Hominid evolution, supralaryngeal vocal tract physiology, and the fossil evidence for reconstructions.

The functional, physiologic aspects of the human supralaryngeal vocal tract, which follow from the equal length of the oral and pharyngeal cavities and their right angle orientation are discussed. Sounds like the vowels [i] and [u], which only the human supralaryngeal vocal tract can produce in a Quantal mode, provide a selective advantage for vocal communication and the evolution of the human vocal tract and matched neural property detectors. The dissimilarity between Neanderthal skulls and specimens of anatomically modern Homo sapiens and other fossil skulls is discussed in relation to the reconstruction of the Neanderthal supralaryngeal vocal tract. The absence of some of the innate neural property detectors that play a part in the perception of human speech can be inferred in Neanderthal hominids from the reconstruction of their supralaryngeal vocal tract.     

Passing markers: A theory of contextual influence in language comprehension

Most Artificial Intelligence theories of language either assume a syntactic component which serves as “front end” for the rest of the system, or else reject all attempts at distinguishing modules within the comprehension system. In this paper we will present an alternative which, while keeping modularity, will account for several puzzles for typical “syntax first” theories. The major addition to this theory is a “marker passing” (or “spreading activation”) component, which operates in parallel to the normal syntactic component.     

The nature and structure of infant form categories

The nature of form categories in 3 to 4-month infants was studied using the visual preference for novelty in the familiarization-novelty paradigm. Novelty preference indicates habituation to and recognition of the familiar. In a series of experiments employing three form categories composed of dot patterns, generalized habituation to new category members was used to assess categorization behavior in the recognition of visual forms. At 3 to 4 months of age, infants did not initially show any systematic preferences for “good” or symmetrical examples of a category relative to “distorted” examples (Experiment 1) and this was true for all three form categories used (i.e., square, triangle, and diamond). Evidence for categorization was seen in the recognition performance of 3- to 4-month infants (Experiment 2). Infants showed generalized habituation to the previously unseen category prototypes following exposure to six exemplars within each of the three form categories. Given evidence that infants could discriminate between the prototype and other category members (Experiment 3), “inability to discriminate” was ruled out as an explanation for this form categorization or generalized habituation effect. Four subsequent experiments were conducted to determine whether infants exhibit a prototypicality structure for their remembered categories and whether certain conditions which have been shown to enhance prototypicality effects with adults have similar effects with infants. No evidence of a prototypicality structure was found for the form categories of infants when the number of exemplars during familiarization was limited to 6 and the test for form recognition followed immediately (Experiment 4). However, a prototypicality structure for the remembered form categories was found when a 3-min delay was introduced between familiarization and tests for form recognition (Experiment 5), when 12 exemplars were presented during familiarization (Experiment 7), or when the prototype was included as one of the six exemplars during the familiarization period (Experiment 6).     

Short-term memory for time intervals

The effect of intertrial interval, preset interval, and retention interval on the performance of rats in a time estimation task was described. On each trial a signal was presented for a duration of 2 to 8 sec. Eighteen rats were trained to press one lever (the short response) if the signal was shorter than 4 sec, and another lever (the long response) if the signal was longer than 4 sec. When trials were massed (Experiment 1), the percentage long response was affected by the classification of the previous signal, but not by its actual duration. This suggests that the animals remembered the response made on the previous trial, but not the signal duration. If a response was not permitted on the previous trial (Experiment 2), the duration or classification of the previous signal had no effect on performance. This supports the conclusion from the first experiment and suggests that an animal can reset its internal clock in less than 2 sec. In Experiment 3, the difference limen of the psychophysical function increased with the duration of the retention interval, but the point of subjective equality did not change. This suggests that resetting of the internal clock occurs on a non-time dimension.     

Selective attention and the processing of integral and nonintegral dimensions: A developmental study

In two experiments, first- and fourth-grade subjects (age 6 and 9 years) performed a speeded card-sorting task with either integral or nonintegral dimensions. The dimensions were so arranged that subjects sorted on three types of task: (1) single dimension, (2) correlated dimensions, and (3) orthogonal dimensions. Results of the first experiment indicate that both first- and fourth-grade subjects sorted integral dimensions in a manner not qualitatively different from that of the adult (Garner & Felfoldy, Cognitive Psychology, 1970, 1, 225–241). In comparison with single-dimension tasks, performance was facilitated on the correlated-dimensions tasks and interference was observed on the orthogonal-dimensions tasks. Performances with nonintegral dimensions revealed an age-related processing difference. Fourth graders sorted nonintegral dimensions like the adult; no differences in performance were observed between the tasks. In contrast, first-graders sorted nonintegral dimensions as if they were integral. Interference was consistently observed on orthogonal-dimensions tasks. On correlated-dimensions tasks, interference was observed on easy tasks and redundancy facilitated difficult tasks. In the second experiment, first graders showed consistent facilitation on the correlated-dimensions task; all other results were indentical to those of Experiment I. The results were interpreted as consistent with perceptual learning theory (Gibson, Principles of perceptual learning and development. New York: Appleton-Century-Crofts, 1969).     

An analysis of generative representation systems

Three ideas are basic to generative theory: (a) Subjects are assumed to attend to the relations among stimuli, extracting the transformations relating pairs of stimuli; (b) the set of abstracted transformations is decomposed or reduced to an elementary set of generators; (c) subjects use the elementary generators as the basis for judging similarity. The purpose of this paper is to illustrate these ideas with an experiment in which subjects were asked to rate the similarity between stimulus pairs. The stimulus materials consisted of the permutations of a 4-item pattern with the properties of a dihedral group which insured the existence of sets of elementary transformations. Three analytic techniques were used to determine the generator set of transformations abstracted by subjects. The first analysis consisted of a monotonic regression between dissimilarity ratings and the number of elementary generators of a given permutation. The residual variance of this monotone regression, suitably normalized, was used as a quantitative goodness-of-fit measure. For the stochastic analysis, cumulative distributions of dissimilarity ratings were obtained for permutations requiring one, two, or three generators. The idea was that permutations requiring fewer generators should be associated with distributions of lower dissimilarity values (higher similarity scores) as compared to permutations predicted to be transformationally more complex. The final analysis, a multidimensional scaling of dissimilarity ratings, converted subjects' ratings into spatial structures to determine whether individual subjects' ratings exhibited the predicted spatial arrangement. The monotone regression and stochastic analyses abstracted similar generator sets for individual subjects, some of which provided perfect fits to the data. Although the scaling analysis yielded similar estimates of generators, for some subjects, transformations with the same number of generators yielded unequal “cognitive” distances resulting in some-what deformed spatial structures for these subjects. It was concluded that the results generally supported a generative model as an approximation to subjects' representations of interstimulus relationships.     

Selective attention and the breadth of learning: A developmental study

Nursery school and second-grade subjects were trained on an optional intradimensional/extradimensional shift task with (1) no overtraining, (2) overtraining on the initial problem only, (3) overtraining on the shift problem only, or (4) overtraining on both the initial and the shift problems. Predictions concerning the effects of age and training conditions on the type of solution and the breadth of learning for the shift problem were derived from selective attention theory. However, the results were not consistent with the one-look assumption of such models. Instead, a multiple-look theory in which the breadth of attention varies with task demands seems most tenable.     

Observing behavior in monkeys (Macaca arctoides): Support for the information hypothesis

A single lever, discrete-trials observing procedure was used with stumptailed monkeys (Macaca arctoides). Lever-presses during a trial produced colored key lights (IS⁺ and IS^?) which signaled whether the trial would end with response-independent food or without food. During the baseline period, both IS⁺ and IS^? were produced on a variable-interval (VI) 15-sec schedule which began operating at the onset of the trial. The two experimental conditions involved a combination of this VI schedule and a DRL schedule. In one of these conditions, only a response that both met the VI requirement and was preceded by at least 6 sec of nonresponding could produce IS^? on nonfood trials, while the schedule for IS⁺ on food trials remained VI 15 sec. In the other experimental condition, the schedules for producing the two stimuli were the reverse. All subjects eventually learned to produce either IS⁺ or IS^? on the combined VI-DRL schedule. These data support an information hypothesis of observing in monkeys and contrast with data from pigeons which support a conditioned reinforcement hypothesis.     

Retrieval of sentence relations: Semantic vs. syntactic deep structure

Two experiments on unaided and cued recall of sentences presented in context are reported. Key nouns in the sentences were arranged to have uniform surface functions, but to vary independently in deep syntactic category and semantic function. Cued recall for sentences in which the semantic function of actor and recipient coincided with the syntactic function of deep subject and object, respectively, was better than for sentences which did not have this normal semantic-syntactic coincidence. Unaided recall was not different for the two types of sentences. Models of sentence processing may have to represent both types of information as available to the language user.     

The confluence model: Parameter estimation for six divergent data sets on family factors and intelligence

Theoretical predictions, based on the confluence model, were made for data from six national surveys of intellectual performance. All six surveys relate intellectual performance scores to family configuration variables. Widely divergent patterns of relationships between the major family factors, such as birth order and family size, and intellectual performance scores characterize the six data sets. Nevertheless, the confluence model was capable of accurate prediction in all cases when all three parameters were estimated. Little accuracy was lost using only two parameters. Variations in the estimated parameter values that reflected the variations in patterns of effects could be meaningfully interpreted for their psychological significance.     

Cerebral lateralization, preferred cognitive mode, and reading ability in normal children

In a sample of 105 children (aged 6 to 12), a stylistic preference for a verbal approach to problem-solving correlated positively with reading ability (independently of age) and degree of right-ear advantage in the report of dichotic stop consonant-vowel syllables (but not with verbal intelligence or hand preference). Verbal strategic preference may: (1) foster the acquisition of reading skill, and (2) bias attention toward input from the right by generating differential left-hemisphere activation.     

Let's pretend: The role of motoric imagery in memory for sentences and words

A number of theories suggest that for young children, concepts should have an important motoric (or sensory-motor) component. A levels-of-processing theory is proposed which predicts that processing on motoric imagery should facilitate memory for both isolated words and for sentences. Experiment 1 examined the effects of motoric enactment (viz., pretend play) of sentences on memory for the sentences. Motoric imagery facilitated memory for both children (5 to 7 years of age) and adults, though, contrary to expectations, the effects were weaker for the children than for the adults. Further, it was found that motoric imagery affected the initial acquisition, but was not important as a retreival cue. Experiment 2 examined the effects of motoric imagery on free recall of lists of unrelated words. Under these conditions, motoric imagery facilitated memory for both children (7 to 9 years of age) and adults equally; in contrast, visual imagery instructions had no effect on memory. These results indicate that motoric imagery may facilitate memory under conditions in which visual imagery has no effect. Theoretical implications are explored for previous experiments on pretend play which suggest that training for pretent enactment can facilitate cognitive development.     

Controllability and human stress: method, evidence and theory.

Concepts are defined and evidence reviewed on whether control reduces stress in man. Individuals seem to prefer instrumental control over an aversive event, seem to prefer to administer it to themselves, and are less aroused when waiting for a controllable event. When groups without control have equal predictability, having control is still less arousing; as potential (but unexercised) control seems to be. The evidence also suggests that controllable events may hurt less. Methodological weaknesses and empirical gaps in these data are pointed out. These data are grossly inconsistent with Relevant Feedback theory and rather inconsistent with Information-seeking theory and Safety Signal theory. A Minimax hypothesis is proposed: When individuals control aversive events, they believe relief to be caused by a stable source—their own response. This belief entails that maximum future danger will be minimized. When they have no control, they believe relief to be less stable, which entails no guarantee that maximum future danger will be minimized. The data are largely consistent with the Minimax hypothesis and wholly consistent when Minimax is supplemented by the premise that aversive events hurt less when encountered against a background of relaxation.