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We introduce and quantify a relatively new form of influence: the Answer Bot Effect (ABE). In a 2015 report in PNAS, researchers demonstrated the power that biased search results have to shift opinions and voting preferences without people's knowledge-by up to 80% in some demographic groups. They labeled this phenomenon the Search Engine Manipulation Effect (SEME), speculating that its power derives from the high level of trust people have in algorithmically-generated content. We now describe three experiments with a total of 1,736 US participants conducted to determine to what extent giving users "the answer"-either via an answer box at the top of a page of search results or via a vocal reply to a question posed to an intelligent personal assistant (IPA)-might also impact opinions and votes. Participants were first given basic information about two candidates running for prime minister of Australia (this, in order to assure that participants were "undecided"), then asked questions about their voting preferences, then given answers to questions they posed about the candidates-either with answer boxes or with vocal answers on an Alexa simulator-and then asked again about their voting preferences. The experiments were controlled, randomized, double-blind, and counterbalanced. Experiments 1 and 2 demonstrated that answer boxes can shift voting preferences by as much as 38.6% and that the appearance of an answer box can reduce search times and clicks on search results. Experiment 3 demonstrated that even a single question-and-answer interaction on an IPA can shift voting preferences by more than 40%. Multiple questions posed to an IPA leading to answers that all have the same bias can shift voting preferences by more than 65%. Simple masking procedures still produced large opinion shifts while reducing awareness of bias to close to zero. ABE poses a serious threat to both democracy and human autonomy because (a) it produces large shifts in opinions and voting preferences with little or no user awareness, (b) it is an ephemeral form of influence that leaves no paper trail, and (c) worldwide, it is controlled almost exclusively by just four American tech companies. ABE will become a greater threat as people increasingly rely on IPAs for answers., Competing Interests: The authors have declared that no competing interests exist.

Chlorophyll d is a photosynthetic pigment that, based on chemical analyses, has only recently been recognized to be widespread in oceanic and lacustrine environments. However, the diversity of organisms harbouring this pigment is not known. Until now, the unicellular cyanobacterium Acaryochloris marina is the only characterized organism that uses chlorophyll d as a major photopigment. In this study we describe a new cyanobacterium possessing a high amount of chlorophyll d, which was isolated from waters around Heron Island, Great Barrier Reef (23° 26' 31.2″ S, 151° 54' 50.4″ E). The 16S ribosomal RNA is 2% divergent from the two previously described isolates of A. marina, which were isolated from waters around the Palau islands (Pacific Ocean) and the Salton Sea lake (California), suggesting that it belongs to a different clade within the genus Acaryochloris. An overview sequence analysis of its genome based on Illumina technology yielded 871 contigs with an accumulated length of 8 371 965 nt. Their analysis revealed typical features associated with Acaryochloris, such as an extended gene family for chlorophyll-binding proteins. However, compared with A. marina MBIC11017, distinct genetic, morphological and physiological differences were observed. Light saturation is reached at lower light intensities, Chl d/a ratios are less variable with light intensity and the phycobiliprotein phycocyanin is lacking, suggesting that cyanobacteria of the genus Acaryochloris occur in distinct ecotypes. These data characterize Acaryochloris as a niche-adapted cyanobacterium and show that more rigorous attempts are worthwhile to isolate, cultivate and analyse chlorophyll d-containing cyanobacteria for understanding the ecophysiology of these organisms.