Instructor pilot reported the student took evasive action due to a near midair collision.

Attributes
ACN	1688295
Time
Date	201909
Local Time Of Day	1201-1800
Place
Locale Reference	MMV.Airport
State Reference	OR
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Cessna 150
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct Visual Approach
Flight Plan	VFR
Aircraft 2
Make Model Name	Cessna Single Piston Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Other Unknown
Person 1
Function	Instructor Pilot Not Flying
Qualification	Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine Flight Crew Commercial
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 3100 Flight Crew Type 300
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 15 Vertical 25

Narrative:

My student pilot appeared to freeze; pull up slightly; and bank right slightly. I looked at her; then looked where she was looking since she did not say anything. A cessna was nearly dead ahead; opposite direction; close enough to see the faces and sunglasses on the occupants. If she had not reacted; small as her evasive action was; we may have collided. It was a clear and beautiful day. We were both looking at the scenery and looking for traffic on a continuous basis. No idea why we did not see the other aircraft until it was just a few hundred feet away with a 200 mph closure rate. I think our rental aircraft has ads-B out; but not in. No idea what the other aircraft has. Needless to say; it appears they did not see us any sooner than we saw them; perhaps even later because I do not think they took any evasive action. Perhaps I spend too much time looking left and right; trying to see who is hiding above the high-wings whenever the aircraft banks even slightly; rather than also focusing more in the forward direction.

Original NASA ASRS Text

Title: Instructor pilot reported the student took evasive action due to a NMAC.

Narrative: My student pilot appeared to freeze; pull up slightly; and bank right slightly. I looked at her; then looked where she was looking since she did not say anything. A Cessna was nearly dead ahead; opposite direction; close enough to see the faces and sunglasses on the occupants. If she had not reacted; small as her evasive action was; we may have collided. It was a clear and beautiful day. We were both looking at the scenery and looking for traffic on a continuous basis. No idea why we did not see the other aircraft until it was just a few hundred feet away with a 200 mph closure rate. I think our rental aircraft has ADS-B out; but not in. No idea what the other aircraft has. Needless to say; it appears they did not see us any sooner than we saw them; perhaps even later because I do not think they took any evasive action. Perhaps I spend too much time looking left and right; trying to see who is hiding above the high-wings whenever the aircraft banks even slightly; rather than also focusing more in the forward direction.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.