The cortical language circuit: from auditory perception to sentence comprehension

Over the years, a large body of work on the brain basis of language comprehension has accumulated, paving the way for the formulation of a comprehensive model. The model proposed here describes the functional neuroanatomy of the different processing steps from auditory perception to comprehension as located in different gray matter brain regions. It also specifies the information flow between these regions, taking into account white matter fiber tract connections. Bottom-up, input-driven processes proceeding from the auditory cortex to the anterior superior temporal cortex and from there to the prefrontal cortex, as well as top-down, controlled and predictive processes from the prefrontal cortex back to the temporal cortex are proposed to constitute the cortical language circuit.     

PROSS: A process control programming language

PROSS, a programming language for small- and medium-scale process control computers, is presented. The PROSS language, whose structure and syntax were expressly designed for ease of use by psychologists, is summarized and exemplified in a sample procedure. The structure of an existing PROSS compiler is briefly summarized.     

A developmental deficit in short-term phonological memory: Implications for language and reading

Abstract

QU, an eight-year-old boy, was identified from a large scale normative study on the basis of his greatly reduced digit span, combined with normal long-term memory and non-verbal intelligence. Further investigation indicated that his visual STM was normal, but that he was clearly impaired on two verbal STM tests, nonword repetition, and memory span for words. His span showed clear effects of phonological similarity and word-length, suggesting qualitatively normal functioning of the phonological loop component of working memory, despite a quantitative impairment in level of performance. This pattern resembles that found in an earlier study of children with a specific language disorder. We tested QU on measures of vocabulary, syntax, and reading, and found him to be substantially below the age norms on all three. The implications of these findings are discussed for the role of the phonological loop in language development.     

A high-level language for control of psychology experiments

A language for controlling learning, memory, and perception experiments is described. The language features the capability of manipulating large amounts of alphanumeric information with ease. A small, but powerful, command set uses the psychologists’, rather than the programmers’, logic and jargon.     

Internal conflict,language, and metaphor: Implications for psychotherapy

The term conflict has only metaphorical validity when applied to internal dynamics, because an organism can never actually be at war with itself. Drawing upon Maturana's theory of living systems, we argue that the concept of conflict has been taken too literally by therapists and clients. Instead of eliminating conflict, we urge therapists to focus on the interpersonal implications of language habits and to explore with clients the options for more effective action in the social community.The authors would like to express their appreciation to G. Craig Caputo, Elsa R. Efran, Joseph Fiorito, Charles E. Gallagher, Christopher K. Germer, Richard J. Leffel, M. Penny Levin, Alan J. Lipman, Michael D. Lukens, Robert J. Lukens, and Richard Sadowsky, each of whom read earlier drafts and contributed valuable suggestions.     

Retroactive interference from translation equivalents: Implications for first language forgetting

First language vocabulary is vulnerable to forgetting after massive exposure to a second language. Two possible factors responsible for the forgetting are degree of semantic overlap between concepts in the two languages and amount of second language exposure. In a laboratory simulation of the language forgetting situation, participants received 10 exposures to a list of words in a foreign language, followed by 2, 5, 10, or 15 exposures to a list in a second foreign language. The second list consisted of either translation equivalents or new concepts. Participants were then tested for retention of the first list. More retroactive interference was found for translation equivalents than for new concepts and for higher degrees of exposure to the second list. When retention of the first list was broken down in terms of gains and losses, effects of both similarity of the second list to the first and amount of exposure to the second list were found only for losses--a fact that points to lack of discriminability as one of the underlying causes of forgetting. Overall, the experimental paradigm proved useful for exploring and developing theories about the causes of first language forgetting.     

The evolution of the critical period for language acquisition

Evidence suggests that there is a critical, or at least a sensitive, period for language acquisition, which ends around puberty. The existence of this period is explained by an evolutionary model which assumes that (a) linguistic ability is in principle (if not in practice) measurable, and (b) the amount of language controlled by an individual conferred selective advantage on it. In this model, the language faculty is seen as adaptive, favoured by natural selection, while the critical period for language acquisition itself is not an adaptation, but arises from the interplay of genetic factors influencing life-history characters in relation to language acquisition. The evolutionary model is implemented on a computer and simulations of populations evolving under various plausible, if idealized, conditions result in clear critical period effects, which end around puberty.     

Semantic operations in aphasic comprehension: implications for the cortical organization of language.

We provide data on the neurological basis of two semantic operations at the sentence level: aspectual coercion and complement coercion. These operations are characterized by being purely semantic in nature; that is, they lack morphosyntactic reflections. Yet, the operations are mandatory (i.e., they are indispensable for the semantic well formedness of a sentence). Results indicate that, whereas Broca's patients have little or no trouble understanding sentences requiring these operations (performance was above chance for all conditions), Wernicke's patients performed at normal-like levels only for sentences that did not require these operations. These findings suggest that sentence-level semantic operations rely very specifically on the integrity of the cortical area associated with Wernicke's aphasia, but not on the region corresponding to Broca's aphasia. In the context of other findings from lesion and imaging studies, this evidence allows a view of the cortical distribution of language capacity that is drawn along a linguistic line, one which distinguishes syntactic from semantic operations.     

TYMES: A high-level language for process control and data manipulation in the behavior laboratory

This paper describes outlines of the TYMES software system designed and developed to control complicated experiments in the behavior laboratory. A versatile programming language is adopted to perform a wide range of real-time data manipulations and interactive controls based on a PDP-11 small computer.     

The neurobiology of addiction: implications for voluntary control of behavior

There continues to be a debate on whether addiction is best understood as a brain disease or a moral condition. This debate, which may influence both the stigma attached to addiction and access to treatment, is often motivated by the question of whether and to what extent we can justly hold addicted individuals responsible for their actions. In fact, there is substantial evidence for a disease model, but the disease model per se does not resolve the question of voluntary control. Recent research at the intersection of neuroscience and psychology suggests that addicted individuals have substantial impairments in cognitive control of behavior, but this "loss of control" is not complete or simple. Possible mechanisms and implications are briefly reviewed.     

The evolution of the language faculty: clarifications and implications

In this response to Pinker and Jackendoff's critique, we extend our previous framework for discussion of language evolution, clarifying certain distinctions and elaborating on a number of points. In the first half of the paper, we reiterate that profitable research into the biology and evolution of language requires fractionation of "language" into component mechanisms and interfaces, a non-trivial endeavor whose results are unlikely to map onto traditional disciplinary boundaries. Our terminological distinction between FLN and FLB is intended to help clarify misunderstandings and aid interdisciplinary rapprochement. By blurring this distinction, Pinker and Jackendoff mischaracterize our hypothesis 3 which concerns only FLN, not "language" as a whole. Many of their arguments and examples are thus irrelevant to this hypothesis. Their critique of the minimalist program is for the most part equally irrelevant, because very few of the arguments in our original paper were tied to this program; in an online appendix we detail the deep inaccuracies in their characterization of this program. Concerning evolution, we believe that Pinker and Jackendoff's emphasis on the past adaptive history of the language faculty is misplaced. Such questions are unlikely to be resolved empirically due to a lack of relevant data, and invite speculation rather than research. Preoccupation with the issue has retarded progress in the field by diverting research away from empirical questions, many of which can be addressed with comparative data. Moreover, offering an adaptive hypothesis as an alternative to our hypothesis concerning mechanisms is a logical error, as questions of function are independent of those concerning mechanism. The second half of our paper consists of a detailed response to the specific data discussed by Pinker and Jackendoff. Although many of their examples are irrelevant to our original paper and arguments, we find several areas of substantive disagreement that could be resolved by future empirical research. We conclude that progress in understanding the evolution of language will require much more empirical research, grounded in modern comparative biology, more interdisciplinary collaboration, and much less of the adaptive storytelling and phylogenetic speculation that has traditionally characterized the field.     

Empirical approaches to the study of language evolution

The study of language evolution, and human cognitive evolution more generally, has often been ridiculed as unscientific, but in fact it differs little from many other disciplines that investigate past events, such as geology or cosmology. Well-crafted models of language evolution make numerous testable hypotheses, and if the principles of strong inference (simultaneous testing of multiple plausible hypotheses) are adopted, there is an increasing amount of relevant data allowing empirical evaluation of such models. The articles in this special issue provide a concise overview of current models of language evolution, emphasizing the testable predictions that they make, along with overviews of the many sources of data available to test them (emphasizing comparative, neural, and genetic data). The key challenge facing the study of language evolution is not a lack of data, but rather a weak commitment to hypothesis-testing approaches and strong inference, exacerbated by the broad and highly interdisciplinary nature of the relevant data. This introduction offers an overview of the field, and a summary of what needed to evolve to provide our species with language-ready brains. It then briefly discusses different contemporary models of language evolution, followed by an overview of different sources of data to test these models. I conclude with my own multistage model of how different components of language could have evolved.     

On the evolution of language and generativity.

One of the properties that most conspicuously distinguishes human language from any other form of animal communication is generativity. Language with this property therefore presumably evolved with the Homo line somewhere between H. habilis and H. sapiens sapiens. Some have suggested that it emerged relatively suddenly and completely with H. sapiens sapiens, and this view is consistent with (a) linguistic estimates as to when vocal language emerged, (b) the relatively late "explosion" of manufacture and cultural artifacts such as body ornamentation and cave drawings, and (c) evidence on changes in the vocal apparatus. However, evidence on brain size and developmental patterns of growth suggests an earlier origin and a more continuous evolution. I propose that these scenarios can be reconciled if it is supposed that generative language evolved, perhaps from H. habilis on, as a system of manual gestures, but switched to a predominantly vocal system with H. sapiens sapiens. The subsequent "cultural explosion" can then be attributed to the freeing of the hands from primary involvement in language, so that they could be exploited, along with generativity, for manufacture, art, and other activities.     

PSYCHOL: A computer language for experimentation

Psychologists employing digital computers in the laboratory to control experimental procedure must construct programs. A language is described that incorporates many data representations and manipulations useful in presenting stimuli, collecting responses, and deciding the course of an experiment. PSYCHOL is an extension to a subset of ALGOL, with data types extended to include simple lists, strings of text, historic variables, and responses. Timing mechanisms, stimulus presentation, and data recording instructions expand the operations available within the language.     

Three-dimensional movement trajectories in Fitts' task: Implications for control

According to Fitts (1954), movement time (MT) is a function of the combined effects of movement amplitude and target width (index of difficulty). Aiming movements with the same index of difficulty and MT may have different planning and control processes depending on the specific combination of movement amplitude and target size. Trajectories were evaluated for a broad range of amplitudes and target sizes. A three-dimensional motion recording system (WATSMART) monitored the position of a stylus during aiming movements. MT results replicated Fitts' Law. Analysis of the resultant velocity profiles indicated the following significant effects: As amplitude of movement increased, so did the time to peak resultant velocity; peak resultant velocity increased slightly with target size, and to a greater extent with increases in the amplitude of movement; the time after peak resultant velocity was a function of both amplitude and target size. Resultant velocity profiles were normalized in the time domain to look for scalar relation in the trajectory shape. This revealed that: the resultant velocity profiles were not symmetrical; the proportion of time spent prior to and after peak speed was sensitive to target size only, i.e. as target size decreased, the profiles became more skewed to the right, indicating a longer decelerative phase; for a given target size, a family of curves might be defined and scaled on movement amplitude. These results suggest that a generalized program (base trajectory representation) exists for a given target width and is parameterized or scaled according to the amplitude of movement.     

Developmental verbal control of behavior: Implications for self-instructional training

Kindergarten, first-grade, and second-grade children (5, 6, and 7 years of age, respectively) performed a Luria-type verbal control task in which motor responses are initiated to positive stimuli and inhibited to negative stimuli. The task was performed by motor responding only and verbal self-directed motor responding, with these conditions reversed in sequence for one half of each grade group. Although motor responding and verbal-motor responding by the two younger groups were generally poor, their performance equalled that of the second graders when the verbalizing condition followed the silent, motor-only condition. For these children, verbalizing appeared to constitute a second task which interfered with motor responding. Prior practice on motor-only responding, however, facilitated subsequent, concurrent performance of the two tasks. No interference or practice effects were found for the second graders. The results suggested that self-instructional training programs are likely to be successful when adequate verbal-motor coordination can be assumed or when the motor response is within the child's repertoire.     

Cognitive control: dynamic, sustained, and voluntary influences

The cost of incongruent stimuli is reduced when conflict is expected. This series of experiments tested whether this improved performance is due to repetition priming or to enhanced cognitive control. Using a paradigm in which Word and Number Stroop alternated every trial, Experiment 1 assessed dynamic trial-to-trial changes. Incongruent trials led to task-specific reduction of conflict (trial n + 2) without cross-task modulation (trial n + 1), but this was fully explained by repetition priming. In contrast, an increased ratio of incongruent words did lead to sustained task-specific enhancement, above and beyond repetition priming (Experiment 2). Experiments 3 and 4 assessed the voluntary modulation of cognitive control: A cue predicted the congruency of the incoming trial, allowing participants to establish the correct mindset (Word Stroop in Experiment 3, Flanker task in Experiment 4). Preparing oneself to process an incongruent word (or flanker) enhanced conflict resolution in the subsequent Number Stroop, an example of cross-task modulation. Taken together, these experiments reveal the multifaceted aspects of conflict resolution: Trial-to-trial changes are often due to repetition priming; sustained modulations brought about by task demands are task specific; and voluntary modulations are task general.