Result of Face Style on Response Period - Research Paper Example

Topic: Effect of face type on reaction time Name: Lecturer: Course name: Course code: Date: Abstract Common knowledge has it that people can only focus their attention to specific information in their vicinity at any given one time. This assertion is of great significant in selection process; hence, several experiments have been conducted to verify the claim. The limitation to pay more attention to small information on visual display implies that the characteristics required for an object to be easily identified are vital for the selection process. In this study, twelve different conditions (face types) were formed from the combination of features that included; race, sex and facial expression (angry, happy and neutral). These conditions uniquely identified the different face types. Different face types showed varying mean reaction time. The study identified that the face type in a visual search trials had an effect on the reaction time. Introduction It is believed that people can only focus their attention at any given time to specific information in their vicinity. Such an assertion is of great significant. The limitation to pay more attention to small information on visual display implies that the characteristics required for an object to be easily identified are vital for the selection process. Therefore attention should be given to those characteristics that guide and influence behavior, (Warren &Warren, 1968). Several experiments have been conducted to identify characteristics which influence selection processes. Such experiments are referred to as visual search experiments. The participants in these trials are asked to identify a particular target from an array with the target present or absent. Such an array usually contains distractors which are deemed irrelevant. However, the combination of characteristics of the target stimuli and the distractors is what determines the ease of identifying the target stimuli from the experiment array. The number of distracters used is usually considered a little effect. However, the efficiency of finding the target stimuli has been found to be influenced greatly by this number of distractors used, (Duncan, 1985). For a participant in the experiment to identify the target stimuli he may need to have a glance at the several distracters in the experiment array before he can finally identify the target stimuli. Hence, this increases the time used by a participant to locate a target stimuli in a given trial. There are several theories which have been developed in relation to visual search tasks. The Treisman’s feature integration theory (Treisman & Souther, 1985) is an example of such theories. The theory claims that visual display observation is processed in two stages. The first stage maps out the entire visual field coding only the significant characteristics. During the second stage attention is focused on a specific area in the field. This is when important conjunction information is derived. It asserts that for characteristics to be conjoined to enable the identification of an object, attention should serially be given to a single object at a time. This serial process limits our ability to see at a glance the entire visual scene. However, the appraisal theories contrast claims of feature integration theories. The theories (appraisal) assert that the highly significantly relevant stimuli are quickly allocated more attention and resources to enable fast processing, (Scherer, 2001). Experiments in relation to reaction time tasks have also been conducted severally. The participants of such experiments were asked to find a given target stimuli from an assortment of distracter-stimuli. The reaction times (time taken to identify the target stimuli) from several trials with different combinations of stimuli were noted and analyzed. T-N similarity by Neisser (1963) established that physical similarities between a target and non targets increased the difficulty of locating the target. The experiment used letters with different shapes. Other subsequent reaction time experiments have established similar findings also using letters, (Corcoran & Jackson, 1977). Methods Participants This experiment required the participants to identify a target from several trials each with (3x3) array of faces. A total of 58 participants took part in the experiment but two participants who were not white/ Caucasian were excluded from the list of participants during the statistical analysis of the findings of the experiment. Procedure For each trial an array of 3x3 faces was presented to the participants to identify whether a target was present or absent. The target comprised of different features categorized by race, sex (gender) and the facial expression (angry, happy and neutral). Thus, the participants were to identify a combination of the features to be either present or absent in each trial that they undertook. Twelve (12) conditions were generated from the combination of features: race, sex (gender) and facial expression. These conditions were as shown in the table 1 below; Table 1 Black angry male White angry male Black angry female White angry female Black happy male White happy male Black happy female White happy female Black neutral male White neutral male Black neutral female White neutral female For each trial to identify a Black African or White/Caucasian face with the combination of features as shown in table 1, other face distractors were present also in the trial. Asian faces were used as distractors from 108 different Asian identities which consisted of 54 males and 54 females. Male distractors were included in trials with male targets while female distractors were included in trials with female targets. For Black African target in a given trial, the Asian distractors used were made darker to match with the colour of the target. The distractors were made lighter to match with the colour of white/ Caucasian target in a given trial. Nine (9) arrays of target-absent trial were used from the 27 arrays created by random selection of faces of the respective gender and race. However, target-present arrays were simply created by adding a target to each of the arrays of target-absent trial. In all the trials which consisted of a 3x3 array of faces, the faces were cropped to oval outline. The participants were required to observe each array and report immediately when they identify the target is present by pressing “p” or absent by pressing “a”. For each of the 12 conditions, 18 trials were conducted; in 9 trials the target was absent while in the other 9 trials the target was present. The inter-trial interval time was 400ms for each of the trial conducted. The mean reaction time for each of the participant for the trials with target present was calculated. However, trials where participant failed to respond as required and individual mean reaction times of more than 5000ms were not considered and removed. Results Descriptive statistics The mean age of the 58 participants was 29.67 years with a standard deviation of 9.06. The participants comprised of 9 males and 49 females. Two participants were not White/Caucasian, one was an Asian and the other Eurasian. The mean reaction time for the 12 conditions with the combination of features; race, sex and facial expression is as summarized in table 2 shown below; Table 2 Combination of features Mean reaction time Standard error mean reaction time Black angry female 950.4874 46.2531 Black happy female 751.2301 26.5271 Black neutral female 838.1491 40.1423 White angry female 1543.2761 61.4584 White happy female 1008.2216 30.0882 White neutral female 1163.0463 49.7076 Black angry male 849.6589 30.6204 Black happy male 901.0080 21.4986 Black neutral male 725.6398 19.1198 White angry male 1575.6579 44.2443 White happy male 1769.6661 63.4872 White neutral male 1504.2479 47.5970 Generally, the participants found the black faces more quickly compared to the white faces. In Figure 1 below, the mean reaction time for black faces is less than that for white faces. The mean reaction time for female faces was less than that for the males. This is illustrated in Figure 2. However, this was mainly when the female faces had happy and neutral expression but not when they had angry facial expression. For the facial expressions (angry, happy and neutral); neutral faces were found fastest followed by happy faces which the participants identified faster than the angry faces. Figure 1 The participants identified the female faces more quickly compared to the male faces among the white faces. However, the male faces were identified faster than the female faces among the black faces. Figure 2 The neutral and angry facial expressions showed larger difference in their mean response time among the white faces compared to that of the black faces. For the combination of all the three facial expressions, the participants identified the white female face more quickly compared to the white male faces. However, as shown in figure 3 below, the black female face was identified faster than the black male face only for the happy facial expression but not for the neutral and angry expressions. Figure 3 Figure 4 shows that the neutral faces had a less mean reaction time compared to the angry and happy faces. The angry faces reported the longest mean reaction time. Figure 4 Inferential Statistics The F-Statistics from tests of within-main effects for race, sex and facial expression was 586.288, 26.609 and 29.998 respectively. The difference in the mean reaction time between the Black Africans and White/Caucasian, male and females and among the facial expressions (angry, happy and neutral) was significant. For the two way interaction effect of race and facial expression, the F statistics = 3.323. The mean reaction time between the race and facial expression combination was not significant. However, consistent with expectations, the F statistics for interaction effects; (race and sex, F statistics = 85.716, p < 0.05), (sex and expression, F statistics = 61.505, p < 0.05) and (race, sex and expression, F-statistics = 14.884, p < 0.05), showed that there was significant differences between the mean reaction time to faces within these groups. Discussion This study tested the null hypothesis that face type has an effect on the reaction time. The twelve different conditions (face types) were formed from the combination of features that included; race, sex and facial expression. These conditions uniquely identified the different face types. Different face types showed varying mean reaction time. Similar visual search studies have been conducted previously. The experiment by Brosch et al., (2007) showed a reliable orientation discrimination gain of the target in both the positive emotion and negative emotion conditions (anger). In this experiment, we established that the black faces were more quickly to be identified compared to the white faces. In addition, consistent with expectations the mean reaction time for female faces was less than that for the males. Hence, female faces were generally identified faster than the male faces. This was mainly when the female faces had happy and neutral expression but not when they had angry facial expression. The neutral faces were found fastest for all the races and sex categories in the experiment followed by happy faces which the participants identified faster compared to the angry faces. Among the white faces, the female faces were more quickly found compared to the male faces. However, the male faces were identified faster than the female faces among the black faces. The neutral and angry facial expressions showed larger difference in their mean response time among the white faces compared to that of the black faces. For the combination of all the three facial expressions, the participants identified the white female face faster than the white male faces. However, the black female face was found more quickly than the black male face only for the happy facial expression but not for the neutral and angry expressions. The difference in the mean reaction time between the target faces with the combination of features; Black Africans and White/Caucasian, male and females and among the facial expressions (angry, happy and neutral) was significant. For the two way interaction effect of race and facial expression, the mean reaction time between the race and facial expression combination was not significant. However, consistent with expectations, the interaction effects; (race and sex), (sex and expression) and (race, sex and expression), showed that there was significant differences between the mean reaction time to faces from these groups with different combinations of features of race, sex and facial expressions (angry, happy and neutral). From this study it was established that the mean reaction time for the different conditions with combination of features; race, sex and facial expression (angry, happy and neutral) vary significantly. Therefore, the face type in a visual search task based on the findings of this study, has an effect on the reaction time. References Brosch, T., Sander, D., & Scherer, K.R. (2007). That baby caught my eye. . . Attention capture by infant faces. Emotion, 7, 685–689. Corcoran, D. W. J. & Jackson, A. (1977). Basic processes and strategies in visual search In S. Dornic (Ed. ),Attention and performance VI(pp. 387-411). Hillsdale, NJ: Erlbaum. Duncan, J. (1985). Visual search and visual attention. In M. I. Posner & O. S. M. Marin (Eds.),Attention and perception XI(pp. 85-105). Hillsdale, NJ: Erlbaum. Neisser, U. (1963). Decision-time without reaction-time: Experiments in visual scanning. American Journal of Psychology, 76, 376-385. Scherer, K.R. (2001). Appraisal considered as a process of multilevel sequential checking. In K.R. Scherer, A. Schorr, & T. Johnstone (Eds.), Appraisal processes in emotion: Theory, methods, research (pp. 92–120). New York: Oxford University Press. Treisman, A. & Souther, J. (1985). Search asymmetry: A diagnostic for preattentive processing of separable features. Journal of Experimental Psychology: General, 114, 285-310. Warren, R. M. & Warren, R. P. (1968). Helmholtz on perception: Its physiology and development. New York: Wiley. Wolfe, J. M., Cave, K. R. & Franzel, S. L. (in press). A modified feature integration model for visual search. 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However, the appraisal theories contrast claims of feature integration theories. The theories (appraisal) assert that the highly significantly relevant stimuli are quickly allocated more attention and resources to enable fast processing, (Scherer, 2001). Experiments in relation to reaction time tasks have also been conducted severally. The participants of such experiments were asked to find a given target stimuli from an assortment of distracter-stimuli. The reaction times (time taken to identify the target stimuli) from several trials with different combinations of stimuli were noted and analyzed.

T-N similarity by Neisser (1963) established that physical similarities between a target and non targets increased the difficulty of locating the target. The experiment used letters with different shapes. Other subsequent reaction time experiments have established similar findings also using letters, (Corcoran & Jackson, 1977). Methods Participants This experiment required the participants to identify a target from several trials each with (3x3) array of faces. A total of 58 participants took part in the experiment but two participants who were not white/ Caucasian were excluded from the list of participants during the statistical analysis of the findings of the experiment.

Procedure For each trial an array of 3x3 faces was presented to the participants to identify whether a target was present or absent. The target comprised of different features categorized by race, sex (gender) and the facial expression (angry, happy and neutral). Thus, the participants were to identify a combination of the features to be either present or absent in each trial that they undertook. Twelve (12) conditions were generated from the combination of features: race, sex (gender) and facial expression.

These conditions were as shown in the table 1 below; Table 1 Black angry male White angry male Black angry female White angry female Black happy male White happy male Black happy female White happy female Black neutral male White neutral male Black neutral female White neutral female For each trial to identify a Black African or White/Caucasian face with the combination of features as shown in table 1, other face distractors were present also in the trial. Asian faces were used as distractors from 108 different Asian identities which consisted of 54 males and 54 females.

Male distractors were included in trials with male targets while female distractors were included in trials with female targets. For Black African target in a given trial, the Asian distractors used were made darker to match with the colour of the target. The distractors were made lighter to match with the colour of white/ Caucasian target in a given trial. Nine (9) arrays of target-absent trial were used from the 27 arrays created by random selection of faces of the respective gender and race.

However, target-present arrays were simply created by adding a target to each of the arrays of target-absent trial. In all the trials which consisted of a 3x3 array of faces, the faces were cropped to oval outline. The participants were required to observe each array and report immediately when they identify the target is present by pressing “p” or absent by pressing “a”. For each of the 12 conditions, 18 trials were conducted; in 9 trials the target was absent while in the other 9 trials the target was present.

The inter-trial interval time was 400ms for each of the trial conducted. The mean reaction time for each of the participant for the trials with target present was calculated. However, trials where participant failed to respond as required and individual mean reaction times of more than 5000ms were not considered and removed. Results Descriptive statistics The mean age of the 58 participants was 29.67 years with a standard deviation of 9.06. The participants comprised of 9 males and 49 females.

Two participants were not White/Caucasian, one was an Asian and the other Eurasian. The mean reaction time for the 12 conditions with the combination of features; race, sex and facial expression is as summarized in table 2 shown below; Table 2 Combination of features Mean reaction time Standard error mean reaction time Black angry female 950.4874 46.

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