Curvilinear Trend Research Articles

Effects of increased speaking rate on temporal and spectral information for coarticulated vowels

As part of a larger study of the role of dynamic (time‐varying) spectral information in the perception of vowels, we are analyzing American English vowels spoken in bisyllables imbedded in a carrier sentence by one female who normally speaks rapidly. Eleven vowels in six /hə C1VC2/ contexts (C1 = b,d,g; C2 = d,t) were produced at the subjects' normal speaking rate and at a “rapid” rate (69% of normal sentence duration). Durations of test syllables were systematically reduced; rapid/normal ratios were 75% for CVd syllables and 83% for CVt syllables. Relative durations were well maintained; the correlation between rapid and normal syllable durations was +0.93, and showed only a slight curvilinear trend suggesting almost no limit of compressibility for the shortest vowels. Dynamic spectral structure and “target undershoot” is also being analyzed. Formant frequencies at three points—one‐third, one‐half, and two‐thirds through the vocalic nucleus—will be compared to explore whether “vowel‐inherent” spectral ch...

New Evidence on the Development of the Word Big

Previous studies of children's understanding of big suggest a curvilinear trend. 3-year-olds, like adults, interpret big as referring to area, while 5-year-olds take big to mean tall. The results of 6 experiments indicate that the curvilinear trend is not obtained in all stimulus contexts. When objects vary extremely, younger and older children take big to mean tall. The object to which big is applied also influences whether height, length, or area is attended to. Moreover, in a production task, adults rarely used the work big to describe the stimuli with which children's understanding of big is typically tested. Taken together, the results suggest that the meaning and use of big is complex and that big may not at any age refer simply to the larger object. It is proposed that the meaning of big is a dynamic system driven by a multiple of perceptual, conceptual, and semantic influences.

Sex-and age-dependent effects of prenatal exposure to caffeine on open-field behavior, emergence latency and adrenal weights in rats

Pregnant rats were provided with drinking water containing 0, 0.23 or 0.3 mg/ml of caffeine throughout gestation. These concentrations gave rise to daily doses of 0, 28 and 36 mg/kg. Open-field behavior and latencies to emerge from a darkened chamber were observed in offspring at regular intervals from 1 to 8 months after birth. The main results revealed increases in open-field locomotor and rearing activity with 28 but not 36 mg/kg/day. The opposite pattern characterized emergence latency. These changes were more typical of male rats particularly when older. Combining the present results with those of an earlier study by the authors strengthened the curvilinear trends observed and led to the conclusion that, low doses of prenatal caffeine increase activity and decrease emotionality. Higher doses may have the opposite effects to the point that the significant differences from control subjects reported earlier can occur. When 8 months old, female but not male rats prenatally exposed to 36 mg/kg/day of caffeine had significantly heavier adrenal glands than controls.

Plate convergence and deformation, North Luzon Ridge, Philippines

Marine geophysical and earthquake seismology data indicate that the North Luzon Ridge, a volcano-capped bathymetrie ridge system that extends between Luzon and Taiwan, is presently undergoing deformation in response to the relative motion between the Asian and Philippine Sea plates. Plate motion models predict convergence along the western side of the Philippine Sea plate, from Japan in the north to Indonesia in the south, and most of this plate margin is defined by active subduction zones. However, the western boundary of the Philippine Sea plate adjacent to the North Luzon Ridge shows no evidence of an active WNW-dipping subduction zone; this is in marked contrast to the presence of both the Philippine Trench/East Luzon Trough subduction zones to the south and the Ryukyu Trench subduction zone to the north. Crustal shortening, in response to ongoing plate convergence in the North Luzon Ridge region, apparently takes place through a complex pattern of strike-slip and thrust faulting, rather than by the typical subduction of oceanic lithosphere along a discreet zone. The curvilinear bathymetrie trends within the North Luzon Ridge represent the traces of active faults. The distribution of these faults, mapped by both multichannel and single-channel seismic reflection methods and earthquake seismicity patterns and focal mechanism solutions, suggest that right-lateral, oblique-slip faulting occurs along NE-trending faults, and left-lateral, oblique-slip faulting takes place on N- and NNW-trending faults. The relative plate convergence accommodated by the deformation of the North Luzon Ridge will probably be taken up in the future by the northward-propagating East Luzon Trough subduction zone.

Comment on "Evangelicals and Status Issues"

I read with interest the Wald, Owen and Hill article linking status politics to the New Christian Right (NCR), a relationship that has been an important concern in my own research (Miller, 1985). The authors' new methods of measuring status politics and discontent is a valuable contribution. However, in my view, there is one conceptual ambiguity in this study which needs to be clarified before the validity of their conclusions can be assessed. Wald et al. are not clear about whether status politics is being used to explain who joins certain types of social movements (recruitment) or why certain social movements, as movements themselves, come into existence at certain times and places. It is possible to see both conceptualizations in this paper. On the one hand, Wald et aL (1989: 1) say say that the status politics model asserts that moral reform movements attract groups who resent their cultural, political, and moral devaluation by the dominant society. This seems to indicate that the authors are using status politics to understand recruitment to the NCR, that a preexistent social movement called the NCR became powerful because it was able to attract individuals who were experiencing status discontent. However, at other points in this article, Wald et aL seem to imply that status politics is being used to explain why the NCR, as a movement in itself, came about at the time it did (e.g., see the discussion in the last paragraph on page two). Why is it important to distinguish analytically between these two ways of using status politics? Because each conceptualization must be tested using a different research design. If the status politics model is concerned strictly with recruitment, then Wald et al.'s design is more than adequate and their conclusions would seem to have validity. However, if status politics is being used to explain why the NCR as a movement developed in the late 1970s, some type of historical and/or longitudinal design is necessary. We must be able to see if the status discontent of fundamentalists was low before NCR mobilization, increased as the movement began forming, and was at its highest point when the NCR entered the political arena in the late 1970s. Wald et al offer no such design. My own research (Miller, 1985) used such a design to test this status politics-NCR relationship. In a quantitative content analysis of fundamentalist publications from 1955 to 1980, I found no systematic linear or curvilinear trends in lifestyle concerns amongst fundamentalists. Status discontent, while high, remained the same throughout this time period. I concluded that status discontent cannot explain why the NCR developed at the time it did. In conclusion, then, while Wald et aL do offer important evidence on who joins and

Optimal insemination interval, semen dose and dilution for optimum fertility in chickens under humid tropical conditions

The effect of insemination interval, semen dose and dilution on fertility was investigated. Good fertility was obtained with twice-weekly insemination using 0.01 to 0.05 ml undiluted semen, 0.03 to 0.05 ml semen diluted 1:1 or 0.04 ml semen diluted 1:3, and also with weekly insemination using 0.04 ml undiluted semen. Fertility showed a downward linear trend with dilution and a curvilinear trend with dosage, for all frequencies.

Mood and Behavior at Adolescence: Evidence for Hormonal Factors*

We studied the relationship among behavior, mood, pubertal development, hormonal levels, and psychological functioning in 100 adolescent white girls between the ages of 10.6-13.3 yr. The girls were grouped by pubertal breast stages and four stages of estradiol secretion. No significant mood or behavior changes were found as a function of pubertal stages, controlling for age effects, except for a decrease in interest in sports. The hormonal stages revealed a significant curvilinear trend for depressive affect (increase, then decrease; P less than 0.01), impulse control (decrease, then increase; P less than 0.04), and psychopathology (increase, then decrease; P less than 0.03) scales, indicating significant changes in these behaviors during times of rapid increases in hormone levels. These data suggest that hormonal changes may be more important than the physical changes as determinants of certain mood and behavior patterns at adolescence.

Quantitative and compositional variations of massese sheep milk by parity and stage of lactation

Effects of parity and length of lactation on physico-chemical characteristics of sheep milk were evaluated on milk samples from the first to the sixth lactation of 100 Massese sheep in Italy. Milk samples were collected twice a month and the following items were studied: quantity of milk, length of lactation, physico-chemical characteristics, amino acids, fatty acids and mineral content of the milk. Milk production showed a decreasing curvilinear trend with days of lactation, according to the formula y=2.1409−0.012 x+0.00002 x 2. Parity had a significant effect on total milk yield ( P⩽0.006), and on physico-chemical milk characteristics ( P⩽0.001), but had no effect on amino acid, fatty acid and mineral contents. Stage of lactation caused high variability in almost all analytical parameters expressed by linear or quadratic regression, with the exception of several amino acids which were independent of this factor.

あいまいさに対する不寛容，政治的関心，および政治的態度の三者関係について

The purpose of this study was to investigate the relationships between intolerance of ambiguity and political interest and political attitudes, Twenty-four items of a political attitudes scale in a “catchphrase” format, 10 items of a scale measuring intolerance of ambiguity and a 12-item political interest scale were prepared and administered to 292 university students living in Shizuoka, Japan. The main results showed that: (1) greater tolerance of ambiguity was observed in subjects with the most innovative political attitudes as compared to both moderate and conservative subjects; (2) among male subjects, conservatives were more tolerant of ambiguity than moderates, but conservatives were most intolerant of ambiguity across all political-attitude groups in females; and, (3) there was a curvilinear trend between political attitudes and political interest in males while a linear relationship was observed in females. These results showed the importance of sex-related factors when considering the nature of the relationships between personality variables, political interest, and political attitudes.

Mother‐child verbal interaction and children's ability level

The study examines mother‐child interaction characteristics of elementary school children at three ability levels. Factor analysis of interaction variables revealed one general factor of mother‐child interaction style named Maternal Verbal Guidance (MVG). It correlated significantly with academic achievement. A curvilinear trend was found, suggesting an interdependence between task difficulty and t he MVG factor for average and superior students, but not for low achievers. Discussion of the results are framed within a Vygotskian perspective of intellectual development.

An interpretation of the tectonostratigraphic framework of the Murray Basin region of southeastern Australia, based on an examination of airborne magnetic patterns

New pixel map representations of regional total magnetic intensity data reveal previously unknown characteristics of the basement concealed beneath thin Cainozoic sediments of the Murray Basin in southeastern Australia. Interpretations of magnetic patterns in terms of structural features allow a revised interpretation of the nature of the tectonostratigraphic framework underlying and flanking the basin. The magnetic data indicate that arcuate or curvilinear structural trends under the Murray Basin do not conform with those of the exposed Lachlan Fold Belt to the east and suggest that the basement concealed beneath the basin, together with that exposed in the Victorian Highlands to the south, forms a distinct composite tectonostratigraphic terrane. Beneath the southwestern Murray Basin ?Proterozoic-Lower Cambrian metasediments of the Padthaway Ridge of the Kanmantoo Fold Belt display a northwesterly trending structural grain and a previously unsuspected continuity of structural trend with Adelaidean-Cambrian rocks of the Mount Lofty Ranges to the west. In the south, Cambrian volcanics of the Black Range and Stavely greenstone belts have similar magnetic response and appear to be components of a single elongate and strongly magnetic domain which extends to the northwest for at least 400 km (Stavely Belt). To the north a similar but entirely concealed northeasterly trending magnetic domain can also be interpreted as volcanics (Lake Wintlow Belt). Together these two magnetic domains appear to form an arcuate zone of volcanics, with a concave-to-the-east configuration, located at a possible suture between the Lachlan and Kanmantoo Fold Belts beneath the western Murray Basin. In the south the magnetic imagery indicates that metasediments of the ?Cambro-Ordovician Stawell Belt produce magnetic patterns distinct from those produced by the metasediments of the adjacent Ordovician Bendigo Belt, which can itself be subdivided into a number of areas of distinct magnetic pattern. Magnetic domains can be interpreted in terms of concealed Proterozoic and Palaeozoic structural belts and tectonostratigraphic terranes. Reconstructions suggest that much of the Murray Basin may be underlain by a former microcontinental block or rifted marginal plateau of Precambrian crust, now welded to the Precambrian craton to the west. Deformation of the Kanmantoo and Adelaide Fold Belts adjacent to and beneath the western and southwestern margins of the basin, can be attributed to Late Cambrian-Early Ordovician convergence between the microcontinental block and the craton. Volcanics of the arcuate Stavely and Lake Wintlow Belts are interpreted to be located at the suture between the microcontinental block and the craton. In addition, the presence of concave-to-the-east, curvilinear magnetic trends in the Cambro-Ordovician metasedimentary belts beneath the Murray Basin suggests that these successions, as well as the volcanics of the Heathcote and Mount Wellington Belts, may form allochthonous sheets. These were possibly emplaced from the east during Late Ordovician-Devonian deformation, possibly related to convergence of a further microcontinental block underlying the adjacent Lachlan Fold Belt to the east of the Murray Basin.

The geochemical evolution of Proterozoic granitoids near Port Lincoln in the Gawler orogenic domain of South Australia

Proterozoic granitoids in the Port Lincoln area of the Gawler orogenic domain of South Australia changed in mineralogy and composition through time. Two older suites, the > 1843 Ma Massena Bay orthogneisses and the 1843 Ma Donington pyroxene granitoids, have curvilinear trends on a modified ACF diagram and relatively unfractionated HREE, consistent with compositional evolution through pyroxene- and plagioclase-dominated crystal fractionation. On the other hand, the 1757 Ma Colbert and 1709 Ma Moody suites have modal hornblende, more strongly fractionated HREE and rectilinear trends on the ACF diagram. They probably require hornblende- and plagioclase-dominated fractionates and/or amphibole (± garnet) as a residual phase during partial melting. Superimposed on this two-fold subdivision of older and younger granitoid suites according to degree of HREE fractionation and ACF trends, there are also progressive compositional changes from the oldest to the youngest granitoids. For example, at comparable SiO 2 levels the granitoid suites become progressively richer in K, LREE, Zr, Nb, Ti and P, but Mg, Ca, Sc, V, Ni and Cr progressively decrease. These secular compositional patterns are similar to those described for the Mt Isa region of northern Australia, including the Ewen-Kalkadoon magmatic association to which the Donington suite bears many compositional similarities. Normalised incompatible element plots for the Port Lincoln area granitoid suites have similar shapes to penecontemporaneous mafic dykes. Major and trace element modelling allows derivation of the granitoids by partial melting in the lower crust of mafic granulites compositionally analogous to the mafic dykes. Proterozoic crustal growth in the Port Lincoln area probably took place by vertical accretion through underplating of new mafic material to the lower crust and subsequent remelting of this to yield magmas of granitoid composition.

Syn- and post-rift igneous activity in the Porcupine Seabight Basin and adjacent continental margin W of Ireland

Summary An igneous province in the Porcupine Seabight Basin and adjacent shelf region W of Ireland records repeated episodes of intrusive and extrusive igneous activity, from the mid-Jurassic to late Oligocene. The ‘Province’ maintains a regionally distinctive NE-SW and NNW-SSE curvilinear trend that is inherent to the basement. Mid-Jurassic pyroclastic airfall deposits were probably contemporaneous with mid-Kimmerian uplift. Voluminous early Cretaceous volcanism was coeval with an episode of rifting during the Valanginian to Barremian interval in the Porcupine and Goban Spur Basins. In particular, the 150 km long ‘Porcupine Median Volcanic Ridge’ (PMVR) is interpreted to be extrusive in the S, but progressively intrusive northwards; from an inferred fissure volcano to a laccolith. Aptian-Albian volcaniclastics are of unknown association, but coincide with the onset of oceanic spreading along the adjacent proto-Atlantic margin. Documented late Cretaceous intrusive and extrusive igneous activity was minor in scale although a period of marked inversion is recorded for the NE Porcupine Basin, which may relate to the emplacement of the areally extensive Brendan Igneous Centre. Intermittent intrusive and extrusive activity throughout the Palaeogene was broadly coincident with the full duration of the ‘Thulean’ Palaeocene igneous event. Further activity, variously dated from Eocene to late Oligocene, is partly attributed to a series of intrabasinal, parallel-aligned plugs of intrusive and extrusive origin situated in the upper Porcupine Basin and termed the ‘Slyne Fissures’. These fissures, whose basement-controlled lineation prolongates onshore as an extended group of sheet intrusions, appear to emanate from the Brendan Centre. Further dykes in County Kerry are also believed to extend towards the same centre. Within the Province a distinction is made between magmatism that is essentially syn-rift and linked to basin development (notably Valanginian-Barremian), and later post-rift activity (Aptian-Tertiary). The size, emplacement character and location of the PMVR may represent a sudden increase in axial volcanism that occurred during advanced stages of basinal rifting, and could be viewed as a prelude to, or transition from rifting to spreading prior to an abrupt failure. Temporal relationships can be proposed between active faulting associated with initial lithospheric stretching (late Kimmerian), late syn-rift igneous activity (Valanginian-early Barremian) and the initiation of subsequent lithospheric stretching (earliest Barremian) and, finally, the onset of seafloor spreading (Albian) on the continental margin W of Goban Spur. The later post-rift activity is described as ‘opportunistic’ and triggered by exterior tectonic events that utilized existing tensile trends within the Basin. Emplacement of the Brendan Centre was probably responsible for a phase of inversion with its concomitant influence on sedimentation patterns. Magmatism in the Eocene and Oligocene was associated with minor faulting, an unconformity and pronounced post-Eocene subsidence, together indicative of a final regional thermal episode.

The digestible and metabolizable energy of two fat blends for growing pigs as influenced by level of inclusion

AbstractTwo fat blends differing in free fatty acid concentration and fatty acid composition were included in cereal-based diets at concentrations of 10, 30, 50, 70, 90 and 110g/kg. The digestible (DE) and metabolizable (ME) energy of each diet were estimated in a metabolism experiment based on three 4 × 4 Latin squares using gilts of 30 kg initial live weight fitted with indwelling bladder catheters. With increasing dietary fat both DE and ME increased linearly (P < 0·001) and the linear equations derived were used to calculate the DE values of the two fats by extrapolation. Values were 26·4 and 24·2 MJ/kg respectively for fats A and B. The change in dietary D E and ME to increasing dietary fat concentration showed a curvilinear trend (P = 0·0987 and 0·1268 respectively for DE and ME ) indicating that fats may not be correctly evaluated at only one rate of inclusion. The quadratic functions derived were interpolated to provide DE and ME data for the two fats. Values for DE for fat A ranged from 32·7 o t 25·7 MJ/kg at 10 and HOg/kg, and for fat B from 38·6 to 26·3 MJ/kg at 10 and 110 g/kg. Data for ME followed similar trends. It was concluded that multi-level assays are important in the evaluation of fats and that the rate of decline of fat DE and ME was specific to the fat examined.

Sulfur and lead isotope studies of stratiform Zn-Pb-Ag deposits, Anvil Range, Yukon; basinal brine exhalation and anoxic bottom-water mixing

Five stratiform Zn-Pb-Ag deposits are known in Early Cambrian metapelitic rocks along a curvilinear trend in the Anvil Range, central Yukon. The Anvil Range deposits occur along the southwestern boundary of the Selwyn basin in the stratigraphic transition zone between metapelites of the Mt. Mye unit and calcareous phyllites of the overlying Vangorda unit. The massive sulfides are associated closely with anomalously thick graphitic phyllites, apparently related to a second-order basin. A typical Anvil cycle of mineralization begins with a ribbon-banded graphitic-quartzitic-pyritic unit. This grades upward into sulfide-bearing quartzite, quartzitic massive sulfide, massive sulfide, and finally a baritic massive sulfide horizon. Sericitic alteration envelopes irregularly encompass each deposit and locally are developed best in footwall rocks.Detailed sulfur isotope studies have been carried out on the DY and Grum deposits and on one representative drill hole from the Faro deposit. The delta 34 S values of sulfide minerals generally range from 10 to 22 per mil and are similar in all three deposits. The delta 34 S values of pyrite in unmineralized samples from the district exhibit a wider range, from 6 to 34 per mil, and show distinct upward stratigraphic increase due to a stagnation cycle in the basin.The delta 34 S values of barite samples are strongly dependent on bottom-water conditions and mode of mixing during brine exhalation. They range from 22 to 26 per mil in the Faro deposit to 36 to 42 per mil in the DY deposit. These variations are due to mixing of isotopically light sulfate (18-20ppm) in Ba-bearing ore fluid and isotopically heavy residual sulfate (30-60ppm) in anoxic seawater.Thirty-eight samples of galena from the DY, Grum, Faro, SB, and Swim deposits have been analyzed for lead isotope ratios. In general, the lead isotope ratio data indicate an upper crustal lead source, with the Proterozoic Grit unit which is inferred to underlie the district being the most likely source rock. A small component of mantle leads from mafic igneous rocks or due to source rock inhomogeneity is also indicated.Graphitic host lithologies, lack of stratiform iron oxides, delta 34 S values of sedimentary pyrite, and sulfide sulfur-organic carbon variations in unmineralized cores indicate formation of the Anvil deposits in strongly reduced bottom water related to a previously unknown Early Cambrian anoxic event.

Analysis of longitudinal “time series” data in toxicology

Studies focusing on chronic toxicity or on the time course of toxicant effect often involve repeated measurements or longitudinal observations of endpoints of interest. Experimental design considerations frequently necessitate between-group comparisons of the resulting trends. Typically, procedures such as the repeated-measures analysis of variance have been used for statistical analysis, even though the required assumptions may not be satisfied in some circumstances. This paper describes an alternative analytical approach which summarizes curvilinear trends by fitting cubic orthogonal polynomials to individual profiles of effect. The resulting regression coefficients serve as quantitative descriptors which can be subjected to group significance testing. Randomization tests based on medians are proposed to provide a comparison of treatment and control groups. Examples from the behavioral toxicology literature are considered, and the results are compared to more traditional approaches, such as repeated-measures analysis of variance.

Analysis of Longitudinal “Time Series” Data in Toxicology

Analysis of Longitudinal “Time Series” Data in Toxicology. COX, C, AND CORY-SLECHTA, D. A. (1987). Fundam. Appt. Toxicol. 8, 159–169. Studies focusing on chronic toxicity or on the time course of toxicant effect often involve repeated measurements or longitudinal observations of endpoints of interest. Experimental design considerations frequently necessitate between-group comparisons of the resulting trends. Typically, procedures such as the repeated-measures analysis of variance have been used for statistical analysis, even though the required assumptions may not be satisfied in some circumstances. This paper describes an alternative analytical approach which summarizes curvilinear trends by fitting cubic orthogonal polynomials to individual profiles of effect. The resulting regression coefficients serve as quantitative descriptors which can be subjected to group significance testing. Randomization tests based on medians are proposed to provide a comparison of treatment and control groups. Examples from the behavioral toxicology literature are considered, and the results are compared to more traditional approaches, such as repeated-measures analysis of variance.

Declines in divergent thinking with age: cross-sectional, longitudinal, and cross-sequential analyses.

Six measures of divergent thinking were administered to 825 men ranging in age from 17 to 101 over the period from 1959 to 1972; repeat administrations were given to a subset of 278 men after a 6-year interval. Cross-sectional analyses showed curvilinear trends, with an increase in scores for men under 40 and a decline thereafter. Repeated measures analyses on subjects initially aged 33 to 74 generally replicated this finding, whereas cross-sequential analyses suggested a decline for all cohorts tested at a later time. Additional analyses suggested that not all of the decline could be attributed to reduced speed of response production. These longitudinal findings confirm earlier cross-sectional reports of decline in divergent thinking abilities with age.

Adolescents' Shifting Orientation toward Parents and Peers: A Curvilinear Trend over Recent Decades

This study examines changes that have occurred in the orientation of young people toward parents and peers over the past two decades. In 1963, 1976, and 1982, identical questionnaires were administered to comparable samples of teenagers (570 total) to investigate whose advice they seek regarding 18 social issues. The purpose was to determine which concerns and problems are peer-oriented and which parent-oriented, and how orientations have fluctuated over time. Major findings of the study are as follows: (a) Different issues activate different reference groups; financial, educational, and career concerns are parentoriented, whereas social activities are peer-oriented. (b) Girls were highly parent-oriented and boys highly peer-oriented in the 1960s. By the '80s the pattern was more balanced, even reversed to some extent. (c) The data for the combined boy/girl groups, and especially for the boys, but not the girls, formed a curvilinear pattern over time, reflecting the decline of parent orientation between the '60s and '70s and its partial recovery during the '80s.

Mental rotation and visual familiarity.

Mental rotation functions often evidence a curvilinear trend indicating relative indifference to small departures from the upright. In Experiment 1, this was true only for normal letters whereas reflected letters yielded a largely linear rotation function. This suggested that the internal representation of familiar visual patterns is characterized by broad orientation tuning that allows recognition despite small disorientations. Since familiar stimuli are often encountered slightly tilted from the upright, broad orientation tuning may reflect this ecological distribution. Experiment 2, however, indicated the possible involvement of two additional processes. Subjects were first trained on unfamiliar nonsense characters that appeared only in their “upright” positions. This was followed by a normal-reflected mental rotation task on these characters. Initially, rotation functions were more curvilinear for normal than for reflected characters. This suggested that practice with upright stimuli automatically contributes to broad tuning. Further practice resulted in a curvilinear trend for reflected characters as well, despite the fact that they appeared with equal probability in all orientations. This suggested that the very process of mentally rotating stimuli to the upright orientation increases insensitivity to slight departures from this orientation. Experiment 3 established that the different functions found for normal and reflected characters were due to stimulus rather than response factors.