Hierarchical coding in speech timing

The analysis of syllable and pause durations in speech production can provide information about the properties of a speaker's grammatical code. The present study was conducted to reveal aspects of this code by analyzing syllable and pause durations in structurally ambiguous sentences. In Experiments 1–6, acoustical measurements were made for a key syllabic segment and a following pause for 10 or more speakers. Each of six structural ambiguities, previously unrelated, involved a grammatical relation between the constituent following the pause and one of two possible constituents preceding the pause. The results showed lengthening of the syllabic segments and pauses for the reading in which the constituent following the pause was hierarchically dominated by the higher of the two possible preceding constituents in a syntactic representation. The effects were also observed, to a lesser extent, when the structurally ambiguous sentences were embedded in disambiguating paragraph contexts (Experiment 7). The results show that a single hierarchical principle can provide a unified account of speech timing effects for a number of otherwise unrelated ambiguities. This principle is superior to a linear alternative and provides specific inferences about hierarchical relations among syntactic constituents in speech coding.     

Increasing and decreasing intrinsic interest with contingent rewards: A test of cognitive evaluation theory

The study examined Deci's (Deci, E. L. Intrinsic motivation. New York: Plenum Press, 1975) hypotheses regarding the effects of contingent rewards on intrinsic task interest. Seventy-two male university students worked on a series of puzzles and were given either a high value reward ($1.50) or a low value reward ($.45). The money was given either contingent upon the simple execution of the task (task-contingent), contingent upon the ostensible attainment of a performance criterion level (criterion-contingent), or noncontingent and unexpected (control). Compared to the high payment control subjects, subjects who received the task-contingent high reward rated the task as less interesting, while subjects who received the criterion-contingent high reward rated it as more interesting. Also, subjects expressed less interest in the task after receiving the high task-contingent reward than the low task-contingent reward, but indicated greater interest after receiving the high criterion-contingent reward than the low criterion-contingent reward. It was concluded that substantial support was obtained for Deci's (1975) cognitive evaluation theory.     

Self-punitive behavior in humans: Effects of a self-fulfilling prophecy

Human subjects were exposed to contingencies which programmed aversive tones (100 db). Two types of contingencies were employed: self-confirming (i.e., self-fulfilling prophecies), in which the aversive tone was occasioned by the prediction it was about to occur; and self-disconfirming, in which the tone was probable when subjects predicted it would not occur. Experiments 1 and 2 used a modified classical conditioning paradigm, and demonstrated that a self-confirming contingency maintained reliable self-punitive responding, i.e., subjects consistently predicted and therefore obtained tones on every trial. Subjects in Experiment 3 were instructed to express predictions continuously throughout four sessions to ensure adequate sampling of the various predictions. Subjects exposed to a self-disconfirming contnngency reliably evidenced awareness of the contingency in effect (judged by answers on a postexperimental questionnaire), whereas subjects exposed to a self-confirming contingency failed to show effective avoidance behavior or contingency awareness. Experiment 4 investigated free-operant self-punitive behavior, utilizing a single prediction response button, which subjects depressed repeatedly. Subjects were exposed to either periodic or aperiodic punishment schedules over as many as four sessions. In general, more persistent self-punitive responding was found in the groups receiving periodic punishment. The results from the four experiments show that self-confirming contingencies can effectively prolong self-punitive responding in human subjects. The findings are consistent with a blocking interpretation of self-punitive behavior, which asserts that when an aversive event is already predicted by stimuli in the situation (including temporal cues), the association between a response and punishment is impaired, and self-punitive responding is likely to be maintained. An integration of human and animal self-punitive research is proposed.     

Origin of the speech apparatus and its reconstruction in fossils.

Renewed enthusiasm has produced provocative speculations in recent literature on the origin of speech. The purpose of the present investigation is to expose the adaptive renovations underlying the emergence of a “Vocal Tract” and from this to define its anatomical substrate which governs the biomechanics of speech production. The vocal tract is a double resonator tube coupled in series and composed of oral and pharyngeal cavities. Analysis is made of the crucial structural elements of this complex from detailed dissections in modern man and the study of modern and fossil hominid crania. The study focuses on relations of the skull base, jaw, hyoid bone and the contained tongue, pharynx and valvular devices, calling into question recent reconstructions built on classical Neanderthal skulls.     

Effects of age,stimuli, and category recognition factors in children's inquiry behavior

One hundred twenty-eight children of average intellectual ability from grades K, 1, 2, and 5 (ages 6, 7, 8, and 11, respectively) were administered a 20-questions task involving the presentation of 24 stimulus pictures and a forced-choice post-test. The four-factor design included four grade levels, two stimulus conditions (basic-level and superordinate), and two instruction conditions (cueing and non-cueing) for boys and girls. Results indicated older children generated more efficient questions, all children in the Cued-instruction condition asked more constraint-seeking questions in the Basic-level condition than in the Superordinate condition on the 20-questions task, and all children in the Basic-level condition selected more efficient questions in the post-test forced-choice task than in Superordinate condition. It was concluded that even younger school-age children will generate efficient constraint-seeking questions when Basic-level stimuli are used and when children are cued.     

Intratrial proactive interference in pigeon short-term memory: Manipulation of stimulus dimension and dimensional similarity

Proactive interference was studied using an intratrial preparation in two delayed matching-to-sample experiments employing pigeons. On interference trials, an interfering sample and a target sample were presented successively and were followed by a test consisting of a choice between two stimuli, one associated with each sample. Control trials were identical to interference trials except that the interfering sample was not presented. On both types of trials, choice of the comparison corresponding to the target sample was defined as correct. Colored fields and line orientations were employed as sample stimuli in Experiment 1, and samples of food and no food and of number of pecks were employed in Experiment 2. Interference was found to be equally robust regardless of whether the interfering and target samples were each selected from any of the four dimensions (color, line orientation, food/no food, or number of pecks). Amount of interference was found to be independent of whether the interfering and target samples employed on a trial were selected from the same dimension or from different dimensions. Evidence was also obtained suggesting that line orientation comparison stimuli are more likely to elicit a response not based on memory than are color comparison stimuli.     

Rate reduction strategies used by normally fluent and stuttering children and adults

Speech rate can be reduced by prolonging the duration of phonetic units, by pausing between words, or through a combination of these approaches. Child and adult normally fluent speakers and stutterers were tested in basal and modified speaking rate conditions. Subjects' utterances in both conditions were converted to spectrographic displays so that measures of phonetic and pause durations could be made. Comparisons of these measures across conditions revealed that all four groups of subjects spontaneously extended pause and phonetic durations, the former more than the latter, when instructed to voluntarily reduce speech rate.     

Speech timing skills of normally fluent and stuttering children and adults

This study was designed to explore the speech timing skills of normally fluent and stuttering children and adults producing two sentences, ten consecutive times at basal and modified speaking rates. Spectrographic displays of subjects' utterances in both conditions were made in order to obtain consonant, vowel, pause, and utterance duration measures. Results showed that (1) the two groups of children produced speech durational values similar to those of the two adult groups and (3) there were no consistent between- and within-group differences in the basal and modified rate conditions. Findings are discussed in terms of methodological and sampling differences that exist between the present study and past research on stutterers' speech production abilities.     

The effects of cue reliability on infants' manual search.

Nine-month-old babies were presented a manual search problem in which toys were hidden in one of two containers, and then the containers were transposed. Over a series of training trials either two, one, or no cues were perfectly correlated with the location of the toy. The infants' first searches became more accurate over training trials in conditions with consistent container and/or position cues. In the final training trial block search performance was best with two cues, intermediate with one cue, and least accurate in the no-cue condition. In a subsequent reversal procedure, in which the toy was placed in the previously unused hiding place, the number of correct first searches also differed according to the nature of cues available across hidings. The implications for learning the concept of object permanence are discussed.