Purpose To investigate ocular surface sensations, specifically ocular discomfort using psychophysical and clinical techniques. The measurement of discomfort on the ocular surface has been limited to the use of traditional rating scales until recently. This thesis focuses on the scaling of discomfort using a psychophysical approach and also investigates the less explored area of the influence of blur on ocular discomfort. The specific aims of each chapter are: Chapter 2: To evaluate the difference thresholds of the central cornea in lens and non-lens wearers. Chapter 3: To devise a novel scale for ocular discomfort, relating subjective estimation of discomfort arising from contact lens wear to discomfort produced by the pneumatic stimuli delivered by a modified Belmonte esthesiometer. Chapter 4: To evaluate the influence of blur on ocular comfort while systematically manipulating vision using habitual refractive correction, induced spatial and optical blur, and under the absence of visual structure. Chapter 5: To examine if subjects rate discomfort and intensity of suprathreshold pneumatic stimuli differently when viewing clear and defocused targets and to examine the suprathreshold scaling of stimuli under the same visual conditions. Methods Chapter 2: The mechanical sensitivity of the central cornea was determined in 12 lens wearers and 12 non-lens wearers using a modified Belmonte pneumatic esthesiometer. The mechanical threshold of the central cornea was first estimated using the method of limits. Then, a series of systematically increasing stimuli were presented, with the first stimuli being 25% less than the threshold. The subjects were asked to compare the intensity of each stimulus with the preceding one and report if any difference in intensity was detectable. The intensities at which the subjects perceived an increased intensity from the previous was recorded. The difference threshold (DL) was the differences between the stimulus intensities at which an increase was perceived and five DLs were measured for each subject. Weber’s constants that relate the size of the difference thresholds to the stimulus intensity were derived for each DL level and repeated measures ANOVA was used to compare the Weber’s constants in the lens and non-lens wearing groups. Chapter 3: Twenty seven participants were enrolled for this magnitude matching study. Soft (HEMA) contact lenses of eight different lens designs varying in base curve and diameter were fit on all participants. The study was conducted on two separate days with four lenses randomly assigned on each day. The assigned soft contact lens was placed on the chosen eye and the sensations were measured using a numerical rating scale. Following this, the subjects were asked to regulate the intensity of the pneumatic stimulus using the control dial in order to match the discomfort from the stimulus to the discomfort from contact lens wear. At the completion of magnitude matching, ratings of sensations were again recorded. Pearson product moment correlation was used to correlate the objective esthesiometer matches to the subjective ratings of discomfort reported by each participant. The method of least log squares was used to derive the power exponents as defined by Stevens’ power law and analyze the psychophysical functions. Repeated measures ANOVA was used to investigate the effect of lens sequence and session on ocular discomfort with contact lens wear. The impact of lens type and time on discomfort was studied using linear mixed modeling. Chapter 4: Twenty emmetropic subjects rated ocular comfort, vision and sensation attributes (burning, itching and warmth) under conditions of normal vision, spatial blur and dioptric defocus, each session lasting for five minutes. Subjects viewed digital targets projected from a distance of 3m, and ocular surface sensations, vision were rated using magnitude estimation. Dioptric defocus was produced using +6.00DS contact lenses and equivalent spatial blur was created by spatially blurring the targets. Clear target images were used during dioptric defocus and blurred images during spatial blur session. Comfort was also rated under the absence of visual structure in fifteen of the participants using a ganzfeld and black occluders. Repeated measures ANOVA was used to compare vision and comfort ratings between the different experimental conditions. Chapter 5: Twenty one participants were enrolled. Ocular discomfort was produced by delivering mechanical stimuli from a pneumatic esthesiometer, and participants were asked to rate the intensity of stimulus and the discomfort induced by it under clear and defocused visual conditions. Esthesiometry was performed on one eye while the fellow eye viewed either a clear or blurred 6/60 fixation target through a trial lens. For the clear visual condition, the trial lens contained +0.25DS over their distance refractive correction and for the defocused condition, an additional +4.00DS was used. Mechanical thresholds from the central cornea were estimated using ascending methods of limits and then stimuli that were 25%, 50%, 75% and 100 % above threshold were presented in random order. Participants rated intensity and discomfort of each stimulus using a 0-100 numerical scale where 0 indicated no sensation and 100 indicated highest imaginable intensity/discomfort. There were 3 sessions with clear visual conditions and 3 sessions with defocus, in random order. Results Chapter 2: The functions relating Weber’s constants to stimulus intensities were slightly different in lens and non-lens wearing groups, although the absolute thresholds were similar. Repeated measures ANOVA revealed a significant main effect of DL level on Weber’s constant (p<0.001), with the Weber’s fraction at the first DL being higher than the following DLs. A significant main effect of the group type was also observed, with the lens wearers showing higher Weber’s constants than the non-lens wearers (p=0.02) However, there was no interaction between DL level and lens wearing group on Weber’s constants (p=0.38). Chapter 3: The average and individual psychophysical functions appeared to follow Stevens’ power function, with mechanical and chemical stimuli giving rise to different power exponents. Examination of the individual transducer functions revealed that only about half of the subjects were able to match the contact lens sensations to the pneumatic stimulus discomfort, with both mechanical and chemical stimulation. The lens types did not have any impact (p=0.65) on the session or sequence in which the lens was presented, although an effect of session and sequence on discomfort was observed. The average discomfort ratings produced by the different lens types were similar. There appeared to be significant effects of time (p<0.001) on the reporting of discomfort with lens wear, with the discomfort upon lens insertion rated to be higher than after lenses settling. Chapter 4: Ratings of vision under spatial blur and dioptric defocus were significantly different (p<0.001) from normal vision condition. Vision with dioptric defocus was rated worse (p<0.001) than spatial blur. Significant differences in comfort were observed between normal vision and blur, including spatial blur (p=0.02) and dioptric defocus (p=0.001). However, there was no significant difference (p=0.99) in comfort between spatial blur and dioptric defocus. Comfort remained unchanged between normal vision, occluders and ganzfeld although vision was absent in the later two conditions. Chapter 5: There was no significant difference in mechanical thresholds under clear and defocused conditions with a paired t-test (p=0.66) and similar results were obtained with repeated measures ANOVA, with no significant difference in discomfort (p=0.10) and intensity (p=0.075) ratings between the two visual conditions. However, paired t-test between the derived exponents under clear and defocused conditions showed significant differences for discomfort (p=0.05) and no significant difference for the ratings of intensity (p=0.22). Comparison of exponents between discomfort and intensity showed a significant difference in both clear (p=0.02) and defocus conditions (p<0.001). Conclusions: Chapter 2: The differential sensitivity of the ocular surface can be successfully measured with a pneumatic esthesiometer and it appears that Weber’s law holds true for corneal nociceptive sensory processing. There are subtle differences in mechanical difference thresholds between lens and non-lens wearers suggesting the possibility of different neural activity levels in the two groups. Chapter 3: Subjective ratings of discomfort can be scaled by corneal esthesiometry in a selective group of people. In the subset of subjects with poorer correlations, perhaps the pneumatic mechanical stimulus was too localized and specific to match the complex sensations experienced while wearing contact lenses. However, there is also a group of subjects who are poor at making judgments about ocular comfort. Hence, the use of special sensory panels should be considered when ocular comfort is the primary outcome. Chapter 4: There does seem to be an association between clarity of vision and ocular comfort, although the pathways for pain and vision are perhaps exclusive. Interactions between vision and other senses have been reported, but a similar inter-sensory interaction between pain and vision is yet to be clearly demonstrated. The decreased comfort observed in this study might perhaps be due to nocebo or Hawthorne effects. Chapter 5: Suprathreshold scaling of pneumatic stimuli can vary with the viewing conditions, with defocus associated with higher exponents than clear visual conditions. However, the ratings of comfort appear to be similar under both the conditions. If defocus does affect comfort, it is subtle and does not affect the sensory components, but tiny effects through the affective aspect of pain can contribute to the differences in power exponents. The differences in the perception of comfort do not appear to be attributable to the differences in threshold or sensory intensity.

Purpose To investigate ocular surface sensations, specifically ocular discomfort using psychophysical and clinical techniques. The measurement of discomfort on the ocular surface has been limited to the use of traditional rating scales until recently. This thesis focuses on the scaling of discomfort using a psychophysical approach and also investigates the less explored area of the influence of blur on ocular discomfort. The specific aims of each chapter are: Chapter 2: To evaluate the difference thresholds of the central cornea in lens and non-lens wearers. Chapter 3: To devise a novel scale for ocular discomfort, relating subjective estimation of discomfort arising from contact lens wear to discomfort produced by the pneumatic stimuli delivered by a modified Belmonte esthesiometer. Chapter 4: To evaluate the influence of blur on ocular comfort while systematically manipulating vision using habitual refractive correction, induced spatial and optical blur, and under the absence of visual structure. Chapter 5: To examine if subjects rate discomfort and intensity of suprathreshold pneumatic stimuli differently when viewing clear and defocused targets and to examine the suprathreshold scaling of stimuli under the same visual conditions. Methods Chapter 2: The mechanical sensitivity of the central cornea was determined in 12 lens wearers and 12 non-lens wearers using a modified Belmonte pneumatic esthesiometer. The mechanical threshold of the central cornea was first estimated using the method of limits. Then, a series of systematically increasing stimuli were presented, with the first stimuli being 25% less than the threshold. The subjects were asked to compare the intensity of each stimulus with the preceding one and report if any difference in intensity was detectable. The intensities at which the subjects perceived an increased intensity from the previous was recorded. The difference threshold (DL) was the differences between the stimulus intensities at which an increase was perceived and five DLs were measured for each subject. Weber’s constants that relate the size of the difference thresholds to the stimulus intensity were derived for each DL level and repeated measures ANOVA was used to compare the Weber’s constants in the lens and non-lens wearing groups. Chapter 3: Twenty seven participants were enrolled for this magnitude matching study. Soft (HEMA) contact lenses of eight different lens designs varying in base curve and diameter were fit on all participants. The study was conducted on two separate days with four lenses randomly assigned on each day. The assigned soft contact lens was placed on the chosen eye and the sensations were measured using a numerical rating scale. Following this, the subjects were asked to regulate the intensity of the pneumatic stimulus using the control dial in order to match the discomfort from the stimulus to the discomfort from contact lens wear. At the completion of magnitude matching, ratings of sensations were again recorded. Pearson product moment correlation was used to correlate the objective esthesiometer matches to the subjective ratings of discomfort reported by each participant. The method of least log squares was used to derive the power exponents as defined by Stevens’ power law and analyze the psychophysical functions. Repeated measures ANOVA was used to investigate the effect of lens sequence and session on ocular discomfort with contact lens wear. The impact of lens type and time on discomfort was studied using linear mixed modeling. Chapter 4: Twenty emmetropic subjects rated ocular comfort, vision and sensation attributes (burning, itching and warmth) under conditions of normal vision, spatial blur and dioptric defocus, each session lasting for five minutes. Subjects viewed digital targets projected from a distance of 3m, and ocular surface sensations, vision were rated using magnitude estimation. Dioptric defocus was produced using +6.00DS contact lenses and equivalent spatial blur was created by spatially blurring the targets. Clear target images were used during dioptric defocus and blurred images during spatial blur session. Comfort was also rated under the absence of visual structure in fifteen of the participants using a ganzfeld and black occluders. Repeated measures ANOVA was used to compare vision and comfort ratings between the different experimental conditions. Chapter 5: Twenty one participants were enrolled. Ocular discomfort was produced by delivering mechanical stimuli from a pneumatic esthesiometer, and participants were asked to rate the intensity of stimulus and the discomfort induced by it under clear and defocused visual conditions. Esthesiometry was performed on one eye while the fellow eye viewed either a clear or blurred 6/60 fixation target through a trial lens. For the clear visual condition, the trial lens contained +0.25DS over their distance refractive correction and for the defocused condition, an additional +4.00DS was used. Mechanical thresholds from the central cornea were estimated using ascending methods of limits and then stimuli that were 25%, 50%, 75% and 100 % above threshold were presented in random order. Participants rated intensity and discomfort of each stimulus using a 0-100 numerical scale where 0 indicated no sensation and 100 indicated highest imaginable intensity/discomfort. There were 3 sessions with clear visual conditions and 3 sessions with defocus, in random order. Results Chapter 2: The functions relating Weber’s constants to stimulus intensities were slightly different in lens and non-lens wearing groups, although the absolute thresholds were similar. Repeated measures ANOVA revealed a significant main effect of DL level on Weber’s constant (p<0.001), with the Weber’s fraction at the first DL being higher than the following DLs. A significant main effect of the group type was also observed, with the lens wearers showing higher Weber’s constants than the non-lens wearers (p=0.02) However, there was no interaction between DL level and lens wearing group on Weber’s constants (p=0.38). Chapter 3: The average and individual psychophysical functions appeared to follow Stevens’ power function, with mechanical and chemical stimuli giving rise to different power exponents. Examination of the individual transducer functions revealed that only about half of the subjects were able to match the contact lens sensations to the pneumatic stimulus discomfort, with both mechanical and chemical stimulation. The lens types did not have any impact (p=0.65) on the session or sequence in which the lens was presented, although an effect of session and sequence on discomfort was observed. The average discomfort ratings produced by the different lens types were similar. There appeared to be significant effects of time (p<0.001) on the reporting of discomfort with lens wear, with the discomfort upon lens insertion rated to be higher than after lenses settling. Chapter 4: Ratings of vision under spatial blur and dioptric defocus were significantly different (p<0.001) from normal vision condition. Vision with dioptric defocus was rated worse (p<0.001) than spatial blur. Significant differences in comfort were observed between normal vision and blur, including spatial blur (p=0.02) and dioptric defocus (p=0.001). However, there was no significant difference (p=0.99) in comfort between spatial blur and dioptric defocus. Comfort remained unchanged between normal vision, occluders and ganzfeld although vision was absent in the later two conditions. Chapter 5: There was no significant difference in mechanical thresholds under clear and defocused conditions with a paired t-test (p=0.66) and similar results were obtained with repeated measures ANOVA, with no significant difference in discomfort (p=0.10) and intensity (p=0.075) ratings between the two visual conditions. However, paired t-test between the derived exponents under clear and defocused conditions showed significant differences for discomfort (p=0.05) and no significant difference for the ratings of intensity (p=0.22). Comparison of exponents between discomfort and intensity showed a significant difference in both clear (p=0.02) and defocus conditions (p<0.001). Conclusions: Chapter 2: The differential sensitivity of the ocular surface can be successfully measured with a pneumatic esthesiometer and it appears that Weber’s law holds true for corneal nociceptive sensory processing. There are subtle differences in mechanical difference thresholds between lens and non-lens wearers suggesting the possibility of different neural activity levels in the two groups. Chapter 3: Subjective ratings of discomfort can be scaled by corneal esthesiometry in a selective group of people. In the subset of subjects with poorer correlations, perhaps the pneumatic mechanical stimulus was too localized and specific to match the complex sensations experienced while wearing contact lenses. However, there is also a group of subjects who are poor at making judgments about ocular comfort. Hence, the use of special sensory panels should be considered when ocular comfort is the primary outcome. Chapter 4: There does seem to be an association between clarity of vision and ocular comfort, although the pathways for pain and vision are perhaps exclusive. Interactions between vision and other senses have been reported, but a similar inter-sensory interaction between pain and vision is yet to be clearly demonstrated. The decreased comfort observed in this study might perhaps be due to nocebo or Hawthorne effects. Chapter 5: Suprathreshold scaling of pneumatic stimuli can vary with the viewing conditions, with defocus associated with higher exponents than clear visual conditions. However, the ratings of comfort appear to be similar under both the conditions. If defocus does affect comfort, it is subtle and does not affect the sensory components, but tiny effects through the affective aspect of pain can contribute to the differences in power exponents. The differences in the perception of comfort do not appear to be attributable to the differences in threshold or sensory intensity.

O objetivo do estudo foi entender a influência da marca na percepção de sabor do chocolate pelos consumidores. Foram avaliados 16 sujeitos (31,8 anos, ± 4,2 anos, 8 mulheres) medindo suas avaliações sobre os sabores de chocolates de diferentes marcas, com e sem o conhecimento da marca, e também sobre as marcas sem degustação do produto, como expectativa de sabor, utilizando Escalonamento Psicofísico de Estimativa de Magnitude Direta (EMD). Este método obtém do sujeito a sua impressão subjetiva direta do estímulo físico. Um chocolate foi escolhido como referencia (módulo) e recebeu o valor numérico de 100. A tarefa dos sujeitos foi degustar os chocolates, comparando com a degustação do módulo, e atribuir notas de acordo com a diferença de percepção de sabor, se a percepção de sabor fosse duas vezes melhor do que o módulo, ele deveria designar uma nota duas vezes o valor de referência. O procedimento foi o mesmo para as duas outras condições experimentais, marca e sabor conhecendo a marca. O expoente da curva de potência foi utilizado como a quantificação da magnitude da percepção dos sujeitos. O expoente obtido na avaliação somente do chocolate foi de 0,389 (Coeficiente de Correlação de Pearson r2=0,94) enquanto que somente da marca foi de 0,581 (r2=0,96). Teoricamente pode-se determinar o expoente da percepção de sabor com conhecimento da marca que seria 0,389/0,581 = 0,669, sendo que o expoente obtido empiricamente foi de 0,675 (r2=0,92). Assim concluí-se que a utilização da metodologia de Estimativa de Magnitude Direta para quantificar a preferência subjetiva dos sujeitos por chocolates considerando 2 variáveis, sabor e marca, foi bem sucedida. Os resultados sugerem que a associação de marca e sabor contribui para um efeito mais poderoso sobre a decisão sobre quanto o chocolate é mais saboroso. E como o expoente da percepção do sabor sabendo a marca é maior que os outros dois expoentes isolados pode-se sugerir que a marca possui uma grande influência na decisão / The aim of study was understand brand influence on consumer perception of chocolate flavor. 16 subjects (31.8 years, ± 4.2 years, 8 women) were evaluated by measuring their reviews of the flavors of different brands of chocolates, with and without the knowledge of the brand, and also about the brands without tasting the product, as expectation of flavor, using Psychophysical Scaling of Direct Ratio Magnitude Estimation (RME). This method gets the subject direct subjective impression of the physical stimulus. A chocolate was chosen as reference (modulus) and received the numerical value of 100. The task of subjects was tasting the chocolates, compare to the tasting of the module and assign grades according to the difference in taste perception, if perception of flavor was twice better than module, he should assign a score twice the reference value. The procedure was the same for the other two experimental conditions brand and flavor knowing the brand. The exponent of power law was used to quantify the magnitude of the perception of the subjects. The obtained exponent when examining only chocolate was 0.389 (Pearson correlation coefficient r2=0.94) while only the brand was 0.581 (r2=0.96). Theoretically, we can determine the exponent of the perception of flavor with brand awareness that would be 0.389/0.581=0.669, where the exponent obtained empirically was 0.675 (r2=0.92). Thus we conclude that the use of the methodology of Direct Ratio Magnitude Estimation to quantify the subject subjective preference for chocolate, considering two variables, flavor and brand, was successful. The results suggest that the association of brand and flavor makes for a more powerful effect on the decision about how much chocolate is tastier. And as the exponent of flavor perception knowing the brand is bigger than the other two isolates exponents can suggest that the brand has a great influence on the decision

O sistema visual é considerado o mais complexo de todos os sistemas sensoriais do ser humano. O objetivo da visão é construir uma representação dos objetos extraindo informações do ambiente, transformando-as em um código neural que origina a percepção. A compreensão dos fatores sensoriais que alteram a percepção é necessária para uma teoria adequada da percepção visual. Evidências sobre os efeitos do contexto ambiental ainda são limitadas, mas sabe-se que alterações no plano de fundo, criação de lacunas e mudanças de textura alteram a percepção de profundidade. Esse estudo teve como objetivo principal investigar quais fatores sensoriais básicos alteram a estimativa de magnitude (EM) de tamanho de círculos nos sujeitos saudáveis, verificando se existiu correlação entre a variação de parâmetros do estímulo físico com os respectivos julgamentos para diferentes condições visuais, além da possibilidade de desenvolver um instrumento para avaliação de algumas psicopatologias. O método da EM se refere a um procedimento no qual o observador faz um julgamento numérico direto de uma magnitude psicológica de uma série de percepções. Para isso, desenvolvemos um programa de computador como uma ferramenta psicofísica para medidas de EM que nos permitiu gerar 15 diferentes condições experimentais separadas em quatro protocolos (P1, P2, P3 e P4). O projeto consistiu em dois blocos: (1) de experimentos básicos, cujo objetivo foi abordar como elementos sensoriais visuais básicos interferiram no julgamento para estímulos simples, usando o P2, cujas variáveis luminância e o P4 no qual a disposição espacial para diferenças na lateralização do processamento visual foram alteradas; e (2) de exploração metodológica, que buscou manipular o valor de referência (P1) e a indução de sensações de profundidade (P3). Foram avaliados 78 indivíduos típicos (m = 27,55, dp = 4,69) com nível superior completo ou incompleto, todos com visão normal ou devidamente corrigida, distribuídos aleatoriamente em os quatro grupos 8 experimentais. Os protocolos 1 e 2 apresentaram os resultados mais satisfatórios que nos permitirão a utilização do programa em indivíduos com psicopatologias para investigação de diferenças da população normal. Ainda que os protocolos 3 e 4 tenham gerado dados controversos, levou-se em consideração que se tratou de um estudo de investigação metodológica, cuja continuidade nos permitirá uma melhor contribuição teórica alcançada com a retomada de estudos no campo da Psicofísica Clássica, principalmente devido a escassez de publicações nas últimas décadas acerca do tema aqui proposto / The visual system is considered the most complex human sensory system. The purpose of the vision is to create a representation of the objects by gathering information of the environment and converting it into a neural code that generates perception. The comprehension of sensory factors that influence the perception is necessary to an adequate theory of visual perception. Evidences about the effects of the context remain still limited, but it is known that some facts such as variations on backgrounds, creation of gaps and texture changes modify the perception of depth. This study aimed to investigate which are the basic sensory factors that change the Magnitude Estimation (ME) of the size of circles in healthy subjects, in order to verify if there was a correlation between parameter variations of physical stimulus and its respective judgments about different visual condition, in addition to the possibility of development of a screening test to assess some psychopathologies. The ME method is the procedure in which the observer makes a direct numeric judgment of a psychological magnitude of a series of perceptions. For this purpose, we developed a computer software which was used as a psychophysical tool in order to measure ME that allowed us to generate 15 different experimental conditions allocated into four protocols (P1, P2, P3 and P4). The project was composed of two blocs: (1) basic experiments, in whichthe objective was to investigate how basic sensory visual elements interfere on the judgment of simple stimulus, using P2 in which the variable luminance was changed and P4 in which spatial position to evaluate differences on lateralization of visual process was altered; and (2) methodological exploration, that aimed to manipulate the reference value (P1) and the induction of depth sensory perception (P3). Seventy-eight healthy subjects were tested (m = 27.55, sd = 4.69), that had a complete or incomplete graduation course, they all had normal or corrected-to-normal visual acuity, and they were randomly distributed into the four experimental groups. The protocols 1 and 2 10 had shown the most satisfactory results that will allow us to use the software in people with psychopathologies in attention to screen differences of the general population. Despite the protocols 3 and 4 had generated controversial data, it is important to consider this as a study about methodological investigation, and its follow up will lead us to an improvement of the theoretical contribution reached by the recovery of Classic Psychophysics experiments, mainly due to the last decades lack of publishing about this purposed topic

O sistema visual é considerado o mais complexo de todos os sistemas sensoriais do ser humano. O objetivo da visão é construir uma representação dos objetos extraindo informações do ambiente, transformando-as em um código neural que origina a percepção. A compreensão dos fatores sensoriais que alteram a percepção é necessária para uma teoria adequada da percepção visual. Evidências sobre os efeitos do contexto ambiental ainda são limitadas, mas sabe-se que alterações no plano de fundo, criação de lacunas e mudanças de textura alteram a percepção de profundidade. Esse estudo teve como objetivo principal investigar quais fatores sensoriais básicos alteram a estimativa de magnitude (EM) de tamanho de círculos nos sujeitos saudáveis, verificando se existiu correlação entre a variação de parâmetros do estímulo físico com os respectivos julgamentos para diferentes condições visuais, além da possibilidade de desenvolver um instrumento para avaliação de algumas psicopatologias. O método da EM se refere a um procedimento no qual o observador faz um julgamento numérico direto de uma magnitude psicológica de uma série de percepções. Para isso, desenvolvemos um programa de computador como uma ferramenta psicofísica para medidas de EM que nos permitiu gerar 15 diferentes condições experimentais separadas em quatro protocolos (P1, P2, P3 e P4). O projeto consistiu em dois blocos: (1) de experimentos básicos, cujo objetivo foi abordar como elementos sensoriais visuais básicos interferiram no julgamento para estímulos simples, usando o P2, cujas variáveis luminância e o P4 no qual a disposição espacial para diferenças na lateralização do processamento visual foram alteradas; e (2) de exploração metodológica, que buscou manipular o valor de referência (P1) e a indução de sensações de profundidade (P3). Foram avaliados 78 indivíduos típicos (m = 27,55, dp = 4,69) com nível superior completo ou incompleto, todos com visão normal ou devidamente corrigida, distribuídos aleatoriamente em os quatro grupos 8 experimentais. Os protocolos 1 e 2 apresentaram os resultados mais satisfatórios que nos permitirão a utilização do programa em indivíduos com psicopatologias para investigação de diferenças da população normal. Ainda que os protocolos 3 e 4 tenham gerado dados controversos, levou-se em consideração que se tratou de um estudo de investigação metodológica, cuja continuidade nos permitirá uma melhor contribuição teórica alcançada com a retomada de estudos no campo da Psicofísica Clássica, principalmente devido a escassez de publicações nas últimas décadas acerca do tema aqui proposto / The visual system is considered the most complex human sensory system. The purpose of the vision is to create a representation of the objects by gathering information of the environment and converting it into a neural code that generates perception. The comprehension of sensory factors that influence the perception is necessary to an adequate theory of visual perception. Evidences about the effects of the context remain still limited, but it is known that some facts such as variations on backgrounds, creation of gaps and texture changes modify the perception of depth. This study aimed to investigate which are the basic sensory factors that change the Magnitude Estimation (ME) of the size of circles in healthy subjects, in order to verify if there was a correlation between parameter variations of physical stimulus and its respective judgments about different visual condition, in addition to the possibility of development of a screening test to assess some psychopathologies. The ME method is the procedure in which the observer makes a direct numeric judgment of a psychological magnitude of a series of perceptions. For this purpose, we developed a computer software which was used as a psychophysical tool in order to measure ME that allowed us to generate 15 different experimental conditions allocated into four protocols (P1, P2, P3 and P4). The project was composed of two blocs: (1) basic experiments, in whichthe objective was to investigate how basic sensory visual elements interfere on the judgment of simple stimulus, using P2 in which the variable luminance was changed and P4 in which spatial position to evaluate differences on lateralization of visual process was altered; and (2) methodological exploration, that aimed to manipulate the reference value (P1) and the induction of depth sensory perception (P3). Seventy-eight healthy subjects were tested (m = 27.55, sd = 4.69), that had a complete or incomplete graduation course, they all had normal or corrected-to-normal visual acuity, and they were randomly distributed into the four experimental groups. The protocols 1 and 2 10 had shown the most satisfactory results that will allow us to use the software in people with psychopathologies in attention to screen differences of the general population. Despite the protocols 3 and 4 had generated controversial data, it is important to consider this as a study about methodological investigation, and its follow up will lead us to an improvement of the theoretical contribution reached by the recovery of Classic Psychophysics experiments, mainly due to the last decades lack of publishing about this purposed topic

O objetivo do estudo foi entender a influência da marca na percepção de sabor do chocolate pelos consumidores. Foram avaliados 16 sujeitos (31,8 anos, ± 4,2 anos, 8 mulheres) medindo suas avaliações sobre os sabores de chocolates de diferentes marcas, com e sem o conhecimento da marca, e também sobre as marcas sem degustação do produto, como expectativa de sabor, utilizando Escalonamento Psicofísico de Estimativa de Magnitude Direta (EMD). Este método obtém do sujeito a sua impressão subjetiva direta do estímulo físico. Um chocolate foi escolhido como referencia (módulo) e recebeu o valor numérico de 100. A tarefa dos sujeitos foi degustar os chocolates, comparando com a degustação do módulo, e atribuir notas de acordo com a diferença de percepção de sabor, se a percepção de sabor fosse duas vezes melhor do que o módulo, ele deveria designar uma nota duas vezes o valor de referência. O procedimento foi o mesmo para as duas outras condições experimentais, marca e sabor conhecendo a marca. O expoente da curva de potência foi utilizado como a quantificação da magnitude da percepção dos sujeitos. O expoente obtido na avaliação somente do chocolate foi de 0,389 (Coeficiente de Correlação de Pearson r2=0,94) enquanto que somente da marca foi de 0,581 (r2=0,96). Teoricamente pode-se determinar o expoente da percepção de sabor com conhecimento da marca que seria 0,389/0,581 = 0,669, sendo que o expoente obtido empiricamente foi de 0,675 (r2=0,92). Assim concluí-se que a utilização da metodologia de Estimativa de Magnitude Direta para quantificar a preferência subjetiva dos sujeitos por chocolates considerando 2 variáveis, sabor e marca, foi bem sucedida. Os resultados sugerem que a associação de marca e sabor contribui para um efeito mais poderoso sobre a decisão sobre quanto o chocolate é mais saboroso. E como o expoente da percepção do sabor sabendo a marca é maior que os outros dois expoentes isolados pode-se sugerir que a marca possui uma grande influência na decisão / The aim of study was understand brand influence on consumer perception of chocolate flavor. 16 subjects (31.8 years, ± 4.2 years, 8 women) were evaluated by measuring their reviews of the flavors of different brands of chocolates, with and without the knowledge of the brand, and also about the brands without tasting the product, as expectation of flavor, using Psychophysical Scaling of Direct Ratio Magnitude Estimation (RME). This method gets the subject direct subjective impression of the physical stimulus. A chocolate was chosen as reference (modulus) and received the numerical value of 100. The task of subjects was tasting the chocolates, compare to the tasting of the module and assign grades according to the difference in taste perception, if perception of flavor was twice better than module, he should assign a score twice the reference value. The procedure was the same for the other two experimental conditions brand and flavor knowing the brand. The exponent of power law was used to quantify the magnitude of the perception of the subjects. The obtained exponent when examining only chocolate was 0.389 (Pearson correlation coefficient r2=0.94) while only the brand was 0.581 (r2=0.96). Theoretically, we can determine the exponent of the perception of flavor with brand awareness that would be 0.389/0.581=0.669, where the exponent obtained empirically was 0.675 (r2=0.92). Thus we conclude that the use of the methodology of Direct Ratio Magnitude Estimation to quantify the subject subjective preference for chocolate, considering two variables, flavor and brand, was successful. The results suggest that the association of brand and flavor makes for a more powerful effect on the decision about how much chocolate is tastier. And as the exponent of flavor perception knowing the brand is bigger than the other two isolates exponents can suggest that the brand has a great influence on the decision

A fruição estética envolve um processo ativo de percepção visual e interpretação de informação capaz de evocar sensações, emoções, e sentimentos. A estética experimental busca entender como artistas utilizam elementos visuais em suas obras e como esses elementos são processados à nível consciente no indivíduo. Diversos experimentos psicológicos e pesquisas recentes em neuroestética permitiram acesso quantitativo sobre julgamento estético. O presente trabalho realizou dois experimentos psicofísicos que permitiram medir julgamento emocional em obras de arte abstrata. Experimento 1. Objetivo: realizar uma tarefa de ordenamento de obras de arte para adjetivos de emoção. 55 participantes (55% sexo feminino, idade média: 31; SD: 11). Foram calculadas as correlações entre as emoções, podendo compará-las com o modelo circular afetivo, e os resultados se mostraram satisfatórios. Experimento 2. Objetivo: desenvolver uma escala psicofísica utilizando o caso V da lei do julgamento comparativo a fim de estabelecer as distâncias subjetivas dos julgamentos emocionais para obras de arte abstrata. 39 participantes (52% sexo feminino, idade média: 28; SD: 10). A formulação psicofísica feita idealmente para julgamento discriminatório de estímulos físicos simples pôde ser aplicada em julgamento discriminatório subjetivo e de bastante complexidade. O uso do escalonamento psicofísico permitiu um eficiente acesso quantitativo das distâncias dos julgamentos das emoções em cada obra de arte. 10 Espera-se que o trabalho proposto permita, através de uma reconciliação interdisciplinar entre neurociência e psicologia, novas abordagens e métodos livres de vieses subjetivos para o estudo de julgamento estético / Aesthetic appreciation involves a process of visual perception and interpretation capable of evoking sensations, emotions and feelings. Experimental aesthetics seeks to understand how artists use elements in their works and how these elements are processed in the individual in a conscientious level. Several psychological experiments and recent researches in neuroesthetics allowed quantitative access on aesthetic judgment. The present work carried out two psychophysical experiments that allow measuring emotional judgment in works of abstract art. Experiment 1. Objective: to carry out a task of ordering works of art for adjectives of emotion. 55 participants (55% female, mean age: 31; SD: 11). They were calculated as correlations between emotions, being able to compare them with the affective circular model, and the results were satisfactory. Experiment 2. Objective: to develop a psychophysical scale using case V the law of comparative judgment in order to establish as subjective distances from emotional judgments to abstract works of art. 39 participants (52% female, mean age: 28; SD: 10). A psychophysical formulation ideally made for discriminatory judgment of simple physical stimuli was applied in subjective and complex discriminatory judgment. The use of psychophysical scaling allowed an efficient access to the distances of the judgments of the emotions in each work of art. It is expected that the proposed work will allow, through an interdisciplinary reconciliation between neuroscience and psychology, new approaches and methods free of bias for the study of aesthetic judgment.

A fruição estética envolve um processo ativo de percepção visual e interpretação de informação capaz de evocar sensações, emoções, e sentimentos. A estética experimental busca entender como artistas utilizam elementos visuais em suas obras e como esses elementos são processados à nível consciente no indivíduo. Diversos experimentos psicológicos e pesquisas recentes em neuroestética permitiram acesso quantitativo sobre julgamento estético. O presente trabalho realizou dois experimentos psicofísicos que permitiram medir julgamento emocional em obras de arte abstrata. Experimento 1. Objetivo: realizar uma tarefa de ordenamento de obras de arte para adjetivos de emoção. 55 participantes (55% sexo feminino, idade média: 31; SD: 11). Foram calculadas as correlações entre as emoções, podendo compará-las com o modelo circular afetivo, e os resultados se mostraram satisfatórios. Experimento 2. Objetivo: desenvolver uma escala psicofísica utilizando o caso V da lei do julgamento comparativo a fim de estabelecer as distâncias subjetivas dos julgamentos emocionais para obras de arte abstrata. 39 participantes (52% sexo feminino, idade média: 28; SD: 10). A formulação psicofísica feita idealmente para julgamento discriminatório de estímulos físicos simples pôde ser aplicada em julgamento discriminatório subjetivo e de bastante complexidade. O uso do escalonamento psicofísico permitiu um eficiente acesso quantitativo das distâncias dos julgamentos das emoções em cada obra de arte. 10 Espera-se que o trabalho proposto permita, através de uma reconciliação interdisciplinar entre neurociência e psicologia, novas abordagens e métodos livres de vieses subjetivos para o estudo de julgamento estético / Aesthetic appreciation involves a process of visual perception and interpretation capable of evoking sensations, emotions and feelings. Experimental aesthetics seeks to understand how artists use elements in their works and how these elements are processed in the individual in a conscientious level. Several psychological experiments and recent researches in neuroesthetics allowed quantitative access on aesthetic judgment. The present work carried out two psychophysical experiments that allow measuring emotional judgment in works of abstract art. Experiment 1. Objective: to carry out a task of ordering works of art for adjectives of emotion. 55 participants (55% female, mean age: 31; SD: 11). They were calculated as correlations between emotions, being able to compare them with the affective circular model, and the results were satisfactory. Experiment 2. Objective: to develop a psychophysical scale using case V the law of comparative judgment in order to establish as subjective distances from emotional judgments to abstract works of art. 39 participants (52% female, mean age: 28; SD: 10). A psychophysical formulation ideally made for discriminatory judgment of simple physical stimuli was applied in subjective and complex discriminatory judgment. The use of psychophysical scaling allowed an efficient access to the distances of the judgments of the emotions in each work of art. It is expected that the proposed work will allow, through an interdisciplinary reconciliation between neuroscience and psychology, new approaches and methods free of bias for the study of aesthetic judgment.

A violência sexual é um problema de saúde pública que afeta boa parte da população mundial. Seu estudo, entretanto, é marcado por dificildades conceptuais, legais, epidemiológicas e metodológicas. Dentre os diversos modos de se entender e examinar a violência sexual, as atitudes são comumente investigadas, sobretudo com o emprego de escalas Likert. Contudo, o escalonamento psicofísico pelos métodos de Thurstone possui características típicas de escalas intervalares que lhe conferem vantagens em relação às escalas ordinais. O principal objetivo da presente pesquisa foi construir uma escala de distâncias psicológicas de descritores sexuais para cada grupo experimental através do Caso V da Lei do Julgamento Comparativo de Thurstone. 132 participantes, divididos em três grupos controle, sobreviventes (mulheres vítimas de violência sexual) e reeducandos (homens agressores sexuais) avaliaram oito termos sexuais (cócegas, cheiro, toque, beijo, nudez, agarrar, esfregar e gemer) pelo método de escolha forçada de julgamento de pares. A cada par de termos sexuais apresentado aleatoriamente, os sujeitos deviam escolher aquele com o maior conteúdo sexual. Resultados indicaram que os descritores toque, cheiro e cócegas foram constantemente julgados com os menores conteúdos sexuais entre os três grupos, enquanto beijo e gemer foram os que mais alteraram de ordem entre os grupos. Literatura sobre aspectos linguísticos dos estímulos utilizados não foi suficiente para explicar a escolha de uma palavra em detrimento de outra, reforçando-se a ideia de que os julgamentos foram diferenciais de acordo com as variáveis e o grupo ao qual os participantes pertenciam. Dessa maneira, homens julgaram os descritores com valores próximos, deixando a escala com menor amplitude, o que indica baixa discriminação e necessidade de menos conteúdo sexual para que as palavras fossem percebidas sexualmente. Reeducandos apresentaram o mesmo padrão de resultados, mas de maneira acentuada. Mulheres, por outro lado, tiveram boa discriminação dos termos sexuais e apresentaram maior amplitude na escala. Para as sobreviventes, o padrão de resultados foi o mesmo das mulheres, com poucas variações. As diferenças encontradas entre grupos podem ser decorrentes de atitudes sexuais e em relação à violência sexual e do modo como mulheres e homens processam informação sexual, sendo atravessadas por questões sociais de gênero / Sexual violence is a public health problem that affects a portion of the world population. Its study, yet, is marked by conceptual, legal, epidemiological, theoretical and methodological difficulties. Among the various ways of understanding and examining sexual violence, attitudes are commonly investigated, mainly by employing Likert scales. However, psychophysical scaling by Thurstones methods possess characteristics typical of interval scales, which gives it advantages over ordinal scales. The major goal of the present research was to build a scale of psychological distances of sexual descriptors for each experimental group through the Case V of Thurstones Law of Comparative Judgment. One hundred and thirty two participants, divided in three groups control, survivors (female victims of sexual violence) and inmates (male sex offenders) evaluated eight sexual words (tickle, smell, touch, kiss, nude, grab, rub, and moan) by the forced choice method of pairwise judgment. To each word pair was presented randomly, subjects were asked to choose the one with the higher sexual content. Results indicated that the descriptor touch, smell, and tickle were constantly judge as having the lowest sexual content amongst the three groups. Literature abou linguistic aspects of the used stimuli was nou sufficient to explain the choice of one word over another, reinforcing the idea that the judgments were differential according to the variables and the group to which the participant belonged. Thus, men judged the descriptors as having similar values, making the scales amplitude smaller, which indicates lower discrimination and the need for less sexual content for the words to be perceived sexually. Inmates showed the same pattern of results, but in a accentuated manner. Women, on the other hand, had good discrimation of the sexual descriptors and exhibited higher scale amplitude. For the survivors, the pattern of results was the same as for the women, with few variations. The found differences between groups may be due to attitudes toward sexuality and sexual violence, and to the way women and men process sexual information, being permeated by gender social issues