Inconsistency in perspective-taking during comprehension.

In order to successfully comprehend referring expressions, a listener must often consider how the speaker's perspective differs from their own. Such consideration of others' perspective is effortful and not always employed. Previous studies disagree about whether executive function predicts perspective-taking use in language comprehension. Furthermore, it is unclear whether or not there are consistent individual differences of perspective-taking ability in comprehension. This study tested participants in three perspective-taking in comprehension tasks and two measures of executive function to determine whether participants show consistency in their perspective-taking ability and whether this ability is predicted by measures of executive function. We found that (1) some but not all perspective-taking in comprehension tasks correlate with one another, and (2) inhibition control and working memory are not linked with any of the three perspective-taking measures. Based on these findings, we conclude that perspective-taking in comprehension may not be a unitary ability.

Anthropomorphism, not depiction, explains interaction with social robots.

We question the role given to depiction in Clark and Fischer's account of interaction with social robots. Specifically, we argue that positing a unique cognitive process for handling depiction is evolutionarily implausible and empirically redundant because the phenomena it is intended to explain are not limited to depictive contexts and are better explained by reference to more general cognitive processes.

Effects of verbal tasks on driving simulator performance.

We report results from a driving simulator paradigm we developed to test the fine temporal effects of verbal tasks on simultaneous tracking performance. A total of 74 undergraduate students participated in two experiments in which they controlled a cursor using the steering wheel to track a moving target and where the dependent measure was overall deviation from target. Experiment 1 tested tracking performance during slow and fast target speeds under conditions involving either no verbal input or output, passive listening to spoken prompts via headphones, or responding to spoken prompts. Experiment 2 was similar except that participants read written prompts overlain on the simulator screen instead of listening to spoken prompts. Performance in both experiments was worse during fast speeds and worst overall during responding conditions. Most significantly, fine scale time-course analysis revealed deteriorating tracking performance as participants prepared and began speaking and steadily improving performance while speaking. Additionally, post-block survey data revealed that conversation recall was best in responding conditions, and perceived difficulty increased with task complexity. Our study is the first to track temporal changes in interference at high resolution during the first hundreds of milliseconds of verbal production and comprehension. Our results are consistent with load-based theories of multitasking performance and show that language production, and, to a lesser extent, language comprehension tap resources also used for tracking. More generally, our paradigm provides a useful tool for measuring dynamical changes in tracking performance during verbal tasks due to the rapidly changing resource requirements of language production and comprehension.

Rightward directional bias in art produced by cultures without a written language.

In this study, we coded art painted on rocks located in southern Africa, which was painted with a mixture of ochre, blood, and clay by the San, a Neolithic culture with no written language. These images depict a mixture of humans and animals in a variety of contexts, including (but not limited to) hunts and dances. We calculated a laterality index for the collected available art from each region, finding that although there was variability across regions in the direction of the laterality scores, most regions contained a majority of figures facing rightward. This is in stark contrast with reports of artists drawing leftward facing animals and human profiles (an effect that is influenced by native language writing system direction, gender, and handedness), but interestingly our sample also contained regions with strong leftward biases. Our results are, however, in accord with studies that report people preferring images that depict left-to-right motion, as well as the left-to-right bias in depicting transitive actions, an effect that seems to result from greater right hemispheric activation in scene processing and interpretation. Thus, this study shows that in the absence of a writing system, right-lateralized neural architecture may guide the hands of artists.

Distinct neural mechanisms underlying conceptual knowledge of manner and instrument verbs.

Studies on the organization of conceptual knowledge have examined categories of concrete nouns extensively. Less is known about the neural basis of verb categories suggested by linguistic theories. We used functional MRI to examine the differences between manner verbs, which encode information about the manner of an action, versus instrument verbs, which encode information about an object as part of their meaning. Using both visual and verbal stimuli and a combination of univariate and multivariate pattern analyses, our results show that accessing conceptual representations of instrument class involves brain regions typically associated with complex action and object perception, including the anterior inferior parietal cortex and occipito-temporal cortex. On the other hand, accessing conceptual representations of the manner class involves regions that are commonly associated with the processing of visual and biological motion, in the posterior superior temporal sulcus. These findings support the idea that the semantics of manner and instrument verbs are supported by distinct neural mechanisms.

The N400 in processing repeated name and pronoun anaphors in sentences and discourse.

We report two EEG/ERP experiments that examined processing of repeated name (e.g., Bill; Experiment 1) and pronoun (e.g., he; Experiment 2) subject anaphors to single antecedents (e.g., Bill) and to antecedents embedded in a conjunction (e.g., Bill and Mary) within sentences and discourses. Experiment 1 replicated previous reports of repeated references to single antecedents eliciting greater N400 negativity than repeated references to conjoined antecedents within sentences, and extended these results to cross-sentence (discourse) references. Experiment 2 found that pronouns also elicited greater N400 negativity following single than conjoined antecedents. In both experiments, references to conjoined antecedents elicited greater frontal negativity than references to single antecedents in both sentences and discourse. Our results indicate that, in processing subject anaphors, the N400 is an index of reference predictability rather than a marker of the fit between antecedent salience and reference form, and that frontal negativity marks referential ambiguity elicited by conjoined phrases.

Syntax response-space biases for hands, not feet.

A number of studies have shown a relationship between comprehending transitive sentences and spatial processing (e.g., Chatterjee, Trends in Cognitive Sciences, 5(2), 55-61, 2001), in which there is an advantage for responding to images that depict the agent of an action to the left of the patient. Boiteau and Almor (Cognitive Science, 2016) demonstrated that a similar effect is found for pure linguistic information, such that after reading a sentence, identifying a word that had appeared earlier as the agent is faster on the left than on the right, but only for left-hand responses. In this study, we examined the role of lateralized manual motor processes in this effect and found that such spatial effects occur even when only the responses, but not the stimuli, have a spatial dimension. In support of the specific role of manual motor processes, we found a response-space effect with manual but not with pedal responses. Our results support an effector-specific (as opposed to an effector-general) hypothesis: Manual responses showed spatial effects compatible with those in previous research, whereas pedal responses did not. This is consistent with theoretical and empirical work arguing that the hands are generally involved with, and perhaps more sensitive to, linguistic information.

Transitivity, Space, and Hand: The Spatial Grounding of Syntax.

Previous research has linked the concept of number and other ordinal series to space via a spatially oriented mental number line. In addition, it has been shown that in visual scene recognition and production, speakers of a language with a left-to-right orthography respond faster to and tend to draw images in which the agent of an action is located to the left of the patient. In this study, we aim to bridge these two lines of research by employing a novel method that measures the spatial bias produced by transitive sentences that use a wide variety of abstract and concrete verbs. Across four experiments, participants read sentences and then responded to probe words appearing on either the left or right sides of the screen. Probe words consisted of agents, patients, other words in the sentence, or newly encountered words. We found consistent lateral biases to responding to agents and patients, which appears to be independent of order of mention in the sentence but which does reflect a correspondence between position in the sentence and role in the causal sequence of the action. Our results also show that this spatial bias is driven by the use of the hands in two different ways: The left hand shows a greater sensitivity to the spatial effect than the right hand, and vocal responses produce no spatial effect.

The Repeated Name Penalty, the Overt Pronoun Penalty, and Topic in Japanese.

When reading sentences with an anaphoric reference to a subject antecedent, repeated-name anaphors result in slower reading times relative to pronouns (the Repeated Name Penalty: RNP), and overt pronouns are read slower than null pronouns (the Overt Pronoun Penalty: OPP). Because in most languages previously tested, the grammatical subject is typically also the discourse topic it remains unclear whether these effects reflect anaphors' subject-hood or their topic-hood. To address this question we conducted a self-paced reading experiment in Japanese, a language which morphologically marks both subjects and topics overtly. Our results show that both repeated-name topic-subject anaphors and repeated-name non-topic-subject anaphors exhibit the RNP and that both overt-pronoun topic-subject and overt-pronoun non-topic-subject anaphors show the OPP. However, a detailed examination of performance revealed an interaction between the anaphor topic marking, reference form, and the antecedent's grammatical status, indicating that the effect of the antecedent's grammatical status is strongest for null pronoun and repeated name subject anaphors and that the overt form most similar to null pronouns is the repeated name topic anaphor. We discuss the implications of these findings for theories of anaphor processing.

Bilateral parietal contributions to spatial language.

It is commonly held that language is largely lateralized to the left hemisphere in most individuals, whereas spatial processing is associated with right hemisphere regions. In recent years, a number of neuroimaging studies have yielded conflicting results regarding the role of language and spatial processing areas in processing language about space (e.g., Carpenter, Just, Keller, Eddy, & Thulborn, 1999; Damasio et al., 2001). In the present study, we used sparse scanning event-related functional magnetic resonance imaging (fMRI) to investigate the neural correlates of spatial language, that is; language used to communicate the spatial relationship of one object to another. During scanning, participants listened to sentences about object relationships that were either spatial or non-spatial in nature (color or size relationships). Sentences describing spatial relationships elicited more activation in the superior parietal lobule and precuneus bilaterally in comparison to sentences describing size or color relationships. Activation of the precuneus suggests that spatial sentences elicit spatial-mental imagery, while the activation of the SPL suggests sentences containing spatial language involve integration of two distinct sets of information - linguistic and spatial.

Co-referential Processing of Pronouns and Repeated Names in Italian.

In this study, we investigate whether co-referential processing across sentence boundaries is driven by universal properties of the general architecture of memory systems and whether cross-linguistic differences concerning the number of anaphoric forms available in a language's referential inventory can impact the process of inter-sentential co-reference resolution. As a window into these questions, we test whether the repeated-name penalty (RNP) and the overt-pronoun penalty (OPP)-comprehension delays associated with repeated names and overt pronouns, respectively, in comparison to more reduced anaphoric forms in reference to salient antecedents-occur in Italian, examining the extent to which Italian resembles other null-subject languages, with focus on Spanish. Our self-paced reading experiment with factors Antecedent (Subject, Object) and Anaphor (Null Pronoun, Overt Pronoun, Repeated Name) found that Italian exhibits both an OPP and a (weaker) RNP, extending previous research that showed these effects in Spanish and strengthening the claim that co-reference resolution might be subject to universal principles.

Referent Predictability is Affected by Syntactic Structure: Evidence from Chinese.

This paper examines the effect of syntactic structures on referent predictability. Focusing on stimulus-experiencer (SE) verbs, we conducted two sentence-completion experiments in Chinese by contrasting SE verbs in three structures (active canonical, active ba, and passive). The results showed that although verb semantics and discourse coherence relations produce a strong referential biases, the stimulus referent is overall less likely to be rementioned in the active canonical structure than in the other two structures. The findings thus indicate that referent predictability is determined by not only semantic but also syntactic factors. We discuss the theoretical implications for the nature of referent predictability and its relationship with referent accessibility.

Semantic Relations Cause Interference in Spoken Language Comprehension When Using Repeated Definite References, Not Pronouns.

The choice and processing of referential expressions depend on the referents' status within the discourse, such that pronouns are generally preferred over full repetitive references when the referent is salient. Here we report two visual-world experiments showing that: (1) in spoken language comprehension, this preference is reflected in delayed fixations to referents mentioned after repeated definite references compared with after pronouns; (2) repeated references are processed differently than new references; (3) long-term semantic memory representations affect the processing of pronouns and repeated names differently. Overall, these results support the role of semantic discourse representation in referential processing and reveal important details about how pronouns and full repeated references are processed in the context of these representations. The results suggest the need for modifications to current theoretical accounts of reference processing such as Discourse Prominence Theory and the Informational Load Hypothesis.

The neural representation of plural discourse entities.

Little is known about the underlying neural structures that mediate the generation and tracking of discourse referents. In two functional magnetic resonance imaging experiments, we examined the neural structures involved in generating and maintaining the representations of multiple referents. Experiment 1 used two-sentence discourses with singular and plural conditions linking back to single or conjoined subjects. In Experiment 2, conjunction type was manipulated in order to keep the number of discourse entities constant across the discourse. Both experiments found greater activation in the superior parietal lobule bilaterally for plural entities relative to singular entities in Experiment 1 and for unconjoined plural entities relative to conjoined plural entities in Experiment 2. This parietal activation suggests that referring to multiple entities evokes multiple representations that need to be integrated and tracked. We discuss these findings in terms of psycholinguistic theories of multiple referent representations.

Singular and plural pronominal reference in Spanish.

In two self-paced, sentence-by-sentence reading experiments, we examined the difference in the processing of Spanish discourses containing overt and null pronouns. In both experiments, antecedents appeared in a single phrase (John met Mary) or in a conjoined phrase (John and Mary met). In Experiment 1, we compared reading times of sentences containing singular overt and null pronouns referring to the first or to the second mentioned antecedent. Overt pronouns caused a processing delay relative to null pronouns when they referred to the first antecedent in single but not in conjoined phrases. In Experiment 2, we compared reading times of sentences containing overt and null pronouns referring to singular or plural entities. Plural null pronouns were read faster than their singular counterparts in conjoined conditions. Plural overt pronouns were read more slowly than their null counterparts both in single and conjoined conditions. We explain our findings in a framework based on the notion of balance between processing cost and discourse function in line with the Informational Load Hypothesis.

Interference between conversation and a concurrent visuomotor task.

We report 2 experiments during which participants conversed with either a confederate (Experiment 1) or a close friend (Experiment 2) while tracking a moving target on a computer screen. In both experiments, talking led to worse performance on the tracking task than listening. We attribute this finding to the increased cognitive demands of speech planning and monitoring. Growth curve analyses of task performance during the beginning and end of conversation segments revealed dynamical changes in the impact of conversation on visuomotor task performance, with increasing impact during the beginning of speaking segments and decreasing impact during the beginning of listening segments. At the end of speaking and listening segments, this pattern reversed. These changes became more pronounced with increased difficulty of the task. Together, these results show that the planning and monitoring aspects of conversation require the majority of the attentional resources that are also used for nonlinguistic visuomotor tasks. The fact that similar results were obtained when conversing with both a confederate and a friend indicates that our findings apply to a wide range of conversational situations. This is the first study to show the fine-grained time course of the shifting attentional demands of conversation on a concurrently performed visuomotor task.

Repeated Names, Overt Pronouns, and Null Pronouns in Spanish.

In two self-paced, sentence-by-sentence reading experiments we examined the difference in the processing of Spanish discourses with repeated names, overt pronouns, and null pronouns in emphatic and non-emphatic contexts. In Experiment 1, repeated names and overt pronouns caused a processing delay when they referred to salient antecedents in non-emphatic contexts. In Experiment 2, both processing delays were eliminated when an emphatic cleft-structure was used. The processing delay caused by overt pronouns referring to salient antecedents in non-emphatic contexts in Spanish contrasts with previous findings in Chinese, where null and overt pronouns elicited similar reading times. We explain both our Spanish findings and the Chinese findings in a unified framework based on the notion of balance between processing cost and discourse function in line with the Informational Load Hypothesis.

A common mechanism in verb and noun naming deficits in Alzheimer's patients.

We tested the ability of Alzheimer's patients and elderly controls to name living and non-living nouns, and manner and instrument verbs. Patients' error patterns and relative performance with different categories showed evidence of graceful degradation for both nouns and verbs, with particular domain-specific impairments for living nouns and instrument verbs. Our results support feature-based, semantic representations for nouns and verbs and support the role of inter-correlated features in noun impairment, and the role of noun knowledge in instrument verb impairment.

Why does language interfere with vision-based tasks?

Conversation with a remote person can interfere with performing vision-based tasks. Two experiments tested the role of general executive resources and spatial attentional resources in this interference. Both experiments assessed performance in vision-based tasks as participants engaged in a language task involving a virtual remote speaker. In both experiments, the language task interfered with the vision task more when participants were speaking or planning what to say next than when they were listening. In Experiment 1, speaking or planning what to say next were also associated with higher interference from a visual distractor than listening, indicating that preparing to speak and speaking pose higher executive requirements than listening. In both experiments, localizing the voice of the remote speaker to the front of participants slightly reduced interference in comparison to other directions. This suggests that remote conversation requires spatial attention resources for representing the position of the remote person.

Angiotensin converting enzyme inhibitors and cognitive and functional decline in patients with Alzheimer's disease: an observational study.

We previously reported that angiotensin converting enzyme inhibitors (ACEIs) decrease the rate of cognitive decline in elderly patients with hypertension, but their impact on patients with Alzheimer's disease (AD) is not known. A total of 62 elderly patients with AD were enrolled, and 52 completed the study for 6 months. Mini-Mental Status Examination (MMSE), Clock Draw Test (CDT), working memory (Digit Ordering), Instrumental Activities of Daily Living (IADL) scale, and the Screen for Caregiver Burden (SCB) were collected at baseline, 3 months, and 6 months. AD patients receiving ACEI (N = 15) demonstrated a slower rate of decline in digit forward (P = .003) and IADL scale (P = .003) and an improved measure of caregiver burden (P = .04) but not MMSE (P =.15) or CDT (P =.9) compared with those not receiving ACEI after adjusting for other risk factors. This study suggests that use of ACEI in AD patients is associated with slower rate of AD progression. A randomized clinical trial is needed to confirm our finding.