Nonverbal Analogue Research Articles

An Analysis of an Autoclitic Analogue in Pigeons.

Using a conditional discrimination procedure, pigeons were exposed to a nonverbal analogue of qualifying autoclitics such as definitely and maybe. It has been suggested that these autoclitics are similar to tacts except that they are under the control of private discriminative stimuli. Instead of the conventional assumption of privacy, which precludes direct manipulation of the controlling variable, the autoclitic was here identified as a response that is jointly determined by its function as a modifier for the consequence of the tact and by some variable that modifies stimulus control of the tact. Following this modified conceptualization, a novel conditional discrimination procedure was developed as an analogue for establishing autoclitic-like behavior in pigeons. Under some conditions, autoclitic-like behavior was established. Methodological challenges in developing an autoclitic analogue in nonhumans are discussed, followed by a consideration of the implications of such analogues for the understanding of verbal and, more broadly, human behavior.

Interference control in children with reading difficulties

Two studies investigated whether the greater Stroop interference reported in children with reading difficulties compared to typical readers of the same age represents a generalized deficit in interference control or a consequence of their reading problems. In Study 1, a color-word Stroop task and a nonverbal task involving responses to locations associated with pictures were administered to 23 children with single word reading difficulties and 22 typically developing children matched for age and nonverbal ability. Children with reading difficulties showed disproportionate interference effects in the color-word Stroop but not the nonverbal task. In Study 2, groups of poor and typical readers completed a spatial Stroop task with printed input that did not require a verbal response and a nonverbal analogue. Both groups showed comparable interference in these two tasks. Thus, the reported problems in the color-word Stroop task in children with reading difficulties do not appear to entail general impairments in interference control.

Differential Effects of Parkinson's Disease and Dopamine Replacement on Memory Encoding and Retrieval

Increasingly memory deficits are recognized in Parkinson's disease (PD). In PD, the dopamine-producing cells of the substantia nigra (SN) are significantly degenerated whereas those in the ventral tegmental area (VTA) are relatively spared. Dopamine-replacement medication improves cognitive processes that implicate the SN-innervated dorsal striatum but is thought to impair those that depend upon the VTA-supplied ventral striatum, limbic and prefrontal cortices. Our aim was to examine memory encoding and retrieval in PD and how they are affected by dopamine replacement. Twenty-nine PD patients performed the Rey Auditory Verbal Learning Test (RAVLT) and a non-verbal analogue, the Aggie Figures Learning Test (AFLT), both on and off dopaminergic medications. Twenty-seven, age-matched controls also performed these memory tests twice and their data were analyzed to correspond to the ON-OFF order of the PD patients to whom they were matched. We contrasted measures that emphasized with those that accentuated retrieval and investigated the effect of PD and dopamine-replacement on these processes separately. For PD patients relative to controls, encoding performance was normal in the off state and was impaired on dopaminergic medication. Retrieval was impaired off medication and improved by dopamine repletion. This pattern of findings suggests that VTA-innervated brain regions such as ventral striatum, limbic and prefrontal cortices are implicated in encoding, whereas the SN-supplied dorsal striatum mediates retrieval. Understanding this pattern of spared functions and deficits in PD, and the effect of dopamine replacement on these distinct memory processes, should prompt closer scrutiny of patients' cognitive complaints to inform titration of dopamine replacement dosages along with motor symptoms.

Tuning to non‐symbolic proportions in the human frontoparietal cortex

Humans share with many species a non-verbal system to estimate absolute quantity. This sense of number has been linked to the activity of quantity-selective neurons that respond maximally to preferred numerosities. With functional magnetic resonance imaging adaptation, we now show that populations of neurons in the human parietal and frontal cortex are also capable of encoding quantity ratios, or proportions, using the same non-verbal analog code as for absolute number. Following adaptation to visually presented constant proportions (specified by the ratio of line lengths or numerosities), we introduced novel relative magnitudes to examine the tuning characteristics of the population of stimulated neurons. In bilateral parietal and frontal cortex we found that blood oxygenation level-dependent signal recovery from adaptation was a function of numerical distance between the deviant proportion and the adaptation stimulus. The strongest effects were observed in the cortex surrounding the anterior intraparietal sulcus, a region considered pivotal for the processing of absolute magnitudes. Overall, there was substantial overlap of frontoparietal structures representing whole numbers and proportions. The identification of tuning to non-symbolic ratio stimuli, irrespective of notation, adds to the magnitude system a remarkable level of sophistication by demonstrating automatic access to a composite, derived quantitative measure. Our results argue that abstract concepts of both absolute and relative number are deeply rooted in the primate brain as fundamental determinants of higher-level numerical cognition.

RAVLT and Nonverbal Analog: French Forms and Clinical Findings

Objective clinical evaluation of memory frequently requires serial testing but the issue of whether multi-formed tests are equivalent and can be used interchangeably is seldom examined. An added problem in bilingual Canadian settings is the extent to which it is appropriate to measure French speakers' performance on translations of English tests. The present work used the Rey Auditory Verbal Learning Test (RAVLT) and a nonverbal analog, the Aggie Figures Learning Test (AFLT), to examine whether a) different forms of the same test are equivalent, b) performance on the two tests is comparable, c) two language groups perform similarly, and d) the RAVLT can detect dysfunction in patients with temporal lobe epilepsy (TLE). We compared three French versions of the RAVLT and three forms of the AFLT in 114 healthy francophone adults. We subsequently compared the performance of the same francophone subjects to a previously obtained sample of anglophones on both tests, and then administered the RAVLT to anglophone or francophone patients with TLE. For both tasks the three forms were equivalent and performance on the RAVLT was comparable to that on the AFLT. Francophone subjects performed slightly worse on the RAVLT compared to anglophones but performance of the two language groups did not differ on the AFLT. Finally, left TLE patients were impaired compared to right on the RAVLT, but no performance differences were observed across the two language groups in the patient sample. The RAVLT and AFLT are useful tools for examination of learning and memory in French and English speaking populations. On the RAVLT, the lesion effect in patients is not affected by differences in performance between language groups.

Lateralized frontal blood flow increases during fluency tasks: influence of cognitive strategy

Difficulties with verbal fluency tasks (VFIT) have been shown mainly to be associated with left frontal lobe pathology in lesion studies. The design fluency test (DFT) is a non-verbal analogue of word fluency tasks and has, in patients with right frontal lobe pathology, been coupled to an inability to perform well. Regional cerebral blood flow measurements (rCBF) were made in normals to elucidate the involvement of frontal and frontotemporal brain regions during the performance of VFT and DFT. In addition, the subjects’ reports were used for obtaining information about the cognitive strategy used when solving the tasks. The results confirm previous CBF findings showing a mainly left-sided frontal activation during the VFT. During the DFT significant flow augmentations were seen in both frontal lobes compared to baseline. Furthermore, the use of different strategies was reflected in different patterns of brain activation. Our results support the proposal that the left frontal cortical area is engaged in the generation of internally driven responses. Furthermore, we argue that the cortical areas engaged during the execution of these tasks may reflect differences in cognitive strategy.

Performance of healthy subjects and patients with resection from the anterior temporal lobe on matched tests of verbal and visuoperceptual learning.

We examined the equivalence of three matched forms of the Rey Auditory Verbal Learning Test (RAVLT) and three parallel forms of a new nonverbal analog, the Aggie Figures Learning Test (AFLT). One hundred and fourteen healthy subjects, primarily college students, were administered corresponding forms of the two tasks. For both tasks the three forms proved to be well-matched; as well, overall performance on the RAVLT was comparable to that on the AFLT. The two tasks were also administered to 23 patients with anterior resection from the left or right temporal lobe (ATL). Findings showed that right ATL patients were significantly impaired on the learning trials of the AFLT as compared to their learning on the RAVLT; they showed little forgetting of figures or words over a 20-min delay interval. By contrast, left ATL patients showed severe forgetting of words as compared to figures, but their learning curve for the RAVLT did not differ from that on the AFLT.

Nonverbal recognition and recency discrimination deficits in Parkinson's disease and Alzheimer's disease.

In a study of verbal temporal ordering, patients with Parkinson's disease (PD) were impaired in making judgements of the relative recency of serially-presented words but were normal in word recognition; by contrast, patients with Alzheimer's disease (AD) were impaired on both verbal tasks (Sagar et al., 1985, 1988b). The present study used a nonverbal analogue of the verbal temporal ordering task to examine whether the deficit in recency discrimination of the PD patients transcended material-specific bounds or was specific to verbal material. The nonverbal task was administered to the patients with PD, patients with AD and normal control subjects studied with the verbal task. The results showed that the retention functions for the recognition of verbal and nonverbal material differed qualitatively from each other and this difference was present in all three subject groups. For verbal and nonverbal recency discrimination and verbal content recognition, performance declined with increasing retention intervals; for nonverbal content recognition, however, performance was essentially unchanging across retention intervals. As on the verbal test, recency discrimination on the nonverbal test was impaired in both patient groups. In contrast to the results with the verbal task, both groups were impaired on content recognition. The patterns of impairment, however, differed between the two patient groups in a parallel way to those of the verbal task: performance of the AD group was impaired at the longest retention intervals but not at the shortest intervals, whereas the performance of the PD group was impaired at the shortest but not at the longest intervals. This deficit in nonverbal short-term recognition memory was present even in PD patients who scored within the normal range on a quantitative test of dementia. These results show that deficits in recency discrimination and short-term memory processing in PD extend to nonverbal as well as verbal material and imply bilateral frontal lobe dysfunction in the genesis of these deficits.

Functional Relationship Between Forward and Backward Digit Repetition and a Non-Verbal Analogue

It has been suggested that the forward digit span employs a verbal representation of sequences of digits, whereas the backward digit span employs a spatial representation. This was tested by comparing the two digit spans with a non-verbal analogue of the forward digit span. The latter did not explain any of the variation in the backward digit span when the forward digit span was stastically controlled. It is concluded that the two digit spans employ a common verbal representation.

A Non-Verbal Analog to the Verbal Transformation Effect

The verbal transformation effect, the phenomenon in which continued listening to recorded repetitions of a stimulus produces perceptual illusory changes in normal listeners, has been elicited by a variety of speech stimuli, including isolated vowels, consonant-vowel nonsense syllables, words, phrases, and sentences. The purpose of this investigation was to determine the effectiveness of non-speech sounds as auditory stimuli in eliciting a non-verbal analog to this perceptual phenomenon. A total of five stimuli, three pure tones (250, 1000, and 4000 Hz), white noise, and a five-note musical motif, were repeatedly presented for a five-minute period to each of 25 adult listeners. Results indicate that the transformations elicited by the non-speech sounds are similar to those produced by speech stimuli in number of forms elicited, specific forms, and types of transformations. However, listeners usually require more repetitions of the non-speech stimuli before perceiving transformations. Implications of these findings for the proposed theory that verbal transformations represent skilled reorganizational mechanisms which aid in speech perception are discussed.