A comparison of five methods of illusion measurement

The relative efficiency of five techniques of illusion measurement were tested on parametric variations of the Mueller-Lyer and Ebbinghaus figures. The methods of average error, reproduction, and selection from a graded series all showed significant effects of configurational variations. The subjective scaling techniques each failed to measure adequately changes in illusion magnitude for one illusion configuration. The suitability of the tested measures for group administration is also discussed.     

Polydipsia induced in the rat by a second-order schedule

Drinking was studied in rats pressing a bar on a second-order schedule in which every third completion of a 1-min fixed interval was followed by food presentation. A brief flash of light signaled the completion of each fixed-interval component. The rats drank not only after the food presentations but also after presentations of the light flash alone. A high rate of steady drinking followed intervals terminated by a food presentation. Drinking that followed intervals terminated by a light flash alone was of comparable rate, but characteristically interrupted by bar pressing. When 250-mg food pellets were used instead of 45-mg pellets, both drinking and bar-pressing rates increased substantially.     

The effect of two schedules of primary and conditioned reinforcement

Of 23 pigeons, 11 received continuous reinforcement for key pecking, and 12 received an FR 10 schedule of reinforcement. The birds were then tested without food, but with potential conditioned reinforcers presented either on the same schedule as in training, on the other schedule, or not at all. Each bird in the subgroup trained on CRF and tested with S^r's at FR 10 not only gave more responses in testing than did each bird in both subgroups receiving no S^r's, but also gave more responses than did each bird in the S^r subgroup receiving CRF training and S^r's at CRF. Cumulative records are presented to show the effects of different schedules of conditioned reinforcers.     

Kinaesthetic judgements of the direction of line by young children

The ability of young children to make kinaesthetic judgements of direction of line has been studied under recognition and detection conditions. Some children were not more accurate than chance when they were required to indicate the same one of a pair of mirror image obliques lines over a series of trials; these children could, however, detect whether two obliques were oriented in the same direction or in different directions. These latter data suggest that the poor recognition of mirror image obliques arises from deficiencies in spatial categorizing and not in input coding. This conclusion is supported by the finding that children who performed poorly on the kinaesthetic recognition of obliques performed poorly on the visual recognition of these figures.     

Experimental Construct Validity of the Outcomes of Study Skills Training and Career Counseling as Treatments for the Retention of At-Risk Students

The authors evaluated the separate and combined effects of study skills training and career counseling on student retention. Participants who were at high risk for dropping out of college were randomly assigned to one of four treatment or control conditions. The study-skills-alone treatment had a significant impact on retention; all of these participants continued their enrollment in the following two semesters. Career-counseling-alone and a combined (study skills plus career counseling) treatment did not register significant effects. Participants who received the study-skills-alone treatment also achieved significantly greater academic success; 88% had grade point averages (GPAs) equal to or greater than 2.0, whereas most other treatment and control participants had GPAs lower than 2.0 and were placed on academic probation. Issues relevant to the construct validity of these changes are discussed.     

Infant use of relative motion as information for form: Evidence for spatiotemporal integration of complex motion displays

Previous studies of infants’ ability to integrate and to utilize relative motion as information for form in the absence of structural cues have primarily involved motions that are uniform in rate, direction, and path within the form to be constructed. In the present study, we examined infants’ ability to integrate relative motion information from motions that are nonuniform along these dimensions, and from this integrative process to construct a coherently rotating two-dimensional form. Infants’ ability to integrate nonuniform motion was measured with regard to their ability to discriminate the rotating form from a noncoherent control display containing the same absolute motions. The results showed that discrimination of the coherent and incoherent displays was not demonstrated until 7 months of age. Two additional experiments were conducted to rule out the possibility that this discrimination was based on the detection of local regions of coherence, rather than the perception of the global rotating form. In both experiments, the results did not support discrimination based exclusively on local cues alone. From the combined results of all three experiments, we conclude that infants demonstrate the capacity to integrate the information contained within nonuniform trajectories into a coherent structure by 7 months of age.     

Phonological and form class relations in the lexicon

Two experiments were conducted to examine the structure of the mental lexicon. A lexical search of American English, using the Brown corpus (Francis and Kucera, 1982), revealed a skewed, frequency-dependent distribution in which the syntactic classes of noun and verb are distinguished in terms of the phonological classification of their vowels. Among high-frequency words, nouns are more likely to have back vowels (57%) rather than front vowels (43%) and verbs more likely to have front vowels (62%) than back vowels (38%). This distribution, however, does not hold for low-frequency nouns and verbs in the language. Noun and verb stimuli containing front and back vowels were examined in both an auditory noun/verb categorization task and an auditory lexical decision task. In general, the phonotactic composition of nouns and verbs in the lexicon was shown to have perceptual consequences. Listeners seem to be differentially sensitive to incoming sound patterns on the basis of distributional properties of the lexicon.These experiments were conducted at the Brown University Phonetics Laboratory. The technical expertise of John Mertus and Andrew Mackie as well as the help of Martha Burton and Annemie Witjes are gratefully acknowledged.     

Conversational time patterns and mutual influence in parent-child interactions: A time series approach

Mutual influencing processes are assumed to be the basic building blocks in establishing parentchild bonding and in influencing cognitive and language behavior. A study by Jasnow and Feldstein (1986) revealed that, within the temporal domain of speech, preverbal (9-month-old) infants and their mothers exhibit a pattern of mutual influence (attunement) in their average durations of switching pauses. The general purpose of this research was to extend those findings to children with higher verbal functioning. In addition, parent and child genders, nature of the interaction, and specific aspects of parents' personalities, expressiveness, and instrumentality were considered. Each parent interacted with their 4-or 5-year-old son or daughter in each of two conversations—unstructured (social conversation) and structured (task activity). Conversations were processed by an automated computer system yielding objective measure of turns, vocalizations, pauses, and switching-pause durations. To examine interspeaker influence or attunement of temporal speech patterns, influence coefficients were computer for each speaker on a turn-by-turn basis using time series regression. Analysis of these coefficients revealed that: (1) Mutual influence is most evident with switching-pause duration. (2) Structure in the conversation (as defined by the task or parental instrumentality) seems to facilitate attunement for vocalization and switching pause duration. (3) Attunement with girls seems to occur equally well with both parents, while boys exhibit a style of temporal patterning influence which suggests greater identification with the father. (4) Expressiveness seems to facilitate attunement to the child's switching-pause duration.     

A multidimensional scaling analysis of vowel discrimination in humans and monkeys

Multidimensional scaling (MDS) was used to compare perceptual maps for 10 synthetic English vowels in humans and Old World monkeys (Macaca fuscata andCercopithecus albogularis). Subjects discriminated among the vowels using a repeating background procedure, and reaction times were submitted to an MDS analysis to derive measures of perceived similarity. The dimensions that emerged related to the frequencies of the first(F1), second(F2), and third(F3) formants. Human data indicated a good match to previous MDS studies using rating procedures or confusion matrices: The dominant dimension mapped onto vowelF2, the phonetically most important formant, and the second and third dimensions mapped ontoF1 andF3, respectively.For monkeys, equal weightings occurred forF1 andF2, andF3 was not clearly represented. Monkey sensitivity to the formants appeared to relate to formant amplitudes. If monkeys are giving an accurate representation of the psychoacoustic relations among the formants, then our human results suggest that species-specific mechanisms, reflecting the salience of the phonetic feature of advancement, may contribute to vowel coding in humans.