(credit: iStock)

The results of two Yale University psychology experiments suggest that what we believe to be a conscious choice may actually be constructed, or confabulated, unconsciously after we act — to rationalize our decisions. A trick of the mind.

“Our minds may be rewriting history,” said Adam Bear, a Ph.D. student in the Department of Psychology and lead author of a paper published April 28 in the journal Psychological Science.

Tricks of the mind

A model of “postdictive” choice. Although choice of a circle is not actually completed until after a circle has turned red, the choice may seem to have occurred before that event because the participant has not yet become conscious of the circle’s turning red. The circle’s turning red can therefore unconsciously bias a participant’s choice when the delay is sufficiently short. (credit: Adam Bear and Paul Bloom/Psychological Science)

Bear and Paul Bloom performed two simple experiments to test how we experience choices. In one experiment, participants were told that five white circles would appear on the computer screen in front of them and, in rapid-fire sequence, one would turn red. They were asked to predict which one would turn red and mentally note this. After a circle turned red, participants then recorded by keystroke whether they had chosen correctly, had chosen incorrectly, or had not had time to complete their choice.

The circle that turned red was always selected by the system randomly, so probability dictates that participants should predict the correct circle 20% of the time. But when they only had a fraction of a second to make a prediction, these participants were likely to report that they correctly predicted which circle would change color more than 20% of the time.

In contrast, when participants had more time to make their guess — approaching a full second — the reported number of accurate predictions dropped back to expected levels of 20% success, suggesting that participants were not simply lying about their accuracy to impress the experimenters.

(In a second experiment to eliminate artifacts, participants chose one of two different-colored circles, with similar results.)

Confabulating reality

What happened, Bear suggests, is that events were rearranged in subjects’ minds: People unconsciously perceived the color red from the screen image before they predicted it would appear, but then right after that, consciously experienced these two things in the opposite order.

Bear said it is unknown whether this “postdictive” illusion is caused by a quirk in perceptual processing that can only be reproduced in the lab, or whether it might have “far more pervasive effects on our everyday lives and sense of free will.”

Previous research at Charité–Universitätsmedizin Berlin suggests the latter, and includes volition. That research involved a “duel” game between a human and a brain-computer interface (see Do we have free will?). It showed that there‘s a “point of no return” in the decision-making process (at about 200 milliseconds before actual movement onset), after which cancellation of a person’s movement is no longer possible.

Abstract of A Simple Task Uncovers a Postdictive Illusion of Choice

Do people know when, or whether, they have made a conscious choice? Here, we explore the possibility that choices can seem to occur before they are actually made. In two studies, participants were asked to quickly choose from a set of options before a randomly selected option was made salient. Even when they believed that they had made their decision prior to this event, participants were significantly more likely than chance to report choosing the salient option when this option was made salient soon after the perceived time of choice. Thus, without participants’ awareness, a seemingly later event influenced choices that were experienced as occurring at an earlier time. These findings suggest that, like certain low-level perceptual experiences, the experience of choice is susceptible to “postdictive” influence and that people may systematically overestimate the role that consciousness plays in their chosen behavior.

This artist’s rendering shows an imagined view of the three planets orbiting an ultracool dwarf star just 40 light-years from Earth that were discovered using the TRAPPIST telescope at ESO’s La Silla Observatory. In this view, one of the inner planets is seen in transit (black dot) across the disc of its tiny and dim parent star. (credit: M. Kornmesser/ESO)

Astronomers have detected three exoplanets just 40 light years from Earth whose sizes and temperatures are comparable to those of Earth. The planets may be the best targets found so far for the search for life outside the solar system.

The results were published Monday (May 2) in the journal Nature.

Because the system is relatively close to Earth, co-author Julien de Wit, a postdoc at MIT, says scientists will soon be able to study the planets’ atmospheric compositions, as well as assess their habitability and whether life actually exists within this planetary system.

The scientists discovered the planets using TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope), a 60-centimeter telescope operated by the University of Liège, based in Chile. Built by lead authors Michael Gillon and Emmanuel Jehin of the University of Liège, TRAPPIST is designed to focus on 60 nearby small, ”ultracool” dwarf stars (those with effective temperatures of less than 2,700 kelvin) — stars that are so faint they are invisible to optical telescopes and are monitored at infrared wavelengths.

The team focused the telescope on the dwarf star, which they named TRAPPIST-1 — a Jupiter-sized star that is one-eighth the size of our sun and significantly cooler. Over several months, the scientists observed the star’s infrared signal fade slightly at regular intervals, suggesting that several objects were passing in front of the star.

Most exoplanetary missions have been focused on finding systems around bright, solar-like stars. These stars emit radiation in the visible band and can be seen with optical telescopes. However, because these stars are so bright, their light can overpower any signal coming from a planet. Ultracool stars emit radiation in the infrared band. Because they are so faint, these tiny red stars would not drown out the image of a planet crossing the star, giving scientists a better chance of detecting orbiting planets.

May be in the habitable zone

From their observations, the scientists determined that all three planets are likely tidally locked, with permanent day and night sides.

The two innermost planets orbit the star in 1.5 and 2.4 days and receive only four and two times, respectively, the amount of radiation the Earth receives from the sun. The third planet may orbit the star in anywhere from four to 73 days, and may receive even less radiation than Earth. But given their size and proximity to their star, all three planets may have regions with temperatures well below 127 degrees C (260 degrees F), within a range that is suitable for sustaining liquid water and life.

The two planets closest to the star may have day sides that are too hot, and night sides too cold, to host any life forms. However, there may be a “sweet spot” — a region that still receives daylight, but with relatively cool temperatures — on the western side of both planets that may be temperate enough to sustain conditions suitable for life. The third planet, furthest from its star, may be entirely within the habitable zone.

“Now we have to investigate if they’re habitable,” de Wit says. “We will investigate what kind of atmosphere they have, and then will search for biomarkers and signs of life. We have facilities all over the globe and in space that are helping us, working from UV to radio, in all different wavelengths to tell us everything we want to know about this system.”

This research was funded, in part, by the Belgian Fund for Scientific Research, the European Research Council, and NASA.

Abstract of Temperate Earth-sized planets transiting a nearby ultracool dwarf star

Star-like objects with effective temperatures of less than 2,700 kelvin are referred to as ‘ultracool dwarfs’. This heterogeneous group includes stars of extremely low mass as well as brown dwarfs (substellar objects not massive enough to sustain hydrogen fusion), and represents about 15 per cent of the population of astronomical objects near the Sun. Core-accretion theory predicts that, given the small masses of these ultracool dwarfs, and the small sizes of their protoplanetary disks, there should be a large but hitherto undetected population of terrestrial planets orbiting them—ranging from metal-rich Mercury-sized planets to more hospitable volatile-rich Earth-sized planets. Here we report observations of three short-period Earth-sized planets transiting an ultracool dwarf star only 12 parsecs away. The inner two planets receive four times and two times the irradiation of Earth, respectively, placing them close to the inner edge of the habitable zone of the star. Our data suggest that 11 orbits remain possible for the third planet, the most likely resulting in irradiation significantly less than that received by Earth. The infrared brightness of the host star, combined with its Jupiter-like size, offers the possibility of thoroughly characterizing the components of this nearby planetary system.

Exploding polymer-coated gold nanoparticles in the world’s tiniest engine (credit: Yi Ju/University of Cambridge NanoPhotonics)

University of Cambridge researchers have developed the world’s tiniest engine, capable of a force per unit-weight nearly 100 times higher* than any motor or muscle.

The new nano-engines could lead to nanorobots small enough to enter living cells to fight disease, the researchers say.

Professor Jeremy Baumberg from the Cavendish Laboratory, who led the research, has named the devices “actuating nanotransducers” (ANTs). “Like real ants, they produce large forces for their weight,” he quipped.

As reported in the journal PNAS, the prototype ANT device —  just a few billionths of a meter in size — is made of gold nanoparticles bound together with temperature-responsive gel polymers. It can function as a piston or spring and works in a reversible cycle. Loose nanoparticles in water are first heated. When the temperature reaches 32 degrees C, they suddenly aggregate into a tight ball. Cooling causes the nanoparticles to rapidly take on water and expand in a sudden explosion.

The ANT reversible cycle. Left: ANTs are created by adding a polymer (gray spheres) called pNIPAM to gold nanoparticles (yellow). A blue-light laser then heats the ANT solution. When heated to 32 degrees C with a laser, the polymer nanoparticles absorb large amounts of elastic energy in a fraction of a second as the polymer coatings expel all the water from the gel and collapse, forcing the gold nanoparticles to bind together into dehydrated tight clusters (right). When the device is cooled (by turning off the laser), the polymers rapidly take on water and expand. That strongly, rapidly, and explosively pushes the gold nanoparticles apart — suddenly releasing energy, similar to release of a tightly compressed spring. (credit: Tao Ding et al./PNAS, adapted)

“It’s like an explosion,” said Tao Ding, PhD., from Cambridge’s Cavendish Laboratory, and the paper’s first author. “We have hundreds of gold balls flying apart in a millionth of a second when water molecules inflate the polymers around them.”

This “explosion” process converts Van de Waals energy — the attraction or repulsion between atoms or molecules — into the elastic energy of polymer molecules and releases it very quickly. “The whole process is like a nano-spring,” explained Baumberg. “The smart part here is we make use of Van de Waals attraction of heavy metal particles to set the springs (polymers) and water molecules to release them, which is very reversible and reproducible.”

Biological, other applications

KurzweilAI has covered a number of kinetic nanorobotic and microrobotic devices, including 3D-motion nanomachines from DNA, a magnetically controlled “nanoswimmer” for delivering drugs, sperm-inspired microrobots controlled by magnetic fields, and bacteria-powered microrobots.  However, the forces exerted by ANT devices are several orders of magnitude larger* than those for any other previously produced device, according to the researchers. ANT devices are bio-compatible, cost-effective to manufacture, fast to respond, and energy-efficient, according to the researchers.

Possible applications include microrobotics, sensing, storage devices, smart windows and walls, and especially biomedical uses, since the spring process occurs at biological temperatures (32 degrees C or 90 degrees F). The team plans to initially commercialize this technology for optically controlled biological microfluidic pumps and valves.

The research is funded as part of a UK Engineering and Physical Sciences Research Council (EPSRC) investment in the Cambridge NanoPhotonics Centre, and by the European Research Council (ERC).

* On the order of nN compared to typically 10 fN/nm², with up to GHz switching speeds.

Abstract of Light-induced actuating nanotransducers

Nanoactuators and nanomachines have long been sought after, but key bottlenecks remain. Forces at submicrometer scales are weak and slow, control is hard to achieve, and power cannot be reliably supplied. Despite the increasing complexity of nanodevices such as DNA origami and molecular machines, rapid mechanical operations are not yet possible. Here, we bind temperature-responsive polymers to charged Au nanoparticles, storing elastic energy that can be rapidly released under light control for repeatable isotropic nanoactuation. Optically heating above a critical temperature T_c = 32 °C using plasmonic absorption of an incident laser causes the coatings to expel water and collapse within a microsecond to the nanoscale, millions of times faster than the base polymer. This triggers a controllable number of nanoparticles to tightly bind in clusters. Surprisingly, by cooling below T_c their strong van der Waals attraction is overcome as the polymer expands, exerting nanoscale forces of several nN. This large force depends on van der Waals attractions between Au cores being very large in the collapsed polymer state, setting up a tightly compressed polymer spring which can be triggered into the inflated state. Our insights lead toward rational design of diverse colloidal nanomachines.

Layout of IBM’s five superconducting quantum bit device. In 2015, IBM scientists demonstrated critical breakthroughs to detect quantum errors by combining superconducting qubits in latticed arrangements, and whose quantum circuit design is the only physical architecture that can scale to larger dimensions. Now, IBM scientists have achieved a further advance by combining five qubits in the lattice architecture, which demonstrates a key operation known as a parity measurement — the basis of many quantum error correction protocols. (credit: IBM Research)

IBM Research has announced that effective Wednesday May 4, it is making quantum computing available free to members of the public, who can access and run experiments on IBM’s quantum processor, via the IBM Cloud, from any desktop or mobile device.

IBM believes quantum computing is the future of computing and has the potential to solve certain problems that are impossible to solve on today’s supercomputers.

The cloud-enabled quantum computing platform, called IBM Quantum Experience, will allow users to run algorithms and experiments on IBM’s quantum processor, work with the individual quantum bits (qubits), and explore tutorials and simulations around what might be possible with quantum computing.

The quantum processor is composed of five superconducting qubits and is housed at the IBM T.J. Watson Research Center in New York. IBM’s quantum architecture can scale to larger quantum systems. It is aimed at building a universal quantum computer that can be programmed to perform any computing task and will be exponentially faster than classical computers for a number of important applications for science and business, IBM says.

IBM envisions medium-sized quantum processors of 50–100 qubits to be possible in the next decade. With a quantum computer built of just 50 qubits, none of today’s TOP500 supercomputers could successfully emulate it, reflecting the tremendous potential of this technology.

“Quantum computing is becoming a reality and it will extend computation far beyond what is imaginable with today’s computers,” said Arvind Krishna, senior vice president and director, IBM Research. “This moment represents the birth of quantum cloud computing. By giving hands-on access to IBM’s experimental quantum systems, the IBM Quantum Experience will make it easier for researchers and the scientific community to accelerate innovations in the quantum field, and help discover new applications for this technology.”

This leap forward in computing could lead to the discovery of new pharmaceutical drugs and completely safeguard cloud computing systems, IBM believes. It could also unlock new facets of artificial intelligence (which could lead to future, more powerful Watson technologies), develop new materials science to transform industries, and search large volumes of big data.

The IBM Quantum Experience

Coupled with software expertise from the IBM Research ecosystem, the team has built a dynamic user interface on the IBM Cloud platform that allows users to easily connect to the quantum hardware via the cloud.

In the future, users will have the opportunity to contribute and review their results in the community hosted on the IBM Quantum Experience and IBM scientists will be directly engaged to offer more research and insights on new advances. IBM plans to add more qubits and different processor arrangements to the IBM Quantum Experience over time, so users can expand their experiments and help uncover new applications for the technology.

IBM employs superconducting qubits that are made with superconducting metals on a silicon chip and can be designed and manufactured using standard silicon fabrication techniques. Last year, IBM scientists demonstrated critical breakthroughs to detect quantum errors by combining superconducting qubits in latticed arrangements, and whose quantum circuit design is the only physical architecture that can scale to larger dimensions.

Now, IBM scientists have achieved a further advance by combining five qubits in the lattice architecture, which demonstrates a key operation known as a parity measurement — the basis of many quantum error correction protocols.

By giving users access to IBM’s experimental quantum systems, IBM believes it will help businesses and organizations begin to understand the technology’s potential, for universities to grow their teaching programs in quantum computing and related subjects, and for students (IBM’s potential future customers) to become aware of promising new career paths. And of course, to raise IBM’s marketing profile in this emerging field.