracking accuracy. This effect aligns with previous studies demonstrating that objects associated with the self are memorised and recalled more accurately than objects associated with others in both TD children (Cunningham et al., 2013) and adults (Cunningham et al., 2008). Conversely, for children with ASD, associating objects with the self did not enhance the salience of their objects over those associated with other people. This result is consistent with previous findings that children (Wuyun et al., 2020) and adults with ASD (Grisdale et al., 2014) do not recall objects associated with the self with superior accuracy, and evidence that children with ASD seemingly disregard their status as owners when valuing objects (Hartley & Fisher, 2018). However, the relatively weak identification accuracy for self-owned objects displayed by our ASD sample contrasts with Hartley et al. (2021), where children with ASD identified their self-owned objects with significantly greater accuracy than objects owned by experimenters and on par with TD children. A likely explanation for this discrepancy concerns differences in the familiarity of self-owned items between these two studies. In Hartley et al. (2021), the objects associated with the self were already owned by the child going into the study (e.g. lunchboxes and items of clothing) and the experimenter’s items were newly introduced to the child, whereas in the present research, both objects associated with the self and objects associated with the experimenter were newly introduced. Hence, children’s increased experience with their self-owned objects in the prior study likely enhanced their identification accuracy.

For children with ASD, associating an object with the self did not induce preferential biases, even when there were no other dimensions on which to base preferences. This result is consistent with previous evidence that children with ASD do not consider randomly endowed objects to be any more valuable than identical copies, which they are often happy to trade for (unlike TD children; Hartley & Fisher, 2018). Interestingly, our data also showed that children with ASD did not drastically differ in their preferences for self-owned items in participant-plain trials (33% preference) in comparison to varied (35%) and identical trials (34%). By contrast, TD children demonstrated a predictable disliking of their assigned objects in participant-plain trials (6%) in comparison to varied (34%) and identical trials (45%). Given that children with ASD reliably inferred that the experimenter preferred their assigned items in participant-plain trials, it seems unlikely that they misunderstood the question or were selecting objects at random. Rather, it could be that objects construed as “undesirable” by TD children were not perceived that way by children with ASD, and their chance-level responding simply reflects the 33.33% likelihood of being assigned their favourite of the three objects on each trial. It is possible that some of the undesirable objects idiosyncratically appealed to children with ASD by providing specific tactile sensorimotor stimulation (Jones et al., 2003), or because their contrast against the two thematically similar toys made them stand out or appear rare (Ferera et al., 2020). In any case, this study provides further evidence that object preferences of children with ASD may qualitatively differ from those of TD children, and additional research is required to elucidate why and how object desirability may differ between these populations.

The owner identification responses and preferences of our children with ASD support theoretical claims that associating objects with the self does not elicit ownership-induced cognitive biases in this population (Hartley & Fisher, 2018; Hartley et al., 2020, 2021; Nijhof & Bird, 2019; Wuyun et al., 2020). In typical development, children’s concept of ownership is thought to arise from extending their psychological sense of self to objects (Diesendruck & Perez, 2015; Rochat, 2010). However, ASD is characterised by differences in the development of self-other understanding, including awareness of mental states (Ben Shalom et al., 2006; Hill et al., 2004; Silani et al., 2008; Williams & Happé, 2010), episodic autobiographical memory (Crane & Goddard, 2008), and the use and comprehension of first-person pronouns (e.g. “I” and “me”; Evans & Demuth, 2012; Overweg et al., 2018; Tager-Flusberg, 1994). Unlike for TD children, information and objects tagged as self-relevant may not occupy a privileged status in the memories of children with ASD (Lind, 2010). Consequently, ownership – which fundamentally constitutes an autobiographical association between an object and the self – may be of reduced psychological importance for children with ASD, and the salience of their property may not be enhanced by the transfer of preferential biases associated with the self.

Apart from children with ASD in participant-plain trials, neither group inferred that the experimenter preferred their assigned items at above chance rates. This broadly aligns with the results of 2- and 3-year-olds, but contrasts with adults (Gelman et al., 2012). It would have been logical for children to infer that the experimenter preferred their objects because they selected the one they liked most at the start of each trial when designating owner-object relationships. It may be that reasoning of this nature would underpin the responding of adult participants, but is contingent on sophisticated mentalising abilities that develop after 4 years (Miller, 2012). Such reasoning abilities may also develop in ASD, as demonstrated by recent evidence that autistic adults understand that other people would be impressed by their ownership of authentic objects (Hartley et al., 2020). Thus, further research is required to pinpoint when and how awareness of others’ ownership-related preferences develops for TD children and children with ASD.

At an applied level, our findings could have implications for social interventions, particularly those that are peer-mediated. Peer-mediated interventions are often designed to promote important social skills in children with ASD, including peer engagement and relationship building (Kasari et al., 2012; Locke et al., 2019). However, reduced understanding and identification of associations between people and property may increase the likelihood of children with ASD interacting with objects without the consent of their owners. Breaching others’ ownership rights in this manner would impact social reputation amongst peers and hinder the development of positive interpersonal relationships. Differences in identifying ownership, and understanding its importance to others, may also contribute to challenging behaviours relating to property destruction that are commonly observed in ASD (e.g. Horner et al., 2002). Furthermore, children with ASD may be at increased risking of exploitation and theft due to their reduced ability to track, and diminished preferences for, self-owned property. We recommend that future studies begin to examine how differences in ownership understanding influence the efficacy of social interventions involving interactions between autistic and TD children.

It is necessary to reflect on the limitations of this research. Firstly, it may be the case that the observed differences between children with ASD and TD children were underpinned by differences in experience (the ASD group were significantly older) or cognitive functioning. Including a group of children with delayed cognitive development matched to our ASD sample on chronological age and nonverbal intelligence would have addressed this issue. Secondly, it is possible that stronger effects of ownership on object preferences may have been observed in both groups had we told children that they could keep the objects they were allocated. Establishing a permanent owner-object relationship may have elicited increased preferences for children’s self-assigned objects as a means of reducing cognitive dissonance (e.g. by aligning their desires with ownership; Elliot & Devine, 1994). Thirdly, it is important to recognise the possibility that more prominent between-population differences may emerge if children were required to independently infer ownership associations between people and property through observing naturalistic behaviour. It would be valuable to investigate how children with ASD interact with owned and non-owned property in social situations with peers and siblings (see O’Brien et al., 2020 and Ross, 2013).

To summarise, this study has provided new insight into how ASD impacts children’s owner identification and object preferences. Our result show that children with ASD may have difficulty tracking invisible historical associations between people and property, irrespective of visual similarity or desirability (although both of these factors may be a hindrance). Our results also show that children with ASD identify novel objects designated to them with no greater accuracy than objects designated to others, and that association with the self does not bias children’s object preferences (even when there are no other dimensions on which preferences could be based). We propose that, due to differences in development of the psychological self, ownership does not increase the attentional or preferential salience of objects for children with ASD. Importantly, differences in ownership understanding may contribute to the social difficulties faced by children with ASD by disrupting their understanding and navigation of relationships between people and property.