On a related note, I have several blind spots that I am well aware of because I have several nevi on my fundi (a nevus is one of those freckle-like dark spots many people have on their skin and have to keep watching so they don't turn cancerous). Because of that, there are no receptor cells where the nevi are located. But I have to really try to find those spots. Under normal day to day conditions I am not aware of them at all - again I attribute it to the constant motion of the eyes.
Annette Annette Kujawski Taylor, Ph.D. Professor, Psychological Sciences University of San Diego 5998 Alcala Park San Diego, CA 921210 [email protected] On Fri, Sep 7, 2018 at 10:00 PM Teaching in the Psychological Sciences (TIPS) digest <[email protected]> wrote: > TIPS Digest for Saturday, September 08, 2018. > > 1. position announcement > 2. Low light level cone function > 3. Re: Low light level cone function > 4. Re: Low light level cone function > 5. Re: Low light level cone function > > ---------------------------------------------------------------------- > > Subject: position announcement > From: Carol DeVolder <[email protected]> > Date: Fri, 7 Sep 2018 13:19:28 -0500 > X-Message-Number: 1 > > Cross-posted just in case. > > Position Announcement: > > > > The Department of Psychology at St. Ambrose University, Davenport, Iowa, > invites applications for a full-time tenure-track position at the Assistant > Professor level, for the 2019-20 academic year. Area of specialization is > open; however, the ideal candidate will be able to teach Applied > Statistics, Tests and Measurements (Assessment), and Personality Theories. > Also, the successful candidate will be responsible for mentoring > undergraduate students in inquiry-based projects related to the applicant’s > area of expertise. A PhD is required, however, candidates who are ABD will > be considered only if completion of the PHD can be documented to occur > within > one year. Priority will be given to applicants showing a strong commitment > to teaching and scholarly engagement, as well as a willingness to teach in > multiple delivery formats. St. Ambrose University is an independent, > comprehensive, and Catholic diocesan university firmly grounded in the > liberal arts. An institution of 3,200 graduate and undergraduate students, > the University’s Core Values include: Catholicity, Integrity, the Liberal > Arts, Life-Long Learning, and Diversity. See www.sau.edu for further > information. People from underrepresented populations are encouraged to > apply. Review of applications will begin October 1st, 2018 and continue > until the position is filled. Please apply online at > http://www.sau.edu/employment and upload your cover letter, statement of > teaching philosophy, curriculum vitae, and unofficial graduate transcript. > Three letters of reference should be sent directly to > [email protected]. > EOE > > > -- > Carol DeVolder, Ph.D. > Professor of Psychology > St. Ambrose University > 518 West Locust Street > Davenport, Iowa 52803 > 563-333-6482 > > ---------------------------------------------------------------------- > > Subject: Low light level cone function > From: Rick Stevens <[email protected]> > Date: Fri, 7 Sep 2018 13:46:19 -0500 > X-Message-Number: 2 > > TIPS had been quiet lately. A question occurred to me when talking about > rod vs cone functioning. > > When light levels get low, the cones lose function. Since the fovea is > 100% cones, why don't we have a blind spot in the center of our vision in > low light, low enough to lose color, but still enough light to move around > in a dark room. While the blind spots of right and left eyes can be > 'filled in' by information from the other eye, I would think that the > foveas would be aimed at exactly the same spot. > > My first thought would be the memory of looking close to some spot, getting > the information with the rods and remembering it when shifting my gaze to > that spot. I know memory stuff better than physiology stuff, so I thought > that there might be a better or at least a more physio-oriented answer. > > Rick Stevens > School of Behavioral and Social Sciences > University of Louisiana at Monroe > > ---------------------------------------------------------------------- > > Subject: Re: Low light level cone function > From: Carol DeVolder <[email protected]> > Date: Fri, 7 Sep 2018 13:52:08 -0500 > X-Message-Number: 3 > > Just a quick response--in some respects, we do have that blind spot, which > is why you can't look directly at a dim star at night if you want to see > it. Furthermore, our eyes are never still, so even if we are looking at > something, there is enough jitter for the foveal area to be filled in. The > fovea is pretty darned small, as well. Also, memory is an amazing > contributor to perception. > Happy Friday, > Carol > > > On Fri, Sep 7, 2018 at 1:47 PM Rick Stevens <[email protected]> > wrote: > > > > > TIPS had been quiet lately. A question occurred to me when talking about > > rod vs cone functioning. > > > > When light levels get low, the cones lose function. Since the fovea is > > 100% cones, why don't we have a blind spot in the center of our vision in > > low light, low enough to lose color, but still enough light to move > around > > in a dark room. While the blind spots of right and left eyes can be > > 'filled in' by information from the other eye, I would think that the > > foveas would be aimed at exactly the same spot. > > > > My first thought would be the memory of looking close to some spot, > > getting the information with the rods and remembering it when shifting my > > gaze to that spot. I know memory stuff better than physiology stuff, so > I > > thought that there might be a better or at least a more physio-oriented > > answer. > > > > Rick Stevens > > School of Behavioral and Social Sciences > > University of Louisiana at Monroe > > > > --- > > > > You are currently subscribed to tips as: [email protected]. > > > > To unsubscribe click here: > > > http://fsulist.frostburg.edu/u?id=177920.a45340211ac7929163a0216244443341&n=T&l=tips&o=52744 > > > > (It may be necessary to cut and paste the above URL if the line is > broken) > > > > or send a blank email to > > > leave-52744-177920.a45340211ac7929163a0216244443...@fsulist.frostburg.edu > > > > > > -- > Carol DeVolder, Ph.D. > Professor of Psychology > St. Ambrose University > 518 West Locust Street > Davenport, Iowa 52803 > 563-333-6482 > > ---------------------------------------------------------------------- > > Subject: Re: Low light level cone function > From: Rick Stevens <[email protected]> > Date: Fri, 7 Sep 2018 14:02:39 -0500 > X-Message-Number: 4 > > Thanks. The constant eye movement and the fovea being so small does sound > like a good physio-type answer. I had considered the idea that we do have > one and I just have not tested it in dark conditions to really see it. > > > Rick Stevens > School of Behavioral and Social Sciences > University of Louisiana at Monroe > > > > On Fri, Sep 7, 2018 at 1:53 PM Carol DeVolder <[email protected]> > wrote: > > > > > Just a quick response--in some respects, we do have that blind spot, > which > > is why you can't look directly at a dim star at night if you want to see > > it. Furthermore, our eyes are never still, so even if we are looking at > > something, there is enough jitter for the foveal area to be filled in. > The > > fovea is pretty darned small, as well. Also, memory is an amazing > > contributor to perception. > > Happy Friday, > > Carol > > > > > > On Fri, Sep 7, 2018 at 1:47 PM Rick Stevens <[email protected]> > > wrote: > > > >> > >> TIPS had been quiet lately. A question occurred to me when talking > about > >> rod vs cone functioning. > >> > >> When light levels get low, the cones lose function. Since the fovea is > >> 100% cones, why don't we have a blind spot in the center of our vision > in > >> low light, low enough to lose color, but still enough light to move > around > >> in a dark room. While the blind spots of right and left eyes can be > >> 'filled in' by information from the other eye, I would think that the > >> foveas would be aimed at exactly the same spot. > >> > >> My first thought would be the memory of looking close to some spot, > >> getting the information with the rods and remembering it when shifting > my > >> gaze to that spot. I know memory stuff better than physiology stuff, > so I > >> thought that there might be a better or at least a more physio-oriented > >> answer. > >> > >> Rick Stevens > >> School of Behavioral and Social Sciences > >> University of Louisiana at Monroe > >> > >> --- > >> > >> You are currently subscribed to tips as: [email protected]. > >> > >> To unsubscribe click here: > >> > http://fsulist.frostburg.edu/u?id=177920.a45340211ac7929163a0216244443341&n=T&l=tips&o=52744 > >> > >> (It may be necessary to cut and paste the above URL if the line is > broken) > >> > >> or send a blank email to > >> > leave-52744-177920.a45340211ac7929163a0216244443...@fsulist.frostburg.edu > >> > >> > > > > -- > > Carol DeVolder, Ph.D. > > Professor of Psychology > > St. Ambrose University > > 518 West Locust Street > > Davenport, Iowa 52803 > > 563-333-6482 > > > > > > > > > > --- > > > > You are currently subscribed to tips as: [email protected]. > > > > To unsubscribe click here: > > > http://fsulist.frostburg.edu/u?id=13526.d532f8e870faf8a0d8f6433b7952f38d&n=T&l=tips&o=52745 > > > > (It may be necessary to cut and paste the above URL if the line is > broken) > > > > or send a blank email to > > leave-52745-13526.d532f8e870faf8a0d8f6433b7952f...@fsulist.frostburg.edu > > > > > > ---------------------------------------------------------------------- > > Subject: Re: Low light level cone function > From: Kenneth Steele <[email protected]> > Date: Fri, 7 Sep 2018 15:07:22 -0400 > X-Message-Number: 5 > > Hi Rick: > > Good to see some action on TIPs. > > I have been thinking about related issues for some time. If you look at > the back of the eye then there are lots of locations where visual > stimulation will not affect the retina. Obviously there is the blind > spot. Notice that people don’t experience a blind spot even when one eye > is closed (such that the other eye can’t compensate). Similarly, there > are blood vessels that block activating photoreceptors all the time but we > don’t experience lines in our vision . (And even more interesting is that > when we do experience “floaters” then it is detritus that is changing > location in out eyes—thus changing the receptors that are affected.) > > Here is my solution. The important fact is that our eyes are changing > gaze locations (through saccades) several times per second. Whenever we > change gaze location then that portion of the world is activating a new set > of receptors. Sometimes I am looking at one location and a portion of the > world is falling on my blind spot and then I change my gaze location and > that portion of the world is falling on a set of active receptors. > > The old stabilized retinal image studies show that the visual system is > expecting visual changes when you make a saccade. > > So here is my answer. The fovea may be functionally shut down in low > light but the effect is similar to the blind spot. Eye movements cause the > area subtended by the fovea to hit a different world location with > subsequent eye movements and such locations will be affecting other parts > of the dark-adapted retina. > > Ken > > > > --------------------------------------------------------------------------------------------- > Kenneth M. Steele, Ph.D. [email protected] <mailto: > [email protected]> > Professor > Department of Psychology http://www.psych.appstate.edu < > http://www.psych.appstate.edu/> > Appalachian State University > Boone, NC 28608 > USA > > --------------------------------------------------------------------------------------------- > > > On Sep 7, 2018, at 2:46 PM, Rick Stevens <[email protected]> wrote: > > > > > > > > > > > > > > TIPS had been quiet lately. A question occurred to me when talking > about rod vs cone functioning. > > > > When light levels get low, the cones lose function. Since the fovea is > 100% cones, why don't we have a blind spot in the center of our vision in > low light, low enough to lose color, but still enough light to move around > in a dark room. While the blind spots of right and left eyes can be > 'filled in' by information from the other eye, I would think that the > foveas would be aimed at exactly the same spot. > > > > My first thought would be the memory of looking close to some spot, > getting the information with the rods and remembering it when shifting my > gaze to that spot. I know memory stuff better than physiology stuff, so I > thought that there might be a better or at least a more physio-oriented > answer. > > > > Rick Stevens > > School of Behavioral and Social Sciences > > University of Louisiana at Monroe > > > > --- > > > > You are currently subscribed to tips as: [email protected] <mailto: > [email protected]>. > > > > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=13524.94845a3ed9806f1cef14973830dd8c39&n=T&l=tips&o=52744 > < > http://fsulist.frostburg.edu/u?id=13524.94845a3ed9806f1cef14973830dd8c39&n=T&l=tips&o=52744 > > > > (It may be necessary to cut and paste the above URL if the line is > broken) > > > > or send a blank email to > leave-52744-13524.94845a3ed9806f1cef14973830dd8...@fsulist.frostburg.edu > <mailto: > leave-52744-13524.94845a3ed9806f1cef14973830dd8...@fsulist.frostburg.edu> > > > > > > > > > > > > > --- > > END OF DIGEST > > --- > You are currently subscribed to tips as: [email protected] > To unsubscribe click here: > http://fsulist.frostburg.edu/u?id=13534.4204dc3a11678c6b1d0be57cfe0a21b0&n=T&l=tips&o=52749 > or send a blank email to > leave-52749-13534.4204dc3a11678c6b1d0be57cfe0a2...@fsulist.frostburg.edu > --- You are currently subscribed to tips as: [email protected]. 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