Subjects decreased gaze duration when the current image required high effort (image eccentricity), but after expenditure of high effort in viewing past images, they spent greater time gazing at the current image. Saccade vigor increased with expectations of future reward and also increased after a history of high rewards. In contrast, after a history of high-valued rewards, they spent less time at the current image. We found that people responded to increases in the local availability of reward (improved image content) by increasing their gaze duration. We manipulated reward magnitude via image content and effort expenditure via image eccentricity. Subjects harvested reward by gazing at the image and then moved their eyes with a saccade to view another image. To test the theory, we performed foraging-like experiments where reward patches consisted of small images. Our experiments confirmed many (but not all) of the predictions, suggesting that harvest duration and movement speed, fundamental aspects of behavior during foraging, may be governed by a shared principle of control. Therefore, the theory presented a principled way with which the brain may control two aspects of behavior: movement speed and harvest duration. After a history of high effort, they elevated their saccade speed and increased gaze duration. In anticipation of future effort, they lowered saccade speed and increased gaze duration. After a history of low rewards, people increased gaze duration and decreased saccade speed. We varied reward via image content and effort via image eccentricity, and then, we measured how these changes affected decision making (gaze duration) and motor control (saccade speed). To test the theory, we examined behavior of people as they gazed at images: they chose how long to look at the image (harvesting information) and then moved their eyes to another image, controlling saccade speed. This optimization could be achieved if the brain compared a local measure of utility with its history. How does the brain decide when to leave, and how does it determine the speed of the ensuing movement? Here, we considered the possibility that both the decision-making and the motor control problems aimed to maximize a single normative utility: the sum of all rewards acquired minus all efforts expended divided by total time. But carrots, Sylvia explained to me, bloom about the same time as Queen Anne’s lace, a biennial wildflower/weed that can be pollinated by them - which would not produce the carrots you want.During foraging, animals decide how long to stay at a patch and harvest reward, and then, they move with certain vigor to another location. You can dig up carrots and store them in soil in a bucket in a cold basement and replant them in the spring. These plants have to be kept alive all winter so they can flower and set seeds in their second year. Most difficult in our climate are the biennials - things like carrots, beets, parsnips and parsley. More: Rhode Island's 7 best dining experiences: A guide for how to start eating in 2023 If you’ve ever let a “pumpkin” grow in your compost pile from last year’s crop, you know that sometimes you get weird things due to cross pollination - a pumpkin crossed with a summer squash by a bee, for example, may not be something you want to eat. Vine crops such as squash, pumpkins and cucumbers are insect-pollinated and more difficult. No insects are needed, and seeds are ready by the end of their season. She said tomatoes, lettuce, beans and peas are all easy. I asked Davatz what vegetable species are the easiest to save. Which vegetables are best for saving seeds? Henry Homeyer: Plan now for a vegetable garden in the lawn Those are not suitable for seed saving - most of their seeds will produce mongrels, not the variety you grew. Hybrid tomatoes are carefully bred by crossing specific varieties of tomatoes so they will have special characteristics, such as surviving long trips in trucks, having a shelf life almost as long as a tennis ball, or resisting certain diseases. He was not growing hybrid tomatoes like those sold in the supermarket. My grandfather saved seeds from his tomatoes and started plants indoors in the early spring. I suppose my mom thought they added some vitamins, too, but I doubt they contributed much. Sliced and added to our iceberg lettuce salads in winter, they added color. The "cello-wraps" - as I think of them - had no flavor whatsoever. At the end of the season, save some seeds and store them in a cool, dry, dark place.Īs a boy in the 1950s, I knew there were two kinds of tomatoes: deep red, plump and tasty ones my grandfather grew, and the kind that came four in a package wrapped in cellophane.My grandfather grew what we now call heirloom tomatoes: time-tested varieties that breed true from seed.
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