More than language: Mental time travel, mentalizing, executive attention, and the left-hemisphere interpreter in human origins

The ensemble hypothesis proposes that language is but one of five cognitive capacities that separate human cognition qualitatively from other animal cognition as a result of their interactions. The ensemble consists of an episodic memory capable of mental time travel, mentalizing to augment social cognition, language for overt communication, advanced executive attention for governing working memory, and inner speech for thinking in the form of causal inference. The order in which each of these components arose in hominin evolution is addressed here. It is proposed that the flourishing of symbolic artifacts during the Upper Paleolithic occurred because, for the first time, all five components were in place and interacting in anatomically modern Homo sapiens. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Mechanical Thrombectomy for the Treatment of Anterior Cerebral Artery Occlusion: A Systematic Review of the Literature

BACKGROUND

The overall safety and efficacy of mechanical thrombectomy for anterior cerebral artery strokes remain unclear.

PURPOSE

Our aim was to summarize procedural and clinical outcomes in patients who underwent mechanical thrombectomy for treatment of anterior cerebral artery ischemic stroke.

DATA SOURCES

A systematic literature review was performed using PubMed, Ovid MEDLINE, and the Web of Science from inception until March 4, 2022.

STUDY SELECTION

We identified 9 studies with a total of 168 patients with mechanical thrombectomy-treated anterior cerebral artery occlusions.

DATA ANALYSIS

Recanalization, procedural data, and clinical outcome at last follow-up were collected and summarized. Categoric variables were reported as proportions. The χ² test of independence or the Kruskal-Wallis test was performed to assess the relationship between selected variables and the anterior cerebral artery embolus type (ie, primary isolated anterior cerebral artery, primary combined anterior cerebral artery, and secondary anterior cerebral artery occlusion) or the mechanical thrombectomy technique.

DATA SYNTHESIS

For mechanical thrombectomy-treated anterior cerebral artery occlusions, recanalization modified TICI 2b/3 was achieved in 80%, postprocedural complications occurred in 17% of patients, and the 90-day mortality rate was 19%. The rate of symptomatic intracranial hemorrhage varied depending on the anterior cerebral artery embolus type (χ² = 8.45, P = .01).

LIMITATIONS

This analysis did not consider factors such as small-study effects that affect reliability and limit interpretation.

CONCLUSIONS

Mechanical thrombectomy for the treatment of anterior cerebral artery occlusions is safe and efficacious, offering a favorable rate of recanalization and procedural complications. Mechanical thrombectomy-treated anterior cerebral artery occlusions appear to have lower rates of short-term good functional outcomes and an increased risk of symptomatic intracerebral hemorrhage compared with mechanical thrombectomy-treated MCA/ICA occlusions. Single and multicenter studies are needed to further examine the safety and efficacy of mechanical thrombectomy-treated anterior cerebral artery occlusions.

The Complex Role of Mental Time Travel in Depressive and Anxiety Disorders: An Ensemble Perspective

The ensemble hypothesis proposes that uniquely human cognitive abilities depend on more than just language. Besides overt language, inner speech, and causal interpretations, executive attention, mental time travel, and theory of mind abilities are essential parts that combine additively and even multiplicatively. In this review, we consider the implications of the ensemble hypothesis for the psychopathologies of anxiety and depression. Generalized anxiety disorder (GAD) and major depressive disorder (MDD) are two of the most common mental disorders worldwide. The mechanisms that differentiate them are difficult to identify, however. Mental time travel has been implicated in models of depressive and anxiety disorders, but here we argue that at least two other ensemble components, namely, interpreter biases and executive attention, must also be considered. Depressive and anxiety disorders have both been found to show impairments in all three of these components, but the precise relationships seem to distinguish the two kinds of disorders. In reviewing the literature, we develop models for depression and anxiety that take into account an ensemble of mental components that are unique for each disorder. We specify how the relations among mental time travel, interpreter biases, and executive attentional control differ in depression and anxiety. We conclude by considering the implications of these models for treating and conceptualizing anxiety and depression.

Simple Feature Frequency versus Feature Validity Models of Formation of Prototypes

The typicality of a concept instance is related to the frequency with which its constituent features occur among all instances of the focal concept and possibly of other contrasting concepts. According to a simple frequency model, the prototype consists of the features that have occurred most often among instances of the focal concept. But according to a validity model, the prototype has the features that have occurred frequently among focal instances and, at the same time, infrequently among instances of contrast categories. By this account, the extent to which features overlap among focal and contrast instances is important in prototype formation. Here the feature frequencies among focal instances and the degree to which these features overlapped with contrast instances were manipulated. Twenty undergraduate college students first studied instances of the contrast category and then instances of the focal category. Next, they provided typicality ratings, frequency estimates of whole stimuli, and frequency estimates of features. All three measures supported the prediction of a simple frequency model of prototype formation.

Interference of Introspection with Thinking in Concept Identification

We examined changes in learning and in the content of verbal reports as a function of the regularity of introspective probes. Using a within-subjects design, concurrent undirected introspection was required on 0%, 50%, or 100% of the trials of a concept-identification task. The data for 18 subjects showed no differences in learning across 3 conditions. Verbal reports were classified according to the types of mental processes they indicated, e.g., hypothesis-testing. Analysis of the proportions of observed types suggested that the attention of subjects under the 100% condition wandered more to thoughts unrelated to the task than under the 50% condition; otherwise, the content of the verbal reports was uniform across these conditions. Undirected concurrent introspection seems to be a noninterfering, useful method for studying the nature of complex thinking.

Category Membership and Semantic Coding in the Cerebral Hemispheres

Although a gradient of category membership seems to form the internal structure of semantic categories, it is unclear whether the 2 hemispheres of the brain differ in terms of this gradient. The 2 experiments reported here examined this empirical question and explored alternative theoretical interpretations. Participants viewed category names centrally and determined whether a closely related or distantly related word presented to either the left visual field/right hemisphere (LVF/RH) or the right visual field/left hemisphere (RVF/LH) was a member of the category. Distantly related words were categorized more slowly in the LVF/RH relative to the RVF/LH, with no difference for words close to the prototype. The finding resolved past mixed results showing an unambiguous typicality effect for both visual field presentations. Furthermore, we examined items near the fuzzy border that were sometimes rejected as nonmembers of the category and found both hemispheres use the same category boundary. In Experiment 2, we presented 2 target words to be categorized, with the expectation of augmenting the speed advantage for the RVF/LH if the 2 hemispheres differ structurally. Instead the results showed a weakening of the hemispheric difference, arguing against a structural in favor of a processing explanation.

Semantic processing in the left versus right cerebral hemispheres following unilateral hand contractions

Unilateral hand contractions increase activation in the motor cortex of the contralateral hemisphere, providing a means to alter the relative degree of activation in the right hemisphere versus the left hemisphere through spreading activation. Prior research reported enhanced verbal creativity as measured by performance on remote associate problems in Hebrew from left-hand contractions (right-hemisphere activation). We sought to extend the previous findings to English problems and to homograph interpretation. In Experiment 1, unilateral hand contractions in fact altered performance on the English remote associates, but in the direction of improved performance following right-hand contractions and left-hemisphere activation. In Experiment 2, the probability of retrieving atypical interpretations of homographs with multiple meanings was least likely for left-hemisphere dominant strong right handers, but the hand contraction manipulation had no effect.

Differential verbal, visual, and spatial working memory in written language production

The contributions of verbal, visual, and spatial working memory to written language production were investigated. Participants composed definitions for nouns while concurrently performing a task which required updating, storing, and retrieving information coded either verbally, visually, or spatially. The present study extended past findings by showing the linguistic encoding of planned conceptual content makes its largest demand on verbal working memory for both low and high frequency nouns. Kellogg, Olive, and Piolat in 2007 found that concrete nouns place substantial demands on visual working memory when imaging the nouns' referents during planning, whereas abstract nouns make no demand. The current study further showed that this pattern was not an artifact of visual working memory being sensitive to manipulation of just any lexical property of the noun prompts. In contrast to past results, writing made a small but detectible demand on spatial working memory.

Improving the writing skills of college students

Advanced writing skills are an important aspect of academic performance as well as of subsequent work-related performance. However, American students rarely attain advanced scores on assessments of writing skills (National Assessment of Educational Progress, 2002). In order to achieve higher levels of writing performance, the working memory demands of writing processes should be reduced so that executive attention is free to coordinate interactions among them. This can in theory be achieved through deliberate practice that trains writers to develop executive control through repeated opportunities to write and through timely and relevant feedback. Automated essay scoring software may offer a way to alleviate the intensive grading demands placed on instructors and, thereby, substantially increase the amount of writing practice that students receive.

Verbal, visual, and spatial working memory in written language production

College students wrote definitions of either abstract or concrete nouns in longhand while performing a concurrent working memory (WM) task. They detected either a verbal (syllable), visual (shape), or spatial (location) stimulus and decided whether it matched the last one presented 15-45s earlier. Writing definitions of both noun types elevated the response time to verbal targets above baseline. Such interference was observed for visual targets only when defining concrete nouns and was eliminated entirely with spatial targets. The interference effect for verbal targets was the same whether they were read or heard, implicating phonological storage. The findings suggest that language production requires phonological or verbal WM. Visual WM is selectively engaged when imaging the referents of concrete nouns.

Are written and spoken recall of text equivalent?

Writing is less practiced than speaking, graphemic codes are activated only in writing, and the retrieved representations of the text must be maintained in working memory longer because handwritten output is slower than speech. These extra demands on working memory could result in less effort being given to retrieval during written compared with spoken text recall. To test this hypothesis, college students read or heard Bartlett's "War of the Ghosts" and then recalled the text in writing or speech. Spoken recall produced more accurately recalled propositions and more major distortions (e.g., inferences) than written recall. The results suggest that writing reduces the retrieval effort given to reconstructing the propositions of a text.

Working memory components in written sentence generation

College students wrote either simple or complex sentences using 2 prompt nouns while components of working memory were distracted with a concurrent task. Loads on the visual and spatial components of working memory (retain a shape) and verbal component (retain 3 or 6 digits) were compared with a no-load control. Only the 6-digit load reliably reduced sentence length relative to the control, suggesting that unimpeded sentence generation requires verbal working memory. The sentence length effect may arise from a failure to retrieve and maintain lexical representations during grammatical encoding. Memory load had no effect on grammatical and spelling errors, implying that syntactic and orthographic processing were undisturbed. Other possibilities locate the difficulty in planning conceptual content or in phonological encoding, but some evidence speaks against them.

Concurrent activation of high- and low-level production processes in written composition

Writing a text requires the coordination of multiple high-level composition processes in working memory, including planning, language generation, and reviewing, in addition to low-level motor transcription. Here, interference in reaction time (RT) for detecting auditory probes was used to measure the attentional demands of (1) copying in longhand a prepared text (transcription), (2) composing a text and pausing handwriting for longer than 250 msec (composition), and (3) composing and currently handwriting (transcription + composition). Greater interference in the transcription + composition condition than in the transcription condition implies that high-level processes are activated concurrently with motor execution, resulting in higher attentional demands. This difference was observed for adults who wrote in standard cursive, but not for children and not for adults who used an unpracticed uppercase script. Greater interference in the composition condition than in the transcription condition implies that high-level processes demand more attention than do motor processes. This difference was observed only when adults wrote with a practiced script. With motor execution being relatively automatic, adults were able to attend fully to the high-level processes required in mature, effective composition. One reason that children fail to engage in such high-level processes is that motor processes deplete available attention.

Competition for working memory among writing processes

Narrative, descriptive, and persuasive texts were written by college students in longhand or on a word processor. Participants concurrently detected auditory probes cuing them to retrospect about whether they were planning ideas, translating ideas into sentences, or reviewing ideas or text at the moment the probes occurred. Narrative planning and longhand motor execution presumably were heavily practiced, freeing capacity for rapid probe detection. Spare capacity was distributed equally among all 3 processes, judging from probe reaction times, when planning demands were low in the narrative condition. When motor execution demands were low in the longhand condition, however, reviewing benefited more than planning. The results indicate that planning, translating, and reviewing processes in writing compete for a common, general-purpose resource of working memory.

Presentation modality and mode of recall in verbal false memory

False memories were investigated for aurally and visually presented lists of semantically associated words. In Experiment 1, false written recall of critical intrusions was reliably lower following visual presentation compared with aural presentation. This presentation modality effect was attributed to the use of orthographic features during written recall to edit critical intrusions from visually presented lists. As predicted by this hypothesis, the modality effect was eliminated when the mode of recall was spoken rather than written. In Experiment 2, the modality effect in written recall was again replicated and then eliminated with an orienting task that ensured orthographic encoding even of aurally presented words. Thus, the modality effect appears to depend on using orthographic information to distinguish true from false verbal memories.

Long-term working memory in text production

In reading and other high-level cognitive tasks, Ericsson and Kintsch (1995) proposed that the limited capacity of short-term working memory (STWM) is supplemented by long- term working memory (LTWM) for individuals with a high degree of domain-specific knowledge. In Experiment 1, college students (N = 80) wrote persuasive and narrative texts concerning baseball; domain-specific knowledge about baseball and verbal ability was assessed. The results showed that verbal ability and domain-specific knowledge independently affected writing skill, supporting the view that literacy depends on both knowledge sources and refuting one argument raised in support of the LTWM hypothesis. Experiment 2 (N = 42) replicated this outcome and tested the prediction that a high degree of domain-specific knowledge would lessen interference on a secondary task. The data supported the interference prediction, offering evidence that LTWM plays a role in the production of text.