Automatic assessment of human personality traits is a non-trivial problem, especially when perception is marked over a fairly short duration of time. In this study, thin slices of behavioral data are analyzed. Perceived physical and behavioral traits are assessed by external observers (raters). Along with the big-five personality trait model, four new traits are introduced and assessed in this work. The relationship between various traits is investigated to obtain a better understanding of observer perception and assessment. Perception change is also considered when participants interact with several virtual characters each with a distinct emotional style. Encapsulating these observations and analysis, an automated system is proposed by firstly computing low level visual features. Using these features a separate model is trained for each trait and performance is evaluated. Further, a weighted model based on rater credibility is proposed to address observer biases. Experimental results indicate that a weighted model show major improvement for automatic prediction of perceived physical and behavioral traits.