Signal-Detection Analysis of Recognition Memory of Obese Subjects

1986 ◽  
Vol 63 (1) ◽  
pp. 227-234 ◽  
Author(s):  
Rick M. Gardner ◽  
Yvonne Sandoval ◽  
Beth Reyes
Keyword(s):  
Recognition Memory ◽  
Signal Detection ◽  
Significant Interaction ◽  
Normal Weight ◽  
Detection Analysis ◽  
Significant Difference ◽  
Main Effect ◽  
Signal Detection Analysis ◽  
Obese Subjects ◽  
And Control

Obese and normal-weight subjects were run on a series of recognition-memory tasks with low and high meaningful CVC trigrams. Subjects received feedback or no feedback regarding the appropriateness of their answers during testing for recognition memory. A signal-detection analysis was used to examine a relatively pure index of memory ( d') as compared to response-bias factors [Ln (β)]. No significant main effect on memory of obese and control subjects was noted although a significant interaction indicated that obese subjects' memory increases over trials in a differential fashion from normal-weight individuals with poorer performance among the obese after 3 trials. Feedback facilitated memory for both groups. Analysis of response criteria [Ln (β)] showed no significant difference between groups. Highly meaningful trigrams had a significantly lower response criterion than low meaningful trigrams and there was a significant interaction of meaningfulness by trials. An interaction of feedback by meaningfulness was also present. Advantages of using a signal-detection analysis in memory studies comparing obese and normal weight subjects are discussed. Ramifications of the present data for the internality/externality hypothesis of obesity are also discussed.

Distortion of body image in the obese: a sensory phenomenon

1988 ◽  
Vol 18 (3) ◽  
pp. 633-641 ◽  
Author(s):  
Rick M. Gardner ◽  
Renée Martinez ◽  
Tracy Espinoza ◽  
Venice Gallegos
Keyword(s):  
Body Image ◽  
Clinical Intervention ◽  
Normal Weight ◽  
The Body ◽  
Sensory Sensitivity ◽  
Detection Analysis ◽  
Body Regions ◽  
Significant Difference ◽  
Obese Subjects ◽  
And Control

SynopsisBody weight in 42 obese and normal weight subjects was measured using a video TV monitor. Tasks included a continuous task where subjects manipulated the width of their body image on TV, and a discrete task, where they judged the accuracy of their TV image which was presented as either normal, too heavy, or too thin. Subjects rated their full body, body regions which included face, waist, and thighs, and two inanimate control objects. Results from the continuous task revealed that obese subjects overestimated body size more than normals. There was also a significant difference in the ratings of the four body regions, with all regions overestimated. Judgements were more accurate for body regions and control objects on ascending trials where the subjects had to increase the width of the image. No differences were obtained between obese and normals on judgements of the control objects. On the discrete discrimination task, a signal detection analysis revealed sensory sensitivity differences between obese and normal weight subjects. Obese subjects were poorer at detecting size distortions of the body regions. The thin/normal discrimination was more difficult than the heavy/normal discrimination. No response criterion differences were found between obese and control subjects, although subjects adopted a more strict criterion with the thin/normal discriminations. Implications of these findings for clinical intervention in eating disorders are discussed.

Obesity and body image: an evaluation of sensory and non-sensory components

1987 ◽  
Vol 17 (4) ◽  
pp. 927-932 ◽  
Author(s):  
Rick M. Gardner ◽  
Renee Martinez ◽  
Yvonne Sandoval
Keyword(s):  
Body Image ◽  
Body Size ◽  
Signal Detection ◽  
Normal Weight ◽  
Sensory Sensitivity ◽  
Initial Image ◽  
Detection Analysis ◽  
Signal Detection Analysis ◽  
Obese Subjects ◽  
Discrete Task

SynopsisBody image in 38 obese and normal weight subjects was measured using a video TV monitor. Tasks included a continuous task where subjects manipulated the size of their body image on a TV screen, and a discrete task, where they judged the accuracy of their TV image which was presented as either too heavy or too thin. Subjects viewed their images in both regular street clothes and with minimal clothing.Results from the continuous task revealed that obese subjects overestimated body size. All subjects were more accurate on trials in which the initial image was adjusted in the heavier direction.On the discrete task, a signal detection analysis revealed sensory sensitivity differences between obese and normal weight subjects. Obese subjects were better at detecting distortion caused by a too thin image, but were inferior in detecting a too heavy distortion. No significant differences were obtained in response criteria or between clothing conditions.

Sensitivity to Proprioceptive Feedback in Obese Subjects

1983 ◽  
Vol 57 (3_suppl) ◽  
pp. 1111-1118 ◽  
Author(s):  
Rick M. Gardner ◽  
Veronica Salaz ◽  
Beth Reyes ◽  
Shirley J. Brake
Keyword(s):  
Discrimination Task ◽  
Proprioceptive Feedback ◽  
Sensory Response ◽  
Weight Discrimination ◽  
Detection Analysis ◽  
Significant Difference ◽  
Signal Detection Analysis ◽  
Obese Subjects ◽  
Normal Males ◽  
Male Subjects

40 subjects, 20 obese and 20 normal, were run on a weight-discrimination task requiring judgments dependent on proprioceptive feedback. A signal-detection analysis was used to separate sensory factors from non-sensory, response-bias factors in the analysis of the discriminations. Obese subjects were inferior to normals in ability to make sensory discriminations; the largest differences occurred between obese and normal males. Obese subjects also adopted a more strict criterion (β); the largest differences again occurred for male subjects. Obese subjects showed more variability in their sensory judgments, although there was a significant difference on only one of the 5 discrimination tasks. Results are discussed in terms of the internal-external explanation of obesity.

Depression, Recognition-Memory and Hedonic Tone a Signal Detection Analysis

1984 ◽  
Vol 144 (4) ◽  
pp. 376-382 ◽  
Author(s):  
G. C. Dunbar ◽  
W. A. Lishman
Keyword(s):  
Recognition Memory ◽  
Signal Detection ◽  
Memory Task ◽  
Hedonic Tone ◽  
State Response ◽  
Detection Analysis ◽  
Depressed State ◽  
Neutral Material ◽  
Signal Detection Analysis ◽  
Response Biases

SummaryA signal detection analysis was used in a recognition memory task involving material of varying hedonic tone. Major differences were found between the control and depressed states. Although overall recognition rates were the same, pleasant material was recognised less and unpleasant material more easily by depressives. Neutral material was recognised equally well by both groups. In the depressed state, response biases were altered such that unpleasant material was handled in a preferential way to neutral or pleasant material.

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