There are large individual differences in the daily pattern and level of physical activity in humans and other species. As it is becoming apparent that activity plays an integral role in a number of physiological processes including arousal, attention, cardiovascular health and body weight regulation, there is an increased interest in quantifying activity. Nonhuman primates are particularly useful experimental models for such studies in that they exhibit a repertoire of activity more similar to humans than the activity of animals such as rodents and domestic animals. Recent studies measuring activity in nonhuman primates have used omnidirectional accelerometers, often worn on collars; however, the exact behaviors and movements detected by monkeys wearing these devices have not yet been characterized. To test the hypothesis that collar-worn accelerometers primarily detect movements that involve movement of the whole body, 16 adult female rhesus monkeys, housed individually in stainless steel cages, wore loose-fitting collars with an attached small metal box housing an activity monitor (Actical omnidirectional accelerometer; MiniMitter Inc., Bend, OR) and behavior was videotaped. Videotaped behaviors were analyzed by frame-by-frame analysis. There was a significant correlation between total (all) movement revealed by videotape analysis and activity counts detected by the accelerometers (r(s)=0.612, P=0.012), primarily reflecting a strong correlation between whole body movement and activity counts (r(s)=0.647, P=0.007). In contrast, arm movement (r(s)=-0.221, P=0.412) and head/neck movement (r(s)=0.193, P=0.474) were not correlated with activity counts. These findings support the hypothesis that activity monitor placement on a collar allows for effective quantification of whole body movement in monkeys, and indicate that behaviors such as chewing and arm movement do not significantly influence activity recorded by collar-mounted accelerometers.

In recent decades, social scientists have shown that the reliability of eyewitness identifications is much worse than laypersons tend to believe. Although courts have only recently begun to react to this evidence, the New Jersey judiciary has reformed its jury instructions to notify jurors about the frailties of human memory, the potential for lineup administrators to nudge witnesses towards suspects that they police have already identified, and the advantages of alternative lineup procedures, including blinding of the administrator. This experiment tested the efficacy of New Jersey’s jury instruction. In a 2×2 between-subjects design, mock jurors (N = 335) watched a 35-minute murder trial, wherein identification quality was either “weak” or “strong” and either the New Jersey or a “standard” instruction was delivered. Jurors were more than twice as likely to convict when the standard instruction was used (OR = 2.55; 95% CI = 1.37–4.89, p < 0.001). The New Jersey instruction, however, did not improve juror's ability to discern quality; rather, jurors receiving those instructions indiscriminatingly discounted “weak” and “strong” testimony in equal measure.

A Fitts’ task was used to investigate how tools are incorporated into the internal representations that underlie pointing movements, and whether such knowledge can be generalized across tasks. We measured the speed-accuracy trade-offs that occurred as target width was varied for both real and imagined movements. The dynamics of the pointing tool used in the task were manipulated—regular pen, top-heavy tool, and bottom-heavy tool—to test the fidelity of internal representations of movements involving the use of novel tools. To test if such representations can be generalized, the orientation of the pointing task was also manipulated (horizontal vs. vertical). In all conditions, both real and imagined performances conformed to the speed-accuracy relationship described by Fitts’ law. We found significant differences in imagined MTs for the two weighted tools compared to the regular pen, but not between the weighted tools. By contrast, real movement durations differed between all tools. These results indicate that even relatively brief experience using novel tools is sufficient to influence the internal representation of the dynamics of the tool-limb system. However, in the absence of feedback, these representations do not make explicit differences in performances resulting from the unique dynamics of these weighted tools.

In recent decades, social scientists have shown that the reliability of eyewitness identifications is much worse than laypersons tend to believe. Although courts have only recently begun to react to this evidence, the New Jersey judiciary has reformed its jury instructions to notify jurors about the frailties of human memory, the potential for lineup administrators to nudge witnesses towards suspects that they police have already identified, and the advantages of alternative lineup procedures, including blinding of the administrator. This experiment tested the efficacy of New Jersey's jury instruction. In a 2×2 between-subjects design, mock jurors (N = 335) watched a 35-minute murder trial, wherein identification quality was either "weak" or "strong" and either the New Jersey or a "standard" instruction was delivered. Jurors were more than twice as likely to convict when the standard instruction was used (OR = 2.55; 95% CI = 1.37-4.89, p < 0.001). The New Jersey instruction, however, did not improve juror's ability to discern quality; rather, jurors receiving those instructions indiscriminatingly discounted "weak" and "strong" testimony in equal measure.