Ambiguity seeking as a result of the status quo bias

Several factors affect attitudes toward ambiguity. What happens, however, when people are asked to exchange an ambiguous alternative in their possession for an unambiguous one? We present three experiments in which individuals preferred to retain the former. This status quo bias emerged both within- and between-subjects, with and without incentives, with different outcome distributions, and with endowments determined by both the experimenter and the participants themselves. Findings emphasize the need to account for the frames of reference under which evaluations of probabilistic information take place as well as modifications that should be incorporated into descriptive models of decision making.Ambiguity, risk, status quo bias, decision making, uncertainty, Leex

Adaptation to variance generalizes across visual domains

Processing the vast amount of visual information available from the world ought to pose a significant challenge to the brain. One of the ways in which the brain appears to encode the structure inherent in the world is through summary statistical representations (e.g., mean size, color etc.). This study investigates whether variance perception can be adapted for color, and then whether the variance adaptation aftereffects generalize from color to another visual domain. In a series of four experiments, we find aftereffects reflecting adaptation to the variance of hues in an ensemble—such that prolonged exposure to a highly variable ensemble of hues makes subsequent ensembles appear less variable in hue. We also found that this effect partially generalized to the perception of orientation variance—adaptation to highly variable color ensembles made subsequent ensembles also appear less variable in orientation. This is a novel demonstration of adaptation aftereffects reflecting processing of visual ensemble information across domains. The results could imply a neural mechanism encoding visual variance that is not selective to the domain from which the variance signal is derived. This mechanism may form the basis for cross-domain visual comparisons, and may play a role in predictive coding, enabling the brain to calibrate to the complexity of the visual environment

Red, yellow, green and blue are not particularly colorful

Colorfulness and saturation have been neglected in research on color appearance and color naming. Perceptual particularities, such as cross-cultural stability, “focality”, “uniqueness”, “salience” and “prominence” have been observed for red, yellow, green, and blue, when those colors were more saturated than other colors in the stimulus samples. The present study tests whether high saturation is a particular property of red, yellow, green and blue, which would explain those observations. First, we carefully determined the category prototypes and unique hues for red, yellow, green, and blue. Using different approaches in two experiments, we assessed discriminable saturation as the number of just-noticeable differences away from the adaptation point (i.e. neutral gray). Results show that some hues can reach much higher levels of maximal saturation than others. However, typical and unique red, yellow, green, and blue are not particularly colorful. Many other, intermediate colors have a larger range of discriminable saturation than these colors. These findings suggest that prior claims of perceptual salience of category prototypes and unique hues actually reflect biases in stimulus sets rather than perceptual properties. Additional analyses show that consistent prototype choices across fundamentally different languages are strongly related to the variation of discriminable saturation in the stimulus sets. Our findings also undermine the idea that every color can be produced by a mixture of unique hues. Finally, the measurements in this study provide a large amount of data on saturation across hues, which allows for reevaluating existing estimates of saturation in future studies

Ensemble perception of hue

In order to rapidly get the gist of new scenes or recognise objects, the brain must have mechanisms to process the large amount of visual information which enters the eye. Previous research has shown that observers tend to extract the average feature from briefly seen sets of multiple stimuli that vary along a dimension (e.g., size), a phenomenon called ensemble perception. This thesis investigates ensemble perception of hue. Paper 1 (Maule, Witzel & Franklin, 2014) demonstrates that human observers have memories biased towards the mean hue of a rapidly-presented ensemble of colours. Paper 2 (Maule & Franklin, 2015) further shows that observers are able to identify the mean hue from a distractor fairly reliably, provided the range of hues is manageable. Paper 3 provides evidence that, while observers’ settings of the mean hue converge quite closely on the true mean across many trials, the precision of those settings is low and does not support claims that ensemble perception can surpass the limits of visual working memory. Paper 4 found that adults with autism have an enhanced ability to discriminate members from non-members of multi-hue ensembles, and a similar ability to extract the mean hue compared to typical adults, but are worse at averaging small sets. Finally, paper 5 investigated colour afterimages in adults with autism and whether they are affected by top-down gist of a scene. It was found that afterimages were no different in autism compared to a typical group. Overall these studies provide the first comprehensive exploration of ensemble perception of hue, showing that observers can extract and estimate the mean hue of a rapidly-presented multi-colour ensemble with a small hue variance. The ability to average hue may be driven by a sub-sampling mechanism, but results from autistic adults suggests that it can be modulated by processing style

Journal of John Maule Hudspeth: A Second Voyage to Greenland 1813

Journals of John Maule Hudspeth written from 1812 to the end of 1816. After medical training he worked as a ship's surgeon finally with the Hudson Bay Company in 1815 prior to emigrating to Van Diemen's Land in 1822. This journal is entitled 'A Second Voyage to Greenland in the good ship Invernels under the command of Captain Thomas Potts 1813'. There are description of whaling and a 'List of ships in the Greenland and Davis Streights Whale Fisheries in 1813' at the end. Contains illustrations of whale tails with measurements and a coloured sketch of a mountainous island. RS2/2(2

Journals of John Maule Hudspeth: Hudson's Bay and the Voyage home to England, 1816

Journals of John Maule Hudspeth written from 1812 to the end of 1816. After medical training he worked as a ship's surgeon finally with the Hudson Bay Company in 1815 prior to emigrating to Van Diemen's Land in 1822. These journals are entitled 'The conclusion of a winter and commencement of summer in Hudson's Bay' and 'Summer in Hudson's Bay and the Voyage home to England'. The later includes a list of Indian names and vocabulary of Indian words and phrases. RS 2/2(6,7

Journals of John Maule Hudspeth: Voyage from London to Hudson's Bay and winter spent there, 1815

Journals of John Maule Hudspeth written from 1812 to the end of 1816. After medical training he worked as a ship's surgeon finally with the Hudson Bay Company in 1815 prior to emigrating to Van Diemen's Land in 1822. These journals are entitled 'A Voyage from London to Hudson's Bay in North America on board the Hadlow, Captain Davidson' and 'A Journal during a winter spent in Hudson's Bay at Eastmain Labrador'. RS 2/2 (4,5

Letter Book of John Maule Hudspeth, England and Van Diemen's Land 1811-1822

Letter book of John Maule Hudspeth written in England from the 31st August 1811 up to May 1822 and in Van Diemen's Land from October until 14th December 1822. RS 2/

Journal of John Maule Hudspeth: A Voyage to Davis Streights 1814

Journals of John Maule Hudspeth written from 1812 to the end of 1816. After medical training he worked as a ship's surgeon finally with the Hudson Bay Company in 1815 prior to emigrating to Van Diemen's Land in 1822. This journal is entitled 'A Voyage to Davis Streights in the Majestic commanded by Captain R. Lawson 1814'. Illustrations of whale tails and measurements, the heads of other mammals and a coloured seascape appear throughout the text. RS 2/2(3

Journal of John Maule Hudspeth: A Voyage to Greenland 1812

Journals of John Maule Hudspeth written from 1812 to the end of 1816. After medical training he worked as a ship's surgeon finally with the Hudson Bay Company in 1815 prior to emigrating to Van Diemen's Land in 1822. This journal is entitled 'A Voyage to Greenland in the good ship Invernels commanded by Captain Thomas Potts 1812'. There are description of whaling and coloured drawings of landscapes, icebergs and a shipwreck at the end of the diary. RS 2/2(1