Effect of the Weight of an Individual and the Extent to Which They Are Hungry - Assignment Example

Part 2: Assignment Task Complete the following Summary Table. (2 points) Source SS df MS F Stomach 2229.35 2229.35 114.53 Weight 281.26 2 140.63 7.22 Stomach × Weight 824.54 2 412.27 21.18 Error 1401.54 72 19.47 Total 4736.68 77 2. Calculate η2 for the main effects and the interaction in the space below. In doing so, do not rely on the SPSS output which provides different values to what are typically reported. (3 points) 47.07% of the variance in amount of food eaten (grams) can be explained by the Stomach effect. 5.93% of the variance in amount of food eaten (grams) can be explained by the Weight effect. 17.41% of the variance in amount of food eaten (grams) can be explained by the Interaction between Stomach and Weight. 3. Conduct a (post hoc) pairwise analysis of the group cell means. Which of these post hoc contrasts are significant? (use α = 0.05) (Circle the appropriate response) (4 points) Empty + Underweight vs Full + Underweight Yes No Empty + Normal vs Full + Normal Yes No Full + Underweight vs Full + Overweight Yes No Empty + Overweight vs Full + Overweight Yes No 4. The interaction in the ANOVA suggests that it would be useful to examine simple main effects. Conduct the appropriate analyses to determine if there is an effect of weight on a participant with an empty stomach and an effect of weight on a participant with a full stomach. Provide the following details of these effects. (2 points) F weight.empty only = 6.10 , df = 2 , 36 , p < .05 F weight.full only = 23.40 , df = 2 , 36 , p < .05 Results Schachter (1968) published to study the effect of the weight of an individual and the extent to which they are hungry on the amount of food eaten by them. Participants were divided into two groups those in group one conducted the test on a full stomach, while those in the other did so on an empty stomach. Both groups had an equal number of participants who were underweight, overweight and of normal weight. Food eaten was measured in grams. The study was conducted on a total of 78 participants; 13 in each cell. In the empty stomach condition, Underweight participants ate an average of 29.92 (SD = 5.33), those within normal weight limits ate an average of 35.54 (SD = 1.98) and those who were overweight ate an average of 30.38 (SD = 5.46). The overall mean amount of food eaten by those on an empty stomach was 31.95 (SD = 5.12). In the full stomach condition, Underweight participants ate an average of 19 (SD = 2.52), those within normal weight limits ate an average of 17 (SD = 1.47) and those who were overweight ate an average of 27.77 (SD = 6.80). The overall mean amount of food eaten by those on a full stomach was 21.26 (SD = 6.30). A two-way ANOVA conducted for the main effect of Stomach resulted in F (1, 72) = 114.53, p < .01, two tailed test showing the previous food consumption affected latter food consumption. The η2 was .47 showing that 47.07% of the variance for food consumed could be explained by whether the person was on an empty or a full stomach. Whereas, the ANOVA conducted for the main effect of Weight resulted in F (2, 72) = 7.22, p < .01, η2 = .06, showing that 5.93% of the variance for food consumed could be explained by whether the person was overweight, underweight or of normal weight. The simple effect for Weight when conducted for participants on an empty stomach was significant, F (2, 36) = 6.10, p < .05; while the simple effect for Weight when conducted for participants on a full stomach was also significant, F (2, 36) = 6.10, p < .05, showing that weight did affect food consumption. Post hoc analysis showed that groups that were underweight and of normal weight differed significantly on the basis of whether they were on a full or an empty stomach; but this difference did not exist for the overweight. The difference between the underweight and overweight on a full stomach was also significant. The interaction between Stomach and Weight was tested to yield a significant F(2, 72) = 21.18, p < .01. The eta-squared was .17 showing that 17.41% of the variance for food consumed could be explained by the interaction of Stomach with Weight. The interaction of the two independent variables as contained in Figure 1. Figure 1. Relationship between weight and amount of food eaten. Average amount of food (in grams) eaten by underweight, normal weight and overweight participants under Full stomach and empty stomach conditions. Discussion The results obtained from this data provide interesting insight into the way an individual’s weight and their previous consumption of food interacts. The results showed that participants who were tested on a full stomach showed behaviour consistent with Schachter’s assumption that the overweight participants would eat more than the underweight and normal participants. The overweight participants in this case ate considerably more than the others; an effect that was found to be significant. On the other hand, for participants who tested on an empty stomach, those within normal weight limits ate the most amount of food, and both underweight and overweight persons ate considerably less. The underweight and normal weight participants in the empty stomach condition ate significantly more than their counterparts in the full stomach condition, while the overweight persons ate almost the same amount whether they had eaten previously or not. From these results, it seems that for people of normal weight, a full stomach does seem to inhibit further eating, while an empty stomach triggers eating more. On the other hand, for an overweight person, this does not seem to be the case. From the results it seems that overweight individual eat approximately the same amount regardless of whether they have eaten previously. This is consistent with the hypothesis put forth by Schachter; that overweight people eat regardless of whether they are hungry, and thus gain more weight. On the other hand, Schachter also believed that underweight people behave similar to people with normal weight. The results of this study refute this assumption, and show that hunger seems to inhibit the eating behavior of underweight people as compared to people of normal weight. Although the hungry underweight group did eat significantly more than the full underweight group (showing that hunger did regulate eating behavior), the underweight persons did not showed the same results as those with normal weight. Having a full stomach seems to have a slightly lesser effect on underweight people as compared to those with normal weight. Thus, the data partially supports Schachter’s hypotheses. The results of this study help us understand the way hunger mechanisms respond differently in overweight, normal and underweight people, and thus provide a clue to the possible reasons for weight management problems. At this point, it is important to note that a confounding factor that could have affected these results is that some of the participants may have consciously abstained from eating much of the initial meal in order to feel more inclined to participate in the ‘actual taste test’; and thus were more inclined to eat later. Personal preferences and dislikes of particular foods presented during measurement could also confound the data. Part 2: Assignment Task (Factorial ANOVA & Post Hocs) Student Name: Conduct the appropriate SPSS analyses to answer the following questions in the spaces provided. 1. Fill in the blanks (be specific) (3 points) Independent Variable #1 two gender levels (Male and Female) Independent Variable #2 Four different level ambient room temperature 25 deg. C., 30 deg. C., 35 deg. C., and 40 deg. C. Dependent Variable: Rating on aggression taken 0(no aggression) to 100 ( extremely aggressive). 2. Formulate the research question being asked in this study as concisely as you can, making sure that you mention the dependent variable and what the two independent variables (and their levels) are. (4 points) Does temperature and gender affect ratings for aggression in behavior such that a progressive increase in ambient room temperature ranging from 25 deg. C to 40 deg. C leads to progressive increase in the extent of displayed aggression differently for males and females? 4. Complete the following Summary Table. (2 points) Source SS Df MS F Gender 2.81 1 2.81 0.17 Temperature 1817.64 3 605.88 36.10 Gender × Temperature 481.94 3 160.65 9.57 Error 1208.50 72 16.79 Total 3510.89 79 5. Calculate η2 for the main effects and the interaction in the space below. In doing so, do not rely on the SPSS output which provides different values to what are typically reported. It is suggested that manual calculations be conducted from the above table. (3 points) 0.8% of the variance in aggression rating can be explained by the Gender effect. 51.77% of the variance in aggression rating can be explained by the Temperature effect. 13.73% of the variance in aggression rating can be explained by the interaction between Gender and Temperature. 6. Conduct a (post hoc) pairwise analysis of the group cell means. Which of these post hoc contrasts are significant (use α = 0.05)? (Circle the appropriate response) (4 points) Male-25 vs. Female-25 Yes No Male-30 vs. Female-30 Yes No Male-35 vs. Female-35 Yes No Male-40 vs. Female-40 Yes No Results This study attempted to explore the effects of temperature on observed aggression as judged by an observer. The study also wished to explore the extent to which gender of the individual played a role in the amount of aggression exhibited, and the interaction between these two factors. For this purpose, data was collected on a total of 80 individuals (40 males and 40 females) who experienced a frustrating situation, were randomly allocated to each of the four ambient room temperature (25 deg. C., 30 deg C., 35 deg. C. and 40 deg C) such that 20 individuals (10 male and 10 female) were exposed to each situation. This data was judged by two persons and rated on a 100 point scale where a higher score meant more aggressive behavior. Males exposed to 25 deg. C. scored a mean aggression score of 63.20 (SD. = 4.39), while those exposed to 30 deg. C scored a mean aggression score of 64.20 (SD = 3.39). Those exposed to 35 deg. C. scored a mean aggression score of 65.70 (SD = 3.59) while those exposed to 40 deg. C. scored a mean aggression score of 69.50 (SD = 4.25). The overall mean aggression score for males across temperatures was 65.65 (S.D. = 4.487). Females exposed to 25 deg. C. scored a mean aggression score of 57.10 (SD = 2.89), while those exposed to 30 deg. C scored a mean of 61.90 (SD = 4.25). Those exposed to 35 deg. C. scored a mean score of 69 (SD = 4.78) while those exposed to 40 deg. C. scored 76.10 (SD = 4.82). The overall mean score for females across temperatures was 66.02 (SD = 8.36). The mean scores across male and female participants exposed to 25 deg. C. was 60.15 (SD = 4.78), while the one for participants exposed to 30 deg. C. was 63.05 (SD = 3.93). The mean score for individuals exposed to 35 deg. C. was 67.35 (SD = 4.45) while the one for individuals exposed to 40 deg. C. was 72.80 (S.D. = 4.452). the overall average score on aggression for all 80 subjects was 65.84 (SD = 6.67). The factorial ANOVA calculated showed that main effect gender was not significant, while that for temperature and the interaction between the two factors were significant. The F values for Gender was F (1, 72) = .17, ns, and the eta-squared was .0008, meaning that 0.08% of the variance in aggression scores were explained by gender. The F value for temperature was F (3, 72) = 36.10, p < .01. The eta-squared was .5177, showing that 51.77% of the variance in aggression scores may be explained by temperature of the room. The F value for interaction was F (3, 72) = 9.57, p < .01and eta-squared was .1371 showing that 13.73% of the variance was explained by the interaction. The interaction between gender and temperature is shows in Figure 2. Figure 2. Average aggression score for gender and room temperature. The post hoc analysis showed that the difference between the 25 deg. C. conditions and the 30 deg. C. conditions were not significant, but all the other groups divided on the basis of temperature were significantly different from each other. Gender difference was seen for 25 deg. C. and 40 deg. C., but not for the intermediately conditions. Discussion The study wished to understand if temperature affected the extent of aggressiveness exhibited by people in frustrating situations. The study also attempted to indentify the role of gender in the extent of aggression depicted by the individuals. The results showed that while temperature by itself does have an effect on the extent to which individual’s exhibit aggressive behavior; gender by itself does not explain differences in levels of exhibited aggression. The interaction between the two variables produces a significant effect showing that females are more susceptible to temperature as a moderating variable in display of aggression. Both the data and the graphical representation showed that as temperature increases, there is a significant rise in the extent to which people behave aggressively when frustrated. Both males and females showed the least aggression when experiencing 25 deg. C., and maximum aggression when experiencing 40 deg. C. Thus, an increase in temperature does cause a significant change in the extent to which an individual would display aggression. The main effect for gender is seen to be not significant; showing that on the whole, males and females show a similar response to frustrating situations under different temperature conditions. There is a significant interaction between gender and temperature, such that females are more sensitive to change in temperature then are males. It is evident from the graph that though both males and females display increased aggression as the temperature increases; the slope of the line is much sharper for women then for men. At 25 deg. C. women exhibit significantly lower levels of aggressive behavior as compared to men. As the temperature rises, the differences reduce, and then reverse, till women display significantly more aggression as compared to men at 40 deg. C. Thus, we may conclude that aggression exhibited by women seems to be more susceptible to the influence of ambient temperature than that displayed by men. On the basis of this data, we may conclude that the research assumptions are supported; as it is evident the temperature does affect the extent to which an individual responds with aggression to frustrating situations; as does the relationship between gender and temperature. We may finally conclude that women are least likely to exhibit aggression at lower temperatures, and although both males and females show heightened aggression at higher temperatures; women are more sensitive to changes in temperature. This study neither takes into account nor controls for the influence of age, mood, life circumstances or previous experiences of a similar nature. Thus, it is not possible to rule out confounding effects from these and similar factors. Regardless, the data does provide valuable insight into the way different people are liable to respond to similarly frustrating situations given different environmental conditions. Studies like these provide valuable contributions towards understanding differences in behavior in relation to environmental conditions, and thus towards the development of public welfare systems that counter the problems highlighted by such research. Read More