"[7] From Oberlin, Hopkins moved to New York City, where he met Franz Kline, Mark Rothko, Robert Motherwell, Willem de Kooning and other abstract expressionists.

[14] Hopkins exhibited his paintings and sculptures in museums, galleries such as Andre Zarre, Levis Fine Art and Poindexter (New York) and Jan Cicero (Chicago), and universities throughout the United States.

He saw collage, the assemblage of fragments and varying points of view, in the poetry, painting, sculpture, music, architecture, and, especially, motion pictures of his day:[27]"Consciously or unconsciously, contemporary artists work to create harmony from distinctly jarring material, forcing warring ideas, materials and spatial systems into a tense and perhaps arbitrary detente.

Many of his works during this time featured circular shapes with primary colors set against black and white backgrounds suggestive of Piet Mondrian.

He considered the radio play a dramatic, theatrical hoax and, because of his childhood scare, felt it added to his skepticism about alien invasions rather than enamor him to the idea of it.

[4][29] Dissatisfied with the response Hopkins received when he reported the incident to nearby Otis Air National Guard Base, he suspected a possible government cover-up.

[citation needed] Behavioral patterns extrapolated from abductee letters led Hopkins to identify core emotional responses based on their experiences: fear, awe or wonderment at alien technological abilities, affection toward their captors (which he likened to the "Patty Hearst" syndrome), anger, and helplessness.

[33] He believed aliens were either incapable of understanding the psychological effects of their encounters with humans or that they were a "callous, indifferent, amoral race bent solely upon gratifying its own scientific needs at whatever cost to us.

[2][3] As a self-described humanist,[33] Hopkins saw his work with alleged alien abduction victims as a way to bring attention to an otherwise marginalized part of society.

[22] His follow-up book Intruders: The Incredible Visitations at Copley Woods, published in 1987,[34] helped establish Hopkins as a prominent leader in the UFO movement.

[35] Hopkins' Intruders: The Incredible Visitations at Copley Woods (1987), spent four weeks on The New York Times Paperback Best Seller list.

[2][32] Abductee Linda Cortile had also participated in Hopkins' support group, starting five months before her alleged abduction, and read his book, Intruders.

[40] In 1989, Hopkins organized the Intruders Foundation in Manhattan[3] to provide support for alleged victims of alien abduction, conduct research and investigations, and promote public awareness of the phenomenon.

[44] Hopkins and his third wife, Carol Rainey, co-wrote the 2003 book Sight Unseen, Science, UFO Invisibility and Transgenic Beings.

[44] Hopkins, along with Elizabeth Slater, who conducted psychological tests of abductees,[33] likened these experiences to rape,[46] specifically for the purpose of human reproductive capabilities.

"[34][49] These victims were, reportedly, taken to spaceships, impregnated by extraterrestrials,[33] then later as the hybrid baby developed, returned to the ship to have the fetus removed and given up to the alien parent.

Much of the phenomenon can, according to researchers such as Ronald K. Siegel of the University of California, Los Angeles, be explained as the consequence of "normal hallucinatory powers of the brain.

[37][51] These hallucinations feel real to the person experiencing sleep paralysis and can often be accompanied by sensory features: musty smells, shuffling sounds, visions of ghosts, aliens, and monsters.

[37][52] Neuroscientist Michael Persinger of Laurentian University[2] in Greater Sudbury, Ontario, Canada, believes that these sensations can spontaneously occur in some people, given the right set of circumstances, leading to the kind of feelings of "tremendous meaningfulness and fear" sometimes expressed by alleged alien abductees.

[37] Hopkins met and encouraged self-proclaimed abductees to discuss their experiences by holding free monthly group therapy sessions.

[4][41] He gave little credence to experts such as psychologist Robert A. Baker, University of Kentucky,[64] whose scientific inquiries into the subject revealed that hypnosis can "transform a dream, a hallucination or fantasy into a seemingly-real event.

"[63] Physical proof of alien abduction for Hopkins, came in the form of scoop marks,[29][30] or indentations of the skin, scars or cuts[29] on the mouth, nose, ears or genital,[2] or unexplained bruises[29] that might clear up in a day,[67] and abductee claims of implants[2][4] interpreted as control or monitoring devices similar to those used by (human) scientists to track and tag animals in the wild.

[30] Hopkins points to "tightly imagined testimonies"[20] by abductees, included victims' stories of observing unconventional objects in the sky,[21] in which they witnessed unusual activity (such as aliens digging for soil samples),[21] flying through the air [52] or being transported to a ship,[43] a sense of being watched or the presence of hooded beings near the bed at night,[43] a sense of paralysis or immobilization while lying in bed or in their cars,[52] impressions of flying or passing through closed windows or walls, a feeling of having been outside upon awakening, invisibility (both alien and human)[68] and, most especially, a sense of missing or lost time.

[3][67] Hopkins believed in his data collection techniques, as outlined in Missing Time,[32] and insisted, despite questions from other researchers and skeptics, that his findings were solidly based in evidence that, cumulatively, was overwhelming.

[37] Critics, including his former wife, Rainey, expressed concern that UFO researcher leaders were not held to scholastic, scientific, or ethical standards.

[68] The lack of physical evidence and the inconsistencies and implausibility of the alien abduction stories led some critics, including Carl Sagan and author Jodi Dean, to question whether these memories are the product of internal, rather than external experiences.

[29][52][72] Critics of Hopkins' position that on alien abduction accounts had "an absolute core of reality" [52] cautioned that media coverage might, inadvertently, be influencing alleged victims' stories.

[37][51] For example, The UFO Incident, a movie based on the Betty and Barney Hill case, aired on October 20, 1975, and exposed millions of viewers to the idea of alien abduction.

[59] Just one month later, O'Barski, Hopkins' neighbor and a New York City liquor store owner,[21] approached him about seeing a spacecraft that, allegedly, landed in New Jersey's North Hudson Park.