Slow and steady: sustained effects of lexico-semantic associations can mediate referential impairments in schizophrenia

The present study investigated the contribution of lexico-semantic associations to impairments in establishing reference in schizophrenia. We examined event-related potentials as schizophrenia patients and healthy, demographically matched controls read five-sentence scenarios. Sentence 4 introduced a noun that referred back to three possible referents introduced in Sentences 1–3. These referents were contextually appropriate, contextually inappropriate but lexico-semantically associated, and contextually inappropriate and lexico-semantically nonassociated. In order to determine whether participants had correctly linked the anaphor to its referent, the final sentence reintroduced each referent, and participants indicated whether the last two sentences referred to the same entity. Results indicated that between 300 and 400 ms, patients, like healthy controls, used discourse context to link the noun with its preceding referent. However, between 400 and 500 ms, neural activity in patients was modulated only by lexico-semantic associations, rather than by discourse context. Moreover, patients were also more likely than controls to incorrectly link the noun with contextually inappropriate but lexico-semantically associated referents. These results suggest that at least some types of referential impairments may be driven by sustained activation of contextually inappropriate lexico-semantic associations.     

Evaluation and integration of speech and pointing gestures during referential understanding

Two experiments investigated the relative influence of speech and pointing gesture information in the interpretation of referential acts. Children averaging 3 and 5 years of age and adults viewed a videotape containing the independent manipulation of speech and gestural forms of reference. A man instructed the subjects to choose a ball or a doll by vocally labeling the referent and/or pointing to it. A synthetic speech continuum between two alternatives was crossed with the pointing gesture in a factorial design. Based on research in other domains, it was predicted that all age groups would utilize gestural information, although both speech and gestures were predicted to influence children less than adults. The main effects and interactions of speech and gesture in combination with quantitative models of performance showed the following similarities in information processing between preschoolers and adults: (1) referential evaluation of gestures occurs independently of the evaluation of linguistic reference; (2) speech and gesture are continuous, rather than discrete, sources of information; (3) 5-year-olds and adults combine the two types of information in such a way that the least ambiguous source has the most impact on the judgment. Greater discriminability of both speech and gesture information for adults compared to preschoolers indicated small quantitative progressions with development in the ability to extract and utilize referential signals.     

“I don't know but I know who to ask”: 12‐month‐olds actively seek information from knowledgeable adults

Active social communication is an effective way for infants to learn about the world. Do pre‐verbal and pre‐pointing infants seek epistemic information from their social partners when motivated to obtain information they cannot discover independently? The present study investigated whether 12‐month‐olds (N = 30) selectively seek information from knowledgeable adults in situations of referential uncertainty. In a live experiment, infants were introduced to two unfamiliar adults, an Informant (reliably labeling objects) and a Non‐Informant (equally socially engaging, but ignorant about object labels). At test, infants were asked to make an impossible choice—locate a novel referent among two novel objects. When facing epistemic uncertainty—but not at other phases of the procedure—infants selectively referred to the Informant rather than the Non‐Informant. These results show that pre‐verbal infants use social referencing to actively and selectively seek information from social partners as part of their interrogative communicative toolkit. A video abstract of this article can be viewed at https://youtu.be/23dLPsa-fAY     

Toward a formal theory of flexible spatial behavior: geometric category biases generalize across pointing and verbal response types

Three experiments tested whether geometric biases--biases away from perceived reference axes--reported in spatial recall tasks with pointing responses generalized to a recognition task that required a verbal response. Seven-year-olds and adults remembered the location of a dot within a rectangle and then either reproduced its location or verbally selected a matching choice dot from a set of colored options. Results demonstrated that geometric biases generalized to verbal responses; however, the spatial span of the choice set influenced performance as well. These data suggest that the same spatial memory process gives rise to both response types in this task. Simulations of a dynamic field model buttress this claim. More generally, these results challenge accounts that posit separate spatial systems for motor and verbal responses.     

Age differences in executive functioning across the lifespan: the role of verbalization in task preparation

Age-related changes in executive functioning across the lifespan were assessed in children (mean age=9.4 years), younger adults (mean age=21.5 years), and older adults (mean age=65.3 years). Executive functioning was investigated with a task-switching paradigm that permits the separation of two control components: to select and to switch between task sets. The specific aims of this study were (a) to determine developmental functions in both control components across the lifespan; and (b) to examine whether age-related changes in these components are influenced by verbal prompts during task preparation. The results revealed an inverted u-shaped developmental function for the ability to select between task sets but not for the ability to switch between task sets. In contrast to younger adults and children, older adults generally benefited from verbalizations during task preparation. Children, but not older adults, showed a facilitation of task execution when verbal prompts were task-compatible. Conversely, older adults, but not children, showed stronger interference when verbal prompts are task-incompatible. Our findings suggest that inner speech in an important modulator of developmental changes in executive functioning across the lifespan.     

Olive baboons communicate intentionally by pointing

A pointing gesture creates a referential triangle that incorporates distant objects into the relationship between the signaller and the gesture’s recipient. Pointing was long assumed to be specific to our species. However, recent reports have shown that pointing emerges spontaneously in captive chimpanzees and can be learned by monkeys. Studies have demonstrated that both human children and great apes use manual gestures (e.g. pointing), and visual and vocal signals, to communicate intentionally about out-of-reach objects. Our study looked at how monkeys understand and use their learned pointing behaviour, asking whether it is a conditioned, reinforcement-dependent response or whether monkeys understand it to be a mechanism for manipulating the attention of a partner (e.g. a human). We tested nine baboons that had been trained to exhibit pointing, using operant conditioning. More specifically, we investigated their ability to communicate intentionally about the location of an unreachable food reward in three contexts that differed according to the human partner’s attentional state. In each context, we quantified the frequency of communicative behaviour (auditory and visual signals), including gestures and gaze alternations between the distal food and the human partner. We found that the baboons were able to modulate their manual and visual communicative signals as a function of the experimenter’s attentional state. These findings indicate that monkeys can intentionally produce pointing gestures and understand that a human recipient must be looking at the pointing gesture for them to perform their attention-directing actions. The referential and intentional nature of baboons’ communicative signalling is discussed.     

Role of referent concreteness in the acquisition of passive sentence comprehension through abstract modeling

The present experiment tested the hypothesis that development of syntactic comprehension through verbal modeling is enhanced by referent concreteness as a contextual influence. Young children heard a model narrate a series of events in passive form while the model either performed the corresponding activities, showed pictures portraying the same activities, or displayed no referential aids. In accord with prediction, verbal modeling with enactive referents produced higher levels of comprehension of passives than modeling with pictorial referents or modeling without referential aids. Modeling with pictorial referents and modeling without referents did not differ in overall efficacy. However, modeling alone produced results that were less consistent across different measures of comprehension. Children who lacked understanding of passives were more dependent on concrete referents than those who had some initial comprehension of the linguistic form. The results suggest that verbal modeling with pictorial referents and verbal modeling alone facilitate comprehension of passives, whereas verbal modeling with enactive referents promotes learning. Findings of a supplemental experiment reveal that the effects of verbal modeling on comprehension are enhanced when syntactic forms occur in a meaningful verbal context.     

Pointing with the left and right hands in congenitally blind children

Congenitally blind and blindfolded sighted children at ages of 6, 8, 10 and 12 years performed a pointing task with their left and right index fingers at an array of three targets on a touch screen to immediate (0 s) and delayed (4 s) instructions. Accuracy was greater for immediate than delayed pointing and there was an effect of delay for the orientation of the main axis of the pointing distribution in both groups, indicating distinct spatial representations with development such as ego- and allocentric frames of reference, respectively. The pointing responses of the blind covered less surface area indicating better overall accuracy as compared to the sighted blindfolded. The hands differed for four of the six precision and accuracy parameters. The right hand performed better and seemed relatively contextually oriented, whereas the responses of the left hand were closer to the body and egocentrically oriented. The elongation of the scatter of the pointing responses was greater for the boys and more allocentrically oriented, indicating gender differences in spatial representation. The study provides a first evidence of ego- and allocentric spatial frames of reference in congenitally blind children and an ability to point at targets with the left and right hands in the total absence of vision.     

The effects of redundant communications on listeners: Why different types may have different effects

Much of our communication is redundant in that we say more than necessary to be informative. How listeners respond to verbal redundancy is important because of its frequency of occurrence and because such knowledge should enable us to increase our understanding of the development of listening skills. Previous research indicated qualitative developmental differences in how listeners respond to differentiating redundancy (several distinguishing features of a referent are mentioned). The present research compared performance with two forms of redundancy: differentiating and structured (e.g., mentioning a distinguishing referential feature and a feature shared by several contiguous stimuli) and investigated causes of differences in responding to the two forms. First- and fifth-graders participated in a referential communication paradigm. Results were discussed in terms of a processing capacity model: Redundancy should facilitate performance only if it decreases processing demands on a listener. Which processing demands will be affected will depend on the specific redundancy and the specific task.I am indebted to the children and staff from Taken Elementary School in Smithtown, New York, and from Bedford, Campfield, and Westchester Elementary Schools and Pilgrim Christian Day School in Baltimore County, Maryland, for participating in this study. The first experiment was part of my doctoral dissertation at SUNY at Stony Brook. I am grateful to the members of my committee, especially Russ Whitehurst, for their guidance and advice. I also wish to thank Linda Baker for reading a preliminary draft of the paper, and Amy Gorback for running some of the subjects.     

Ontogenetic Emergence of Cognitive Reference Comprehension

Prelinguistic cognitive reference comprehension is foundational to language acquisition and higher cognitive functions. However, its ontogenetic origins in the first year of life are currently not well understood. The current study pitted cognitivist against social interactionist views. We worked with infants monthly from 10 to 13 months of age and observed their behavioral search during a reference comprehension task. Our goal was to first establish the age at which infants begin to cognitively expect an occluded object in one of two locations following a communicative pointing cue. We then tested whether infants' cognitive referential expectations would prospectively predict social interaction skills and experiences (as assessed by spontaneous infant and parent pointing) or, conversely, be predicted by social interaction skills and experiences. Results revealed a linear increase in cognitive reference comprehension, with clear above chance performance, individual stability in month-to-month correlations, and a synchronous correlation to referential pointing all emerging at 12 months but not earlier. Regarding developmental predictions, infants' cognitive referential expectations were not predictive of social interaction skills and experiences; on the contrary, they were predicted by social interaction skills and experiences. Findings suggest that a nonverbal cognitive understanding of reference to occluded entities is neither early emerging, hard wired, nor causal to infants' or caregivers' referential pointing. Instead, this foundational skill is predicted by earlier social interaction. Findings are consistent with the view that cognitive reference comprehension develops via a social construction process in the first year of life.     

Spanish-speaking caregivers’ use of referential labels with toddlers is a better predictor of later vocabulary than their use of referential gestures

Variation in how frequently caregivers engage with their children is associated with variation in children's later language outcomes. One explanation for this link is that caregivers use both verbal behaviors, such as labels, and non-verbal behaviors, such as gestures, to help children establish reference to objects or events in the world. However, few studies have directly explored whether language outcomes are more strongly associated with referential behaviors that are expressed verbally, such as labels, or non-verbally, such as gestures, or whether both are equally predictive. Here, we observed caregivers from 42 Spanish-speaking families in the US engage with their 18-month-old children during 5-min lab-based, play sessions. Children's language processing speed and vocabulary size were assessed when children were 25 months. Bayesian model comparisons assessed the extent to which the frequencies of caregivers’ referential labels, referential gestures, or labels and gestures together, were more strongly associated with children's language outcomes than a model with caregiver total words, or overall talkativeness. The best-fitting models showed that children who heard more referential labels at 18 months were faster in language processing and had larger vocabularies at 25 months. Models including gestures, or labels and gestures together, showed weaker fits to the data. Caregivers’ total words predicted children's language processing speed, but predicted vocabulary size less well. These results suggest that the frequency with which caregivers of 18-month-old children use referential labels, more so than referential gestures, is a critical feature of caregiver verbal engagement that contributes to language processing development and vocabulary growth.

Research Highlights

• We examined the frequency of referential communicative behaviors, via labels and/or gestures, produced by caregivers during a 5-min play interaction with their 18-month-old children.
• We assessed predictive relations between labels, gestures, their combination, as well as total words spoken, and children's processing speed and vocabulary growth at 25 months.
• Bayesian model comparisons showed that caregivers’ referential labels at 18 months best predicted both 25-month vocabulary measures, although total words also predicted later processing speed.
• Frequent use of referential labels by caregivers, more so than referential gestures, is a critical feature of communicative behavior that supports children's later vocabulary learning.

     

Locating targets from imagined perspectives: Comparing labelling with pointing responses

Participants in two experiments adopted imagined perspectives in a perceptually available spatial scene and located targets by using either verbal terms (labelling) or arrows (pointing). Results revealed that performance was faster and more accurate for labelling than for pointing and more so when the adopted perspectives were misaligned with the physical orientation of the participant. This finding was obtained even when an orientation cue allowed participants to adopt the imagined perspective in advance of target presentation. A third experiment replicated these findings using traditional pointing and verbal responding. We argue that performance from misaligned perspectives in perspective-taking tasks suffers due to reference frame conflicts and that these conflicts are more pronounced with pointing and other manual responses that rely more on the reference frame of the physical body.