Effect of psychosocial variables on maximum acceptable weight of lift

The objectives of this study were (l) to determine the effects of personality type in conjunction with social facilitation effects on the psychophysically-determined maximum acceptable weight of lift (MAWL), and 2) to establish guidelines for the psychophysical approach which control for the effects of psychosocial factors.

To accomplish this, a laboratory study was conducted using 15 male subjects classified as Type A personalities (aggressive, impatient) and 15 Type B subjects (passive, patient). Following a training period, the subjects performed 5 psychophysical lifting tasks consisting of a floor to 30 inch lift using various frequencies of lift. (For the social facilitation manipulation, the subject lifted the box under 3 conditions: alone (box lowered automatically), with a confederate of similar physical ability lowering the box, and with a confederate of superior physical ability lowering the box^ The confederate conditions were introduced under the guise that the lowering apparatus was broken.

Results indicated that Type A subjects worked at a higher percentage of their physical work capacity and selected heavier MAWLs than Type B subjects. Type A subjects required significantly less time deciding their MAWL, and made fewer weight adjustments in terms of decreasing box weight, than Type B subjects. Significant social facilitation effects were not obtained, nor was there a significant personality type x social condition interaction.