We measured binocular rivalry between dichoptic, orthogonal, sinusoidal gratings both having spatial frequencies of 0.5, 1, 2, 4, 8 or 16 c deg-1 in fields ranging from 0.5 to 8 deg of visual angle in diameter. Total time that one or the other grating was exclusively visible had an inverted U-shaped relationship with spatial frequency, with the peak shifting to coarser spatial frequencies as the field size increased. We computed for each spatial frequency the maximum field size over which a criterion duration of exclusive visibility would spread. When expressed as areas, these sizes were inversely proportional to spatial frequency. This dependence of rivalry on spatial frequency is similar to those for stereopsis and fusion, consistent with the notion that all three binocular phenomena have a common mechanism.

Objective This cross-sectional survey aimed to establish the views and intentions of New Zealand (NZ) psychiatrists regarding their role as competence assessors in the NZ End of Life Choice Act (‘Act’). Some questions were replicated from a pre-existing Ministry of Health workforce survey regarding the Act, for comparative analysis between psychiatrists and other health professionals. Methods The survey was disseminated via email to all NZ psychiatrists registered with the Royal Australia and NZ College of Psychiatry and promoted by snowballing methods to reach non-members. Results There were similar (moderate) levels of understanding of the Act, compared to other health professionals. Psychiatrists show similar levels of support for assisted dying as other health professionals (55% and 47%, respectively), however psychiatrists are significantly less likely to be willing to provide assisted dying services than other health professionals. Concerns were raised regarding the challenges faced by psychiatrists and need for more clarity around the psychiatrist’s role. Conclusions Few NZ psychiatrists were willing to be involved with the Act. There was a perceived lack of information around a psychiatrist’s role, responsibilities and legal protections. Further guidance is needed regarding the concept of capacity in assisted dying and the factors that challenge these assessments.