Does eye-tracking have an effect on economic behavior?

Eye-tracking is becoming an increasingly popular tool for understanding the underlying behavior driving human decisions. However, an important unanswered methodological question is whether the use of an eye-tracking device itself induces changes in participants' behavior. We study this question using eight popular games in experimental economics chosen for their varying levels of theorized susceptibility to social desirability bias. We implement a simple between-subject design where participants are randomly assigned to either a control or an eye-tracking treatment. In seven of the eight games, eye-tracking did not produce different outcomes. In the Holt and Laury risk assessment (HL), subjects with multiple calibration attempts demonstrated more risk averse behavior in eye-tracking conditions. However, this effect only appeared during the first five (of ten) rounds. Because calibration difficulty is correlated with eye-tracking data quality, the standard practice of removing participants with low eye-tracking data quality resulted in no difference between the treatment and control groups in HL. Our results suggest that experiments may incorporate eye-tracking equipment without inducing changes in the economic behavior of participants, particularly after observations with low quality eye-tracking data are removed.

An essential role for Orc6 in DNA replication through maintenance of pre-replicative complexes.

The heterohexameric origin recognition complex (ORC) acts as a scaffold for the G(1) phase assembly of pre-replicative complexes (pre-RC). Only the Orc1-5 subunits appear to be required for origin binding in budding yeast, yet Orc6 is an essential protein for cell proliferation. Imaging of Orc6-YFP in live cells revealed a punctate pattern consistent with the organization of replication origins into subnuclear foci. Orc6 was not detected at the site of division between mother and daughter cells, in contrast to observations for metazoans, and is not required for mitosis or cytokinesis. An essential role for Orc6 in DNA replication was identified by depleting it at specific cell cycle stages. Interestingly, Orc6 was required for entry into S phase after pre-RC formation, in contrast to previous models suggesting ORC is dispensable at this point in the cell cycle. When Orc6 was depleted in late G(1), Mcm2 and Mcm10 were displaced from chromatin, cells failed to progress through S phase, and DNA combing analysis following bromodeoxyuridine incorporation revealed that the efficiency of replication origin firing was severely compromised.