Measures
Heading angle
The first few seconds can say a lot.
Heading angle looks at the direction the animal sets off in, compared with a straight line to the platform. A small angle suggests the animal knew where it was going from the start.
Why it matters
Heading angle shows whether the subject set off in the right direction, a clear sign of where it thinks the platform is.
More detail
It is the angle between the start-to-target line and the start-to-heading-point line, after a distance set as a proportion of pool diameter. In probe trials, angles consistently close to zero for a group indicate strong spatial memory; large or scattered angles suggest a lack of it.
Heading shows spatial intent even when other measures do not capture it, for example when slowness or distraction lengthens latency. Consistent, indirect heading angles may indicate procedural strategies such as chaining. The heading distance setting changes the result, so report the exported Heading range.
Heading angle
Heading angle shows how directly the subject set off towards the target. Near-zero angles across a group in probe trials indicate strong memory; during learning, angles falling towards zero indicate spatial learning.
More detail
The angle is between the start-to-target line and the start-to-heading-point line (the heading point is the blue circle on plots). Consistent indirect angles may indicate a procedural strategy such as chaining. Cross-check with path ratio, Gallagher, circling and thigmotaxis.
Heading is often more sensitive than whole-trial crossings or quadrant time unless a first slice is used. The heading distance in use is exported as Heading range, so report it: the program default and the shipped configuration file have differed.
Questions people ask
How do I interpret heading angle in probe and learning trials?
Heading angle is the angle between the direct line from the start to the target and the direction the subject actually set off in, so 0° means it headed straight for the target. Near-zero heading angles across a group in probe trials indicate strong memory; during learning, angles falling towards zero indicate spatial learning. Consistent indirect angles may indicate a procedural strategy such as chaining.
More detail
Heading angle is between the start-to-target line and the start-to-heading-point line (heading point = blue circle on plots), measured after a distance set as a proportion of pool diameter (default 0.4 in 2026). Shorten it if subjects start facing the centre, lengthen it if they start facing the wall. Cross-check with path ratio, Gallagher, circling and thigmotaxis.
Going deeper
Heading is often more sensitive than whole-trial crossings or quadrant time unless a first slice is used.
See also HVS Image's page on heading angle in Morris water maze analysis.
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